use go 1.16, GODEBUG=x509ignoreCN=0, upgrade some old deps, replace travis with actions

vendor/github.com/prometheus/client_golang/AUTHORS.md

@@ -1,18 +0,0 @@
-The Prometheus project was started by Matt T. Proud (emeritus) and
-Julius Volz in 2012.
-
-Maintainers of this repository:
-
-* Björn Rabenstein <beorn@soundcloud.com>
-
-The following individuals have contributed code to this repository
-(listed in alphabetical order):
-
-* Bernerd Schaefer <bj.schaefer@gmail.com>
-* Björn Rabenstein <beorn@soundcloud.com>
-* Daniel Bornkessel <daniel@soundcloud.com>
-* Jeff Younker <jeff@drinktomi.com>
-* Julius Volz <julius.volz@gmail.com>
-* Matt T. Proud <matt.proud@gmail.com>
-* Tobias Schmidt <ts@soundcloud.com>
-

vendor/github.com/prometheus/client_golang/NOTICE

@@ -7,11 +7,6 @@ SoundCloud Ltd. (http://soundcloud.com/).
 
 The following components are included in this product:
 
-goautoneg
-http://bitbucket.org/ww/goautoneg
-Copyright 2011, Open Knowledge Foundation Ltd.
-See README.txt for license details.
-
 perks - a fork of https://github.com/bmizerany/perks
 https://github.com/beorn7/perks
 Copyright 2013-2015 Blake Mizerany, Björn Rabenstein

vendor/github.com/prometheus/client_golang/prometheus/README.md

@@ -1,53 +1 @@
-# Overview
-This is the [Prometheus](http://www.prometheus.io) telemetric
-instrumentation client [Go](http://golang.org) client library.  It
-enable authors to define process-space metrics for their servers and
-expose them through a web service interface for extraction,
-aggregation, and a whole slew of other post processing techniques.
-
-# Installing
-    $ go get github.com/prometheus/client_golang/prometheus
-
-# Example
-```go
-package main
-
-import (
-	"net/http"
-
-	"github.com/prometheus/client_golang/prometheus"
-)
-
-var (
-	indexed = prometheus.NewCounter(prometheus.CounterOpts{
-		Namespace: "my_company",
-		Subsystem: "indexer",
-		Name:      "documents_indexed",
-		Help:      "The number of documents indexed.",
-	})
-	size = prometheus.NewGauge(prometheus.GaugeOpts{
-		Namespace: "my_company",
-		Subsystem: "storage",
-		Name:      "documents_total_size_bytes",
-		Help:      "The total size of all documents in the storage.",
-	})
-)
-
-func main() {
-	http.Handle("/metrics", prometheus.Handler())
-
-	indexed.Inc()
-	size.Set(5)
-
-	http.ListenAndServe(":8080", nil)
-}
-
-func init() {
-	prometheus.MustRegister(indexed)
-	prometheus.MustRegister(size)
-}
-```
-
-# Documentation
-
-[![GoDoc](https://godoc.org/github.com/prometheus/client_golang?status.png)](https://godoc.org/github.com/prometheus/client_golang)
+See [![go-doc](https://godoc.org/github.com/prometheus/client_golang/prometheus?status.svg)](https://godoc.org/github.com/prometheus/client_golang/prometheus).

vendor/github.com/prometheus/client_golang/prometheus/collector.go

@@ -15,61 +15,106 @@ package prometheus
 
 // Collector is the interface implemented by anything that can be used by
 // Prometheus to collect metrics. A Collector has to be registered for
-// collection. See Register, MustRegister, RegisterOrGet, and MustRegisterOrGet.
+// collection. See Registerer.Register.
 //
-// The stock metrics provided by this package (like Gauge, Counter, Summary) are
-// also Collectors (which only ever collect one metric, namely itself). An
-// implementer of Collector may, however, collect multiple metrics in a
-// coordinated fashion and/or create metrics on the fly. Examples for collectors
-// already implemented in this library are the metric vectors (i.e. collection
-// of multiple instances of the same Metric but with different label values)
-// like GaugeVec or SummaryVec, and the ExpvarCollector.
+// The stock metrics provided by this package (Gauge, Counter, Summary,
+// Histogram, Untyped) are also Collectors (which only ever collect one metric,
+// namely itself). An implementer of Collector may, however, collect multiple
+// metrics in a coordinated fashion and/or create metrics on the fly. Examples
+// for collectors already implemented in this library are the metric vectors
+// (i.e. collection of multiple instances of the same Metric but with different
+// label values) like GaugeVec or SummaryVec, and the ExpvarCollector.
 type Collector interface {
 	// Describe sends the super-set of all possible descriptors of metrics
 	// collected by this Collector to the provided channel and returns once
 	// the last descriptor has been sent. The sent descriptors fulfill the
 	// consistency and uniqueness requirements described in the Desc
-	// documentation. (It is valid if one and the same Collector sends
-	// duplicate descriptors. Those duplicates are simply ignored. However,
-	// two different Collectors must not send duplicate descriptors.) This
-	// method idempotently sends the same descriptors throughout the
-	// lifetime of the Collector. If a Collector encounters an error while
-	// executing this method, it must send an invalid descriptor (created
-	// with NewInvalidDesc) to signal the error to the registry.
+	// documentation.
+	//
+	// It is valid if one and the same Collector sends duplicate
+	// descriptors. Those duplicates are simply ignored. However, two
+	// different Collectors must not send duplicate descriptors.
+	//
+	// Sending no descriptor at all marks the Collector as “unchecked”,
+	// i.e. no checks will be performed at registration time, and the
+	// Collector may yield any Metric it sees fit in its Collect method.
+	//
+	// This method idempotently sends the same descriptors throughout the
+	// lifetime of the Collector. It may be called concurrently and
+	// therefore must be implemented in a concurrency safe way.
+	//
+	// If a Collector encounters an error while executing this method, it
+	// must send an invalid descriptor (created with NewInvalidDesc) to
+	// signal the error to the registry.
 	Describe(chan<- *Desc)
-	// Collect is called by Prometheus when collecting metrics. The
-	// implementation sends each collected metric via the provided channel
-	// and returns once the last metric has been sent. The descriptor of
-	// each sent metric is one of those returned by Describe. Returned
-	// metrics that share the same descriptor must differ in their variable
-	// label values. This method may be called concurrently and must
-	// therefore be implemented in a concurrency safe way. Blocking occurs
-	// at the expense of total performance of rendering all registered
-	// metrics. Ideally, Collector implementations support concurrent
-	// readers.
+	// Collect is called by the Prometheus registry when collecting
+	// metrics. The implementation sends each collected metric via the
+	// provided channel and returns once the last metric has been sent. The
+	// descriptor of each sent metric is one of those returned by Describe
+	// (unless the Collector is unchecked, see above). Returned metrics that
+	// share the same descriptor must differ in their variable label
+	// values.
+	//
+	// This method may be called concurrently and must therefore be
+	// implemented in a concurrency safe way. Blocking occurs at the expense
+	// of total performance of rendering all registered metrics. Ideally,
+	// Collector implementations support concurrent readers.
 	Collect(chan<- Metric)
 }
 
-// SelfCollector implements Collector for a single Metric so that that the
-// Metric collects itself. Add it as an anonymous field to a struct that
-// implements Metric, and call Init with the Metric itself as an argument.
-type SelfCollector struct {
+// DescribeByCollect is a helper to implement the Describe method of a custom
+// Collector. It collects the metrics from the provided Collector and sends
+// their descriptors to the provided channel.
+//
+// If a Collector collects the same metrics throughout its lifetime, its
+// Describe method can simply be implemented as:
+//
+//   func (c customCollector) Describe(ch chan<- *Desc) {
+//   	DescribeByCollect(c, ch)
+//   }
+//
+// However, this will not work if the metrics collected change dynamically over
+// the lifetime of the Collector in a way that their combined set of descriptors
+// changes as well. The shortcut implementation will then violate the contract
+// of the Describe method. If a Collector sometimes collects no metrics at all
+// (for example vectors like CounterVec, GaugeVec, etc., which only collect
+// metrics after a metric with a fully specified label set has been accessed),
+// it might even get registered as an unchecked Collector (cf. the Register
+// method of the Registerer interface). Hence, only use this shortcut
+// implementation of Describe if you are certain to fulfill the contract.
+//
+// The Collector example demonstrates a use of DescribeByCollect.
+func DescribeByCollect(c Collector, descs chan<- *Desc) {
+	metrics := make(chan Metric)
+	go func() {
+		c.Collect(metrics)
+		close(metrics)
+	}()
+	for m := range metrics {
+		descs <- m.Desc()
+	}
+}
+
+// selfCollector implements Collector for a single Metric so that the Metric
+// collects itself. Add it as an anonymous field to a struct that implements
+// Metric, and call init with the Metric itself as an argument.
+type selfCollector struct {
 	self Metric
 }
 
-// Init provides the SelfCollector with a reference to the metric it is supposed
+// init provides the selfCollector with a reference to the metric it is supposed
 // to collect. It is usually called within the factory function to create a
 // metric. See example.
-func (c *SelfCollector) Init(self Metric) {
+func (c *selfCollector) init(self Metric) {
 	c.self = self
 }
 
 // Describe implements Collector.
-func (c *SelfCollector) Describe(ch chan<- *Desc) {
+func (c *selfCollector) Describe(ch chan<- *Desc) {
 	ch <- c.self.Desc()
 }
 
 // Collect implements Collector.
-func (c *SelfCollector) Collect(ch chan<- Metric) {
+func (c *selfCollector) Collect(ch chan<- Metric) {
 	ch <- c.self
 }

vendor/github.com/prometheus/client_golang/prometheus/counter.go

@@ -15,6 +15,11 @@ package prometheus
 
 import (
 	"errors"
+	"math"
+	"sync/atomic"
+	"time"
+
+	dto "github.com/prometheus/client_model/go"
 )
 
 // Counter is a Metric that represents a single numerical value that only ever
@@ -30,23 +35,42 @@ type Counter interface {
 	Metric
 	Collector
 
-	// Set is used to set the Counter to an arbitrary value. It is only used
-	// if you have to transfer a value from an external counter into this
-	// Prometheus metric. Do not use it for regular handling of a
-	// Prometheus counter (as it can be used to break the contract of
-	// monotonically increasing values).
-	Set(float64)
-	// Inc increments the counter by 1.
+	// Inc increments the counter by 1. Use Add to increment it by arbitrary
+	// non-negative values.
 	Inc()
 	// Add adds the given value to the counter. It panics if the value is <
 	// 0.
 	Add(float64)
 }
 
+// ExemplarAdder is implemented by Counters that offer the option of adding a
+// value to the Counter together with an exemplar. Its AddWithExemplar method
+// works like the Add method of the Counter interface but also replaces the
+// currently saved exemplar (if any) with a new one, created from the provided
+// value, the current time as timestamp, and the provided labels. Empty Labels
+// will lead to a valid (label-less) exemplar. But if Labels is nil, the current
+// exemplar is left in place. AddWithExemplar panics if the value is < 0, if any
+// of the provided labels are invalid, or if the provided labels contain more
+// than 64 runes in total.
+type ExemplarAdder interface {
+	AddWithExemplar(value float64, exemplar Labels)
+}
+
 // CounterOpts is an alias for Opts. See there for doc comments.
 type CounterOpts Opts
 
 // NewCounter creates a new Counter based on the provided CounterOpts.
+//
+// The returned implementation also implements ExemplarAdder. It is safe to
+// perform the corresponding type assertion.
+//
+// The returned implementation tracks the counter value in two separate
+// variables, a float64 and a uint64. The latter is used to track calls of the
+// Inc method and calls of the Add method with a value that can be represented
+// as a uint64. This allows atomic increments of the counter with optimal
+// performance. (It is common to have an Inc call in very hot execution paths.)
+// Both internal tracking values are added up in the Write method. This has to
+// be taken into account when it comes to precision and overflow behavior.
 func NewCounter(opts CounterOpts) Counter {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -54,20 +78,83 @@ func NewCounter(opts CounterOpts) Counter {
 		nil,
 		opts.ConstLabels,
 	)
-	result := &counter{value: value{desc: desc, valType: CounterValue, labelPairs: desc.constLabelPairs}}
-	result.Init(result) // Init self-collection.
+	result := &counter{desc: desc, labelPairs: desc.constLabelPairs, now: time.Now}
+	result.init(result) // Init self-collection.
 	return result
 }
 
 type counter struct {
-	value
+	// valBits contains the bits of the represented float64 value, while
+	// valInt stores values that are exact integers. Both have to go first
+	// in the struct to guarantee alignment for atomic operations.
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	valBits uint64
+	valInt  uint64
+
+	selfCollector
+	desc *Desc
+
+	labelPairs []*dto.LabelPair
+	exemplar   atomic.Value // Containing nil or a *dto.Exemplar.
+
+	now func() time.Time // To mock out time.Now() for testing.
+}
+
+func (c *counter) Desc() *Desc {
+	return c.desc
 }
 
 func (c *counter) Add(v float64) {
 	if v < 0 {
 		panic(errors.New("counter cannot decrease in value"))
 	}
-	c.value.Add(v)
+
+	ival := uint64(v)
+	if float64(ival) == v {
+		atomic.AddUint64(&c.valInt, ival)
+		return
+	}
+
+	for {
+		oldBits := atomic.LoadUint64(&c.valBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
+		if atomic.CompareAndSwapUint64(&c.valBits, oldBits, newBits) {
+			return
+		}
+	}
+}
+
+func (c *counter) AddWithExemplar(v float64, e Labels) {
+	c.Add(v)
+	c.updateExemplar(v, e)
+}
+
+func (c *counter) Inc() {
+	atomic.AddUint64(&c.valInt, 1)
+}
+
+func (c *counter) Write(out *dto.Metric) error {
+	fval := math.Float64frombits(atomic.LoadUint64(&c.valBits))
+	ival := atomic.LoadUint64(&c.valInt)
+	val := fval + float64(ival)
+
+	var exemplar *dto.Exemplar
+	if e := c.exemplar.Load(); e != nil {
+		exemplar = e.(*dto.Exemplar)
+	}
+
+	return populateMetric(CounterValue, val, c.labelPairs, exemplar, out)
+}
+
+func (c *counter) updateExemplar(v float64, l Labels) {
+	if l == nil {
+		return
+	}
+	e, err := newExemplar(v, c.now(), l)
+	if err != nil {
+		panic(err)
+	}
+	c.exemplar.Store(e)
 }
 
 // CounterVec is a Collector that bundles a set of Counters that all share the
@@ -75,16 +162,12 @@ func (c *counter) Add(v float64) {
 // if you want to count the same thing partitioned by various dimensions
 // (e.g. number of HTTP requests, partitioned by response code and
 // method). Create instances with NewCounterVec.
-//
-// CounterVec embeds MetricVec. See there for a full list of methods with
-// detailed documentation.
 type CounterVec struct {
-	MetricVec
+	*MetricVec
 }
 
 // NewCounterVec creates a new CounterVec based on the provided CounterOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -93,38 +176,62 @@ func NewCounterVec(opts CounterOpts, labelNames []string) *CounterVec {
 		opts.ConstLabels,
 	)
 	return &CounterVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
-				result := &counter{value: value{
-					desc:       desc,
-					valType:    CounterValue,
-					labelPairs: makeLabelPairs(desc, lvs),
-				}}
-				result.Init(result) // Init self-collection.
-				return result
-			},
-		},
+		MetricVec: NewMetricVec(desc, func(lvs ...string) Metric {
+			if len(lvs) != len(desc.variableLabels) {
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+			}
+			result := &counter{desc: desc, labelPairs: MakeLabelPairs(desc, lvs), now: time.Now}
+			result.init(result) // Init self-collection.
+			return result
+		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Counter and not a
-// Metric so that no type conversion is required.
-func (m *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Counter for the given slice of label
+// values (same order as the variable labels in Desc). If that combination of
+// label values is accessed for the first time, a new Counter is created.
+//
+// It is possible to call this method without using the returned Counter to only
+// create the new Counter but leave it at its starting value 0. See also the
+// SummaryVec example.
+//
+// Keeping the Counter for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Counter from the CounterVec. In that case,
+// the Counter will still exist, but it will not be exported anymore, even if a
+// Counter with the same label values is created later.
+//
+// An error is returned if the number of label values is not the same as the
+// number of variable labels in Desc (minus any curried labels).
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the GaugeVec example.
+func (v *CounterVec) GetMetricWithLabelValues(lvs ...string) (Counter, error) {
+	metric, err := v.MetricVec.GetMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Counter), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Counter and not a Metric so that no
-// type conversion is required.
-func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Counter for the given Labels map (the label names
+// must match those of the variable labels in Desc). If that label map is
+// accessed for the first time, a new Counter is created. Implications of
+// creating a Counter without using it and keeping the Counter for later use are
+// the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the variable labels in Desc (minus any curried labels).
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (v *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
+	metric, err := v.MetricVec.GetMetricWith(labels)
 	if metric != nil {
 		return metric.(Counter), err
 	}
@@ -132,18 +239,57 @@ func (m *CounterVec) GetMetricWith(labels Labels) (Counter, error) {
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Add(42)
-func (m *CounterVec) WithLabelValues(lvs ...string) Counter {
-	return m.MetricVec.WithLabelValues(lvs...).(Counter)
+func (v *CounterVec) WithLabelValues(lvs ...string) Counter {
+	c, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return c
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-func (m *CounterVec) With(labels Labels) Counter {
-	return m.MetricVec.With(labels).(Counter)
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
+func (v *CounterVec) With(labels Labels) Counter {
+	c, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return c
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the CounterVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *CounterVec) CurryWith(labels Labels) (*CounterVec, error) {
+	vec, err := v.MetricVec.CurryWith(labels)
+	if vec != nil {
+		return &CounterVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *CounterVec) MustCurryWith(labels Labels) *CounterVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 // CounterFunc is a Counter whose value is determined at collect time by calling a
@@ -163,6 +309,8 @@ type CounterFunc interface {
 // provided function must be concurrency-safe. The function should also honor
 // the contract for a Counter (values only go up, not down), but compliance will
 // not be checked.
+//
+// Check out the ExampleGaugeFunc examples for the similar GaugeFunc.
 func NewCounterFunc(opts CounterOpts, function func() float64) CounterFunc {
 	return newValueFunc(NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),

vendor/github.com/prometheus/client_golang/prometheus/desc.go

@@ -1,35 +1,32 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package prometheus
 
 import (
 	"errors"
 	"fmt"
-	"regexp"
 	"sort"
 	"strings"
 
+	"github.com/cespare/xxhash/v2"
+	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/common/model"
 
 	dto "github.com/prometheus/client_model/go"
 )
 
-var (
-	metricNameRE = regexp.MustCompile(`^[a-zA-Z_][a-zA-Z0-9_:]*$`)
-	labelNameRE  = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$")
-)
-
-// reservedLabelPrefix is a prefix which is not legal in user-supplied
-// label names.
-const reservedLabelPrefix = "__"
-
-// Labels represents a collection of label name -> value mappings. This type is
-// commonly used with the With(Labels) and GetMetricWith(Labels) methods of
-// metric vector Collectors, e.g.:
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-//
-// The other use-case is the specification of constant label pairs in Opts or to
-// create a Desc.
-type Labels map[string]string
-
 // Desc is the descriptor used by every Prometheus Metric. It is essentially
 // the immutable meta-data of a Metric. The normal Metric implementations
 // included in this package manage their Desc under the hood. Users only have to
@@ -54,7 +51,7 @@ type Desc struct {
 	// constLabelPairs contains precalculated DTO label pairs based on
 	// the constant labels.
 	constLabelPairs []*dto.LabelPair
-	// VariableLabels contains names of labels for which the metric
+	// variableLabels contains names of labels for which the metric
 	// maintains variable values.
 	variableLabels []string
 	// id is a hash of the values of the ConstLabels and fqName. This
@@ -65,32 +62,27 @@ type Desc struct {
 	// Help string. Each Desc with the same fqName must have the same
 	// dimHash.
 	dimHash uint64
-	// err is an error that occured during construction. It is reported on
+	// err is an error that occurred during construction. It is reported on
 	// registration time.
 	err error
 }
 
 // NewDesc allocates and initializes a new Desc. Errors are recorded in the Desc
 // and will be reported on registration time. variableLabels and constLabels can
-// be nil if no such labels should be set. fqName and help must not be empty.
+// be nil if no such labels should be set. fqName must not be empty.
 //
 // variableLabels only contain the label names. Their label values are variable
 // and therefore not part of the Desc. (They are managed within the Metric.)
 //
 // For constLabels, the label values are constant. Therefore, they are fully
-// specified in the Desc. See the Opts documentation for the implications of
-// constant labels.
+// specified in the Desc. See the Collector example for a usage pattern.
 func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *Desc {
 	d := &Desc{
 		fqName:         fqName,
 		help:           help,
 		variableLabels: variableLabels,
 	}
-	if help == "" {
-		d.err = errors.New("empty help string")
-		return d
-	}
-	if !metricNameRE.MatchString(fqName) {
+	if !model.IsValidMetricName(model.LabelValue(fqName)) {
 		d.err = fmt.Errorf("%q is not a valid metric name", fqName)
 		return d
 	}
@@ -103,7 +95,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	// First add only the const label names and sort them...
 	for labelName := range constLabels {
 		if !checkLabelName(labelName) {
-			d.err = fmt.Errorf("%q is not a valid label name", labelName)
+			d.err = fmt.Errorf("%q is not a valid label name for metric %q", labelName, fqName)
 			return d
 		}
 		labelNames = append(labelNames, labelName)
@@ -114,12 +106,18 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 	for _, labelName := range labelNames {
 		labelValues = append(labelValues, constLabels[labelName])
 	}
+	// Validate the const label values. They can't have a wrong cardinality, so
+	// use in len(labelValues) as expectedNumberOfValues.
+	if err := validateLabelValues(labelValues, len(labelValues)); err != nil {
+		d.err = err
+		return d
+	}
 	// Now add the variable label names, but prefix them with something that
 	// cannot be in a regular label name. That prevents matching the label
 	// dimension with a different mix between preset and variable labels.
 	for _, labelName := range variableLabels {
 		if !checkLabelName(labelName) {
-			d.err = fmt.Errorf("%q is not a valid label name", labelName)
+			d.err = fmt.Errorf("%q is not a valid label name for metric %q", labelName, fqName)
 			return d
 		}
 		labelNames = append(labelNames, "$"+labelName)
@@ -129,24 +127,25 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 		d.err = errors.New("duplicate label names")
 		return d
 	}
-	vh := hashNew()
+
+	xxh := xxhash.New()
 	for _, val := range labelValues {
-		vh = hashAdd(vh, val)
-		vh = hashAddByte(vh, separatorByte)
+		xxh.WriteString(val)
+		xxh.Write(separatorByteSlice)
 	}
-	d.id = vh
+	d.id = xxh.Sum64()
 	// Sort labelNames so that order doesn't matter for the hash.
 	sort.Strings(labelNames)
 	// Now hash together (in this order) the help string and the sorted
 	// label names.
-	lh := hashNew()
-	lh = hashAdd(lh, help)
-	lh = hashAddByte(lh, separatorByte)
+	xxh.Reset()
+	xxh.WriteString(help)
+	xxh.Write(separatorByteSlice)
 	for _, labelName := range labelNames {
-		lh = hashAdd(lh, labelName)
-		lh = hashAddByte(lh, separatorByte)
+		xxh.WriteString(labelName)
+		xxh.Write(separatorByteSlice)
 	}
-	d.dimHash = lh
+	d.dimHash = xxh.Sum64()
 
 	d.constLabelPairs = make([]*dto.LabelPair, 0, len(constLabels))
 	for n, v := range constLabels {
@@ -155,7 +154,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 			Value: proto.String(v),
 		})
 	}
-	sort.Sort(LabelPairSorter(d.constLabelPairs))
+	sort.Sort(labelPairSorter(d.constLabelPairs))
 	return d
 }
 
@@ -185,8 +184,3 @@ func (d *Desc) String() string {
 		d.variableLabels,
 	)
 }
-
-func checkLabelName(l string) bool {
-	return labelNameRE.MatchString(l) &&
-		!strings.HasPrefix(l, reservedLabelPrefix)
-}

vendor/github.com/prometheus/client_golang/prometheus/doc.go

@@ -11,25 +11,28 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package prometheus provides embeddable metric primitives for servers and
-// standardized exposition of telemetry through a web services interface.
+// Package prometheus is the core instrumentation package. It provides metrics
+// primitives to instrument code for monitoring. It also offers a registry for
+// metrics. Sub-packages allow to expose the registered metrics via HTTP
+// (package promhttp) or push them to a Pushgateway (package push). There is
+// also a sub-package promauto, which provides metrics constructors with
+// automatic registration.
 //
 // All exported functions and methods are safe to be used concurrently unless
 // specified otherwise.
 //
-// To expose metrics registered with the Prometheus registry, an HTTP server
-// needs to know about the Prometheus handler. The usual endpoint is "/metrics".
+// A Basic Example
 //
-//     http.Handle("/metrics", prometheus.Handler())
-//
-// As a starting point a very basic usage example:
+// As a starting point, a very basic usage example:
 //
 //    package main
 //
 //    import (
+//    	"log"
 //    	"net/http"
 //
 //    	"github.com/prometheus/client_golang/prometheus"
+//    	"github.com/prometheus/client_golang/prometheus/promhttp"
 //    )
 //
 //    var (
@@ -37,32 +40,48 @@
 //    		Name: "cpu_temperature_celsius",
 //    		Help: "Current temperature of the CPU.",
 //    	})
-//    	hdFailures = prometheus.NewCounter(prometheus.CounterOpts{
-//    		Name: "hd_errors_total",
-//    		Help: "Number of hard-disk errors.",
-//    	})
+//    	hdFailures = prometheus.NewCounterVec(
+//    		prometheus.CounterOpts{
+//    			Name: "hd_errors_total",
+//    			Help: "Number of hard-disk errors.",
+//    		},
+//    		[]string{"device"},
+//    	)
 //    )
 //
 //    func init() {
+//    	// Metrics have to be registered to be exposed:
 //    	prometheus.MustRegister(cpuTemp)
 //    	prometheus.MustRegister(hdFailures)
 //    }
 //
 //    func main() {
 //    	cpuTemp.Set(65.3)
-//    	hdFailures.Inc()
+//    	hdFailures.With(prometheus.Labels{"device":"/dev/sda"}).Inc()
 //
-//    	http.Handle("/metrics", prometheus.Handler())
-//    	http.ListenAndServe(":8080", nil)
+//    	// The Handler function provides a default handler to expose metrics
+//    	// via an HTTP server. "/metrics" is the usual endpoint for that.
+//    	http.Handle("/metrics", promhttp.Handler())
+//    	log.Fatal(http.ListenAndServe(":8080", nil))
 //    }
 //
 //
-// This is a complete program that exports two metrics, a Gauge and a Counter.
-// It also exports some stats about the HTTP usage of the /metrics
-// endpoint. (See the Handler function for more detail.)
+// This is a complete program that exports two metrics, a Gauge and a Counter,
+// the latter with a label attached to turn it into a (one-dimensional) vector.
 //
-// Two more advanced metric types are the Summary and Histogram. A more
-// thorough description of metric types can be found in the prometheus docs:
+// Metrics
+//
+// The number of exported identifiers in this package might appear a bit
+// overwhelming. However, in addition to the basic plumbing shown in the example
+// above, you only need to understand the different metric types and their
+// vector versions for basic usage. Furthermore, if you are not concerned with
+// fine-grained control of when and how to register metrics with the registry,
+// have a look at the promauto package, which will effectively allow you to
+// ignore registration altogether in simple cases.
+//
+// Above, you have already touched the Counter and the Gauge. There are two more
+// advanced metric types: the Summary and Histogram. A more thorough description
+// of those four metric types can be found in the Prometheus docs:
 // https://prometheus.io/docs/concepts/metric_types/
 //
 // In addition to the fundamental metric types Gauge, Counter, Summary, and
@@ -71,41 +90,110 @@
 // metric vectors. The fundamental types are GaugeVec, CounterVec, SummaryVec,
 // and HistogramVec.
 //
-// Those are all the parts needed for basic usage. Detailed documentation and
-// examples are provided below.
+// While only the fundamental metric types implement the Metric interface, both
+// the metrics and their vector versions implement the Collector interface. A
+// Collector manages the collection of a number of Metrics, but for convenience,
+// a Metric can also “collect itself”. Note that Gauge, Counter, Summary, and
+// Histogram are interfaces themselves while GaugeVec, CounterVec, SummaryVec,
+// and HistogramVec are not.
 //
-// Everything else this package offers is essentially for "power users" only. A
-// few pointers to "power user features":
+// To create instances of Metrics and their vector versions, you need a suitable
+// …Opts struct, i.e. GaugeOpts, CounterOpts, SummaryOpts, or HistogramOpts.
 //
-// All the various ...Opts structs have a ConstLabels field for labels that
-// never change their value (which is only useful under special circumstances,
-// see documentation of the Opts type).
+// Custom Collectors and constant Metrics
 //
-// The Untyped metric behaves like a Gauge, but signals the Prometheus server
-// not to assume anything about its type.
+// While you could create your own implementations of Metric, most likely you
+// will only ever implement the Collector interface on your own. At a first
+// glance, a custom Collector seems handy to bundle Metrics for common
+// registration (with the prime example of the different metric vectors above,
+// which bundle all the metrics of the same name but with different labels).
 //
-// Functions to fine-tune how the metric registry works: EnableCollectChecks,
-// PanicOnCollectError, Register, Unregister, SetMetricFamilyInjectionHook.
+// There is a more involved use case, too: If you already have metrics
+// available, created outside of the Prometheus context, you don't need the
+// interface of the various Metric types. You essentially want to mirror the
+// existing numbers into Prometheus Metrics during collection. An own
+// implementation of the Collector interface is perfect for that. You can create
+// Metric instances “on the fly” using NewConstMetric, NewConstHistogram, and
+// NewConstSummary (and their respective Must… versions). NewConstMetric is used
+// for all metric types with just a float64 as their value: Counter, Gauge, and
+// a special “type” called Untyped. Use the latter if you are not sure if the
+// mirrored metric is a Counter or a Gauge. Creation of the Metric instance
+// happens in the Collect method. The Describe method has to return separate
+// Desc instances, representative of the “throw-away” metrics to be created
+// later.  NewDesc comes in handy to create those Desc instances. Alternatively,
+// you could return no Desc at all, which will mark the Collector “unchecked”.
+// No checks are performed at registration time, but metric consistency will
+// still be ensured at scrape time, i.e. any inconsistencies will lead to scrape
+// errors. Thus, with unchecked Collectors, the responsibility to not collect
+// metrics that lead to inconsistencies in the total scrape result lies with the
+// implementer of the Collector. While this is not a desirable state, it is
+// sometimes necessary. The typical use case is a situation where the exact
+// metrics to be returned by a Collector cannot be predicted at registration
+// time, but the implementer has sufficient knowledge of the whole system to
+// guarantee metric consistency.
 //
-// For custom metric collection, there are two entry points: Custom Metric
-// implementations and custom Collector implementations. A Metric is the
-// fundamental unit in the Prometheus data model: a sample at a point in time
-// together with its meta-data (like its fully-qualified name and any number of
-// pairs of label name and label value) that knows how to marshal itself into a
-// data transfer object (aka DTO, implemented as a protocol buffer). A Collector
-// gets registered with the Prometheus registry and manages the collection of
-// one or more Metrics. Many parts of this package are building blocks for
-// Metrics and Collectors. Desc is the metric descriptor, actually used by all
-// metrics under the hood, and by Collectors to describe the Metrics to be
-// collected, but only to be dealt with by users if they implement their own
-// Metrics or Collectors. To create a Desc, the BuildFQName function will come
-// in handy. Other useful components for Metric and Collector implementation
-// include: LabelPairSorter to sort the DTO version of label pairs,
-// NewConstMetric and MustNewConstMetric to create "throw away" Metrics at
-// collection time, MetricVec to bundle custom Metrics into a metric vector
-// Collector, SelfCollector to make a custom Metric collect itself.
+// The Collector example illustrates the use case. You can also look at the
+// source code of the processCollector (mirroring process metrics), the
+// goCollector (mirroring Go metrics), or the expvarCollector (mirroring expvar
+// metrics) as examples that are used in this package itself.
 //
-// A good example for a custom Collector is the ExpVarCollector included in this
-// package, which exports variables exported via the "expvar" package as
-// Prometheus metrics.
+// If you just need to call a function to get a single float value to collect as
+// a metric, GaugeFunc, CounterFunc, or UntypedFunc might be interesting
+// shortcuts.
+//
+// Advanced Uses of the Registry
+//
+// While MustRegister is the by far most common way of registering a Collector,
+// sometimes you might want to handle the errors the registration might cause.
+// As suggested by the name, MustRegister panics if an error occurs. With the
+// Register function, the error is returned and can be handled.
+//
+// An error is returned if the registered Collector is incompatible or
+// inconsistent with already registered metrics. The registry aims for
+// consistency of the collected metrics according to the Prometheus data model.
+// Inconsistencies are ideally detected at registration time, not at collect
+// time. The former will usually be detected at start-up time of a program,
+// while the latter will only happen at scrape time, possibly not even on the
+// first scrape if the inconsistency only becomes relevant later. That is the
+// main reason why a Collector and a Metric have to describe themselves to the
+// registry.
+//
+// So far, everything we did operated on the so-called default registry, as it
+// can be found in the global DefaultRegisterer variable. With NewRegistry, you
+// can create a custom registry, or you can even implement the Registerer or
+// Gatherer interfaces yourself. The methods Register and Unregister work in the
+// same way on a custom registry as the global functions Register and Unregister
+// on the default registry.
+//
+// There are a number of uses for custom registries: You can use registries with
+// special properties, see NewPedanticRegistry. You can avoid global state, as
+// it is imposed by the DefaultRegisterer. You can use multiple registries at
+// the same time to expose different metrics in different ways.  You can use
+// separate registries for testing purposes.
+//
+// Also note that the DefaultRegisterer comes registered with a Collector for Go
+// runtime metrics (via NewGoCollector) and a Collector for process metrics (via
+// NewProcessCollector). With a custom registry, you are in control and decide
+// yourself about the Collectors to register.
+//
+// HTTP Exposition
+//
+// The Registry implements the Gatherer interface. The caller of the Gather
+// method can then expose the gathered metrics in some way. Usually, the metrics
+// are served via HTTP on the /metrics endpoint. That's happening in the example
+// above. The tools to expose metrics via HTTP are in the promhttp sub-package.
+//
+// Pushing to the Pushgateway
+//
+// Function for pushing to the Pushgateway can be found in the push sub-package.
+//
+// Graphite Bridge
+//
+// Functions and examples to push metrics from a Gatherer to Graphite can be
+// found in the graphite sub-package.
+//
+// Other Means of Exposition
+//
+// More ways of exposing metrics can easily be added by following the approaches
+// of the existing implementations.
 package prometheus

vendor/github.com/prometheus/client_golang/prometheus/expvar.go

@@ -1,119 +0,0 @@
-// Copyright 2014 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package prometheus
-
-import (
-	"encoding/json"
-	"expvar"
-)
-
-// ExpvarCollector collects metrics from the expvar interface. It provides a
-// quick way to expose numeric values that are already exported via expvar as
-// Prometheus metrics. Note that the data models of expvar and Prometheus are
-// fundamentally different, and that the ExpvarCollector is inherently
-// slow. Thus, the ExpvarCollector is probably great for experiments and
-// prototying, but you should seriously consider a more direct implementation of
-// Prometheus metrics for monitoring production systems.
-//
-// Use NewExpvarCollector to create new instances.
-type ExpvarCollector struct {
-	exports map[string]*Desc
-}
-
-// NewExpvarCollector returns a newly allocated ExpvarCollector that still has
-// to be registered with the Prometheus registry.
-//
-// The exports map has the following meaning:
-//
-// The keys in the map correspond to expvar keys, i.e. for every expvar key you
-// want to export as Prometheus metric, you need an entry in the exports
-// map. The descriptor mapped to each key describes how to export the expvar
-// value. It defines the name and the help string of the Prometheus metric
-// proxying the expvar value. The type will always be Untyped.
-//
-// For descriptors without variable labels, the expvar value must be a number or
-// a bool. The number is then directly exported as the Prometheus sample
-// value. (For a bool, 'false' translates to 0 and 'true' to 1). Expvar values
-// that are not numbers or bools are silently ignored.
-//
-// If the descriptor has one variable label, the expvar value must be an expvar
-// map. The keys in the expvar map become the various values of the one
-// Prometheus label. The values in the expvar map must be numbers or bools again
-// as above.
-//
-// For descriptors with more than one variable label, the expvar must be a
-// nested expvar map, i.e. where the values of the topmost map are maps again
-// etc. until a depth is reached that corresponds to the number of labels. The
-// leaves of that structure must be numbers or bools as above to serve as the
-// sample values.
-//
-// Anything that does not fit into the scheme above is silently ignored.
-func NewExpvarCollector(exports map[string]*Desc) *ExpvarCollector {
-	return &ExpvarCollector{
-		exports: exports,
-	}
-}
-
-// Describe implements Collector.
-func (e *ExpvarCollector) Describe(ch chan<- *Desc) {
-	for _, desc := range e.exports {
-		ch <- desc
-	}
-}
-
-// Collect implements Collector.
-func (e *ExpvarCollector) Collect(ch chan<- Metric) {
-	for name, desc := range e.exports {
-		var m Metric
-		expVar := expvar.Get(name)
-		if expVar == nil {
-			continue
-		}
-		var v interface{}
-		labels := make([]string, len(desc.variableLabels))
-		if err := json.Unmarshal([]byte(expVar.String()), &v); err != nil {
-			ch <- NewInvalidMetric(desc, err)
-			continue
-		}
-		var processValue func(v interface{}, i int)
-		processValue = func(v interface{}, i int) {
-			if i >= len(labels) {
-				copiedLabels := append(make([]string, 0, len(labels)), labels...)
-				switch v := v.(type) {
-				case float64:
-					m = MustNewConstMetric(desc, UntypedValue, v, copiedLabels...)
-				case bool:
-					if v {
-						m = MustNewConstMetric(desc, UntypedValue, 1, copiedLabels...)
-					} else {
-						m = MustNewConstMetric(desc, UntypedValue, 0, copiedLabels...)
-					}
-				default:
-					return
-				}
-				ch <- m
-				return
-			}
-			vm, ok := v.(map[string]interface{})
-			if !ok {
-				return
-			}
-			for lv, val := range vm {
-				labels[i] = lv
-				processValue(val, i+1)
-			}
-		}
-		processValue(v, 0)
-	}
-}

vendor/github.com/prometheus/client_golang/prometheus/expvar_collector.go

@@ -0,0 +1,86 @@
+// Copyright 2014 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import (
+	"encoding/json"
+	"expvar"
+)
+
+type expvarCollector struct {
+	exports map[string]*Desc
+}
+
+// NewExpvarCollector is the obsolete version of collectors.NewExpvarCollector.
+// See there for documentation.
+//
+// Deprecated: Use collectors.NewExpvarCollector instead.
+func NewExpvarCollector(exports map[string]*Desc) Collector {
+	return &expvarCollector{
+		exports: exports,
+	}
+}
+
+// Describe implements Collector.
+func (e *expvarCollector) Describe(ch chan<- *Desc) {
+	for _, desc := range e.exports {
+		ch <- desc
+	}
+}
+
+// Collect implements Collector.
+func (e *expvarCollector) Collect(ch chan<- Metric) {
+	for name, desc := range e.exports {
+		var m Metric
+		expVar := expvar.Get(name)
+		if expVar == nil {
+			continue
+		}
+		var v interface{}
+		labels := make([]string, len(desc.variableLabels))
+		if err := json.Unmarshal([]byte(expVar.String()), &v); err != nil {
+			ch <- NewInvalidMetric(desc, err)
+			continue
+		}
+		var processValue func(v interface{}, i int)
+		processValue = func(v interface{}, i int) {
+			if i >= len(labels) {
+				copiedLabels := append(make([]string, 0, len(labels)), labels...)
+				switch v := v.(type) {
+				case float64:
+					m = MustNewConstMetric(desc, UntypedValue, v, copiedLabels...)
+				case bool:
+					if v {
+						m = MustNewConstMetric(desc, UntypedValue, 1, copiedLabels...)
+					} else {
+						m = MustNewConstMetric(desc, UntypedValue, 0, copiedLabels...)
+					}
+				default:
+					return
+				}
+				ch <- m
+				return
+			}
+			vm, ok := v.(map[string]interface{})
+			if !ok {
+				return
+			}
+			for lv, val := range vm {
+				labels[i] = lv
+				processValue(val, i+1)
+			}
+		}
+		processValue(v, 0)
+	}
+}

vendor/github.com/prometheus/client_golang/prometheus/fnv.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package prometheus
 
 // Inline and byte-free variant of hash/fnv's fnv64a.

vendor/github.com/prometheus/client_golang/prometheus/gauge.go

@@ -13,6 +13,14 @@
 
 package prometheus
 
+import (
+	"math"
+	"sync/atomic"
+	"time"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
 // Gauge is a Metric that represents a single numerical value that can
 // arbitrarily go up and down.
 //
@@ -27,29 +35,95 @@ type Gauge interface {
 
 	// Set sets the Gauge to an arbitrary value.
 	Set(float64)
-	// Inc increments the Gauge by 1.
+	// Inc increments the Gauge by 1. Use Add to increment it by arbitrary
+	// values.
 	Inc()
-	// Dec decrements the Gauge by 1.
+	// Dec decrements the Gauge by 1. Use Sub to decrement it by arbitrary
+	// values.
 	Dec()
-	// Add adds the given value to the Gauge. (The value can be
-	// negative, resulting in a decrease of the Gauge.)
+	// Add adds the given value to the Gauge. (The value can be negative,
+	// resulting in a decrease of the Gauge.)
 	Add(float64)
 	// Sub subtracts the given value from the Gauge. (The value can be
 	// negative, resulting in an increase of the Gauge.)
 	Sub(float64)
+
+	// SetToCurrentTime sets the Gauge to the current Unix time in seconds.
+	SetToCurrentTime()
 }
 
 // GaugeOpts is an alias for Opts. See there for doc comments.
 type GaugeOpts Opts
 
 // NewGauge creates a new Gauge based on the provided GaugeOpts.
+//
+// The returned implementation is optimized for a fast Set method. If you have a
+// choice for managing the value of a Gauge via Set vs. Inc/Dec/Add/Sub, pick
+// the former. For example, the Inc method of the returned Gauge is slower than
+// the Inc method of a Counter returned by NewCounter. This matches the typical
+// scenarios for Gauges and Counters, where the former tends to be Set-heavy and
+// the latter Inc-heavy.
 func NewGauge(opts GaugeOpts) Gauge {
-	return newValue(NewDesc(
+	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
 		nil,
 		opts.ConstLabels,
-	), GaugeValue, 0)
+	)
+	result := &gauge{desc: desc, labelPairs: desc.constLabelPairs}
+	result.init(result) // Init self-collection.
+	return result
+}
+
+type gauge struct {
+	// valBits contains the bits of the represented float64 value. It has
+	// to go first in the struct to guarantee alignment for atomic
+	// operations.  http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	valBits uint64
+
+	selfCollector
+
+	desc       *Desc
+	labelPairs []*dto.LabelPair
+}
+
+func (g *gauge) Desc() *Desc {
+	return g.desc
+}
+
+func (g *gauge) Set(val float64) {
+	atomic.StoreUint64(&g.valBits, math.Float64bits(val))
+}
+
+func (g *gauge) SetToCurrentTime() {
+	g.Set(float64(time.Now().UnixNano()) / 1e9)
+}
+
+func (g *gauge) Inc() {
+	g.Add(1)
+}
+
+func (g *gauge) Dec() {
+	g.Add(-1)
+}
+
+func (g *gauge) Add(val float64) {
+	for {
+		oldBits := atomic.LoadUint64(&g.valBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + val)
+		if atomic.CompareAndSwapUint64(&g.valBits, oldBits, newBits) {
+			return
+		}
+	}
+}
+
+func (g *gauge) Sub(val float64) {
+	g.Add(val * -1)
+}
+
+func (g *gauge) Write(out *dto.Metric) error {
+	val := math.Float64frombits(atomic.LoadUint64(&g.valBits))
+	return populateMetric(GaugeValue, val, g.labelPairs, nil, out)
 }
 
 // GaugeVec is a Collector that bundles a set of Gauges that all share the same
@@ -58,12 +132,11 @@ func NewGauge(opts GaugeOpts) Gauge {
 // (e.g. number of operations queued, partitioned by user and operation
 // type). Create instances with NewGaugeVec.
 type GaugeVec struct {
-	MetricVec
+	*MetricVec
 }
 
 // NewGaugeVec creates a new GaugeVec based on the provided GaugeOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -72,32 +145,62 @@ func NewGaugeVec(opts GaugeOpts, labelNames []string) *GaugeVec {
 		opts.ConstLabels,
 	)
 	return &GaugeVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
-				return newValue(desc, GaugeValue, 0, lvs...)
-			},
-		},
+		MetricVec: NewMetricVec(desc, func(lvs ...string) Metric {
+			if len(lvs) != len(desc.variableLabels) {
+				panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, lvs))
+			}
+			result := &gauge{desc: desc, labelPairs: MakeLabelPairs(desc, lvs)}
+			result.init(result) // Init self-collection.
+			return result
+		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Gauge and not a
-// Metric so that no type conversion is required.
-func (m *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Gauge for the given slice of label
+// values (same order as the variable labels in Desc). If that combination of
+// label values is accessed for the first time, a new Gauge is created.
+//
+// It is possible to call this method without using the returned Gauge to only
+// create the new Gauge but leave it at its starting value 0. See also the
+// SummaryVec example.
+//
+// Keeping the Gauge for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Gauge from the GaugeVec. In that case, the
+// Gauge will still exist, but it will not be exported anymore, even if a
+// Gauge with the same label values is created later. See also the CounterVec
+// example.
+//
+// An error is returned if the number of label values is not the same as the
+// number of variable labels in Desc (minus any curried labels).
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+func (v *GaugeVec) GetMetricWithLabelValues(lvs ...string) (Gauge, error) {
+	metric, err := v.MetricVec.GetMetricWithLabelValues(lvs...)
 	if metric != nil {
 		return metric.(Gauge), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Gauge and not a Metric so that no
-// type conversion is required.
-func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Gauge for the given Labels map (the label names
+// must match those of the variable labels in Desc). If that label map is
+// accessed for the first time, a new Gauge is created. Implications of
+// creating a Gauge without using it and keeping the Gauge for later use are
+// the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the variable labels in Desc (minus any curried labels).
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (v *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
+	metric, err := v.MetricVec.GetMetricWith(labels)
 	if metric != nil {
 		return metric.(Gauge), err
 	}
@@ -105,18 +208,57 @@ func (m *GaugeVec) GetMetricWith(labels Labels) (Gauge, error) {
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Add(42)
-func (m *GaugeVec) WithLabelValues(lvs ...string) Gauge {
-	return m.MetricVec.WithLabelValues(lvs...).(Gauge)
+func (v *GaugeVec) WithLabelValues(lvs ...string) Gauge {
+	g, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return g
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-func (m *GaugeVec) With(labels Labels) Gauge {
-	return m.MetricVec.With(labels).(Gauge)
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Add(42)
+func (v *GaugeVec) With(labels Labels) Gauge {
+	g, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return g
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the GaugeVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *GaugeVec) CurryWith(labels Labels) (*GaugeVec, error) {
+	vec, err := v.MetricVec.CurryWith(labels)
+	if vec != nil {
+		return &GaugeVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *GaugeVec) MustCurryWith(labels Labels) *GaugeVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 // GaugeFunc is a Gauge whose value is determined at collect time by calling a
@@ -131,9 +273,12 @@ type GaugeFunc interface {
 // NewGaugeFunc creates a new GaugeFunc based on the provided GaugeOpts. The
 // value reported is determined by calling the given function from within the
 // Write method. Take into account that metric collection may happen
-// concurrently. If that results in concurrent calls to Write, like in the case
-// where a GaugeFunc is directly registered with Prometheus, the provided
-// function must be concurrency-safe.
+// concurrently. Therefore, it must be safe to call the provided function
+// concurrently.
+//
+// NewGaugeFunc is a good way to create an “info” style metric with a constant
+// value of 1. Example:
+// https://github.com/prometheus/common/blob/8558a5b7db3c84fa38b4766966059a7bd5bfa2ee/version/info.go#L36-L56
 func NewGaugeFunc(opts GaugeOpts, function func() float64) GaugeFunc {
 	return newValueFunc(NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),

vendor/github.com/prometheus/client_golang/prometheus/go_collector.go

@@ -1,34 +1,68 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package prometheus
 
 import (
-	"fmt"
 	"runtime"
 	"runtime/debug"
+	"sync"
 	"time"
 )
 
 type goCollector struct {
-	goroutines Gauge
-	gcDesc     *Desc
+	goroutinesDesc *Desc
+	threadsDesc    *Desc
+	gcDesc         *Desc
+	goInfoDesc     *Desc
 
-	// metrics to describe and collect
-	metrics memStatsMetrics
+	// ms... are memstats related.
+	msLast          *runtime.MemStats // Previously collected memstats.
+	msLastTimestamp time.Time
+	msMtx           sync.Mutex // Protects msLast and msLastTimestamp.
+	msMetrics       memStatsMetrics
+	msRead          func(*runtime.MemStats) // For mocking in tests.
+	msMaxWait       time.Duration           // Wait time for fresh memstats.
+	msMaxAge        time.Duration           // Maximum allowed age of old memstats.
 }
 
-// NewGoCollector returns a collector which exports metrics about the current
-// go process.
-func NewGoCollector() *goCollector {
+// NewGoCollector is the obsolete version of collectors.NewGoCollector.
+// See there for documentation.
+//
+// Deprecated: Use collectors.NewGoCollector instead.
+func NewGoCollector() Collector {
 	return &goCollector{
-		goroutines: NewGauge(GaugeOpts{
-			Namespace: "go",
-			Name:      "goroutines",
-			Help:      "Number of goroutines that currently exist.",
-		}),
+		goroutinesDesc: NewDesc(
+			"go_goroutines",
+			"Number of goroutines that currently exist.",
+			nil, nil),
+		threadsDesc: NewDesc(
+			"go_threads",
+			"Number of OS threads created.",
+			nil, nil),
 		gcDesc: NewDesc(
 			"go_gc_duration_seconds",
-			"A summary of the GC invocation durations.",
+			"A summary of the pause duration of garbage collection cycles.",
 			nil, nil),
-		metrics: memStatsMetrics{
+		goInfoDesc: NewDesc(
+			"go_info",
+			"Information about the Go environment.",
+			nil, Labels{"version": runtime.Version()}),
+		msLast:    &runtime.MemStats{},
+		msRead:    runtime.ReadMemStats,
+		msMaxWait: time.Second,
+		msMaxAge:  5 * time.Minute,
+		msMetrics: memStatsMetrics{
 			{
 				desc: NewDesc(
 					memstatNamespace("alloc_bytes"),
@@ -48,7 +82,7 @@ func NewGoCollector() *goCollector {
 			}, {
 				desc: NewDesc(
 					memstatNamespace("sys_bytes"),
-					"Number of bytes obtained by system. Sum of all system allocations.",
+					"Number of bytes obtained from system.",
 					nil, nil,
 				),
 				eval:    func(ms *runtime.MemStats) float64 { return float64(ms.Sys) },
@@ -111,12 +145,12 @@ func NewGoCollector() *goCollector {
 				valType: GaugeValue,
 			}, {
 				desc: NewDesc(
-					memstatNamespace("heap_released_bytes_total"),
-					"Total number of heap bytes released to OS.",
+					memstatNamespace("heap_released_bytes"),
+					"Number of heap bytes released to OS.",
 					nil, nil,
 				),
 				eval:    func(ms *runtime.MemStats) float64 { return float64(ms.HeapReleased) },
-				valType: CounterValue,
+				valType: GaugeValue,
 			}, {
 				desc: NewDesc(
 					memstatNamespace("heap_objects"),
@@ -213,29 +247,53 @@ func NewGoCollector() *goCollector {
 				),
 				eval:    func(ms *runtime.MemStats) float64 { return float64(ms.LastGC) / 1e9 },
 				valType: GaugeValue,
+			}, {
+				desc: NewDesc(
+					memstatNamespace("gc_cpu_fraction"),
+					"The fraction of this program's available CPU time used by the GC since the program started.",
+					nil, nil,
+				),
+				eval:    func(ms *runtime.MemStats) float64 { return ms.GCCPUFraction },
+				valType: GaugeValue,
 			},
 		},
 	}
 }
 
 func memstatNamespace(s string) string {
-	return fmt.Sprintf("go_memstats_%s", s)
+	return "go_memstats_" + s
 }
 
 // Describe returns all descriptions of the collector.
 func (c *goCollector) Describe(ch chan<- *Desc) {
-	ch <- c.goroutines.Desc()
+	ch <- c.goroutinesDesc
+	ch <- c.threadsDesc
 	ch <- c.gcDesc
-
-	for _, i := range c.metrics {
+	ch <- c.goInfoDesc
+	for _, i := range c.msMetrics {
 		ch <- i.desc
 	}
 }
 
 // Collect returns the current state of all metrics of the collector.
 func (c *goCollector) Collect(ch chan<- Metric) {
-	c.goroutines.Set(float64(runtime.NumGoroutine()))
-	ch <- c.goroutines
+	var (
+		ms   = &runtime.MemStats{}
+		done = make(chan struct{})
+	)
+	// Start reading memstats first as it might take a while.
+	go func() {
+		c.msRead(ms)
+		c.msMtx.Lock()
+		c.msLast = ms
+		c.msLastTimestamp = time.Now()
+		c.msMtx.Unlock()
+		close(done)
+	}()
+
+	ch <- MustNewConstMetric(c.goroutinesDesc, GaugeValue, float64(runtime.NumGoroutine()))
+	n, _ := runtime.ThreadCreateProfile(nil)
+	ch <- MustNewConstMetric(c.threadsDesc, GaugeValue, float64(n))
 
 	var stats debug.GCStats
 	stats.PauseQuantiles = make([]time.Duration, 5)
@@ -246,11 +304,35 @@ func (c *goCollector) Collect(ch chan<- Metric) {
 		quantiles[float64(idx+1)/float64(len(stats.PauseQuantiles)-1)] = pq.Seconds()
 	}
 	quantiles[0.0] = stats.PauseQuantiles[0].Seconds()
-	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), float64(stats.PauseTotal.Seconds()), quantiles)
+	ch <- MustNewConstSummary(c.gcDesc, uint64(stats.NumGC), stats.PauseTotal.Seconds(), quantiles)
 
-	ms := &runtime.MemStats{}
-	runtime.ReadMemStats(ms)
-	for _, i := range c.metrics {
+	ch <- MustNewConstMetric(c.goInfoDesc, GaugeValue, 1)
+
+	timer := time.NewTimer(c.msMaxWait)
+	select {
+	case <-done: // Our own ReadMemStats succeeded in time. Use it.
+		timer.Stop() // Important for high collection frequencies to not pile up timers.
+		c.msCollect(ch, ms)
+		return
+	case <-timer.C: // Time out, use last memstats if possible. Continue below.
+	}
+	c.msMtx.Lock()
+	if time.Since(c.msLastTimestamp) < c.msMaxAge {
+		// Last memstats are recent enough. Collect from them under the lock.
+		c.msCollect(ch, c.msLast)
+		c.msMtx.Unlock()
+		return
+	}
+	// If we are here, the last memstats are too old or don't exist. We have
+	// to wait until our own ReadMemStats finally completes. For that to
+	// happen, we have to release the lock.
+	c.msMtx.Unlock()
+	<-done
+	c.msCollect(ch, ms)
+}
+
+func (c *goCollector) msCollect(ch chan<- Metric, ms *runtime.MemStats) {
+	for _, i := range c.msMetrics {
 		ch <- MustNewConstMetric(i.desc, i.valType, i.eval(ms))
 	}
 }
@@ -261,3 +343,25 @@ type memStatsMetrics []struct {
 	eval    func(*runtime.MemStats) float64
 	valType ValueType
 }
+
+// NewBuildInfoCollector is the obsolete version of collectors.NewBuildInfoCollector.
+// See there for documentation.
+//
+// Deprecated: Use collectors.NewBuildInfoCollector instead.
+func NewBuildInfoCollector() Collector {
+	path, version, sum := "unknown", "unknown", "unknown"
+	if bi, ok := debug.ReadBuildInfo(); ok {
+		path = bi.Main.Path
+		version = bi.Main.Version
+		sum = bi.Main.Sum
+	}
+	c := &selfCollector{MustNewConstMetric(
+		NewDesc(
+			"go_build_info",
+			"Build information about the main Go module.",
+			nil, Labels{"path": path, "version": version, "checksum": sum},
+		),
+		GaugeValue, 1)}
+	c.init(c.self)
+	return c
+}

vendor/github.com/prometheus/client_golang/prometheus/histogram.go

@@ -16,9 +16,13 @@ package prometheus
 import (
 	"fmt"
 	"math"
+	"runtime"
 	"sort"
+	"sync"
 	"sync/atomic"
+	"time"
 
+	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
 
 	dto "github.com/prometheus/client_model/go"
@@ -43,7 +47,12 @@ type Histogram interface {
 	Metric
 	Collector
 
-	// Observe adds a single observation to the histogram.
+	// Observe adds a single observation to the histogram. Observations are
+	// usually positive or zero. Negative observations are accepted but
+	// prevent current versions of Prometheus from properly detecting
+	// counter resets in the sum of observations. See
+	// https://prometheus.io/docs/practices/histograms/#count-and-sum-of-observations
+	// for details.
 	Observe(float64)
 }
 
@@ -51,11 +60,11 @@ type Histogram interface {
 // bucket of a histogram ("le" -> "less or equal").
 const bucketLabel = "le"
 
+// DefBuckets are the default Histogram buckets. The default buckets are
+// tailored to broadly measure the response time (in seconds) of a network
+// service. Most likely, however, you will be required to define buckets
+// customized to your use case.
 var (
-	// DefBuckets are the default Histogram buckets. The default buckets are
-	// tailored to broadly measure the response time (in seconds) of a
-	// network service. Most likely, however, you will be required to define
-	// buckets customized to your use case.
 	DefBuckets = []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10}
 
 	errBucketLabelNotAllowed = fmt.Errorf(
@@ -108,8 +117,9 @@ func ExponentialBuckets(start, factor float64, count int) []float64 {
 }
 
 // HistogramOpts bundles the options for creating a Histogram metric. It is
-// mandatory to set Name and Help to a non-empty string. All other fields are
-// optional and can safely be left at their zero value.
+// mandatory to set Name to a non-empty string. All other fields are optional
+// and can safely be left at their zero value, although it is strongly
+// encouraged to set a Help string.
 type HistogramOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Histogram (created by joining these components with
@@ -120,29 +130,22 @@ type HistogramOpts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this Histogram. Mandatory!
+	// Help provides information about this Histogram.
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
 	Help string
 
-	// ConstLabels are used to attach fixed labels to this
-	// Histogram. Histograms with the same fully-qualified name must have the
-	// same label names in their ConstLabels.
+	// ConstLabels are used to attach fixed labels to this metric. Metrics
+	// with the same fully-qualified name must have the same label names in
+	// their ConstLabels.
 	//
-	// Note that in most cases, labels have a value that varies during the
-	// lifetime of a process. Those labels are usually managed with a
-	// HistogramVec. ConstLabels serve only special purposes. One is for the
-	// special case where the value of a label does not change during the
-	// lifetime of a process, e.g. if the revision of the running binary is
-	// put into a label. Another, more advanced purpose is if more than one
-	// Collector needs to collect Histograms with the same fully-qualified
-	// name. In that case, those Summaries must differ in the values of
-	// their ConstLabels. See the Collector examples.
-	//
-	// If the value of a label never changes (not even between binaries),
-	// that label most likely should not be a label at all (but part of the
-	// metric name).
+	// ConstLabels are only used rarely. In particular, do not use them to
+	// attach the same labels to all your metrics. Those use cases are
+	// better covered by target labels set by the scraping Prometheus
+	// server, or by one specific metric (e.g. a build_info or a
+	// machine_role metric). See also
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
 	ConstLabels Labels
 
 	// Buckets defines the buckets into which observations are counted. Each
@@ -155,6 +158,10 @@ type HistogramOpts struct {
 
 // NewHistogram creates a new Histogram based on the provided HistogramOpts. It
 // panics if the buckets in HistogramOpts are not in strictly increasing order.
+//
+// The returned implementation also implements ExemplarObserver. It is safe to
+// perform the corresponding type assertion. Exemplars are tracked separately
+// for each bucket.
 func NewHistogram(opts HistogramOpts) Histogram {
 	return newHistogram(
 		NewDesc(
@@ -169,7 +176,7 @@ func NewHistogram(opts HistogramOpts) Histogram {
 
 func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogram {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(errInconsistentCardinality)
+		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
 	}
 
 	for _, n := range desc.variableLabels {
@@ -190,7 +197,9 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 	h := &histogram{
 		desc:        desc,
 		upperBounds: opts.Buckets,
-		labelPairs:  makeLabelPairs(desc, labelValues),
+		labelPairs:  MakeLabelPairs(desc, labelValues),
+		counts:      [2]*histogramCounts{{}, {}},
+		now:         time.Now,
 	}
 	for i, upperBound := range h.upperBounds {
 		if i < len(h.upperBounds)-1 {
@@ -207,30 +216,60 @@ func newHistogram(desc *Desc, opts HistogramOpts, labelValues ...string) Histogr
 			}
 		}
 	}
-	// Finally we know the final length of h.upperBounds and can make counts.
-	h.counts = make([]uint64, len(h.upperBounds))
+	// Finally we know the final length of h.upperBounds and can make buckets
+	// for both counts as well as exemplars:
+	h.counts[0].buckets = make([]uint64, len(h.upperBounds))
+	h.counts[1].buckets = make([]uint64, len(h.upperBounds))
+	h.exemplars = make([]atomic.Value, len(h.upperBounds)+1)
 
-	h.Init(h) // Init self-collection.
+	h.init(h) // Init self-collection.
 	return h
 }
 
-type histogram struct {
+type histogramCounts struct {
 	// sumBits contains the bits of the float64 representing the sum of all
 	// observations. sumBits and count have to go first in the struct to
 	// guarantee alignment for atomic operations.
 	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
 	sumBits uint64
 	count   uint64
+	buckets []uint64
+}
 
-	SelfCollector
-	// Note that there is no mutex required.
+type histogram struct {
+	// countAndHotIdx enables lock-free writes with use of atomic updates.
+	// The most significant bit is the hot index [0 or 1] of the count field
+	// below. Observe calls update the hot one. All remaining bits count the
+	// number of Observe calls. Observe starts by incrementing this counter,
+	// and finish by incrementing the count field in the respective
+	// histogramCounts, as a marker for completion.
+	//
+	// Calls of the Write method (which are non-mutating reads from the
+	// perspective of the histogram) swap the hot–cold under the writeMtx
+	// lock. A cooldown is awaited (while locked) by comparing the number of
+	// observations with the initiation count. Once they match, then the
+	// last observation on the now cool one has completed. All cool fields must
+	// be merged into the new hot before releasing writeMtx.
+	//
+	// Fields with atomic access first! See alignment constraint:
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	countAndHotIdx uint64
 
-	desc *Desc
+	selfCollector
+	desc     *Desc
+	writeMtx sync.Mutex // Only used in the Write method.
+
+	// Two counts, one is "hot" for lock-free observations, the other is
+	// "cold" for writing out a dto.Metric. It has to be an array of
+	// pointers to guarantee 64bit alignment of the histogramCounts, see
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG.
+	counts [2]*histogramCounts
 
 	upperBounds []float64
-	counts      []uint64
+	labelPairs  []*dto.LabelPair
+	exemplars   []atomic.Value // One more than buckets (to include +Inf), each a *dto.Exemplar.
 
-	labelPairs []*dto.LabelPair
+	now func() time.Time // To mock out time.Now() for testing.
 }
 
 func (h *histogram) Desc() *Desc {
@@ -238,6 +277,89 @@ func (h *histogram) Desc() *Desc {
 }
 
 func (h *histogram) Observe(v float64) {
+	h.observe(v, h.findBucket(v))
+}
+
+func (h *histogram) ObserveWithExemplar(v float64, e Labels) {
+	i := h.findBucket(v)
+	h.observe(v, i)
+	h.updateExemplar(v, i, e)
+}
+
+func (h *histogram) Write(out *dto.Metric) error {
+	// For simplicity, we protect this whole method by a mutex. It is not in
+	// the hot path, i.e. Observe is called much more often than Write. The
+	// complication of making Write lock-free isn't worth it, if possible at
+	// all.
+	h.writeMtx.Lock()
+	defer h.writeMtx.Unlock()
+
+	// Adding 1<<63 switches the hot index (from 0 to 1 or from 1 to 0)
+	// without touching the count bits. See the struct comments for a full
+	// description of the algorithm.
+	n := atomic.AddUint64(&h.countAndHotIdx, 1<<63)
+	// count is contained unchanged in the lower 63 bits.
+	count := n & ((1 << 63) - 1)
+	// The most significant bit tells us which counts is hot. The complement
+	// is thus the cold one.
+	hotCounts := h.counts[n>>63]
+	coldCounts := h.counts[(^n)>>63]
+
+	// Await cooldown.
+	for count != atomic.LoadUint64(&coldCounts.count) {
+		runtime.Gosched() // Let observations get work done.
+	}
+
+	his := &dto.Histogram{
+		Bucket:      make([]*dto.Bucket, len(h.upperBounds)),
+		SampleCount: proto.Uint64(count),
+		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+	}
+	var cumCount uint64
+	for i, upperBound := range h.upperBounds {
+		cumCount += atomic.LoadUint64(&coldCounts.buckets[i])
+		his.Bucket[i] = &dto.Bucket{
+			CumulativeCount: proto.Uint64(cumCount),
+			UpperBound:      proto.Float64(upperBound),
+		}
+		if e := h.exemplars[i].Load(); e != nil {
+			his.Bucket[i].Exemplar = e.(*dto.Exemplar)
+		}
+	}
+	// If there is an exemplar for the +Inf bucket, we have to add that bucket explicitly.
+	if e := h.exemplars[len(h.upperBounds)].Load(); e != nil {
+		b := &dto.Bucket{
+			CumulativeCount: proto.Uint64(count),
+			UpperBound:      proto.Float64(math.Inf(1)),
+			Exemplar:        e.(*dto.Exemplar),
+		}
+		his.Bucket = append(his.Bucket, b)
+	}
+
+	out.Histogram = his
+	out.Label = h.labelPairs
+
+	// Finally add all the cold counts to the new hot counts and reset the cold counts.
+	atomic.AddUint64(&hotCounts.count, count)
+	atomic.StoreUint64(&coldCounts.count, 0)
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + his.GetSampleSum())
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			atomic.StoreUint64(&coldCounts.sumBits, 0)
+			break
+		}
+	}
+	for i := range h.upperBounds {
+		atomic.AddUint64(&hotCounts.buckets[i], atomic.LoadUint64(&coldCounts.buckets[i]))
+		atomic.StoreUint64(&coldCounts.buckets[i], 0)
+	}
+	return nil
+}
+
+// findBucket returns the index of the bucket for the provided value, or
+// len(h.upperBounds) for the +Inf bucket.
+func (h *histogram) findBucket(v float64) int {
 	// TODO(beorn7): For small numbers of buckets (<30), a linear search is
 	// slightly faster than the binary search. If we really care, we could
 	// switch from one search strategy to the other depending on the number
@@ -247,38 +369,43 @@ func (h *histogram) Observe(v float64) {
 	// 11 buckets: 38.3 ns/op linear - binary 48.7 ns/op
 	// 100 buckets: 78.1 ns/op linear - binary 54.9 ns/op
 	// 300 buckets: 154 ns/op linear - binary 61.6 ns/op
-	i := sort.SearchFloat64s(h.upperBounds, v)
-	if i < len(h.counts) {
-		atomic.AddUint64(&h.counts[i], 1)
+	return sort.SearchFloat64s(h.upperBounds, v)
+}
+
+// observe is the implementation for Observe without the findBucket part.
+func (h *histogram) observe(v float64, bucket int) {
+	// We increment h.countAndHotIdx so that the counter in the lower
+	// 63 bits gets incremented. At the same time, we get the new value
+	// back, which we can use to find the currently-hot counts.
+	n := atomic.AddUint64(&h.countAndHotIdx, 1)
+	hotCounts := h.counts[n>>63]
+
+	if bucket < len(h.upperBounds) {
+		atomic.AddUint64(&hotCounts.buckets[bucket], 1)
 	}
-	atomic.AddUint64(&h.count, 1)
 	for {
-		oldBits := atomic.LoadUint64(&h.sumBits)
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
 		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
-		if atomic.CompareAndSwapUint64(&h.sumBits, oldBits, newBits) {
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
 			break
 		}
 	}
+	// Increment count last as we take it as a signal that the observation
+	// is complete.
+	atomic.AddUint64(&hotCounts.count, 1)
 }
 
-func (h *histogram) Write(out *dto.Metric) error {
-	his := &dto.Histogram{}
-	buckets := make([]*dto.Bucket, len(h.upperBounds))
-
-	his.SampleSum = proto.Float64(math.Float64frombits(atomic.LoadUint64(&h.sumBits)))
-	his.SampleCount = proto.Uint64(atomic.LoadUint64(&h.count))
-	var count uint64
-	for i, upperBound := range h.upperBounds {
-		count += atomic.LoadUint64(&h.counts[i])
-		buckets[i] = &dto.Bucket{
-			CumulativeCount: proto.Uint64(count),
-			UpperBound:      proto.Float64(upperBound),
-		}
+// updateExemplar replaces the exemplar for the provided bucket. With empty
+// labels, it's a no-op. It panics if any of the labels is invalid.
+func (h *histogram) updateExemplar(v float64, bucket int, l Labels) {
+	if l == nil {
+		return
 	}
-	his.Bucket = buckets
-	out.Histogram = his
-	out.Label = h.labelPairs
-	return nil
+	e, err := newExemplar(v, h.now(), l)
+	if err != nil {
+		panic(err)
+	}
+	h.exemplars[bucket].Store(e)
 }
 
 // HistogramVec is a Collector that bundles a set of Histograms that all share the
@@ -287,12 +414,11 @@ func (h *histogram) Write(out *dto.Metric) error {
 // (e.g. HTTP request latencies, partitioned by status code and method). Create
 // instances with NewHistogramVec.
 type HistogramVec struct {
-	MetricVec
+	*MetricVec
 }
 
 // NewHistogramVec creates a new HistogramVec based on the provided HistogramOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
 func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
@@ -301,51 +427,116 @@ func NewHistogramVec(opts HistogramOpts, labelNames []string) *HistogramVec {
 		opts.ConstLabels,
 	)
 	return &HistogramVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
-				return newHistogram(desc, opts, lvs...)
-			},
-		},
+		MetricVec: NewMetricVec(desc, func(lvs ...string) Metric {
+			return newHistogram(desc, opts, lvs...)
+		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Histogram and not a
-// Metric so that no type conversion is required.
-func (m *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Histogram, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Histogram for the given slice of label
+// values (same order as the variable labels in Desc). If that combination of
+// label values is accessed for the first time, a new Histogram is created.
+//
+// It is possible to call this method without using the returned Histogram to only
+// create the new Histogram but leave it at its starting value, a Histogram without
+// any observations.
+//
+// Keeping the Histogram for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Histogram from the HistogramVec. In that case, the
+// Histogram will still exist, but it will not be exported anymore, even if a
+// Histogram with the same label values is created later. See also the CounterVec
+// example.
+//
+// An error is returned if the number of label values is not the same as the
+// number of variable labels in Desc (minus any curried labels).
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the GaugeVec example.
+func (v *HistogramVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
+	metric, err := v.MetricVec.GetMetricWithLabelValues(lvs...)
 	if metric != nil {
-		return metric.(Histogram), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Histogram and not a Metric so that no
-// type conversion is required.
-func (m *HistogramVec) GetMetricWith(labels Labels) (Histogram, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Histogram for the given Labels map (the label names
+// must match those of the variable labels in Desc). If that label map is
+// accessed for the first time, a new Histogram is created. Implications of
+// creating a Histogram without using it and keeping the Histogram for later use
+// are the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the variable labels in Desc (minus any curried labels).
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (v *HistogramVec) GetMetricWith(labels Labels) (Observer, error) {
+	metric, err := v.MetricVec.GetMetricWith(labels)
 	if metric != nil {
-		return metric.(Histogram), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Observe(42.21)
-func (m *HistogramVec) WithLabelValues(lvs ...string) Histogram {
-	return m.MetricVec.WithLabelValues(lvs...).(Histogram)
+func (v *HistogramVec) WithLabelValues(lvs ...string) Observer {
+	h, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return h
 }
 
-// With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Observe(42.21)
-func (m *HistogramVec) With(labels Labels) Histogram {
-	return m.MetricVec.With(labels).(Histogram)
+// With works as GetMetricWith but panics where GetMetricWithLabels would have
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)
+func (v *HistogramVec) With(labels Labels) Observer {
+	h, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return h
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the HistogramVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *HistogramVec) CurryWith(labels Labels) (ObserverVec, error) {
+	vec, err := v.MetricVec.CurryWith(labels)
+	if vec != nil {
+		return &HistogramVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *HistogramVec) MustCurryWith(labels Labels) ObserverVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 type constHistogram struct {
@@ -397,7 +588,7 @@ func (h *constHistogram) Write(out *dto.Metric) error {
 // bucket.
 //
 // NewConstHistogram returns an error if the length of labelValues is not
-// consistent with the variable labels in Desc.
+// consistent with the variable labels in Desc or if Desc is invalid.
 func NewConstHistogram(
 	desc *Desc,
 	count uint64,
@@ -405,20 +596,23 @@ func NewConstHistogram(
 	buckets map[float64]uint64,
 	labelValues ...string,
 ) (Metric, error) {
-	if len(desc.variableLabels) != len(labelValues) {
-		return nil, errInconsistentCardinality
+	if desc.err != nil {
+		return nil, desc.err
+	}
+	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
+		return nil, err
 	}
 	return &constHistogram{
 		desc:       desc,
 		count:      count,
 		sum:        sum,
 		buckets:    buckets,
-		labelPairs: makeLabelPairs(desc, labelValues),
+		labelPairs: MakeLabelPairs(desc, labelValues),
 	}, nil
 }
 
 // MustNewConstHistogram is a version of NewConstHistogram that panics where
-// NewConstMetric would have returned an error.
+// NewConstHistogram would have returned an error.
 func MustNewConstHistogram(
 	desc *Desc,
 	count uint64,

vendor/github.com/prometheus/client_golang/prometheus/http.go

@@ -1,381 +0,0 @@
-// Copyright 2014 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package prometheus
-
-import (
-	"bufio"
-	"io"
-	"net"
-	"net/http"
-	"strconv"
-	"strings"
-	"time"
-)
-
-var instLabels = []string{"method", "code"}
-
-type nower interface {
-	Now() time.Time
-}
-
-type nowFunc func() time.Time
-
-func (n nowFunc) Now() time.Time {
-	return n()
-}
-
-var now nower = nowFunc(func() time.Time {
-	return time.Now()
-})
-
-func nowSeries(t ...time.Time) nower {
-	return nowFunc(func() time.Time {
-		defer func() {
-			t = t[1:]
-		}()
-
-		return t[0]
-	})
-}
-
-// InstrumentHandler wraps the given HTTP handler for instrumentation. It
-// registers four metric collectors (if not already done) and reports HTTP
-// metrics to the (newly or already) registered collectors: http_requests_total
-// (CounterVec), http_request_duration_microseconds (Summary),
-// http_request_size_bytes (Summary), http_response_size_bytes (Summary). Each
-// has a constant label named "handler" with the provided handlerName as
-// value. http_requests_total is a metric vector partitioned by HTTP method
-// (label name "method") and HTTP status code (label name "code").
-//
-// Note that InstrumentHandler has several issues:
-//
-// - It uses Summaries rather than Histograms. Summaries are not useful if
-// aggregation across multiple instances is required.
-//
-// - It uses microseconds as unit, which is deprecated and should be replaced by
-// seconds.
-//
-// - The size of the request is calculated in a separate goroutine. Since this
-// calculator requires access to the request header, it creates a race with
-// any writes to the header performed during request handling.
-// httputil.ReverseProxy is a prominent example for a handler
-// performing such writes.
-//
-// Upcoming versions of this package will provide ways of instrumenting HTTP
-// handlers that are more flexible and have fewer issues. Consider this function
-// DEPRECATED and prefer direct instrumentation in the meantime.
-func InstrumentHandler(handlerName string, handler http.Handler) http.HandlerFunc {
-	return InstrumentHandlerFunc(handlerName, handler.ServeHTTP)
-}
-
-// InstrumentHandlerFunc wraps the given function for instrumentation. It
-// otherwise works in the same way as InstrumentHandler (and shares the same
-// issues).
-func InstrumentHandlerFunc(handlerName string, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
-	return InstrumentHandlerFuncWithOpts(
-		SummaryOpts{
-			Subsystem:   "http",
-			ConstLabels: Labels{"handler": handlerName},
-		},
-		handlerFunc,
-	)
-}
-
-// InstrumentHandlerWithOpts works like InstrumentHandler (and shares the same
-// issues) but provides more flexibility (at the cost of a more complex call
-// syntax). As InstrumentHandler, this function registers four metric
-// collectors, but it uses the provided SummaryOpts to create them. However, the
-// fields "Name" and "Help" in the SummaryOpts are ignored. "Name" is replaced
-// by "requests_total", "request_duration_microseconds", "request_size_bytes",
-// and "response_size_bytes", respectively. "Help" is replaced by an appropriate
-// help string. The names of the variable labels of the http_requests_total
-// CounterVec are "method" (get, post, etc.), and "code" (HTTP status code).
-//
-// If InstrumentHandlerWithOpts is called as follows, it mimics exactly the
-// behavior of InstrumentHandler:
-//
-//     prometheus.InstrumentHandlerWithOpts(
-//         prometheus.SummaryOpts{
-//              Subsystem:   "http",
-//              ConstLabels: prometheus.Labels{"handler": handlerName},
-//         },
-//         handler,
-//     )
-//
-// Technical detail: "requests_total" is a CounterVec, not a SummaryVec, so it
-// cannot use SummaryOpts. Instead, a CounterOpts struct is created internally,
-// and all its fields are set to the equally named fields in the provided
-// SummaryOpts.
-func InstrumentHandlerWithOpts(opts SummaryOpts, handler http.Handler) http.HandlerFunc {
-	return InstrumentHandlerFuncWithOpts(opts, handler.ServeHTTP)
-}
-
-// InstrumentHandlerFuncWithOpts works like InstrumentHandlerFunc (and shares
-// the same issues) but provides more flexibility (at the cost of a more complex
-// call syntax). See InstrumentHandlerWithOpts for details how the provided
-// SummaryOpts are used.
-func InstrumentHandlerFuncWithOpts(opts SummaryOpts, handlerFunc func(http.ResponseWriter, *http.Request)) http.HandlerFunc {
-	reqCnt := NewCounterVec(
-		CounterOpts{
-			Namespace:   opts.Namespace,
-			Subsystem:   opts.Subsystem,
-			Name:        "requests_total",
-			Help:        "Total number of HTTP requests made.",
-			ConstLabels: opts.ConstLabels,
-		},
-		instLabels,
-	)
-
-	opts.Name = "request_duration_microseconds"
-	opts.Help = "The HTTP request latencies in microseconds."
-	reqDur := NewSummary(opts)
-
-	opts.Name = "request_size_bytes"
-	opts.Help = "The HTTP request sizes in bytes."
-	reqSz := NewSummary(opts)
-
-	opts.Name = "response_size_bytes"
-	opts.Help = "The HTTP response sizes in bytes."
-	resSz := NewSummary(opts)
-
-	regReqCnt := MustRegisterOrGet(reqCnt).(*CounterVec)
-	regReqDur := MustRegisterOrGet(reqDur).(Summary)
-	regReqSz := MustRegisterOrGet(reqSz).(Summary)
-	regResSz := MustRegisterOrGet(resSz).(Summary)
-
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		now := time.Now()
-
-		delegate := &responseWriterDelegator{ResponseWriter: w}
-		out := make(chan int)
-		urlLen := 0
-		if r.URL != nil {
-			urlLen = len(r.URL.String())
-		}
-		go computeApproximateRequestSize(r, out, urlLen)
-
-		_, cn := w.(http.CloseNotifier)
-		_, fl := w.(http.Flusher)
-		_, hj := w.(http.Hijacker)
-		_, rf := w.(io.ReaderFrom)
-		var rw http.ResponseWriter
-		if cn && fl && hj && rf {
-			rw = &fancyResponseWriterDelegator{delegate}
-		} else {
-			rw = delegate
-		}
-		handlerFunc(rw, r)
-
-		elapsed := float64(time.Since(now)) / float64(time.Microsecond)
-
-		method := sanitizeMethod(r.Method)
-		code := sanitizeCode(delegate.status)
-		regReqCnt.WithLabelValues(method, code).Inc()
-		regReqDur.Observe(elapsed)
-		regResSz.Observe(float64(delegate.written))
-		regReqSz.Observe(float64(<-out))
-	})
-}
-
-func computeApproximateRequestSize(r *http.Request, out chan int, s int) {
-	s += len(r.Method)
-	s += len(r.Proto)
-	for name, values := range r.Header {
-		s += len(name)
-		for _, value := range values {
-			s += len(value)
-		}
-	}
-	s += len(r.Host)
-
-	// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
-
-	if r.ContentLength != -1 {
-		s += int(r.ContentLength)
-	}
-	out <- s
-}
-
-type responseWriterDelegator struct {
-	http.ResponseWriter
-
-	handler, method string
-	status          int
-	written         int64
-	wroteHeader     bool
-}
-
-func (r *responseWriterDelegator) WriteHeader(code int) {
-	r.status = code
-	r.wroteHeader = true
-	r.ResponseWriter.WriteHeader(code)
-}
-
-func (r *responseWriterDelegator) Write(b []byte) (int, error) {
-	if !r.wroteHeader {
-		r.WriteHeader(http.StatusOK)
-	}
-	n, err := r.ResponseWriter.Write(b)
-	r.written += int64(n)
-	return n, err
-}
-
-type fancyResponseWriterDelegator struct {
-	*responseWriterDelegator
-}
-
-func (f *fancyResponseWriterDelegator) CloseNotify() <-chan bool {
-	return f.ResponseWriter.(http.CloseNotifier).CloseNotify()
-}
-
-func (f *fancyResponseWriterDelegator) Flush() {
-	f.ResponseWriter.(http.Flusher).Flush()
-}
-
-func (f *fancyResponseWriterDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-	return f.ResponseWriter.(http.Hijacker).Hijack()
-}
-
-func (f *fancyResponseWriterDelegator) ReadFrom(r io.Reader) (int64, error) {
-	if !f.wroteHeader {
-		f.WriteHeader(http.StatusOK)
-	}
-	n, err := f.ResponseWriter.(io.ReaderFrom).ReadFrom(r)
-	f.written += n
-	return n, err
-}
-
-func sanitizeMethod(m string) string {
-	switch m {
-	case "GET", "get":
-		return "get"
-	case "PUT", "put":
-		return "put"
-	case "HEAD", "head":
-		return "head"
-	case "POST", "post":
-		return "post"
-	case "DELETE", "delete":
-		return "delete"
-	case "CONNECT", "connect":
-		return "connect"
-	case "OPTIONS", "options":
-		return "options"
-	case "NOTIFY", "notify":
-		return "notify"
-	default:
-		return strings.ToLower(m)
-	}
-}
-
-func sanitizeCode(s int) string {
-	switch s {
-	case 100:
-		return "100"
-	case 101:
-		return "101"
-
-	case 200:
-		return "200"
-	case 201:
-		return "201"
-	case 202:
-		return "202"
-	case 203:
-		return "203"
-	case 204:
-		return "204"
-	case 205:
-		return "205"
-	case 206:
-		return "206"
-
-	case 300:
-		return "300"
-	case 301:
-		return "301"
-	case 302:
-		return "302"
-	case 304:
-		return "304"
-	case 305:
-		return "305"
-	case 307:
-		return "307"
-
-	case 400:
-		return "400"
-	case 401:
-		return "401"
-	case 402:
-		return "402"
-	case 403:
-		return "403"
-	case 404:
-		return "404"
-	case 405:
-		return "405"
-	case 406:
-		return "406"
-	case 407:
-		return "407"
-	case 408:
-		return "408"
-	case 409:
-		return "409"
-	case 410:
-		return "410"
-	case 411:
-		return "411"
-	case 412:
-		return "412"
-	case 413:
-		return "413"
-	case 414:
-		return "414"
-	case 415:
-		return "415"
-	case 416:
-		return "416"
-	case 417:
-		return "417"
-	case 418:
-		return "418"
-
-	case 500:
-		return "500"
-	case 501:
-		return "501"
-	case 502:
-		return "502"
-	case 503:
-		return "503"
-	case 504:
-		return "504"
-	case 505:
-		return "505"
-
-	case 428:
-		return "428"
-	case 429:
-		return "429"
-	case 431:
-		return "431"
-	case 511:
-		return "511"
-
-	default:
-		return strconv.Itoa(s)
-	}
-}

vendor/github.com/prometheus/client_golang/prometheus/internal/metric.go

@@ -0,0 +1,85 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal
+
+import (
+	"sort"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// metricSorter is a sortable slice of *dto.Metric.
+type metricSorter []*dto.Metric
+
+func (s metricSorter) Len() int {
+	return len(s)
+}
+
+func (s metricSorter) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+func (s metricSorter) Less(i, j int) bool {
+	if len(s[i].Label) != len(s[j].Label) {
+		// This should not happen. The metrics are
+		// inconsistent. However, we have to deal with the fact, as
+		// people might use custom collectors or metric family injection
+		// to create inconsistent metrics. So let's simply compare the
+		// number of labels in this case. That will still yield
+		// reproducible sorting.
+		return len(s[i].Label) < len(s[j].Label)
+	}
+	for n, lp := range s[i].Label {
+		vi := lp.GetValue()
+		vj := s[j].Label[n].GetValue()
+		if vi != vj {
+			return vi < vj
+		}
+	}
+
+	// We should never arrive here. Multiple metrics with the same
+	// label set in the same scrape will lead to undefined ingestion
+	// behavior. However, as above, we have to provide stable sorting
+	// here, even for inconsistent metrics. So sort equal metrics
+	// by their timestamp, with missing timestamps (implying "now")
+	// coming last.
+	if s[i].TimestampMs == nil {
+		return false
+	}
+	if s[j].TimestampMs == nil {
+		return true
+	}
+	return s[i].GetTimestampMs() < s[j].GetTimestampMs()
+}
+
+// NormalizeMetricFamilies returns a MetricFamily slice with empty
+// MetricFamilies pruned and the remaining MetricFamilies sorted by name within
+// the slice, with the contained Metrics sorted within each MetricFamily.
+func NormalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {
+	for _, mf := range metricFamiliesByName {
+		sort.Sort(metricSorter(mf.Metric))
+	}
+	names := make([]string, 0, len(metricFamiliesByName))
+	for name, mf := range metricFamiliesByName {
+		if len(mf.Metric) > 0 {
+			names = append(names, name)
+		}
+	}
+	sort.Strings(names)
+	result := make([]*dto.MetricFamily, 0, len(names))
+	for _, name := range names {
+		result = append(result, metricFamiliesByName[name])
+	}
+	return result
+}

vendor/github.com/prometheus/client_golang/prometheus/labels.go

@@ -0,0 +1,87 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"github.com/prometheus/common/model"
+)
+
+// Labels represents a collection of label name -> value mappings. This type is
+// commonly used with the With(Labels) and GetMetricWith(Labels) methods of
+// metric vector Collectors, e.g.:
+//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
+//
+// The other use-case is the specification of constant label pairs in Opts or to
+// create a Desc.
+type Labels map[string]string
+
+// reservedLabelPrefix is a prefix which is not legal in user-supplied
+// label names.
+const reservedLabelPrefix = "__"
+
+var errInconsistentCardinality = errors.New("inconsistent label cardinality")
+
+func makeInconsistentCardinalityError(fqName string, labels, labelValues []string) error {
+	return fmt.Errorf(
+		"%s: %q has %d variable labels named %q but %d values %q were provided",
+		errInconsistentCardinality, fqName,
+		len(labels), labels,
+		len(labelValues), labelValues,
+	)
+}
+
+func validateValuesInLabels(labels Labels, expectedNumberOfValues int) error {
+	if len(labels) != expectedNumberOfValues {
+		return fmt.Errorf(
+			"%s: expected %d label values but got %d in %#v",
+			errInconsistentCardinality, expectedNumberOfValues,
+			len(labels), labels,
+		)
+	}
+
+	for name, val := range labels {
+		if !utf8.ValidString(val) {
+			return fmt.Errorf("label %s: value %q is not valid UTF-8", name, val)
+		}
+	}
+
+	return nil
+}
+
+func validateLabelValues(vals []string, expectedNumberOfValues int) error {
+	if len(vals) != expectedNumberOfValues {
+		return fmt.Errorf(
+			"%s: expected %d label values but got %d in %#v",
+			errInconsistentCardinality, expectedNumberOfValues,
+			len(vals), vals,
+		)
+	}
+
+	for _, val := range vals {
+		if !utf8.ValidString(val) {
+			return fmt.Errorf("label value %q is not valid UTF-8", val)
+		}
+	}
+
+	return nil
+}
+
+func checkLabelName(l string) bool {
+	return model.LabelName(l).IsValid() && !strings.HasPrefix(l, reservedLabelPrefix)
+}

vendor/github.com/prometheus/client_golang/prometheus/metric.go

@@ -15,17 +15,20 @@ package prometheus
 
 import (
 	"strings"
+	"time"
+
+	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
+	"github.com/golang/protobuf/proto"
+	"github.com/prometheus/common/model"
 
 	dto "github.com/prometheus/client_model/go"
 )
 
-const separatorByte byte = 255
+var separatorByteSlice = []byte{model.SeparatorByte} // For convenient use with xxhash.
 
 // A Metric models a single sample value with its meta data being exported to
-// Prometheus. Implementers of Metric in this package inclued Gauge, Counter,
-// Untyped, and Summary. Users can implement their own Metric types, but that
-// should be rarely needed. See the example for SelfCollector, which is also an
-// example for a user-implemented Metric.
+// Prometheus. Implementations of Metric in this package are Gauge, Counter,
+// Histogram, Summary, and Untyped.
 type Metric interface {
 	// Desc returns the descriptor for the Metric. This method idempotently
 	// returns the same descriptor throughout the lifetime of the
@@ -36,29 +39,31 @@ type Metric interface {
 	// Write encodes the Metric into a "Metric" Protocol Buffer data
 	// transmission object.
 	//
-	// Implementers of custom Metric types must observe concurrency safety
-	// as reads of this metric may occur at any time, and any blocking
-	// occurs at the expense of total performance of rendering all
-	// registered metrics. Ideally Metric implementations should support
-	// concurrent readers.
+	// Metric implementations must observe concurrency safety as reads of
+	// this metric may occur at any time, and any blocking occurs at the
+	// expense of total performance of rendering all registered
+	// metrics. Ideally, Metric implementations should support concurrent
+	// readers.
 	//
-	// The Prometheus client library attempts to minimize memory allocations
-	// and will provide a pre-existing reset dto.Metric pointer. Prometheus
-	// may recycle the dto.Metric proto message, so Metric implementations
-	// should just populate the provided dto.Metric and then should not keep
-	// any reference to it.
-	//
-	// While populating dto.Metric, labels must be sorted lexicographically.
-	// (Implementers may find LabelPairSorter useful for that.)
+	// While populating dto.Metric, it is the responsibility of the
+	// implementation to ensure validity of the Metric protobuf (like valid
+	// UTF-8 strings or syntactically valid metric and label names). It is
+	// recommended to sort labels lexicographically. Callers of Write should
+	// still make sure of sorting if they depend on it.
 	Write(*dto.Metric) error
+	// TODO(beorn7): The original rationale of passing in a pre-allocated
+	// dto.Metric protobuf to save allocations has disappeared. The
+	// signature of this method should be changed to "Write() (*dto.Metric,
+	// error)".
 }
 
 // Opts bundles the options for creating most Metric types. Each metric
-// implementation XXX has its own XXXOpts type, but in most cases, it is just be
+// implementation XXX has its own XXXOpts type, but in most cases, it is just
 // an alias of this type (which might change when the requirement arises.)
 //
-// It is mandatory to set Name and Help to a non-empty string. All other fields
-// are optional and can safely be left at their zero value.
+// It is mandatory to set Name to a non-empty string. All other fields are
+// optional and can safely be left at their zero value, although it is strongly
+// encouraged to set a Help string.
 type Opts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Metric (created by joining these components with
@@ -69,7 +74,7 @@ type Opts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this metric. Mandatory!
+	// Help provides information about this metric.
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
@@ -79,20 +84,12 @@ type Opts struct {
 	// with the same fully-qualified name must have the same label names in
 	// their ConstLabels.
 	//
-	// Note that in most cases, labels have a value that varies during the
-	// lifetime of a process. Those labels are usually managed with a metric
-	// vector collector (like CounterVec, GaugeVec, UntypedVec). ConstLabels
-	// serve only special purposes. One is for the special case where the
-	// value of a label does not change during the lifetime of a process,
-	// e.g. if the revision of the running binary is put into a
-	// label. Another, more advanced purpose is if more than one Collector
-	// needs to collect Metrics with the same fully-qualified name. In that
-	// case, those Metrics must differ in the values of their
-	// ConstLabels. See the Collector examples.
-	//
-	// If the value of a label never changes (not even between binaries),
-	// that label most likely should not be a label at all (but part of the
-	// metric name).
+	// ConstLabels are only used rarely. In particular, do not use them to
+	// attach the same labels to all your metrics. Those use cases are
+	// better covered by target labels set by the scraping Prometheus
+	// server, or by one specific metric (e.g. a build_info or a
+	// machine_role metric). See also
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
 	ConstLabels Labels
 }
 
@@ -118,37 +115,22 @@ func BuildFQName(namespace, subsystem, name string) string {
 	return name
 }
 
-// LabelPairSorter implements sort.Interface. It is used to sort a slice of
-// dto.LabelPair pointers. This is useful for implementing the Write method of
-// custom metrics.
-type LabelPairSorter []*dto.LabelPair
+// labelPairSorter implements sort.Interface. It is used to sort a slice of
+// dto.LabelPair pointers.
+type labelPairSorter []*dto.LabelPair
 
-func (s LabelPairSorter) Len() int {
+func (s labelPairSorter) Len() int {
 	return len(s)
 }
 
-func (s LabelPairSorter) Swap(i, j int) {
+func (s labelPairSorter) Swap(i, j int) {
 	s[i], s[j] = s[j], s[i]
 }
 
-func (s LabelPairSorter) Less(i, j int) bool {
+func (s labelPairSorter) Less(i, j int) bool {
 	return s[i].GetName() < s[j].GetName()
 }
 
-type hashSorter []uint64
-
-func (s hashSorter) Len() int {
-	return len(s)
-}
-
-func (s hashSorter) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
-func (s hashSorter) Less(i, j int) bool {
-	return s[i] < s[j]
-}
-
 type invalidMetric struct {
 	desc *Desc
 	err  error
@@ -164,3 +146,31 @@ func NewInvalidMetric(desc *Desc, err error) Metric {
 func (m *invalidMetric) Desc() *Desc { return m.desc }
 
 func (m *invalidMetric) Write(*dto.Metric) error { return m.err }
+
+type timestampedMetric struct {
+	Metric
+	t time.Time
+}
+
+func (m timestampedMetric) Write(pb *dto.Metric) error {
+	e := m.Metric.Write(pb)
+	pb.TimestampMs = proto.Int64(m.t.Unix()*1000 + int64(m.t.Nanosecond()/1000000))
+	return e
+}
+
+// NewMetricWithTimestamp returns a new Metric wrapping the provided Metric in a
+// way that it has an explicit timestamp set to the provided Time. This is only
+// useful in rare cases as the timestamp of a Prometheus metric should usually
+// be set by the Prometheus server during scraping. Exceptions include mirroring
+// metrics with given timestamps from other metric
+// sources.
+//
+// NewMetricWithTimestamp works best with MustNewConstMetric,
+// MustNewConstHistogram, and MustNewConstSummary, see example.
+//
+// Currently, the exposition formats used by Prometheus are limited to
+// millisecond resolution. Thus, the provided time will be rounded down to the
+// next full millisecond value.
+func NewMetricWithTimestamp(t time.Time, m Metric) Metric {
+	return timestampedMetric{Metric: m, t: t}
+}

vendor/github.com/prometheus/client_golang/prometheus/observer.go

@@ -0,0 +1,64 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+// Observer is the interface that wraps the Observe method, which is used by
+// Histogram and Summary to add observations.
+type Observer interface {
+	Observe(float64)
+}
+
+// The ObserverFunc type is an adapter to allow the use of ordinary
+// functions as Observers. If f is a function with the appropriate
+// signature, ObserverFunc(f) is an Observer that calls f.
+//
+// This adapter is usually used in connection with the Timer type, and there are
+// two general use cases:
+//
+// The most common one is to use a Gauge as the Observer for a Timer.
+// See the "Gauge" Timer example.
+//
+// The more advanced use case is to create a function that dynamically decides
+// which Observer to use for observing the duration. See the "Complex" Timer
+// example.
+type ObserverFunc func(float64)
+
+// Observe calls f(value). It implements Observer.
+func (f ObserverFunc) Observe(value float64) {
+	f(value)
+}
+
+// ObserverVec is an interface implemented by `HistogramVec` and `SummaryVec`.
+type ObserverVec interface {
+	GetMetricWith(Labels) (Observer, error)
+	GetMetricWithLabelValues(lvs ...string) (Observer, error)
+	With(Labels) Observer
+	WithLabelValues(...string) Observer
+	CurryWith(Labels) (ObserverVec, error)
+	MustCurryWith(Labels) ObserverVec
+
+	Collector
+}
+
+// ExemplarObserver is implemented by Observers that offer the option of
+// observing a value together with an exemplar. Its ObserveWithExemplar method
+// works like the Observe method of an Observer but also replaces the currently
+// saved exemplar (if any) with a new one, created from the provided value, the
+// current time as timestamp, and the provided Labels. Empty Labels will lead to
+// a valid (label-less) exemplar. But if Labels is nil, the current exemplar is
+// left in place. ObserveWithExemplar panics if any of the provided labels are
+// invalid or if the provided labels contain more than 64 runes in total.
+type ExemplarObserver interface {
+	ObserveWithExemplar(value float64, exemplar Labels)
+}

vendor/github.com/prometheus/client_golang/prometheus/process_collector.go

@@ -13,89 +13,124 @@
 
 package prometheus
 
-import "github.com/prometheus/procfs"
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strconv"
+	"strings"
+)
 
 type processCollector struct {
-	pid             int
 	collectFn       func(chan<- Metric)
 	pidFn           func() (int, error)
-	cpuTotal        Counter
-	openFDs, maxFDs Gauge
-	vsize, rss      Gauge
-	startTime       Gauge
+	reportErrors    bool
+	cpuTotal        *Desc
+	openFDs, maxFDs *Desc
+	vsize, maxVsize *Desc
+	rss             *Desc
+	startTime       *Desc
 }
 
-// NewProcessCollector returns a collector which exports the current state of
-// process metrics including cpu, memory and file descriptor usage as well as
-// the process start time for the given process id under the given namespace.
-func NewProcessCollector(pid int, namespace string) *processCollector {
-	return NewProcessCollectorPIDFn(
-		func() (int, error) { return pid, nil },
-		namespace,
-	)
+// ProcessCollectorOpts defines the behavior of a process metrics collector
+// created with NewProcessCollector.
+type ProcessCollectorOpts struct {
+	// PidFn returns the PID of the process the collector collects metrics
+	// for. It is called upon each collection. By default, the PID of the
+	// current process is used, as determined on construction time by
+	// calling os.Getpid().
+	PidFn func() (int, error)
+	// If non-empty, each of the collected metrics is prefixed by the
+	// provided string and an underscore ("_").
+	Namespace string
+	// If true, any error encountered during collection is reported as an
+	// invalid metric (see NewInvalidMetric). Otherwise, errors are ignored
+	// and the collected metrics will be incomplete. (Possibly, no metrics
+	// will be collected at all.) While that's usually not desired, it is
+	// appropriate for the common "mix-in" of process metrics, where process
+	// metrics are nice to have, but failing to collect them should not
+	// disrupt the collection of the remaining metrics.
+	ReportErrors bool
 }
 
-// NewProcessCollectorPIDFn returns a collector which exports the current state
-// of process metrics including cpu, memory and file descriptor usage as well
-// as the process start time under the given namespace. The given pidFn is
-// called on each collect and is used to determine the process to export
-// metrics for.
-func NewProcessCollectorPIDFn(
-	pidFn func() (int, error),
-	namespace string,
-) *processCollector {
-	c := processCollector{
-		pidFn:     pidFn,
-		collectFn: func(chan<- Metric) {},
+// NewProcessCollector is the obsolete version of collectors.NewProcessCollector.
+// See there for documentation.
+//
+// Deprecated: Use collectors.NewProcessCollector instead.
+func NewProcessCollector(opts ProcessCollectorOpts) Collector {
+	ns := ""
+	if len(opts.Namespace) > 0 {
+		ns = opts.Namespace + "_"
+	}
 
-		cpuTotal: NewCounter(CounterOpts{
-			Namespace: namespace,
-			Name:      "process_cpu_seconds_total",
-			Help:      "Total user and system CPU time spent in seconds.",
-		}),
-		openFDs: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_open_fds",
-			Help:      "Number of open file descriptors.",
-		}),
-		maxFDs: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_max_fds",
-			Help:      "Maximum number of open file descriptors.",
-		}),
-		vsize: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_virtual_memory_bytes",
-			Help:      "Virtual memory size in bytes.",
-		}),
-		rss: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_resident_memory_bytes",
-			Help:      "Resident memory size in bytes.",
-		}),
-		startTime: NewGauge(GaugeOpts{
-			Namespace: namespace,
-			Name:      "process_start_time_seconds",
-			Help:      "Start time of the process since unix epoch in seconds.",
-		}),
+	c := &processCollector{
+		reportErrors: opts.ReportErrors,
+		cpuTotal: NewDesc(
+			ns+"process_cpu_seconds_total",
+			"Total user and system CPU time spent in seconds.",
+			nil, nil,
+		),
+		openFDs: NewDesc(
+			ns+"process_open_fds",
+			"Number of open file descriptors.",
+			nil, nil,
+		),
+		maxFDs: NewDesc(
+			ns+"process_max_fds",
+			"Maximum number of open file descriptors.",
+			nil, nil,
+		),
+		vsize: NewDesc(
+			ns+"process_virtual_memory_bytes",
+			"Virtual memory size in bytes.",
+			nil, nil,
+		),
+		maxVsize: NewDesc(
+			ns+"process_virtual_memory_max_bytes",
+			"Maximum amount of virtual memory available in bytes.",
+			nil, nil,
+		),
+		rss: NewDesc(
+			ns+"process_resident_memory_bytes",
+			"Resident memory size in bytes.",
+			nil, nil,
+		),
+		startTime: NewDesc(
+			ns+"process_start_time_seconds",
+			"Start time of the process since unix epoch in seconds.",
+			nil, nil,
+		),
+	}
+
+	if opts.PidFn == nil {
+		pid := os.Getpid()
+		c.pidFn = func() (int, error) { return pid, nil }
+	} else {
+		c.pidFn = opts.PidFn
 	}
 
 	// Set up process metric collection if supported by the runtime.
-	if _, err := procfs.NewStat(); err == nil {
+	if canCollectProcess() {
 		c.collectFn = c.processCollect
+	} else {
+		c.collectFn = func(ch chan<- Metric) {
+			c.reportError(ch, nil, errors.New("process metrics not supported on this platform"))
+		}
 	}
 
-	return &c
+	return c
 }
 
 // Describe returns all descriptions of the collector.
 func (c *processCollector) Describe(ch chan<- *Desc) {
-	ch <- c.cpuTotal.Desc()
-	ch <- c.openFDs.Desc()
-	ch <- c.maxFDs.Desc()
-	ch <- c.vsize.Desc()
-	ch <- c.rss.Desc()
-	ch <- c.startTime.Desc()
+	ch <- c.cpuTotal
+	ch <- c.openFDs
+	ch <- c.maxFDs
+	ch <- c.vsize
+	ch <- c.maxVsize
+	ch <- c.rss
+	ch <- c.startTime
 }
 
 // Collect returns the current state of all metrics of the collector.
@@ -103,40 +138,29 @@ func (c *processCollector) Collect(ch chan<- Metric) {
 	c.collectFn(ch)
 }
 
-// TODO(ts): Bring back error reporting by reverting 7faf9e7 as soon as the
-// client allows users to configure the error behavior.
-func (c *processCollector) processCollect(ch chan<- Metric) {
-	pid, err := c.pidFn()
-	if err != nil {
+func (c *processCollector) reportError(ch chan<- Metric, desc *Desc, err error) {
+	if !c.reportErrors {
 		return
 	}
-
-	p, err := procfs.NewProc(pid)
-	if err != nil {
-		return
+	if desc == nil {
+		desc = NewInvalidDesc(err)
 	}
+	ch <- NewInvalidMetric(desc, err)
+}
 
-	if stat, err := p.NewStat(); err == nil {
-		c.cpuTotal.Set(stat.CPUTime())
-		ch <- c.cpuTotal
-		c.vsize.Set(float64(stat.VirtualMemory()))
-		ch <- c.vsize
-		c.rss.Set(float64(stat.ResidentMemory()))
-		ch <- c.rss
-
-		if startTime, err := stat.StartTime(); err == nil {
-			c.startTime.Set(startTime)
-			ch <- c.startTime
+// NewPidFileFn returns a function that retrieves a pid from the specified file.
+// It is meant to be used for the PidFn field in ProcessCollectorOpts.
+func NewPidFileFn(pidFilePath string) func() (int, error) {
+	return func() (int, error) {
+		content, err := ioutil.ReadFile(pidFilePath)
+		if err != nil {
+			return 0, fmt.Errorf("can't read pid file %q: %+v", pidFilePath, err)
+		}
+		pid, err := strconv.Atoi(strings.TrimSpace(string(content)))
+		if err != nil {
+			return 0, fmt.Errorf("can't parse pid file %q: %+v", pidFilePath, err)
 		}
-	}
 
-	if fds, err := p.FileDescriptorsLen(); err == nil {
-		c.openFDs.Set(float64(fds))
-		ch <- c.openFDs
-	}
-
-	if limits, err := p.NewLimits(); err == nil {
-		c.maxFDs.Set(float64(limits.OpenFiles))
-		ch <- c.maxFDs
+		return pid, nil
 	}
 }

vendor/github.com/prometheus/client_golang/prometheus/process_collector_other.go

@@ -0,0 +1,65 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !windows
+
+package prometheus
+
+import (
+	"github.com/prometheus/procfs"
+)
+
+func canCollectProcess() bool {
+	_, err := procfs.NewDefaultFS()
+	return err == nil
+}
+
+func (c *processCollector) processCollect(ch chan<- Metric) {
+	pid, err := c.pidFn()
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+
+	p, err := procfs.NewProc(pid)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+
+	if stat, err := p.Stat(); err == nil {
+		ch <- MustNewConstMetric(c.cpuTotal, CounterValue, stat.CPUTime())
+		ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(stat.VirtualMemory()))
+		ch <- MustNewConstMetric(c.rss, GaugeValue, float64(stat.ResidentMemory()))
+		if startTime, err := stat.StartTime(); err == nil {
+			ch <- MustNewConstMetric(c.startTime, GaugeValue, startTime)
+		} else {
+			c.reportError(ch, c.startTime, err)
+		}
+	} else {
+		c.reportError(ch, nil, err)
+	}
+
+	if fds, err := p.FileDescriptorsLen(); err == nil {
+		ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(fds))
+	} else {
+		c.reportError(ch, c.openFDs, err)
+	}
+
+	if limits, err := p.Limits(); err == nil {
+		ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(limits.OpenFiles))
+		ch <- MustNewConstMetric(c.maxVsize, GaugeValue, float64(limits.AddressSpace))
+	} else {
+		c.reportError(ch, nil, err)
+	}
+}

vendor/github.com/prometheus/client_golang/prometheus/process_collector_windows.go

@@ -0,0 +1,116 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+func canCollectProcess() bool {
+	return true
+}
+
+var (
+	modpsapi    = syscall.NewLazyDLL("psapi.dll")
+	modkernel32 = syscall.NewLazyDLL("kernel32.dll")
+
+	procGetProcessMemoryInfo  = modpsapi.NewProc("GetProcessMemoryInfo")
+	procGetProcessHandleCount = modkernel32.NewProc("GetProcessHandleCount")
+)
+
+type processMemoryCounters struct {
+	// System interface description
+	// https://docs.microsoft.com/en-us/windows/desktop/api/psapi/ns-psapi-process_memory_counters_ex
+
+	// Refer to the Golang internal implementation
+	// https://golang.org/src/internal/syscall/windows/psapi_windows.go
+	_                          uint32
+	PageFaultCount             uint32
+	PeakWorkingSetSize         uintptr
+	WorkingSetSize             uintptr
+	QuotaPeakPagedPoolUsage    uintptr
+	QuotaPagedPoolUsage        uintptr
+	QuotaPeakNonPagedPoolUsage uintptr
+	QuotaNonPagedPoolUsage     uintptr
+	PagefileUsage              uintptr
+	PeakPagefileUsage          uintptr
+	PrivateUsage               uintptr
+}
+
+func getProcessMemoryInfo(handle windows.Handle) (processMemoryCounters, error) {
+	mem := processMemoryCounters{}
+	r1, _, err := procGetProcessMemoryInfo.Call(
+		uintptr(handle),
+		uintptr(unsafe.Pointer(&mem)),
+		uintptr(unsafe.Sizeof(mem)),
+	)
+	if r1 != 1 {
+		return mem, err
+	} else {
+		return mem, nil
+	}
+}
+
+func getProcessHandleCount(handle windows.Handle) (uint32, error) {
+	var count uint32
+	r1, _, err := procGetProcessHandleCount.Call(
+		uintptr(handle),
+		uintptr(unsafe.Pointer(&count)),
+	)
+	if r1 != 1 {
+		return 0, err
+	} else {
+		return count, nil
+	}
+}
+
+func (c *processCollector) processCollect(ch chan<- Metric) {
+	h, err := windows.GetCurrentProcess()
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+
+	var startTime, exitTime, kernelTime, userTime windows.Filetime
+	err = windows.GetProcessTimes(h, &startTime, &exitTime, &kernelTime, &userTime)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+	ch <- MustNewConstMetric(c.startTime, GaugeValue, float64(startTime.Nanoseconds()/1e9))
+	ch <- MustNewConstMetric(c.cpuTotal, CounterValue, fileTimeToSeconds(kernelTime)+fileTimeToSeconds(userTime))
+
+	mem, err := getProcessMemoryInfo(h)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+	ch <- MustNewConstMetric(c.vsize, GaugeValue, float64(mem.PrivateUsage))
+	ch <- MustNewConstMetric(c.rss, GaugeValue, float64(mem.WorkingSetSize))
+
+	handles, err := getProcessHandleCount(h)
+	if err != nil {
+		c.reportError(ch, nil, err)
+		return
+	}
+	ch <- MustNewConstMetric(c.openFDs, GaugeValue, float64(handles))
+	ch <- MustNewConstMetric(c.maxFDs, GaugeValue, float64(16*1024*1024)) // Windows has a hard-coded max limit, not per-process.
+}
+
+func fileTimeToSeconds(ft windows.Filetime) float64 {
+	return float64(uint64(ft.HighDateTime)<<32+uint64(ft.LowDateTime)) / 1e7
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/delegator.go

@@ -0,0 +1,368 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package promhttp
+
+import (
+	"bufio"
+	"io"
+	"net"
+	"net/http"
+)
+
+const (
+	closeNotifier = 1 << iota
+	flusher
+	hijacker
+	readerFrom
+	pusher
+)
+
+type delegator interface {
+	http.ResponseWriter
+
+	Status() int
+	Written() int64
+}
+
+type responseWriterDelegator struct {
+	http.ResponseWriter
+
+	status             int
+	written            int64
+	wroteHeader        bool
+	observeWriteHeader func(int)
+}
+
+func (r *responseWriterDelegator) Status() int {
+	return r.status
+}
+
+func (r *responseWriterDelegator) Written() int64 {
+	return r.written
+}
+
+func (r *responseWriterDelegator) WriteHeader(code int) {
+	if r.observeWriteHeader != nil && !r.wroteHeader {
+		// Only call observeWriteHeader for the 1st time. It's a bug if
+		// WriteHeader is called more than once, but we want to protect
+		// against it here. Note that we still delegate the WriteHeader
+		// to the original ResponseWriter to not mask the bug from it.
+		r.observeWriteHeader(code)
+	}
+	r.status = code
+	r.wroteHeader = true
+	r.ResponseWriter.WriteHeader(code)
+}
+
+func (r *responseWriterDelegator) Write(b []byte) (int, error) {
+	// If applicable, call WriteHeader here so that observeWriteHeader is
+	// handled appropriately.
+	if !r.wroteHeader {
+		r.WriteHeader(http.StatusOK)
+	}
+	n, err := r.ResponseWriter.Write(b)
+	r.written += int64(n)
+	return n, err
+}
+
+type closeNotifierDelegator struct{ *responseWriterDelegator }
+type flusherDelegator struct{ *responseWriterDelegator }
+type hijackerDelegator struct{ *responseWriterDelegator }
+type readerFromDelegator struct{ *responseWriterDelegator }
+type pusherDelegator struct{ *responseWriterDelegator }
+
+func (d closeNotifierDelegator) CloseNotify() <-chan bool {
+	//nolint:staticcheck // Ignore SA1019. http.CloseNotifier is deprecated but we keep it here to not break existing users.
+	return d.ResponseWriter.(http.CloseNotifier).CloseNotify()
+}
+func (d flusherDelegator) Flush() {
+	// If applicable, call WriteHeader here so that observeWriteHeader is
+	// handled appropriately.
+	if !d.wroteHeader {
+		d.WriteHeader(http.StatusOK)
+	}
+	d.ResponseWriter.(http.Flusher).Flush()
+}
+func (d hijackerDelegator) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	return d.ResponseWriter.(http.Hijacker).Hijack()
+}
+func (d readerFromDelegator) ReadFrom(re io.Reader) (int64, error) {
+	// If applicable, call WriteHeader here so that observeWriteHeader is
+	// handled appropriately.
+	if !d.wroteHeader {
+		d.WriteHeader(http.StatusOK)
+	}
+	n, err := d.ResponseWriter.(io.ReaderFrom).ReadFrom(re)
+	d.written += n
+	return n, err
+}
+func (d pusherDelegator) Push(target string, opts *http.PushOptions) error {
+	return d.ResponseWriter.(http.Pusher).Push(target, opts)
+}
+
+var pickDelegator = make([]func(*responseWriterDelegator) delegator, 32)
+
+func init() {
+	// TODO(beorn7): Code generation would help here.
+	pickDelegator[0] = func(d *responseWriterDelegator) delegator { // 0
+		return d
+	}
+	pickDelegator[closeNotifier] = func(d *responseWriterDelegator) delegator { // 1
+		return closeNotifierDelegator{d}
+	}
+	pickDelegator[flusher] = func(d *responseWriterDelegator) delegator { // 2
+		return flusherDelegator{d}
+	}
+	pickDelegator[flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 3
+		return struct {
+			*responseWriterDelegator
+			http.Flusher
+			http.CloseNotifier
+		}{d, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[hijacker] = func(d *responseWriterDelegator) delegator { // 4
+		return hijackerDelegator{d}
+	}
+	pickDelegator[hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 5
+		return struct {
+			*responseWriterDelegator
+			http.Hijacker
+			http.CloseNotifier
+		}{d, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 6
+		return struct {
+			*responseWriterDelegator
+			http.Hijacker
+			http.Flusher
+		}{d, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 7
+		return struct {
+			*responseWriterDelegator
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom] = func(d *responseWriterDelegator) delegator { // 8
+		return readerFromDelegator{d}
+	}
+	pickDelegator[readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 9
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.CloseNotifier
+		}{d, readerFromDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 10
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Flusher
+		}{d, readerFromDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 11
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Flusher
+			http.CloseNotifier
+		}{d, readerFromDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 12
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 13
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+			http.CloseNotifier
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 14
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 15
+		return struct {
+			*responseWriterDelegator
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher] = func(d *responseWriterDelegator) delegator { // 16
+		return pusherDelegator{d}
+	}
+	pickDelegator[pusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 17
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+flusher] = func(d *responseWriterDelegator) delegator { // 18
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+		}{d, pusherDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 19
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker] = func(d *responseWriterDelegator) delegator { // 20
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+		}{d, pusherDelegator{d}, hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 21
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 22
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+		}{d, pusherDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { //23
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom] = func(d *responseWriterDelegator) delegator { // 24
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+		}{d, pusherDelegator{d}, readerFromDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+closeNotifier] = func(d *responseWriterDelegator) delegator { // 25
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher] = func(d *responseWriterDelegator) delegator { // 26
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 27
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker] = func(d *responseWriterDelegator) delegator { // 28
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+closeNotifier] = func(d *responseWriterDelegator) delegator { // 29
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, closeNotifierDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher] = func(d *responseWriterDelegator) delegator { // 30
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}}
+	}
+	pickDelegator[pusher+readerFrom+hijacker+flusher+closeNotifier] = func(d *responseWriterDelegator) delegator { // 31
+		return struct {
+			*responseWriterDelegator
+			http.Pusher
+			io.ReaderFrom
+			http.Hijacker
+			http.Flusher
+			http.CloseNotifier
+		}{d, pusherDelegator{d}, readerFromDelegator{d}, hijackerDelegator{d}, flusherDelegator{d}, closeNotifierDelegator{d}}
+	}
+}
+
+func newDelegator(w http.ResponseWriter, observeWriteHeaderFunc func(int)) delegator {
+	d := &responseWriterDelegator{
+		ResponseWriter:     w,
+		observeWriteHeader: observeWriteHeaderFunc,
+	}
+
+	id := 0
+	//nolint:staticcheck // Ignore SA1019. http.CloseNotifier is deprecated but we keep it here to not break existing users.
+	if _, ok := w.(http.CloseNotifier); ok {
+		id += closeNotifier
+	}
+	if _, ok := w.(http.Flusher); ok {
+		id += flusher
+	}
+	if _, ok := w.(http.Hijacker); ok {
+		id += hijacker
+	}
+	if _, ok := w.(io.ReaderFrom); ok {
+		id += readerFrom
+	}
+	if _, ok := w.(http.Pusher); ok {
+		id += pusher
+	}
+
+	return pickDelegator[id](d)
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/http.go

@@ -0,0 +1,383 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package promhttp provides tooling around HTTP servers and clients.
+//
+// First, the package allows the creation of http.Handler instances to expose
+// Prometheus metrics via HTTP. promhttp.Handler acts on the
+// prometheus.DefaultGatherer. With HandlerFor, you can create a handler for a
+// custom registry or anything that implements the Gatherer interface. It also
+// allows the creation of handlers that act differently on errors or allow to
+// log errors.
+//
+// Second, the package provides tooling to instrument instances of http.Handler
+// via middleware. Middleware wrappers follow the naming scheme
+// InstrumentHandlerX, where X describes the intended use of the middleware.
+// See each function's doc comment for specific details.
+//
+// Finally, the package allows for an http.RoundTripper to be instrumented via
+// middleware. Middleware wrappers follow the naming scheme
+// InstrumentRoundTripperX, where X describes the intended use of the
+// middleware. See each function's doc comment for specific details.
+package promhttp
+
+import (
+	"compress/gzip"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/prometheus/common/expfmt"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	contentTypeHeader     = "Content-Type"
+	contentEncodingHeader = "Content-Encoding"
+	acceptEncodingHeader  = "Accept-Encoding"
+)
+
+var gzipPool = sync.Pool{
+	New: func() interface{} {
+		return gzip.NewWriter(nil)
+	},
+}
+
+// Handler returns an http.Handler for the prometheus.DefaultGatherer, using
+// default HandlerOpts, i.e. it reports the first error as an HTTP error, it has
+// no error logging, and it applies compression if requested by the client.
+//
+// The returned http.Handler is already instrumented using the
+// InstrumentMetricHandler function and the prometheus.DefaultRegisterer. If you
+// create multiple http.Handlers by separate calls of the Handler function, the
+// metrics used for instrumentation will be shared between them, providing
+// global scrape counts.
+//
+// This function is meant to cover the bulk of basic use cases. If you are doing
+// anything that requires more customization (including using a non-default
+// Gatherer, different instrumentation, and non-default HandlerOpts), use the
+// HandlerFor function. See there for details.
+func Handler() http.Handler {
+	return InstrumentMetricHandler(
+		prometheus.DefaultRegisterer, HandlerFor(prometheus.DefaultGatherer, HandlerOpts{}),
+	)
+}
+
+// HandlerFor returns an uninstrumented http.Handler for the provided
+// Gatherer. The behavior of the Handler is defined by the provided
+// HandlerOpts. Thus, HandlerFor is useful to create http.Handlers for custom
+// Gatherers, with non-default HandlerOpts, and/or with custom (or no)
+// instrumentation. Use the InstrumentMetricHandler function to apply the same
+// kind of instrumentation as it is used by the Handler function.
+func HandlerFor(reg prometheus.Gatherer, opts HandlerOpts) http.Handler {
+	var (
+		inFlightSem chan struct{}
+		errCnt      = prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Name: "promhttp_metric_handler_errors_total",
+				Help: "Total number of internal errors encountered by the promhttp metric handler.",
+			},
+			[]string{"cause"},
+		)
+	)
+
+	if opts.MaxRequestsInFlight > 0 {
+		inFlightSem = make(chan struct{}, opts.MaxRequestsInFlight)
+	}
+	if opts.Registry != nil {
+		// Initialize all possibilities that can occur below.
+		errCnt.WithLabelValues("gathering")
+		errCnt.WithLabelValues("encoding")
+		if err := opts.Registry.Register(errCnt); err != nil {
+			if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+				errCnt = are.ExistingCollector.(*prometheus.CounterVec)
+			} else {
+				panic(err)
+			}
+		}
+	}
+
+	h := http.HandlerFunc(func(rsp http.ResponseWriter, req *http.Request) {
+		if inFlightSem != nil {
+			select {
+			case inFlightSem <- struct{}{}: // All good, carry on.
+				defer func() { <-inFlightSem }()
+			default:
+				http.Error(rsp, fmt.Sprintf(
+					"Limit of concurrent requests reached (%d), try again later.", opts.MaxRequestsInFlight,
+				), http.StatusServiceUnavailable)
+				return
+			}
+		}
+		mfs, err := reg.Gather()
+		if err != nil {
+			if opts.ErrorLog != nil {
+				opts.ErrorLog.Println("error gathering metrics:", err)
+			}
+			errCnt.WithLabelValues("gathering").Inc()
+			switch opts.ErrorHandling {
+			case PanicOnError:
+				panic(err)
+			case ContinueOnError:
+				if len(mfs) == 0 {
+					// Still report the error if no metrics have been gathered.
+					httpError(rsp, err)
+					return
+				}
+			case HTTPErrorOnError:
+				httpError(rsp, err)
+				return
+			}
+		}
+
+		var contentType expfmt.Format
+		if opts.EnableOpenMetrics {
+			contentType = expfmt.NegotiateIncludingOpenMetrics(req.Header)
+		} else {
+			contentType = expfmt.Negotiate(req.Header)
+		}
+		header := rsp.Header()
+		header.Set(contentTypeHeader, string(contentType))
+
+		w := io.Writer(rsp)
+		if !opts.DisableCompression && gzipAccepted(req.Header) {
+			header.Set(contentEncodingHeader, "gzip")
+			gz := gzipPool.Get().(*gzip.Writer)
+			defer gzipPool.Put(gz)
+
+			gz.Reset(w)
+			defer gz.Close()
+
+			w = gz
+		}
+
+		enc := expfmt.NewEncoder(w, contentType)
+
+		// handleError handles the error according to opts.ErrorHandling
+		// and returns true if we have to abort after the handling.
+		handleError := func(err error) bool {
+			if err == nil {
+				return false
+			}
+			if opts.ErrorLog != nil {
+				opts.ErrorLog.Println("error encoding and sending metric family:", err)
+			}
+			errCnt.WithLabelValues("encoding").Inc()
+			switch opts.ErrorHandling {
+			case PanicOnError:
+				panic(err)
+			case HTTPErrorOnError:
+				// We cannot really send an HTTP error at this
+				// point because we most likely have written
+				// something to rsp already. But at least we can
+				// stop sending.
+				return true
+			}
+			// Do nothing in all other cases, including ContinueOnError.
+			return false
+		}
+
+		for _, mf := range mfs {
+			if handleError(enc.Encode(mf)) {
+				return
+			}
+		}
+		if closer, ok := enc.(expfmt.Closer); ok {
+			// This in particular takes care of the final "# EOF\n" line for OpenMetrics.
+			if handleError(closer.Close()) {
+				return
+			}
+		}
+	})
+
+	if opts.Timeout <= 0 {
+		return h
+	}
+	return http.TimeoutHandler(h, opts.Timeout, fmt.Sprintf(
+		"Exceeded configured timeout of %v.\n",
+		opts.Timeout,
+	))
+}
+
+// InstrumentMetricHandler is usually used with an http.Handler returned by the
+// HandlerFor function. It instruments the provided http.Handler with two
+// metrics: A counter vector "promhttp_metric_handler_requests_total" to count
+// scrapes partitioned by HTTP status code, and a gauge
+// "promhttp_metric_handler_requests_in_flight" to track the number of
+// simultaneous scrapes. This function idempotently registers collectors for
+// both metrics with the provided Registerer. It panics if the registration
+// fails. The provided metrics are useful to see how many scrapes hit the
+// monitored target (which could be from different Prometheus servers or other
+// scrapers), and how often they overlap (which would result in more than one
+// scrape in flight at the same time). Note that the scrapes-in-flight gauge
+// will contain the scrape by which it is exposed, while the scrape counter will
+// only get incremented after the scrape is complete (as only then the status
+// code is known). For tracking scrape durations, use the
+// "scrape_duration_seconds" gauge created by the Prometheus server upon each
+// scrape.
+func InstrumentMetricHandler(reg prometheus.Registerer, handler http.Handler) http.Handler {
+	cnt := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "promhttp_metric_handler_requests_total",
+			Help: "Total number of scrapes by HTTP status code.",
+		},
+		[]string{"code"},
+	)
+	// Initialize the most likely HTTP status codes.
+	cnt.WithLabelValues("200")
+	cnt.WithLabelValues("500")
+	cnt.WithLabelValues("503")
+	if err := reg.Register(cnt); err != nil {
+		if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+			cnt = are.ExistingCollector.(*prometheus.CounterVec)
+		} else {
+			panic(err)
+		}
+	}
+
+	gge := prometheus.NewGauge(prometheus.GaugeOpts{
+		Name: "promhttp_metric_handler_requests_in_flight",
+		Help: "Current number of scrapes being served.",
+	})
+	if err := reg.Register(gge); err != nil {
+		if are, ok := err.(prometheus.AlreadyRegisteredError); ok {
+			gge = are.ExistingCollector.(prometheus.Gauge)
+		} else {
+			panic(err)
+		}
+	}
+
+	return InstrumentHandlerCounter(cnt, InstrumentHandlerInFlight(gge, handler))
+}
+
+// HandlerErrorHandling defines how a Handler serving metrics will handle
+// errors.
+type HandlerErrorHandling int
+
+// These constants cause handlers serving metrics to behave as described if
+// errors are encountered.
+const (
+	// Serve an HTTP status code 500 upon the first error
+	// encountered. Report the error message in the body. Note that HTTP
+	// errors cannot be served anymore once the beginning of a regular
+	// payload has been sent. Thus, in the (unlikely) case that encoding the
+	// payload into the negotiated wire format fails, serving the response
+	// will simply be aborted. Set an ErrorLog in HandlerOpts to detect
+	// those errors.
+	HTTPErrorOnError HandlerErrorHandling = iota
+	// Ignore errors and try to serve as many metrics as possible.  However,
+	// if no metrics can be served, serve an HTTP status code 500 and the
+	// last error message in the body. Only use this in deliberate "best
+	// effort" metrics collection scenarios. In this case, it is highly
+	// recommended to provide other means of detecting errors: By setting an
+	// ErrorLog in HandlerOpts, the errors are logged. By providing a
+	// Registry in HandlerOpts, the exposed metrics include an error counter
+	// "promhttp_metric_handler_errors_total", which can be used for
+	// alerts.
+	ContinueOnError
+	// Panic upon the first error encountered (useful for "crash only" apps).
+	PanicOnError
+)
+
+// Logger is the minimal interface HandlerOpts needs for logging. Note that
+// log.Logger from the standard library implements this interface, and it is
+// easy to implement by custom loggers, if they don't do so already anyway.
+type Logger interface {
+	Println(v ...interface{})
+}
+
+// HandlerOpts specifies options how to serve metrics via an http.Handler. The
+// zero value of HandlerOpts is a reasonable default.
+type HandlerOpts struct {
+	// ErrorLog specifies an optional Logger for errors collecting and
+	// serving metrics. If nil, errors are not logged at all. Note that the
+	// type of a reported error is often prometheus.MultiError, which
+	// formats into a multi-line error string. If you want to avoid the
+	// latter, create a Logger implementation that detects a
+	// prometheus.MultiError and formats the contained errors into one line.
+	ErrorLog Logger
+	// ErrorHandling defines how errors are handled. Note that errors are
+	// logged regardless of the configured ErrorHandling provided ErrorLog
+	// is not nil.
+	ErrorHandling HandlerErrorHandling
+	// If Registry is not nil, it is used to register a metric
+	// "promhttp_metric_handler_errors_total", partitioned by "cause". A
+	// failed registration causes a panic. Note that this error counter is
+	// different from the instrumentation you get from the various
+	// InstrumentHandler... helpers. It counts errors that don't necessarily
+	// result in a non-2xx HTTP status code. There are two typical cases:
+	// (1) Encoding errors that only happen after streaming of the HTTP body
+	// has already started (and the status code 200 has been sent). This
+	// should only happen with custom collectors. (2) Collection errors with
+	// no effect on the HTTP status code because ErrorHandling is set to
+	// ContinueOnError.
+	Registry prometheus.Registerer
+	// If DisableCompression is true, the handler will never compress the
+	// response, even if requested by the client.
+	DisableCompression bool
+	// The number of concurrent HTTP requests is limited to
+	// MaxRequestsInFlight. Additional requests are responded to with 503
+	// Service Unavailable and a suitable message in the body. If
+	// MaxRequestsInFlight is 0 or negative, no limit is applied.
+	MaxRequestsInFlight int
+	// If handling a request takes longer than Timeout, it is responded to
+	// with 503 ServiceUnavailable and a suitable Message. No timeout is
+	// applied if Timeout is 0 or negative. Note that with the current
+	// implementation, reaching the timeout simply ends the HTTP requests as
+	// described above (and even that only if sending of the body hasn't
+	// started yet), while the bulk work of gathering all the metrics keeps
+	// running in the background (with the eventual result to be thrown
+	// away). Until the implementation is improved, it is recommended to
+	// implement a separate timeout in potentially slow Collectors.
+	Timeout time.Duration
+	// If true, the experimental OpenMetrics encoding is added to the
+	// possible options during content negotiation. Note that Prometheus
+	// 2.5.0+ will negotiate OpenMetrics as first priority. OpenMetrics is
+	// the only way to transmit exemplars. However, the move to OpenMetrics
+	// is not completely transparent. Most notably, the values of "quantile"
+	// labels of Summaries and "le" labels of Histograms are formatted with
+	// a trailing ".0" if they would otherwise look like integer numbers
+	// (which changes the identity of the resulting series on the Prometheus
+	// server).
+	EnableOpenMetrics bool
+}
+
+// gzipAccepted returns whether the client will accept gzip-encoded content.
+func gzipAccepted(header http.Header) bool {
+	a := header.Get(acceptEncodingHeader)
+	parts := strings.Split(a, ",")
+	for _, part := range parts {
+		part = strings.TrimSpace(part)
+		if part == "gzip" || strings.HasPrefix(part, "gzip;") {
+			return true
+		}
+	}
+	return false
+}
+
+// httpError removes any content-encoding header and then calls http.Error with
+// the provided error and http.StatusInternalServerError. Error contents is
+// supposed to be uncompressed plain text. Same as with a plain http.Error, this
+// must not be called if the header or any payload has already been sent.
+func httpError(rsp http.ResponseWriter, err error) {
+	rsp.Header().Del(contentEncodingHeader)
+	http.Error(
+		rsp,
+		"An error has occurred while serving metrics:\n\n"+err.Error(),
+		http.StatusInternalServerError,
+	)
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_client.go

@@ -0,0 +1,219 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package promhttp
+
+import (
+	"crypto/tls"
+	"net/http"
+	"net/http/httptrace"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// The RoundTripperFunc type is an adapter to allow the use of ordinary
+// functions as RoundTrippers. If f is a function with the appropriate
+// signature, RountTripperFunc(f) is a RoundTripper that calls f.
+type RoundTripperFunc func(req *http.Request) (*http.Response, error)
+
+// RoundTrip implements the RoundTripper interface.
+func (rt RoundTripperFunc) RoundTrip(r *http.Request) (*http.Response, error) {
+	return rt(r)
+}
+
+// InstrumentRoundTripperInFlight is a middleware that wraps the provided
+// http.RoundTripper. It sets the provided prometheus.Gauge to the number of
+// requests currently handled by the wrapped http.RoundTripper.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperInFlight(gauge prometheus.Gauge, next http.RoundTripper) RoundTripperFunc {
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		gauge.Inc()
+		defer gauge.Dec()
+		return next.RoundTrip(r)
+	})
+}
+
+// InstrumentRoundTripperCounter is a middleware that wraps the provided
+// http.RoundTripper to observe the request result with the provided CounterVec.
+// The CounterVec must have zero, one, or two non-const non-curried labels. For
+// those, the only allowed label names are "code" and "method". The function
+// panics otherwise. Partitioning of the CounterVec happens by HTTP status code
+// and/or HTTP method if the respective instance label names are present in the
+// CounterVec. For unpartitioned counting, use a CounterVec with zero labels.
+//
+// If the wrapped RoundTripper panics or returns a non-nil error, the Counter
+// is not incremented.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperCounter(counter *prometheus.CounterVec, next http.RoundTripper) RoundTripperFunc {
+	code, method := checkLabels(counter)
+
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		resp, err := next.RoundTrip(r)
+		if err == nil {
+			counter.With(labels(code, method, r.Method, resp.StatusCode)).Inc()
+		}
+		return resp, err
+	})
+}
+
+// InstrumentRoundTripperDuration is a middleware that wraps the provided
+// http.RoundTripper to observe the request duration with the provided
+// ObserverVec.  The ObserverVec must have zero, one, or two non-const
+// non-curried labels. For those, the only allowed label names are "code" and
+// "method". The function panics otherwise. The Observe method of the Observer
+// in the ObserverVec is called with the request duration in
+// seconds. Partitioning happens by HTTP status code and/or HTTP method if the
+// respective instance label names are present in the ObserverVec. For
+// unpartitioned observations, use an ObserverVec with zero labels. Note that
+// partitioning of Histograms is expensive and should be used judiciously.
+//
+// If the wrapped RoundTripper panics or returns a non-nil error, no values are
+// reported.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+func InstrumentRoundTripperDuration(obs prometheus.ObserverVec, next http.RoundTripper) RoundTripperFunc {
+	code, method := checkLabels(obs)
+
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		start := time.Now()
+		resp, err := next.RoundTrip(r)
+		if err == nil {
+			obs.With(labels(code, method, r.Method, resp.StatusCode)).Observe(time.Since(start).Seconds())
+		}
+		return resp, err
+	})
+}
+
+// InstrumentTrace is used to offer flexibility in instrumenting the available
+// httptrace.ClientTrace hook functions. Each function is passed a float64
+// representing the time in seconds since the start of the http request. A user
+// may choose to use separately buckets Histograms, or implement custom
+// instance labels on a per function basis.
+type InstrumentTrace struct {
+	GotConn              func(float64)
+	PutIdleConn          func(float64)
+	GotFirstResponseByte func(float64)
+	Got100Continue       func(float64)
+	DNSStart             func(float64)
+	DNSDone              func(float64)
+	ConnectStart         func(float64)
+	ConnectDone          func(float64)
+	TLSHandshakeStart    func(float64)
+	TLSHandshakeDone     func(float64)
+	WroteHeaders         func(float64)
+	Wait100Continue      func(float64)
+	WroteRequest         func(float64)
+}
+
+// InstrumentRoundTripperTrace is a middleware that wraps the provided
+// RoundTripper and reports times to hook functions provided in the
+// InstrumentTrace struct. Hook functions that are not present in the provided
+// InstrumentTrace struct are ignored. Times reported to the hook functions are
+// time since the start of the request. Only with Go1.9+, those times are
+// guaranteed to never be negative. (Earlier Go versions are not using a
+// monotonic clock.) Note that partitioning of Histograms is expensive and
+// should be used judiciously.
+//
+// For hook functions that receive an error as an argument, no observations are
+// made in the event of a non-nil error value.
+//
+// See the example for ExampleInstrumentRoundTripperDuration for example usage.
+func InstrumentRoundTripperTrace(it *InstrumentTrace, next http.RoundTripper) RoundTripperFunc {
+	return RoundTripperFunc(func(r *http.Request) (*http.Response, error) {
+		start := time.Now()
+
+		trace := &httptrace.ClientTrace{
+			GotConn: func(_ httptrace.GotConnInfo) {
+				if it.GotConn != nil {
+					it.GotConn(time.Since(start).Seconds())
+				}
+			},
+			PutIdleConn: func(err error) {
+				if err != nil {
+					return
+				}
+				if it.PutIdleConn != nil {
+					it.PutIdleConn(time.Since(start).Seconds())
+				}
+			},
+			DNSStart: func(_ httptrace.DNSStartInfo) {
+				if it.DNSStart != nil {
+					it.DNSStart(time.Since(start).Seconds())
+				}
+			},
+			DNSDone: func(_ httptrace.DNSDoneInfo) {
+				if it.DNSDone != nil {
+					it.DNSDone(time.Since(start).Seconds())
+				}
+			},
+			ConnectStart: func(_, _ string) {
+				if it.ConnectStart != nil {
+					it.ConnectStart(time.Since(start).Seconds())
+				}
+			},
+			ConnectDone: func(_, _ string, err error) {
+				if err != nil {
+					return
+				}
+				if it.ConnectDone != nil {
+					it.ConnectDone(time.Since(start).Seconds())
+				}
+			},
+			GotFirstResponseByte: func() {
+				if it.GotFirstResponseByte != nil {
+					it.GotFirstResponseByte(time.Since(start).Seconds())
+				}
+			},
+			Got100Continue: func() {
+				if it.Got100Continue != nil {
+					it.Got100Continue(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeStart: func() {
+				if it.TLSHandshakeStart != nil {
+					it.TLSHandshakeStart(time.Since(start).Seconds())
+				}
+			},
+			TLSHandshakeDone: func(_ tls.ConnectionState, err error) {
+				if err != nil {
+					return
+				}
+				if it.TLSHandshakeDone != nil {
+					it.TLSHandshakeDone(time.Since(start).Seconds())
+				}
+			},
+			WroteHeaders: func() {
+				if it.WroteHeaders != nil {
+					it.WroteHeaders(time.Since(start).Seconds())
+				}
+			},
+			Wait100Continue: func() {
+				if it.Wait100Continue != nil {
+					it.Wait100Continue(time.Since(start).Seconds())
+				}
+			},
+			WroteRequest: func(_ httptrace.WroteRequestInfo) {
+				if it.WroteRequest != nil {
+					it.WroteRequest(time.Since(start).Seconds())
+				}
+			},
+		}
+		r = r.WithContext(httptrace.WithClientTrace(r.Context(), trace))
+
+		return next.RoundTrip(r)
+	})
+}

vendor/github.com/prometheus/client_golang/prometheus/promhttp/instrument_server.go

@@ -0,0 +1,458 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package promhttp
+
+import (
+	"errors"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// magicString is used for the hacky label test in checkLabels. Remove once fixed.
+const magicString = "zZgWfBxLqvG8kc8IMv3POi2Bb0tZI3vAnBx+gBaFi9FyPzB/CzKUer1yufDa"
+
+// InstrumentHandlerInFlight is a middleware that wraps the provided
+// http.Handler. It sets the provided prometheus.Gauge to the number of
+// requests currently handled by the wrapped http.Handler.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		g.Inc()
+		defer g.Dec()
+		next.ServeHTTP(w, r)
+	})
+}
+
+// InstrumentHandlerDuration is a middleware that wraps the provided
+// http.Handler to observe the request duration with the provided ObserverVec.
+// The ObserverVec must have valid metric and label names and must have zero,
+// one, or two non-const non-curried labels. For those, the only allowed label
+// names are "code" and "method". The function panics otherwise. The Observe
+// method of the Observer in the ObserverVec is called with the request duration
+// in seconds. Partitioning happens by HTTP status code and/or HTTP method if
+// the respective instance label names are present in the ObserverVec. For
+// unpartitioned observations, use an ObserverVec with zero labels. Note that
+// partitioning of Histograms is expensive and should be used judiciously.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, no values are reported.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(obs)
+
+	if code {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			now := time.Now()
+			d := newDelegator(w, nil)
+			next.ServeHTTP(d, r)
+
+			obs.With(labels(code, method, r.Method, d.Status())).Observe(time.Since(now).Seconds())
+		})
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		now := time.Now()
+		next.ServeHTTP(w, r)
+		obs.With(labels(code, method, r.Method, 0)).Observe(time.Since(now).Seconds())
+	})
+}
+
+// InstrumentHandlerCounter is a middleware that wraps the provided http.Handler
+// to observe the request result with the provided CounterVec. The CounterVec
+// must have valid metric and label names and must have zero, one, or two
+// non-const non-curried labels. For those, the only allowed label names are
+// "code" and "method". The function panics otherwise. Partitioning of the
+// CounterVec happens by HTTP status code and/or HTTP method if the respective
+// instance label names are present in the CounterVec. For unpartitioned
+// counting, use a CounterVec with zero labels.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, the Counter is not incremented.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(counter)
+
+	if code {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			d := newDelegator(w, nil)
+			next.ServeHTTP(d, r)
+			counter.With(labels(code, method, r.Method, d.Status())).Inc()
+		})
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		next.ServeHTTP(w, r)
+		counter.With(labels(code, method, r.Method, 0)).Inc()
+	})
+}
+
+// InstrumentHandlerTimeToWriteHeader is a middleware that wraps the provided
+// http.Handler to observe with the provided ObserverVec the request duration
+// until the response headers are written. The ObserverVec must have valid
+// metric and label names and must have zero, one, or two non-const non-curried
+// labels. For those, the only allowed label names are "code" and "method". The
+// function panics otherwise. The Observe method of the Observer in the
+// ObserverVec is called with the request duration in seconds. Partitioning
+// happens by HTTP status code and/or HTTP method if the respective instance
+// label names are present in the ObserverVec. For unpartitioned observations,
+// use an ObserverVec with zero labels. Note that partitioning of Histograms is
+// expensive and should be used judiciously.
+//
+// If the wrapped Handler panics before calling WriteHeader, no value is
+// reported.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerTimeToWriteHeader(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(obs)
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		now := time.Now()
+		d := newDelegator(w, func(status int) {
+			obs.With(labels(code, method, r.Method, status)).Observe(time.Since(now).Seconds())
+		})
+		next.ServeHTTP(d, r)
+	})
+}
+
+// InstrumentHandlerRequestSize is a middleware that wraps the provided
+// http.Handler to observe the request size with the provided ObserverVec. The
+// ObserverVec must have valid metric and label names and must have zero, one,
+// or two non-const non-curried labels. For those, the only allowed label names
+// are "code" and "method". The function panics otherwise. The Observe method of
+// the Observer in the ObserverVec is called with the request size in
+// bytes. Partitioning happens by HTTP status code and/or HTTP method if the
+// respective instance label names are present in the ObserverVec. For
+// unpartitioned observations, use an ObserverVec with zero labels. Note that
+// partitioning of Histograms is expensive and should be used judiciously.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, no values are reported.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerRequestSize(obs prometheus.ObserverVec, next http.Handler) http.HandlerFunc {
+	code, method := checkLabels(obs)
+
+	if code {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			d := newDelegator(w, nil)
+			next.ServeHTTP(d, r)
+			size := computeApproximateRequestSize(r)
+			obs.With(labels(code, method, r.Method, d.Status())).Observe(float64(size))
+		})
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		next.ServeHTTP(w, r)
+		size := computeApproximateRequestSize(r)
+		obs.With(labels(code, method, r.Method, 0)).Observe(float64(size))
+	})
+}
+
+// InstrumentHandlerResponseSize is a middleware that wraps the provided
+// http.Handler to observe the response size with the provided ObserverVec. The
+// ObserverVec must have valid metric and label names and must have zero, one,
+// or two non-const non-curried labels. For those, the only allowed label names
+// are "code" and "method". The function panics otherwise. The Observe method of
+// the Observer in the ObserverVec is called with the response size in
+// bytes. Partitioning happens by HTTP status code and/or HTTP method if the
+// respective instance label names are present in the ObserverVec. For
+// unpartitioned observations, use an ObserverVec with zero labels. Note that
+// partitioning of Histograms is expensive and should be used judiciously.
+//
+// If the wrapped Handler does not set a status code, a status code of 200 is assumed.
+//
+// If the wrapped Handler panics, no values are reported.
+//
+// See the example for InstrumentHandlerDuration for example usage.
+func InstrumentHandlerResponseSize(obs prometheus.ObserverVec, next http.Handler) http.Handler {
+	code, method := checkLabels(obs)
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		d := newDelegator(w, nil)
+		next.ServeHTTP(d, r)
+		obs.With(labels(code, method, r.Method, d.Status())).Observe(float64(d.Written()))
+	})
+}
+
+// checkLabels returns whether the provided Collector has a non-const,
+// non-curried label named "code" and/or "method". It panics if the provided
+// Collector does not have a Desc or has more than one Desc or its Desc is
+// invalid. It also panics if the Collector has any non-const, non-curried
+// labels that are not named "code" or "method".
+func checkLabels(c prometheus.Collector) (code bool, method bool) {
+	// TODO(beorn7): Remove this hacky way to check for instance labels
+	// once Descriptors can have their dimensionality queried.
+	var (
+		desc *prometheus.Desc
+		m    prometheus.Metric
+		pm   dto.Metric
+		lvs  []string
+	)
+
+	// Get the Desc from the Collector.
+	descc := make(chan *prometheus.Desc, 1)
+	c.Describe(descc)
+
+	select {
+	case desc = <-descc:
+	default:
+		panic("no description provided by collector")
+	}
+	select {
+	case <-descc:
+		panic("more than one description provided by collector")
+	default:
+	}
+
+	close(descc)
+
+	// Make sure the Collector has a valid Desc by registering it with a
+	// temporary registry.
+	prometheus.NewRegistry().MustRegister(c)
+
+	// Create a ConstMetric with the Desc. Since we don't know how many
+	// variable labels there are, try for as long as it needs.
+	for err := errors.New("dummy"); err != nil; lvs = append(lvs, magicString) {
+		m, err = prometheus.NewConstMetric(desc, prometheus.UntypedValue, 0, lvs...)
+	}
+
+	// Write out the metric into a proto message and look at the labels.
+	// If the value is not the magicString, it is a constLabel, which doesn't interest us.
+	// If the label is curried, it doesn't interest us.
+	// In all other cases, only "code" or "method" is allowed.
+	if err := m.Write(&pm); err != nil {
+		panic("error checking metric for labels")
+	}
+	for _, label := range pm.Label {
+		name, value := label.GetName(), label.GetValue()
+		if value != magicString || isLabelCurried(c, name) {
+			continue
+		}
+		switch name {
+		case "code":
+			code = true
+		case "method":
+			method = true
+		default:
+			panic("metric partitioned with non-supported labels")
+		}
+	}
+	return
+}
+
+func isLabelCurried(c prometheus.Collector, label string) bool {
+	// This is even hackier than the label test above.
+	// We essentially try to curry again and see if it works.
+	// But for that, we need to type-convert to the two
+	// types we use here, ObserverVec or *CounterVec.
+	switch v := c.(type) {
+	case *prometheus.CounterVec:
+		if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil {
+			return false
+		}
+	case prometheus.ObserverVec:
+		if _, err := v.CurryWith(prometheus.Labels{label: "dummy"}); err == nil {
+			return false
+		}
+	default:
+		panic("unsupported metric vec type")
+	}
+	return true
+}
+
+// emptyLabels is a one-time allocation for non-partitioned metrics to avoid
+// unnecessary allocations on each request.
+var emptyLabels = prometheus.Labels{}
+
+func labels(code, method bool, reqMethod string, status int) prometheus.Labels {
+	if !(code || method) {
+		return emptyLabels
+	}
+	labels := prometheus.Labels{}
+
+	if code {
+		labels["code"] = sanitizeCode(status)
+	}
+	if method {
+		labels["method"] = sanitizeMethod(reqMethod)
+	}
+
+	return labels
+}
+
+func computeApproximateRequestSize(r *http.Request) int {
+	s := 0
+	if r.URL != nil {
+		s += len(r.URL.String())
+	}
+
+	s += len(r.Method)
+	s += len(r.Proto)
+	for name, values := range r.Header {
+		s += len(name)
+		for _, value := range values {
+			s += len(value)
+		}
+	}
+	s += len(r.Host)
+
+	// N.B. r.Form and r.MultipartForm are assumed to be included in r.URL.
+
+	if r.ContentLength != -1 {
+		s += int(r.ContentLength)
+	}
+	return s
+}
+
+func sanitizeMethod(m string) string {
+	switch m {
+	case "GET", "get":
+		return "get"
+	case "PUT", "put":
+		return "put"
+	case "HEAD", "head":
+		return "head"
+	case "POST", "post":
+		return "post"
+	case "DELETE", "delete":
+		return "delete"
+	case "CONNECT", "connect":
+		return "connect"
+	case "OPTIONS", "options":
+		return "options"
+	case "NOTIFY", "notify":
+		return "notify"
+	default:
+		return strings.ToLower(m)
+	}
+}
+
+// If the wrapped http.Handler has not set a status code, i.e. the value is
+// currently 0, santizeCode will return 200, for consistency with behavior in
+// the stdlib.
+func sanitizeCode(s int) string {
+	switch s {
+	case 100:
+		return "100"
+	case 101:
+		return "101"
+
+	case 200, 0:
+		return "200"
+	case 201:
+		return "201"
+	case 202:
+		return "202"
+	case 203:
+		return "203"
+	case 204:
+		return "204"
+	case 205:
+		return "205"
+	case 206:
+		return "206"
+
+	case 300:
+		return "300"
+	case 301:
+		return "301"
+	case 302:
+		return "302"
+	case 304:
+		return "304"
+	case 305:
+		return "305"
+	case 307:
+		return "307"
+
+	case 400:
+		return "400"
+	case 401:
+		return "401"
+	case 402:
+		return "402"
+	case 403:
+		return "403"
+	case 404:
+		return "404"
+	case 405:
+		return "405"
+	case 406:
+		return "406"
+	case 407:
+		return "407"
+	case 408:
+		return "408"
+	case 409:
+		return "409"
+	case 410:
+		return "410"
+	case 411:
+		return "411"
+	case 412:
+		return "412"
+	case 413:
+		return "413"
+	case 414:
+		return "414"
+	case 415:
+		return "415"
+	case 416:
+		return "416"
+	case 417:
+		return "417"
+	case 418:
+		return "418"
+
+	case 500:
+		return "500"
+	case 501:
+		return "501"
+	case 502:
+		return "502"
+	case 503:
+		return "503"
+	case 504:
+		return "504"
+	case 505:
+		return "505"
+
+	case 428:
+		return "428"
+	case 429:
+		return "429"
+	case 431:
+		return "431"
+	case 511:
+		return "511"
+
+	default:
+		return strconv.Itoa(s)
+	}
+}

vendor/github.com/prometheus/client_golang/prometheus/push.go

@@ -1,65 +0,0 @@
-// Copyright 2015 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// Copyright (c) 2013, The Prometheus Authors
-// All rights reserved.
-//
-// Use of this source code is governed by a BSD-style license that can be found
-// in the LICENSE file.
-
-package prometheus
-
-// Push triggers a metric collection by the default registry and pushes all
-// collected metrics to the Pushgateway specified by url. See the Pushgateway
-// documentation for detailed implications of the job and instance
-// parameter. instance can be left empty. You can use just host:port or ip:port
-// as url, in which case 'http://' is added automatically. You can also include
-// the schema in the URL. However, do not include the '/metrics/jobs/...' part.
-//
-// Note that all previously pushed metrics with the same job and instance will
-// be replaced with the metrics pushed by this call. (It uses HTTP method 'PUT'
-// to push to the Pushgateway.)
-func Push(job, instance, url string) error {
-	return defRegistry.Push(job, instance, url, "PUT")
-}
-
-// PushAdd works like Push, but only previously pushed metrics with the same
-// name (and the same job and instance) will be replaced. (It uses HTTP method
-// 'POST' to push to the Pushgateway.)
-func PushAdd(job, instance, url string) error {
-	return defRegistry.Push(job, instance, url, "POST")
-}
-
-// PushCollectors works like Push, but it does not collect from the default
-// registry. Instead, it collects from the provided collectors. It is a
-// convenient way to push only a few metrics.
-func PushCollectors(job, instance, url string, collectors ...Collector) error {
-	return pushCollectors(job, instance, url, "PUT", collectors...)
-}
-
-// PushAddCollectors works like PushAdd, but it does not collect from the
-// default registry. Instead, it collects from the provided collectors. It is a
-// convenient way to push only a few metrics.
-func PushAddCollectors(job, instance, url string, collectors ...Collector) error {
-	return pushCollectors(job, instance, url, "POST", collectors...)
-}
-
-func pushCollectors(job, instance, url, method string, collectors ...Collector) error {
-	r := newRegistry()
-	for _, collector := range collectors {
-		if _, err := r.Register(collector); err != nil {
-			return err
-		}
-	}
-	return r.Push(job, instance, url, method)
-}

vendor/github.com/prometheus/client_golang/prometheus/summary.go

@@ -16,11 +16,14 @@ package prometheus
 import (
 	"fmt"
 	"math"
+	"runtime"
 	"sort"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/beorn7/perks/quantile"
+	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/golang/protobuf/proto"
 
 	dto "github.com/prometheus/client_model/go"
@@ -36,7 +39,10 @@ const quantileLabel = "quantile"
 //
 // A typical use-case is the observation of request latencies. By default, a
 // Summary provides the median, the 90th and the 99th percentile of the latency
-// as rank estimations.
+// as rank estimations. However, the default behavior will change in the
+// upcoming v1.0.0 of the library. There will be no rank estimations at all by
+// default. For a sane transition, it is recommended to set the desired rank
+// estimations explicitly.
 //
 // Note that the rank estimations cannot be aggregated in a meaningful way with
 // the Prometheus query language (i.e. you cannot average or add them). If you
@@ -49,17 +55,17 @@ type Summary interface {
 	Metric
 	Collector
 
-	// Observe adds a single observation to the summary.
+	// Observe adds a single observation to the summary. Observations are
+	// usually positive or zero. Negative observations are accepted but
+	// prevent current versions of Prometheus from properly detecting
+	// counter resets in the sum of observations. See
+	// https://prometheus.io/docs/practices/histograms/#count-and-sum-of-observations
+	// for details.
 	Observe(float64)
 }
 
-var (
-	// DefObjectives are the default Summary quantile values.
-	DefObjectives = map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001}
-
-	errQuantileLabelNotAllowed = fmt.Errorf(
-		"%q is not allowed as label name in summaries", quantileLabel,
-	)
+var errQuantileLabelNotAllowed = fmt.Errorf(
+	"%q is not allowed as label name in summaries", quantileLabel,
 )
 
 // Default values for SummaryOpts.
@@ -75,8 +81,10 @@ const (
 )
 
 // SummaryOpts bundles the options for creating a Summary metric. It is
-// mandatory to set Name and Help to a non-empty string. All other fields are
-// optional and can safely be left at their zero value.
+// mandatory to set Name to a non-empty string. While all other fields are
+// optional and can safely be left at their zero value, it is recommended to set
+// a help string and to explicitly set the Objectives field to the desired value
+// as the default value will change in the upcoming v1.0.0 of the library.
 type SummaryOpts struct {
 	// Namespace, Subsystem, and Name are components of the fully-qualified
 	// name of the Summary (created by joining these components with
@@ -87,39 +95,40 @@ type SummaryOpts struct {
 	Subsystem string
 	Name      string
 
-	// Help provides information about this Summary. Mandatory!
+	// Help provides information about this Summary.
 	//
 	// Metrics with the same fully-qualified name must have the same Help
 	// string.
 	Help string
 
-	// ConstLabels are used to attach fixed labels to this
-	// Summary. Summaries with the same fully-qualified name must have the
-	// same label names in their ConstLabels.
+	// ConstLabels are used to attach fixed labels to this metric. Metrics
+	// with the same fully-qualified name must have the same label names in
+	// their ConstLabels.
 	//
-	// Note that in most cases, labels have a value that varies during the
-	// lifetime of a process. Those labels are usually managed with a
-	// SummaryVec. ConstLabels serve only special purposes. One is for the
-	// special case where the value of a label does not change during the
-	// lifetime of a process, e.g. if the revision of the running binary is
-	// put into a label. Another, more advanced purpose is if more than one
-	// Collector needs to collect Summaries with the same fully-qualified
-	// name. In that case, those Summaries must differ in the values of
-	// their ConstLabels. See the Collector examples.
+	// Due to the way a Summary is represented in the Prometheus text format
+	// and how it is handled by the Prometheus server internally, “quantile”
+	// is an illegal label name. Construction of a Summary or SummaryVec
+	// will panic if this label name is used in ConstLabels.
 	//
-	// If the value of a label never changes (not even between binaries),
-	// that label most likely should not be a label at all (but part of the
-	// metric name).
+	// ConstLabels are only used rarely. In particular, do not use them to
+	// attach the same labels to all your metrics. Those use cases are
+	// better covered by target labels set by the scraping Prometheus
+	// server, or by one specific metric (e.g. a build_info or a
+	// machine_role metric). See also
+	// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
 	ConstLabels Labels
 
 	// Objectives defines the quantile rank estimates with their respective
-	// absolute error. If Objectives[q] = e, then the value reported
-	// for q will be the φ-quantile value for some φ between q-e and q+e.
-	// The default value is DefObjectives.
+	// absolute error. If Objectives[q] = e, then the value reported for q
+	// will be the φ-quantile value for some φ between q-e and q+e.  The
+	// default value is an empty map, resulting in a summary without
+	// quantiles.
 	Objectives map[float64]float64
 
 	// MaxAge defines the duration for which an observation stays relevant
-	// for the summary. Must be positive. The default value is DefMaxAge.
+	// for the summary. Only applies to pre-calculated quantiles, does not
+	// apply to _sum and _count. Must be positive. The default value is
+	// DefMaxAge.
 	MaxAge time.Duration
 
 	// AgeBuckets is the number of buckets used to exclude observations that
@@ -139,11 +148,11 @@ type SummaryOpts struct {
 	BufCap uint32
 }
 
-// TODO: Great fuck-up with the sliding-window decay algorithm... The Merge
-// method of perk/quantile is actually not working as advertised - and it might
-// be unfixable, as the underlying algorithm is apparently not capable of
-// merging summaries in the first place. To avoid using Merge, we are currently
-// adding observations to _each_ age bucket, i.e. the effort to add a sample is
+// Problem with the sliding-window decay algorithm... The Merge method of
+// perk/quantile is actually not working as advertised - and it might be
+// unfixable, as the underlying algorithm is apparently not capable of merging
+// summaries in the first place. To avoid using Merge, we are currently adding
+// observations to _each_ age bucket, i.e. the effort to add a sample is
 // essentially multiplied by the number of age buckets. When rotating age
 // buckets, we empty the previous head stream. On scrape time, we simply take
 // the quantiles from the head stream (no merging required). Result: More effort
@@ -169,7 +178,7 @@ func NewSummary(opts SummaryOpts) Summary {
 
 func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	if len(desc.variableLabels) != len(labelValues) {
-		panic(errInconsistentCardinality)
+		panic(makeInconsistentCardinalityError(desc.fqName, desc.variableLabels, labelValues))
 	}
 
 	for _, n := range desc.variableLabels {
@@ -183,8 +192,8 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 		}
 	}
 
-	if len(opts.Objectives) == 0 {
-		opts.Objectives = DefObjectives
+	if opts.Objectives == nil {
+		opts.Objectives = map[float64]float64{}
 	}
 
 	if opts.MaxAge < 0 {
@@ -202,13 +211,24 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 		opts.BufCap = DefBufCap
 	}
 
+	if len(opts.Objectives) == 0 {
+		// Use the lock-free implementation of a Summary without objectives.
+		s := &noObjectivesSummary{
+			desc:       desc,
+			labelPairs: MakeLabelPairs(desc, labelValues),
+			counts:     [2]*summaryCounts{{}, {}},
+		}
+		s.init(s) // Init self-collection.
+		return s
+	}
+
 	s := &summary{
 		desc: desc,
 
 		objectives:       opts.Objectives,
 		sortedObjectives: make([]float64, 0, len(opts.Objectives)),
 
-		labelPairs: makeLabelPairs(desc, labelValues),
+		labelPairs: MakeLabelPairs(desc, labelValues),
 
 		hotBuf:         make([]float64, 0, opts.BufCap),
 		coldBuf:        make([]float64, 0, opts.BufCap),
@@ -227,12 +247,12 @@ func newSummary(desc *Desc, opts SummaryOpts, labelValues ...string) Summary {
 	}
 	sort.Float64s(s.sortedObjectives)
 
-	s.Init(s) // Init self-collection.
+	s.init(s) // Init self-collection.
 	return s
 }
 
 type summary struct {
-	SelfCollector
+	selfCollector
 
 	bufMtx sync.Mutex // Protects hotBuf and hotBufExpTime.
 	mtx    sync.Mutex // Protects every other moving part.
@@ -370,6 +390,116 @@ func (s *summary) swapBufs(now time.Time) {
 	}
 }
 
+type summaryCounts struct {
+	// sumBits contains the bits of the float64 representing the sum of all
+	// observations. sumBits and count have to go first in the struct to
+	// guarantee alignment for atomic operations.
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	sumBits uint64
+	count   uint64
+}
+
+type noObjectivesSummary struct {
+	// countAndHotIdx enables lock-free writes with use of atomic updates.
+	// The most significant bit is the hot index [0 or 1] of the count field
+	// below. Observe calls update the hot one. All remaining bits count the
+	// number of Observe calls. Observe starts by incrementing this counter,
+	// and finish by incrementing the count field in the respective
+	// summaryCounts, as a marker for completion.
+	//
+	// Calls of the Write method (which are non-mutating reads from the
+	// perspective of the summary) swap the hot–cold under the writeMtx
+	// lock. A cooldown is awaited (while locked) by comparing the number of
+	// observations with the initiation count. Once they match, then the
+	// last observation on the now cool one has completed. All cool fields must
+	// be merged into the new hot before releasing writeMtx.
+
+	// Fields with atomic access first! See alignment constraint:
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG
+	countAndHotIdx uint64
+
+	selfCollector
+	desc     *Desc
+	writeMtx sync.Mutex // Only used in the Write method.
+
+	// Two counts, one is "hot" for lock-free observations, the other is
+	// "cold" for writing out a dto.Metric. It has to be an array of
+	// pointers to guarantee 64bit alignment of the histogramCounts, see
+	// http://golang.org/pkg/sync/atomic/#pkg-note-BUG.
+	counts [2]*summaryCounts
+
+	labelPairs []*dto.LabelPair
+}
+
+func (s *noObjectivesSummary) Desc() *Desc {
+	return s.desc
+}
+
+func (s *noObjectivesSummary) Observe(v float64) {
+	// We increment h.countAndHotIdx so that the counter in the lower
+	// 63 bits gets incremented. At the same time, we get the new value
+	// back, which we can use to find the currently-hot counts.
+	n := atomic.AddUint64(&s.countAndHotIdx, 1)
+	hotCounts := s.counts[n>>63]
+
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + v)
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			break
+		}
+	}
+	// Increment count last as we take it as a signal that the observation
+	// is complete.
+	atomic.AddUint64(&hotCounts.count, 1)
+}
+
+func (s *noObjectivesSummary) Write(out *dto.Metric) error {
+	// For simplicity, we protect this whole method by a mutex. It is not in
+	// the hot path, i.e. Observe is called much more often than Write. The
+	// complication of making Write lock-free isn't worth it, if possible at
+	// all.
+	s.writeMtx.Lock()
+	defer s.writeMtx.Unlock()
+
+	// Adding 1<<63 switches the hot index (from 0 to 1 or from 1 to 0)
+	// without touching the count bits. See the struct comments for a full
+	// description of the algorithm.
+	n := atomic.AddUint64(&s.countAndHotIdx, 1<<63)
+	// count is contained unchanged in the lower 63 bits.
+	count := n & ((1 << 63) - 1)
+	// The most significant bit tells us which counts is hot. The complement
+	// is thus the cold one.
+	hotCounts := s.counts[n>>63]
+	coldCounts := s.counts[(^n)>>63]
+
+	// Await cooldown.
+	for count != atomic.LoadUint64(&coldCounts.count) {
+		runtime.Gosched() // Let observations get work done.
+	}
+
+	sum := &dto.Summary{
+		SampleCount: proto.Uint64(count),
+		SampleSum:   proto.Float64(math.Float64frombits(atomic.LoadUint64(&coldCounts.sumBits))),
+	}
+
+	out.Summary = sum
+	out.Label = s.labelPairs
+
+	// Finally add all the cold counts to the new hot counts and reset the cold counts.
+	atomic.AddUint64(&hotCounts.count, count)
+	atomic.StoreUint64(&coldCounts.count, 0)
+	for {
+		oldBits := atomic.LoadUint64(&hotCounts.sumBits)
+		newBits := math.Float64bits(math.Float64frombits(oldBits) + sum.GetSampleSum())
+		if atomic.CompareAndSwapUint64(&hotCounts.sumBits, oldBits, newBits) {
+			atomic.StoreUint64(&coldCounts.sumBits, 0)
+			break
+		}
+	}
+	return nil
+}
+
 type quantSort []*dto.Quantile
 
 func (s quantSort) Len() int {
@@ -390,13 +520,21 @@ func (s quantSort) Less(i, j int) bool {
 // (e.g. HTTP request latencies, partitioned by status code and method). Create
 // instances with NewSummaryVec.
 type SummaryVec struct {
-	MetricVec
+	*MetricVec
 }
 
 // NewSummaryVec creates a new SummaryVec based on the provided SummaryOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
+// partitioned by the given label names.
+//
+// Due to the way a Summary is represented in the Prometheus text format and how
+// it is handled by the Prometheus server internally, “quantile” is an illegal
+// label name. NewSummaryVec will panic if this label name is used.
 func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
+	for _, ln := range labelNames {
+		if ln == quantileLabel {
+			panic(errQuantileLabelNotAllowed)
+		}
+	}
 	desc := NewDesc(
 		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
 		opts.Help,
@@ -404,51 +542,116 @@ func NewSummaryVec(opts SummaryOpts, labelNames []string) *SummaryVec {
 		opts.ConstLabels,
 	)
 	return &SummaryVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
-				return newSummary(desc, opts, lvs...)
-			},
-		},
+		MetricVec: NewMetricVec(desc, func(lvs ...string) Metric {
+			return newSummary(desc, opts, lvs...)
+		}),
 	}
 }
 
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns a Summary and not a
-// Metric so that no type conversion is required.
-func (m *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Summary, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
+// GetMetricWithLabelValues returns the Summary for the given slice of label
+// values (same order as the variable labels in Desc). If that combination of
+// label values is accessed for the first time, a new Summary is created.
+//
+// It is possible to call this method without using the returned Summary to only
+// create the new Summary but leave it at its starting value, a Summary without
+// any observations.
+//
+// Keeping the Summary for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Summary from the SummaryVec. In that case,
+// the Summary will still exist, but it will not be exported anymore, even if a
+// Summary with the same label values is created later. See also the CounterVec
+// example.
+//
+// An error is returned if the number of label values is not the same as the
+// number of variable labels in Desc (minus any curried labels).
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+// See also the GaugeVec example.
+func (v *SummaryVec) GetMetricWithLabelValues(lvs ...string) (Observer, error) {
+	metric, err := v.MetricVec.GetMetricWithLabelValues(lvs...)
 	if metric != nil {
-		return metric.(Summary), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns a Summary and not a Metric so that no
-// type conversion is required.
-func (m *SummaryVec) GetMetricWith(labels Labels) (Summary, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
+// GetMetricWith returns the Summary for the given Labels map (the label names
+// must match those of the variable labels in Desc). If that label map is
+// accessed for the first time, a new Summary is created. Implications of
+// creating a Summary without using it and keeping the Summary for later use are
+// the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the variable labels in Desc (minus any curried labels).
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+func (v *SummaryVec) GetMetricWith(labels Labels) (Observer, error) {
+	metric, err := v.MetricVec.GetMetricWith(labels)
 	if metric != nil {
-		return metric.(Summary), err
+		return metric.(Observer), err
 	}
 	return nil, err
 }
 
 // WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
+// GetMetricWithLabelValues would have returned an error. Not returning an
+// error allows shortcuts like
 //     myVec.WithLabelValues("404", "GET").Observe(42.21)
-func (m *SummaryVec) WithLabelValues(lvs ...string) Summary {
-	return m.MetricVec.WithLabelValues(lvs...).(Summary)
+func (v *SummaryVec) WithLabelValues(lvs ...string) Observer {
+	s, err := v.GetMetricWithLabelValues(lvs...)
+	if err != nil {
+		panic(err)
+	}
+	return s
 }
 
 // With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Observe(42.21)
-func (m *SummaryVec) With(labels Labels) Summary {
-	return m.MetricVec.With(labels).(Summary)
+// returned an error. Not returning an error allows shortcuts like
+//     myVec.With(prometheus.Labels{"code": "404", "method": "GET"}).Observe(42.21)
+func (v *SummaryVec) With(labels Labels) Observer {
+	s, err := v.GetMetricWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return s
+}
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the SummaryVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+func (v *SummaryVec) CurryWith(labels Labels) (ObserverVec, error) {
+	vec, err := v.MetricVec.CurryWith(labels)
+	if vec != nil {
+		return &SummaryVec{vec}, err
+	}
+	return nil, err
+}
+
+// MustCurryWith works as CurryWith but panics where CurryWith would have
+// returned an error.
+func (v *SummaryVec) MustCurryWith(labels Labels) ObserverVec {
+	vec, err := v.CurryWith(labels)
+	if err != nil {
+		panic(err)
+	}
+	return vec
 }
 
 type constSummary struct {
@@ -501,7 +704,7 @@ func (s *constSummary) Write(out *dto.Metric) error {
 //     map[float64]float64{0.5: 0.23, 0.99: 0.56}
 //
 // NewConstSummary returns an error if the length of labelValues is not
-// consistent with the variable labels in Desc.
+// consistent with the variable labels in Desc or if Desc is invalid.
 func NewConstSummary(
 	desc *Desc,
 	count uint64,
@@ -509,15 +712,18 @@ func NewConstSummary(
 	quantiles map[float64]float64,
 	labelValues ...string,
 ) (Metric, error) {
-	if len(desc.variableLabels) != len(labelValues) {
-		return nil, errInconsistentCardinality
+	if desc.err != nil {
+		return nil, desc.err
+	}
+	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
+		return nil, err
 	}
 	return &constSummary{
 		desc:       desc,
 		count:      count,
 		sum:        sum,
 		quantiles:  quantiles,
-		labelPairs: makeLabelPairs(desc, labelValues),
+		labelPairs: MakeLabelPairs(desc, labelValues),
 	}, nil
 }
 

vendor/github.com/prometheus/client_golang/prometheus/timer.go

@@ -0,0 +1,54 @@
+// Copyright 2016 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import "time"
+
+// Timer is a helper type to time functions. Use NewTimer to create new
+// instances.
+type Timer struct {
+	begin    time.Time
+	observer Observer
+}
+
+// NewTimer creates a new Timer. The provided Observer is used to observe a
+// duration in seconds. Timer is usually used to time a function call in the
+// following way:
+//    func TimeMe() {
+//        timer := NewTimer(myHistogram)
+//        defer timer.ObserveDuration()
+//        // Do actual work.
+//    }
+func NewTimer(o Observer) *Timer {
+	return &Timer{
+		begin:    time.Now(),
+		observer: o,
+	}
+}
+
+// ObserveDuration records the duration passed since the Timer was created with
+// NewTimer. It calls the Observe method of the Observer provided during
+// construction with the duration in seconds as an argument. The observed
+// duration is also returned. ObserveDuration is usually called with a defer
+// statement.
+//
+// Note that this method is only guaranteed to never observe negative durations
+// if used with Go1.9+.
+func (t *Timer) ObserveDuration() time.Duration {
+	d := time.Since(t.begin)
+	if t.observer != nil {
+		t.observer.Observe(d.Seconds())
+	}
+	return d
+}

vendor/github.com/prometheus/client_golang/prometheus/untyped.go

@@ -13,112 +13,12 @@
 
 package prometheus
 
-// Untyped is a Metric that represents a single numerical value that can
-// arbitrarily go up and down.
-//
-// An Untyped metric works the same as a Gauge. The only difference is that to
-// no type information is implied.
-//
-// To create Untyped instances, use NewUntyped.
-type Untyped interface {
-	Metric
-	Collector
-
-	// Set sets the Untyped metric to an arbitrary value.
-	Set(float64)
-	// Inc increments the Untyped metric by 1.
-	Inc()
-	// Dec decrements the Untyped metric by 1.
-	Dec()
-	// Add adds the given value to the Untyped metric. (The value can be
-	// negative, resulting in a decrease.)
-	Add(float64)
-	// Sub subtracts the given value from the Untyped metric. (The value can
-	// be negative, resulting in an increase.)
-	Sub(float64)
-}
-
 // UntypedOpts is an alias for Opts. See there for doc comments.
 type UntypedOpts Opts
 
-// NewUntyped creates a new Untyped metric from the provided UntypedOpts.
-func NewUntyped(opts UntypedOpts) Untyped {
-	return newValue(NewDesc(
-		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
-		opts.Help,
-		nil,
-		opts.ConstLabels,
-	), UntypedValue, 0)
-}
-
-// UntypedVec is a Collector that bundles a set of Untyped metrics that all
-// share the same Desc, but have different values for their variable
-// labels. This is used if you want to count the same thing partitioned by
-// various dimensions. Create instances with NewUntypedVec.
-type UntypedVec struct {
-	MetricVec
-}
-
-// NewUntypedVec creates a new UntypedVec based on the provided UntypedOpts and
-// partitioned by the given label names. At least one label name must be
-// provided.
-func NewUntypedVec(opts UntypedOpts, labelNames []string) *UntypedVec {
-	desc := NewDesc(
-		BuildFQName(opts.Namespace, opts.Subsystem, opts.Name),
-		opts.Help,
-		labelNames,
-		opts.ConstLabels,
-	)
-	return &UntypedVec{
-		MetricVec: MetricVec{
-			children: map[uint64]Metric{},
-			desc:     desc,
-			newMetric: func(lvs ...string) Metric {
-				return newValue(desc, UntypedValue, 0, lvs...)
-			},
-		},
-	}
-}
-
-// GetMetricWithLabelValues replaces the method of the same name in
-// MetricVec. The difference is that this method returns an Untyped and not a
-// Metric so that no type conversion is required.
-func (m *UntypedVec) GetMetricWithLabelValues(lvs ...string) (Untyped, error) {
-	metric, err := m.MetricVec.GetMetricWithLabelValues(lvs...)
-	if metric != nil {
-		return metric.(Untyped), err
-	}
-	return nil, err
-}
-
-// GetMetricWith replaces the method of the same name in MetricVec. The
-// difference is that this method returns an Untyped and not a Metric so that no
-// type conversion is required.
-func (m *UntypedVec) GetMetricWith(labels Labels) (Untyped, error) {
-	metric, err := m.MetricVec.GetMetricWith(labels)
-	if metric != nil {
-		return metric.(Untyped), err
-	}
-	return nil, err
-}
-
-// WithLabelValues works as GetMetricWithLabelValues, but panics where
-// GetMetricWithLabelValues would have returned an error. By not returning an
-// error, WithLabelValues allows shortcuts like
-//     myVec.WithLabelValues("404", "GET").Add(42)
-func (m *UntypedVec) WithLabelValues(lvs ...string) Untyped {
-	return m.MetricVec.WithLabelValues(lvs...).(Untyped)
-}
-
-// With works as GetMetricWith, but panics where GetMetricWithLabels would have
-// returned an error. By not returning an error, With allows shortcuts like
-//     myVec.With(Labels{"code": "404", "method": "GET"}).Add(42)
-func (m *UntypedVec) With(labels Labels) Untyped {
-	return m.MetricVec.With(labels).(Untyped)
-}
-
-// UntypedFunc is an Untyped whose value is determined at collect time by
-// calling a provided function.
+// UntypedFunc works like GaugeFunc but the collected metric is of type
+// "Untyped". UntypedFunc is useful to mirror an external metric of unknown
+// type.
 //
 // To create UntypedFunc instances, use NewUntypedFunc.
 type UntypedFunc interface {

vendor/github.com/prometheus/client_golang/prometheus/value.go

@@ -14,21 +14,23 @@
 package prometheus
 
 import (
-	"errors"
 	"fmt"
-	"math"
 	"sort"
-	"sync/atomic"
+	"time"
+	"unicode/utf8"
+
+	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
+	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/ptypes"
 
 	dto "github.com/prometheus/client_model/go"
-
-	"github.com/golang/protobuf/proto"
 )
 
 // ValueType is an enumeration of metric types that represent a simple value.
 type ValueType int
 
-// Possible values for the ValueType enum.
+// Possible values for the ValueType enum. Use UntypedValue to mark a metric
+// with an unknown type.
 const (
 	_ ValueType = iota
 	CounterValue
@@ -36,84 +38,13 @@ const (
 	UntypedValue
 )
 
-var errInconsistentCardinality = errors.New("inconsistent label cardinality")
-
-// value is a generic metric for simple values. It implements Metric, Collector,
-// Counter, Gauge, and Untyped. Its effective type is determined by
-// ValueType. This is a low-level building block used by the library to back the
-// implementations of Counter, Gauge, and Untyped.
-type value struct {
-	// valBits containst the bits of the represented float64 value. It has
-	// to go first in the struct to guarantee alignment for atomic
-	// operations.  http://golang.org/pkg/sync/atomic/#pkg-note-BUG
-	valBits uint64
-
-	SelfCollector
-
-	desc       *Desc
-	valType    ValueType
-	labelPairs []*dto.LabelPair
-}
-
-// newValue returns a newly allocated value with the given Desc, ValueType,
-// sample value and label values. It panics if the number of label
-// values is different from the number of variable labels in Desc.
-func newValue(desc *Desc, valueType ValueType, val float64, labelValues ...string) *value {
-	if len(labelValues) != len(desc.variableLabels) {
-		panic(errInconsistentCardinality)
-	}
-	result := &value{
-		desc:       desc,
-		valType:    valueType,
-		valBits:    math.Float64bits(val),
-		labelPairs: makeLabelPairs(desc, labelValues),
-	}
-	result.Init(result)
-	return result
-}
-
-func (v *value) Desc() *Desc {
-	return v.desc
-}
-
-func (v *value) Set(val float64) {
-	atomic.StoreUint64(&v.valBits, math.Float64bits(val))
-}
-
-func (v *value) Inc() {
-	v.Add(1)
-}
-
-func (v *value) Dec() {
-	v.Add(-1)
-}
-
-func (v *value) Add(val float64) {
-	for {
-		oldBits := atomic.LoadUint64(&v.valBits)
-		newBits := math.Float64bits(math.Float64frombits(oldBits) + val)
-		if atomic.CompareAndSwapUint64(&v.valBits, oldBits, newBits) {
-			return
-		}
-	}
-}
-
-func (v *value) Sub(val float64) {
-	v.Add(val * -1)
-}
-
-func (v *value) Write(out *dto.Metric) error {
-	val := math.Float64frombits(atomic.LoadUint64(&v.valBits))
-	return populateMetric(v.valType, val, v.labelPairs, out)
-}
-
 // valueFunc is a generic metric for simple values retrieved on collect time
 // from a function. It implements Metric and Collector. Its effective type is
 // determined by ValueType. This is a low-level building block used by the
 // library to back the implementations of CounterFunc, GaugeFunc, and
 // UntypedFunc.
 type valueFunc struct {
-	SelfCollector
+	selfCollector
 
 	desc       *Desc
 	valType    ValueType
@@ -132,9 +63,9 @@ func newValueFunc(desc *Desc, valueType ValueType, function func() float64) *val
 		desc:       desc,
 		valType:    valueType,
 		function:   function,
-		labelPairs: makeLabelPairs(desc, nil),
+		labelPairs: MakeLabelPairs(desc, nil),
 	}
-	result.Init(result)
+	result.init(result)
 	return result
 }
 
@@ -143,7 +74,7 @@ func (v *valueFunc) Desc() *Desc {
 }
 
 func (v *valueFunc) Write(out *dto.Metric) error {
-	return populateMetric(v.valType, v.function(), v.labelPairs, out)
+	return populateMetric(v.valType, v.function(), v.labelPairs, nil, out)
 }
 
 // NewConstMetric returns a metric with one fixed value that cannot be
@@ -151,16 +82,20 @@ func (v *valueFunc) Write(out *dto.Metric) error {
 // operations. However, when implementing custom Collectors, it is useful as a
 // throw-away metric that is generated on the fly to send it to Prometheus in
 // the Collect method. NewConstMetric returns an error if the length of
-// labelValues is not consistent with the variable labels in Desc.
+// labelValues is not consistent with the variable labels in Desc or if Desc is
+// invalid.
 func NewConstMetric(desc *Desc, valueType ValueType, value float64, labelValues ...string) (Metric, error) {
-	if len(desc.variableLabels) != len(labelValues) {
-		return nil, errInconsistentCardinality
+	if desc.err != nil {
+		return nil, desc.err
+	}
+	if err := validateLabelValues(labelValues, len(desc.variableLabels)); err != nil {
+		return nil, err
 	}
 	return &constMetric{
 		desc:       desc,
 		valType:    valueType,
 		val:        value,
-		labelPairs: makeLabelPairs(desc, labelValues),
+		labelPairs: MakeLabelPairs(desc, labelValues),
 	}, nil
 }
 
@@ -186,19 +121,20 @@ func (m *constMetric) Desc() *Desc {
 }
 
 func (m *constMetric) Write(out *dto.Metric) error {
-	return populateMetric(m.valType, m.val, m.labelPairs, out)
+	return populateMetric(m.valType, m.val, m.labelPairs, nil, out)
 }
 
 func populateMetric(
 	t ValueType,
 	v float64,
 	labelPairs []*dto.LabelPair,
+	e *dto.Exemplar,
 	m *dto.Metric,
 ) error {
 	m.Label = labelPairs
 	switch t {
 	case CounterValue:
-		m.Counter = &dto.Counter{Value: proto.Float64(v)}
+		m.Counter = &dto.Counter{Value: proto.Float64(v), Exemplar: e}
 	case GaugeValue:
 		m.Gauge = &dto.Gauge{Value: proto.Float64(v)}
 	case UntypedValue:
@@ -209,7 +145,14 @@ func populateMetric(
 	return nil
 }
 
-func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
+// MakeLabelPairs is a helper function to create protobuf LabelPairs from the
+// variable and constant labels in the provided Desc. The values for the
+// variable labels are defined by the labelValues slice, which must be in the
+// same order as the corresponding variable labels in the Desc.
+//
+// This function is only needed for custom Metric implementations. See MetricVec
+// example.
+func MakeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 	totalLen := len(desc.variableLabels) + len(desc.constLabelPairs)
 	if totalLen == 0 {
 		// Super fast path.
@@ -226,9 +169,44 @@ func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 			Value: proto.String(labelValues[i]),
 		})
 	}
-	for _, lp := range desc.constLabelPairs {
-		labelPairs = append(labelPairs, lp)
-	}
-	sort.Sort(LabelPairSorter(labelPairs))
+	labelPairs = append(labelPairs, desc.constLabelPairs...)
+	sort.Sort(labelPairSorter(labelPairs))
 	return labelPairs
 }
+
+// ExemplarMaxRunes is the max total number of runes allowed in exemplar labels.
+const ExemplarMaxRunes = 64
+
+// newExemplar creates a new dto.Exemplar from the provided values. An error is
+// returned if any of the label names or values are invalid or if the total
+// number of runes in the label names and values exceeds ExemplarMaxRunes.
+func newExemplar(value float64, ts time.Time, l Labels) (*dto.Exemplar, error) {
+	e := &dto.Exemplar{}
+	e.Value = proto.Float64(value)
+	tsProto, err := ptypes.TimestampProto(ts)
+	if err != nil {
+		return nil, err
+	}
+	e.Timestamp = tsProto
+	labelPairs := make([]*dto.LabelPair, 0, len(l))
+	var runes int
+	for name, value := range l {
+		if !checkLabelName(name) {
+			return nil, fmt.Errorf("exemplar label name %q is invalid", name)
+		}
+		runes += utf8.RuneCountInString(name)
+		if !utf8.ValidString(value) {
+			return nil, fmt.Errorf("exemplar label value %q is not valid UTF-8", value)
+		}
+		runes += utf8.RuneCountInString(value)
+		labelPairs = append(labelPairs, &dto.LabelPair{
+			Name:  proto.String(name),
+			Value: proto.String(value),
+		})
+	}
+	if runes > ExemplarMaxRunes {
+		return nil, fmt.Errorf("exemplar labels have %d runes, exceeding the limit of %d", runes, ExemplarMaxRunes)
+	}
+	e.Label = labelPairs
+	return e, nil
+}

vendor/github.com/prometheus/client_golang/prometheus/vec.go

@@ -16,142 +16,53 @@ package prometheus
 import (
 	"fmt"
 	"sync"
+
+	"github.com/prometheus/common/model"
 )
 
-// MetricVec is a Collector to bundle metrics of the same name that
-// differ in their label values. MetricVec is usually not used directly but as a
-// building block for implementations of vectors of a given metric
-// type. GaugeVec, CounterVec, SummaryVec, and UntypedVec are examples already
-// provided in this package.
+// MetricVec is a Collector to bundle metrics of the same name that differ in
+// their label values. MetricVec is not used directly but as a building block
+// for implementations of vectors of a given metric type, like GaugeVec,
+// CounterVec, SummaryVec, and HistogramVec. It is exported so that it can be
+// used for custom Metric implementations.
+//
+// To create a FooVec for custom Metric Foo, embed a pointer to MetricVec in
+// FooVec and initialize it with NewMetricVec. Implement wrappers for
+// GetMetricWithLabelValues and GetMetricWith that return (Foo, error) rather
+// than (Metric, error). Similarly, create a wrapper for CurryWith that returns
+// (*FooVec, error) rather than (*MetricVec, error). It is recommended to also
+// add the convenience methods WithLabelValues, With, and MustCurryWith, which
+// panic instead of returning errors. See also the MetricVec example.
 type MetricVec struct {
-	mtx      sync.RWMutex // Protects the children.
-	children map[uint64]Metric
-	desc     *Desc
+	*metricMap
 
-	newMetric func(labelValues ...string) Metric
+	curry []curriedLabelValue
+
+	// hashAdd and hashAddByte can be replaced for testing collision handling.
+	hashAdd     func(h uint64, s string) uint64
+	hashAddByte func(h uint64, b byte) uint64
 }
 
-// Describe implements Collector. The length of the returned slice
-// is always one.
-func (m *MetricVec) Describe(ch chan<- *Desc) {
-	ch <- m.desc
-}
-
-// Collect implements Collector.
-func (m *MetricVec) Collect(ch chan<- Metric) {
-	m.mtx.RLock()
-	defer m.mtx.RUnlock()
-
-	for _, metric := range m.children {
-		ch <- metric
+// NewMetricVec returns an initialized metricVec.
+func NewMetricVec(desc *Desc, newMetric func(lvs ...string) Metric) *MetricVec {
+	return &MetricVec{
+		metricMap: &metricMap{
+			metrics:   map[uint64][]metricWithLabelValues{},
+			desc:      desc,
+			newMetric: newMetric,
+		},
+		hashAdd:     hashAdd,
+		hashAddByte: hashAddByte,
 	}
 }
 
-// GetMetricWithLabelValues returns the Metric for the given slice of label
-// values (same order as the VariableLabels in Desc). If that combination of
-// label values is accessed for the first time, a new Metric is created.
-//
-// It is possible to call this method without using the returned Metric to only
-// create the new Metric but leave it at its start value (e.g. a Summary or
-// Histogram without any observations). See also the SummaryVec example.
-//
-// Keeping the Metric for later use is possible (and should be considered if
-// performance is critical), but keep in mind that Reset, DeleteLabelValues and
-// Delete can be used to delete the Metric from the MetricVec. In that case, the
-// Metric will still exist, but it will not be exported anymore, even if a
-// Metric with the same label values is created later. See also the CounterVec
-// example.
-//
-// An error is returned if the number of label values is not the same as the
-// number of VariableLabels in Desc.
-//
-// Note that for more than one label value, this method is prone to mistakes
-// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
-// an alternative to avoid that type of mistake. For higher label numbers, the
-// latter has a much more readable (albeit more verbose) syntax, but it comes
-// with a performance overhead (for creating and processing the Labels map).
-// See also the GaugeVec example.
-func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
-	h, err := m.hashLabelValues(lvs)
-	if err != nil {
-		return nil, err
-	}
-
-	m.mtx.RLock()
-	metric, ok := m.children[h]
-	m.mtx.RUnlock()
-	if ok {
-		return metric, nil
-	}
-
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-	return m.getOrCreateMetric(h, lvs...), nil
-}
-
-// GetMetricWith returns the Metric for the given Labels map (the label names
-// must match those of the VariableLabels in Desc). If that label map is
-// accessed for the first time, a new Metric is created. Implications of
-// creating a Metric without using it and keeping the Metric for later use are
-// the same as for GetMetricWithLabelValues.
-//
-// An error is returned if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in Desc.
-//
-// This method is used for the same purpose as
-// GetMetricWithLabelValues(...string). See there for pros and cons of the two
-// methods.
-func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) {
-	h, err := m.hashLabels(labels)
-	if err != nil {
-		return nil, err
-	}
-
-	m.mtx.RLock()
-	metric, ok := m.children[h]
-	m.mtx.RUnlock()
-	if ok {
-		return metric, nil
-	}
-
-	lvs := make([]string, len(labels))
-	for i, label := range m.desc.variableLabels {
-		lvs[i] = labels[label]
-	}
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-	return m.getOrCreateMetric(h, lvs...), nil
-}
-
-// WithLabelValues works as GetMetricWithLabelValues, but panics if an error
-// occurs. The method allows neat syntax like:
-//     httpReqs.WithLabelValues("404", "POST").Inc()
-func (m *MetricVec) WithLabelValues(lvs ...string) Metric {
-	metric, err := m.GetMetricWithLabelValues(lvs...)
-	if err != nil {
-		panic(err)
-	}
-	return metric
-}
-
-// With works as GetMetricWith, but panics if an error occurs. The method allows
-// neat syntax like:
-//     httpReqs.With(Labels{"status":"404", "method":"POST"}).Inc()
-func (m *MetricVec) With(labels Labels) Metric {
-	metric, err := m.GetMetricWith(labels)
-	if err != nil {
-		panic(err)
-	}
-	return metric
-}
-
 // DeleteLabelValues removes the metric where the variable labels are the same
 // as those passed in as labels (same order as the VariableLabels in Desc). It
 // returns true if a metric was deleted.
 //
 // It is not an error if the number of label values is not the same as the
-// number of VariableLabels in Desc.  However, such inconsistent label count can
-// never match an actual Metric, so the method will always return false in that
+// number of VariableLabels in Desc. However, such inconsistent label count can
+// never match an actual metric, so the method will always return false in that
 // case.
 //
 // Note that for more than one label value, this method is prone to mistakes
@@ -161,89 +72,485 @@ func (m *MetricVec) With(labels Labels) Metric {
 // with a performance overhead (for creating and processing the Labels map).
 // See also the CounterVec example.
 func (m *MetricVec) DeleteLabelValues(lvs ...string) bool {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-
 	h, err := m.hashLabelValues(lvs)
 	if err != nil {
 		return false
 	}
-	if _, ok := m.children[h]; !ok {
-		return false
-	}
-	delete(m.children, h)
-	return true
+
+	return m.metricMap.deleteByHashWithLabelValues(h, lvs, m.curry)
 }
 
 // Delete deletes the metric where the variable labels are the same as those
 // passed in as labels. It returns true if a metric was deleted.
 //
 // It is not an error if the number and names of the Labels are inconsistent
-// with those of the VariableLabels in the Desc of the MetricVec. However, such
-// inconsistent Labels can never match an actual Metric, so the method will
-// always return false in that case.
+// with those of the VariableLabels in Desc. However, such inconsistent Labels
+// can never match an actual metric, so the method will always return false in
+// that case.
 //
 // This method is used for the same purpose as DeleteLabelValues(...string). See
 // there for pros and cons of the two methods.
 func (m *MetricVec) Delete(labels Labels) bool {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
-
 	h, err := m.hashLabels(labels)
 	if err != nil {
 		return false
 	}
-	if _, ok := m.children[h]; !ok {
-		return false
-	}
-	delete(m.children, h)
-	return true
+
+	return m.metricMap.deleteByHashWithLabels(h, labels, m.curry)
 }
 
-// Reset deletes all metrics in this vector.
-func (m *MetricVec) Reset() {
-	m.mtx.Lock()
-	defer m.mtx.Unlock()
+// Without explicit forwarding of Describe, Collect, Reset, those methods won't
+// show up in GoDoc.
 
-	for h := range m.children {
-		delete(m.children, h)
+// Describe implements Collector.
+func (m *MetricVec) Describe(ch chan<- *Desc) { m.metricMap.Describe(ch) }
+
+// Collect implements Collector.
+func (m *MetricVec) Collect(ch chan<- Metric) { m.metricMap.Collect(ch) }
+
+// Reset deletes all metrics in this vector.
+func (m *MetricVec) Reset() { m.metricMap.Reset() }
+
+// CurryWith returns a vector curried with the provided labels, i.e. the
+// returned vector has those labels pre-set for all labeled operations performed
+// on it. The cardinality of the curried vector is reduced accordingly. The
+// order of the remaining labels stays the same (just with the curried labels
+// taken out of the sequence – which is relevant for the
+// (GetMetric)WithLabelValues methods). It is possible to curry a curried
+// vector, but only with labels not yet used for currying before.
+//
+// The metrics contained in the MetricVec are shared between the curried and
+// uncurried vectors. They are just accessed differently. Curried and uncurried
+// vectors behave identically in terms of collection. Only one must be
+// registered with a given registry (usually the uncurried version). The Reset
+// method deletes all metrics, even if called on a curried vector.
+//
+// Note that CurryWith is usually not called directly but through a wrapper
+// around MetricVec, implementing a vector for a specific Metric
+// implementation, for example GaugeVec.
+func (m *MetricVec) CurryWith(labels Labels) (*MetricVec, error) {
+	var (
+		newCurry []curriedLabelValue
+		oldCurry = m.curry
+		iCurry   int
+	)
+	for i, label := range m.desc.variableLabels {
+		val, ok := labels[label]
+		if iCurry < len(oldCurry) && oldCurry[iCurry].index == i {
+			if ok {
+				return nil, fmt.Errorf("label name %q is already curried", label)
+			}
+			newCurry = append(newCurry, oldCurry[iCurry])
+			iCurry++
+		} else {
+			if !ok {
+				continue // Label stays uncurried.
+			}
+			newCurry = append(newCurry, curriedLabelValue{i, val})
+		}
 	}
+	if l := len(oldCurry) + len(labels) - len(newCurry); l > 0 {
+		return nil, fmt.Errorf("%d unknown label(s) found during currying", l)
+	}
+
+	return &MetricVec{
+		metricMap:   m.metricMap,
+		curry:       newCurry,
+		hashAdd:     m.hashAdd,
+		hashAddByte: m.hashAddByte,
+	}, nil
+}
+
+// GetMetricWithLabelValues returns the Metric for the given slice of label
+// values (same order as the variable labels in Desc). If that combination of
+// label values is accessed for the first time, a new Metric is created (by
+// calling the newMetric function provided during construction of the
+// MetricVec).
+//
+// It is possible to call this method without using the returned Metric to only
+// create the new Metric but leave it in its initial state.
+//
+// Keeping the Metric for later use is possible (and should be considered if
+// performance is critical), but keep in mind that Reset, DeleteLabelValues and
+// Delete can be used to delete the Metric from the MetricVec. In that case, the
+// Metric will still exist, but it will not be exported anymore, even if a
+// Metric with the same label values is created later.
+//
+// An error is returned if the number of label values is not the same as the
+// number of variable labels in Desc (minus any curried labels).
+//
+// Note that for more than one label value, this method is prone to mistakes
+// caused by an incorrect order of arguments. Consider GetMetricWith(Labels) as
+// an alternative to avoid that type of mistake. For higher label numbers, the
+// latter has a much more readable (albeit more verbose) syntax, but it comes
+// with a performance overhead (for creating and processing the Labels map).
+//
+// Note that GetMetricWithLabelValues is usually not called directly but through
+// a wrapper around MetricVec, implementing a vector for a specific Metric
+// implementation, for example GaugeVec.
+func (m *MetricVec) GetMetricWithLabelValues(lvs ...string) (Metric, error) {
+	h, err := m.hashLabelValues(lvs)
+	if err != nil {
+		return nil, err
+	}
+
+	return m.metricMap.getOrCreateMetricWithLabelValues(h, lvs, m.curry), nil
+}
+
+// GetMetricWith returns the Metric for the given Labels map (the label names
+// must match those of the variable labels in Desc). If that label map is
+// accessed for the first time, a new Metric is created. Implications of
+// creating a Metric without using it and keeping the Metric for later use
+// are the same as for GetMetricWithLabelValues.
+//
+// An error is returned if the number and names of the Labels are inconsistent
+// with those of the variable labels in Desc (minus any curried labels).
+//
+// This method is used for the same purpose as
+// GetMetricWithLabelValues(...string). See there for pros and cons of the two
+// methods.
+//
+// Note that GetMetricWith is usually not called directly but through a wrapper
+// around MetricVec, implementing a vector for a specific Metric implementation,
+// for example GaugeVec.
+func (m *MetricVec) GetMetricWith(labels Labels) (Metric, error) {
+	h, err := m.hashLabels(labels)
+	if err != nil {
+		return nil, err
+	}
+
+	return m.metricMap.getOrCreateMetricWithLabels(h, labels, m.curry), nil
 }
 
 func (m *MetricVec) hashLabelValues(vals []string) (uint64, error) {
-	if len(vals) != len(m.desc.variableLabels) {
-		return 0, errInconsistentCardinality
+	if err := validateLabelValues(vals, len(m.desc.variableLabels)-len(m.curry)); err != nil {
+		return 0, err
 	}
-	h := hashNew()
-	for _, val := range vals {
-		h = hashAdd(h, val)
+
+	var (
+		h             = hashNew()
+		curry         = m.curry
+		iVals, iCurry int
+	)
+	for i := 0; i < len(m.desc.variableLabels); i++ {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			h = m.hashAdd(h, curry[iCurry].value)
+			iCurry++
+		} else {
+			h = m.hashAdd(h, vals[iVals])
+			iVals++
+		}
+		h = m.hashAddByte(h, model.SeparatorByte)
 	}
 	return h, nil
 }
 
 func (m *MetricVec) hashLabels(labels Labels) (uint64, error) {
-	if len(labels) != len(m.desc.variableLabels) {
-		return 0, errInconsistentCardinality
+	if err := validateValuesInLabels(labels, len(m.desc.variableLabels)-len(m.curry)); err != nil {
+		return 0, err
 	}
-	h := hashNew()
-	for _, label := range m.desc.variableLabels {
+
+	var (
+		h      = hashNew()
+		curry  = m.curry
+		iCurry int
+	)
+	for i, label := range m.desc.variableLabels {
 		val, ok := labels[label]
-		if !ok {
-			return 0, fmt.Errorf("label name %q missing in label map", label)
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			if ok {
+				return 0, fmt.Errorf("label name %q is already curried", label)
+			}
+			h = m.hashAdd(h, curry[iCurry].value)
+			iCurry++
+		} else {
+			if !ok {
+				return 0, fmt.Errorf("label name %q missing in label map", label)
+			}
+			h = m.hashAdd(h, val)
 		}
-		h = hashAdd(h, val)
+		h = m.hashAddByte(h, model.SeparatorByte)
 	}
 	return h, nil
 }
 
-func (m *MetricVec) getOrCreateMetric(hash uint64, labelValues ...string) Metric {
-	metric, ok := m.children[hash]
+// metricWithLabelValues provides the metric and its label values for
+// disambiguation on hash collision.
+type metricWithLabelValues struct {
+	values []string
+	metric Metric
+}
+
+// curriedLabelValue sets the curried value for a label at the given index.
+type curriedLabelValue struct {
+	index int
+	value string
+}
+
+// metricMap is a helper for metricVec and shared between differently curried
+// metricVecs.
+type metricMap struct {
+	mtx       sync.RWMutex // Protects metrics.
+	metrics   map[uint64][]metricWithLabelValues
+	desc      *Desc
+	newMetric func(labelValues ...string) Metric
+}
+
+// Describe implements Collector. It will send exactly one Desc to the provided
+// channel.
+func (m *metricMap) Describe(ch chan<- *Desc) {
+	ch <- m.desc
+}
+
+// Collect implements Collector.
+func (m *metricMap) Collect(ch chan<- Metric) {
+	m.mtx.RLock()
+	defer m.mtx.RUnlock()
+
+	for _, metrics := range m.metrics {
+		for _, metric := range metrics {
+			ch <- metric.metric
+		}
+	}
+}
+
+// Reset deletes all metrics in this vector.
+func (m *metricMap) Reset() {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	for h := range m.metrics {
+		delete(m.metrics, h)
+	}
+}
+
+// deleteByHashWithLabelValues removes the metric from the hash bucket h. If
+// there are multiple matches in the bucket, use lvs to select a metric and
+// remove only that metric.
+func (m *metricMap) deleteByHashWithLabelValues(
+	h uint64, lvs []string, curry []curriedLabelValue,
+) bool {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	metrics, ok := m.metrics[h]
 	if !ok {
-		// Copy labelValues. Otherwise, they would be allocated even if we don't go
-		// down this code path.
-		copiedLabelValues := append(make([]string, 0, len(labelValues)), labelValues...)
-		metric = m.newMetric(copiedLabelValues...)
-		m.children[hash] = metric
+		return false
+	}
+
+	i := findMetricWithLabelValues(metrics, lvs, curry)
+	if i >= len(metrics) {
+		return false
+	}
+
+	if len(metrics) > 1 {
+		old := metrics
+		m.metrics[h] = append(metrics[:i], metrics[i+1:]...)
+		old[len(old)-1] = metricWithLabelValues{}
+	} else {
+		delete(m.metrics, h)
+	}
+	return true
+}
+
+// deleteByHashWithLabels removes the metric from the hash bucket h. If there
+// are multiple matches in the bucket, use lvs to select a metric and remove
+// only that metric.
+func (m *metricMap) deleteByHashWithLabels(
+	h uint64, labels Labels, curry []curriedLabelValue,
+) bool {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	metrics, ok := m.metrics[h]
+	if !ok {
+		return false
+	}
+	i := findMetricWithLabels(m.desc, metrics, labels, curry)
+	if i >= len(metrics) {
+		return false
+	}
+
+	if len(metrics) > 1 {
+		old := metrics
+		m.metrics[h] = append(metrics[:i], metrics[i+1:]...)
+		old[len(old)-1] = metricWithLabelValues{}
+	} else {
+		delete(m.metrics, h)
+	}
+	return true
+}
+
+// getOrCreateMetricWithLabelValues retrieves the metric by hash and label value
+// or creates it and returns the new one.
+//
+// This function holds the mutex.
+func (m *metricMap) getOrCreateMetricWithLabelValues(
+	hash uint64, lvs []string, curry []curriedLabelValue,
+) Metric {
+	m.mtx.RLock()
+	metric, ok := m.getMetricWithHashAndLabelValues(hash, lvs, curry)
+	m.mtx.RUnlock()
+	if ok {
+		return metric
+	}
+
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+	metric, ok = m.getMetricWithHashAndLabelValues(hash, lvs, curry)
+	if !ok {
+		inlinedLVs := inlineLabelValues(lvs, curry)
+		metric = m.newMetric(inlinedLVs...)
+		m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: inlinedLVs, metric: metric})
 	}
 	return metric
 }
+
+// getOrCreateMetricWithLabelValues retrieves the metric by hash and label value
+// or creates it and returns the new one.
+//
+// This function holds the mutex.
+func (m *metricMap) getOrCreateMetricWithLabels(
+	hash uint64, labels Labels, curry []curriedLabelValue,
+) Metric {
+	m.mtx.RLock()
+	metric, ok := m.getMetricWithHashAndLabels(hash, labels, curry)
+	m.mtx.RUnlock()
+	if ok {
+		return metric
+	}
+
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+	metric, ok = m.getMetricWithHashAndLabels(hash, labels, curry)
+	if !ok {
+		lvs := extractLabelValues(m.desc, labels, curry)
+		metric = m.newMetric(lvs...)
+		m.metrics[hash] = append(m.metrics[hash], metricWithLabelValues{values: lvs, metric: metric})
+	}
+	return metric
+}
+
+// getMetricWithHashAndLabelValues gets a metric while handling possible
+// collisions in the hash space. Must be called while holding the read mutex.
+func (m *metricMap) getMetricWithHashAndLabelValues(
+	h uint64, lvs []string, curry []curriedLabelValue,
+) (Metric, bool) {
+	metrics, ok := m.metrics[h]
+	if ok {
+		if i := findMetricWithLabelValues(metrics, lvs, curry); i < len(metrics) {
+			return metrics[i].metric, true
+		}
+	}
+	return nil, false
+}
+
+// getMetricWithHashAndLabels gets a metric while handling possible collisions in
+// the hash space. Must be called while holding read mutex.
+func (m *metricMap) getMetricWithHashAndLabels(
+	h uint64, labels Labels, curry []curriedLabelValue,
+) (Metric, bool) {
+	metrics, ok := m.metrics[h]
+	if ok {
+		if i := findMetricWithLabels(m.desc, metrics, labels, curry); i < len(metrics) {
+			return metrics[i].metric, true
+		}
+	}
+	return nil, false
+}
+
+// findMetricWithLabelValues returns the index of the matching metric or
+// len(metrics) if not found.
+func findMetricWithLabelValues(
+	metrics []metricWithLabelValues, lvs []string, curry []curriedLabelValue,
+) int {
+	for i, metric := range metrics {
+		if matchLabelValues(metric.values, lvs, curry) {
+			return i
+		}
+	}
+	return len(metrics)
+}
+
+// findMetricWithLabels returns the index of the matching metric or len(metrics)
+// if not found.
+func findMetricWithLabels(
+	desc *Desc, metrics []metricWithLabelValues, labels Labels, curry []curriedLabelValue,
+) int {
+	for i, metric := range metrics {
+		if matchLabels(desc, metric.values, labels, curry) {
+			return i
+		}
+	}
+	return len(metrics)
+}
+
+func matchLabelValues(values []string, lvs []string, curry []curriedLabelValue) bool {
+	if len(values) != len(lvs)+len(curry) {
+		return false
+	}
+	var iLVs, iCurry int
+	for i, v := range values {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			if v != curry[iCurry].value {
+				return false
+			}
+			iCurry++
+			continue
+		}
+		if v != lvs[iLVs] {
+			return false
+		}
+		iLVs++
+	}
+	return true
+}
+
+func matchLabels(desc *Desc, values []string, labels Labels, curry []curriedLabelValue) bool {
+	if len(values) != len(labels)+len(curry) {
+		return false
+	}
+	iCurry := 0
+	for i, k := range desc.variableLabels {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			if values[i] != curry[iCurry].value {
+				return false
+			}
+			iCurry++
+			continue
+		}
+		if values[i] != labels[k] {
+			return false
+		}
+	}
+	return true
+}
+
+func extractLabelValues(desc *Desc, labels Labels, curry []curriedLabelValue) []string {
+	labelValues := make([]string, len(labels)+len(curry))
+	iCurry := 0
+	for i, k := range desc.variableLabels {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			labelValues[i] = curry[iCurry].value
+			iCurry++
+			continue
+		}
+		labelValues[i] = labels[k]
+	}
+	return labelValues
+}
+
+func inlineLabelValues(lvs []string, curry []curriedLabelValue) []string {
+	labelValues := make([]string, len(lvs)+len(curry))
+	var iCurry, iLVs int
+	for i := range labelValues {
+		if iCurry < len(curry) && curry[iCurry].index == i {
+			labelValues[i] = curry[iCurry].value
+			iCurry++
+			continue
+		}
+		labelValues[i] = lvs[iLVs]
+		iLVs++
+	}
+	return labelValues
+}

vendor/github.com/prometheus/client_golang/prometheus/wrap.go

@@ -0,0 +1,214 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package prometheus
+
+import (
+	"fmt"
+	"sort"
+
+	//nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
+	"github.com/golang/protobuf/proto"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// WrapRegistererWith returns a Registerer wrapping the provided
+// Registerer. Collectors registered with the returned Registerer will be
+// registered with the wrapped Registerer in a modified way. The modified
+// Collector adds the provided Labels to all Metrics it collects (as
+// ConstLabels). The Metrics collected by the unmodified Collector must not
+// duplicate any of those labels. Wrapping a nil value is valid, resulting
+// in a no-op Registerer.
+//
+// WrapRegistererWith provides a way to add fixed labels to a subset of
+// Collectors. It should not be used to add fixed labels to all metrics
+// exposed. See also
+// https://prometheus.io/docs/instrumenting/writing_exporters/#target-labels-not-static-scraped-labels
+//
+// Conflicts between Collectors registered through the original Registerer with
+// Collectors registered through the wrapping Registerer will still be
+// detected. Any AlreadyRegisteredError returned by the Register method of
+// either Registerer will contain the ExistingCollector in the form it was
+// provided to the respective registry.
+//
+// The Collector example demonstrates a use of WrapRegistererWith.
+func WrapRegistererWith(labels Labels, reg Registerer) Registerer {
+	return &wrappingRegisterer{
+		wrappedRegisterer: reg,
+		labels:            labels,
+	}
+}
+
+// WrapRegistererWithPrefix returns a Registerer wrapping the provided
+// Registerer. Collectors registered with the returned Registerer will be
+// registered with the wrapped Registerer in a modified way. The modified
+// Collector adds the provided prefix to the name of all Metrics it collects.
+// Wrapping a nil value is valid, resulting in a no-op Registerer.
+//
+// WrapRegistererWithPrefix is useful to have one place to prefix all metrics of
+// a sub-system. To make this work, register metrics of the sub-system with the
+// wrapping Registerer returned by WrapRegistererWithPrefix. It is rarely useful
+// to use the same prefix for all metrics exposed. In particular, do not prefix
+// metric names that are standardized across applications, as that would break
+// horizontal monitoring, for example the metrics provided by the Go collector
+// (see NewGoCollector) and the process collector (see NewProcessCollector). (In
+// fact, those metrics are already prefixed with “go_” or “process_”,
+// respectively.)
+//
+// Conflicts between Collectors registered through the original Registerer with
+// Collectors registered through the wrapping Registerer will still be
+// detected. Any AlreadyRegisteredError returned by the Register method of
+// either Registerer will contain the ExistingCollector in the form it was
+// provided to the respective registry.
+func WrapRegistererWithPrefix(prefix string, reg Registerer) Registerer {
+	return &wrappingRegisterer{
+		wrappedRegisterer: reg,
+		prefix:            prefix,
+	}
+}
+
+type wrappingRegisterer struct {
+	wrappedRegisterer Registerer
+	prefix            string
+	labels            Labels
+}
+
+func (r *wrappingRegisterer) Register(c Collector) error {
+	if r.wrappedRegisterer == nil {
+		return nil
+	}
+	return r.wrappedRegisterer.Register(&wrappingCollector{
+		wrappedCollector: c,
+		prefix:           r.prefix,
+		labels:           r.labels,
+	})
+}
+
+func (r *wrappingRegisterer) MustRegister(cs ...Collector) {
+	if r.wrappedRegisterer == nil {
+		return
+	}
+	for _, c := range cs {
+		if err := r.Register(c); err != nil {
+			panic(err)
+		}
+	}
+}
+
+func (r *wrappingRegisterer) Unregister(c Collector) bool {
+	if r.wrappedRegisterer == nil {
+		return false
+	}
+	return r.wrappedRegisterer.Unregister(&wrappingCollector{
+		wrappedCollector: c,
+		prefix:           r.prefix,
+		labels:           r.labels,
+	})
+}
+
+type wrappingCollector struct {
+	wrappedCollector Collector
+	prefix           string
+	labels           Labels
+}
+
+func (c *wrappingCollector) Collect(ch chan<- Metric) {
+	wrappedCh := make(chan Metric)
+	go func() {
+		c.wrappedCollector.Collect(wrappedCh)
+		close(wrappedCh)
+	}()
+	for m := range wrappedCh {
+		ch <- &wrappingMetric{
+			wrappedMetric: m,
+			prefix:        c.prefix,
+			labels:        c.labels,
+		}
+	}
+}
+
+func (c *wrappingCollector) Describe(ch chan<- *Desc) {
+	wrappedCh := make(chan *Desc)
+	go func() {
+		c.wrappedCollector.Describe(wrappedCh)
+		close(wrappedCh)
+	}()
+	for desc := range wrappedCh {
+		ch <- wrapDesc(desc, c.prefix, c.labels)
+	}
+}
+
+func (c *wrappingCollector) unwrapRecursively() Collector {
+	switch wc := c.wrappedCollector.(type) {
+	case *wrappingCollector:
+		return wc.unwrapRecursively()
+	default:
+		return wc
+	}
+}
+
+type wrappingMetric struct {
+	wrappedMetric Metric
+	prefix        string
+	labels        Labels
+}
+
+func (m *wrappingMetric) Desc() *Desc {
+	return wrapDesc(m.wrappedMetric.Desc(), m.prefix, m.labels)
+}
+
+func (m *wrappingMetric) Write(out *dto.Metric) error {
+	if err := m.wrappedMetric.Write(out); err != nil {
+		return err
+	}
+	if len(m.labels) == 0 {
+		// No wrapping labels.
+		return nil
+	}
+	for ln, lv := range m.labels {
+		out.Label = append(out.Label, &dto.LabelPair{
+			Name:  proto.String(ln),
+			Value: proto.String(lv),
+		})
+	}
+	sort.Sort(labelPairSorter(out.Label))
+	return nil
+}
+
+func wrapDesc(desc *Desc, prefix string, labels Labels) *Desc {
+	constLabels := Labels{}
+	for _, lp := range desc.constLabelPairs {
+		constLabels[*lp.Name] = *lp.Value
+	}
+	for ln, lv := range labels {
+		if _, alreadyUsed := constLabels[ln]; alreadyUsed {
+			return &Desc{
+				fqName:          desc.fqName,
+				help:            desc.help,
+				variableLabels:  desc.variableLabels,
+				constLabelPairs: desc.constLabelPairs,
+				err:             fmt.Errorf("attempted wrapping with already existing label name %q", ln),
+			}
+		}
+		constLabels[ln] = lv
+	}
+	// NewDesc will do remaining validations.
+	newDesc := NewDesc(prefix+desc.fqName, desc.help, desc.variableLabels, constLabels)
+	// Propagate errors if there was any. This will override any errer
+	// created by NewDesc above, i.e. earlier errors get precedence.
+	if desc.err != nil {
+		newDesc.err = desc.err
+	}
+	return newDesc
+}

vendor/github.com/prometheus/client_model/AUTHORS.md

@@ -1,13 +0,0 @@
-The Prometheus project was started by Matt T. Proud (emeritus) and
-Julius Volz in 2012.
-
-Maintainers of this repository:
-
-* Björn Rabenstein <beorn@soundcloud.com>
-
-The following individuals have contributed code to this repository
-(listed in alphabetical order):
-
-* Björn Rabenstein <beorn@soundcloud.com>
-* Matt T. Proud <matt.proud@gmail.com>
-* Tobias Schmidt <ts@soundcloud.com>

vendor/github.com/prometheus/client_model/go/metrics.pb.go

@@ -1,34 +1,26 @@
-// Code generated by protoc-gen-go.
+// Code generated by protoc-gen-go. DO NOT EDIT.
 // source: metrics.proto
-// DO NOT EDIT!
 
-/*
-Package io_prometheus_client is a generated protocol buffer package.
-
-It is generated from these files:
-	metrics.proto
-
-It has these top-level messages:
-	LabelPair
-	Gauge
-	Counter
-	Quantile
-	Summary
-	Untyped
-	Histogram
-	Bucket
-	Metric
-	MetricFamily
-*/
 package io_prometheus_client
 
-import proto "github.com/golang/protobuf/proto"
-import math "math"
+import (
+	fmt "fmt"
+	proto "github.com/golang/protobuf/proto"
+	timestamp "github.com/golang/protobuf/ptypes/timestamp"
+	math "math"
+)
 
 // Reference imports to suppress errors if they are not otherwise used.
 var _ = proto.Marshal
+var _ = fmt.Errorf
 var _ = math.Inf
 
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion3 // please upgrade the proto package
+
 type MetricType int32
 
 const (
@@ -46,6 +38,7 @@ var MetricType_name = map[int32]string{
 	3: "UNTYPED",
 	4: "HISTOGRAM",
 }
+
 var MetricType_value = map[string]int32{
 	"COUNTER":   0,
 	"GAUGE":     1,
@@ -59,9 +52,11 @@ func (x MetricType) Enum() *MetricType {
 	*p = x
 	return p
 }
+
 func (x MetricType) String() string {
 	return proto.EnumName(MetricType_name, int32(x))
 }
+
 func (x *MetricType) UnmarshalJSON(data []byte) error {
 	value, err := proto.UnmarshalJSONEnum(MetricType_value, data, "MetricType")
 	if err != nil {
@@ -71,15 +66,42 @@ func (x *MetricType) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
+func (MetricType) EnumDescriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{0}
+}
+
 type LabelPair struct {
-	Name             *string `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
-	Value            *string `protobuf:"bytes,2,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte  `json:"-"`
+	Name                 *string  `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
+	Value                *string  `protobuf:"bytes,2,opt,name=value" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
 }
 
 func (m *LabelPair) Reset()         { *m = LabelPair{} }
 func (m *LabelPair) String() string { return proto.CompactTextString(m) }
 func (*LabelPair) ProtoMessage()    {}
+func (*LabelPair) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{0}
+}
+
+func (m *LabelPair) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_LabelPair.Unmarshal(m, b)
+}
+func (m *LabelPair) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_LabelPair.Marshal(b, m, deterministic)
+}
+func (m *LabelPair) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_LabelPair.Merge(m, src)
+}
+func (m *LabelPair) XXX_Size() int {
+	return xxx_messageInfo_LabelPair.Size(m)
+}
+func (m *LabelPair) XXX_DiscardUnknown() {
+	xxx_messageInfo_LabelPair.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_LabelPair proto.InternalMessageInfo
 
 func (m *LabelPair) GetName() string {
 	if m != nil && m.Name != nil {
@@ -96,13 +118,36 @@ func (m *LabelPair) GetValue() string {
 }
 
 type Gauge struct {
-	Value            *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	Value                *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
 }
 
 func (m *Gauge) Reset()         { *m = Gauge{} }
 func (m *Gauge) String() string { return proto.CompactTextString(m) }
 func (*Gauge) ProtoMessage()    {}
+func (*Gauge) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{1}
+}
+
+func (m *Gauge) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Gauge.Unmarshal(m, b)
+}
+func (m *Gauge) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Gauge.Marshal(b, m, deterministic)
+}
+func (m *Gauge) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Gauge.Merge(m, src)
+}
+func (m *Gauge) XXX_Size() int {
+	return xxx_messageInfo_Gauge.Size(m)
+}
+func (m *Gauge) XXX_DiscardUnknown() {
+	xxx_messageInfo_Gauge.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Gauge proto.InternalMessageInfo
 
 func (m *Gauge) GetValue() float64 {
 	if m != nil && m.Value != nil {
@@ -112,13 +157,37 @@ func (m *Gauge) GetValue() float64 {
 }
 
 type Counter struct {
-	Value            *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	Value                *float64  `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
+	Exemplar             *Exemplar `protobuf:"bytes,2,opt,name=exemplar" json:"exemplar,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}  `json:"-"`
+	XXX_unrecognized     []byte    `json:"-"`
+	XXX_sizecache        int32     `json:"-"`
 }
 
 func (m *Counter) Reset()         { *m = Counter{} }
 func (m *Counter) String() string { return proto.CompactTextString(m) }
 func (*Counter) ProtoMessage()    {}
+func (*Counter) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{2}
+}
+
+func (m *Counter) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Counter.Unmarshal(m, b)
+}
+func (m *Counter) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Counter.Marshal(b, m, deterministic)
+}
+func (m *Counter) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Counter.Merge(m, src)
+}
+func (m *Counter) XXX_Size() int {
+	return xxx_messageInfo_Counter.Size(m)
+}
+func (m *Counter) XXX_DiscardUnknown() {
+	xxx_messageInfo_Counter.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Counter proto.InternalMessageInfo
 
 func (m *Counter) GetValue() float64 {
 	if m != nil && m.Value != nil {
@@ -127,15 +196,45 @@ func (m *Counter) GetValue() float64 {
 	return 0
 }
 
+func (m *Counter) GetExemplar() *Exemplar {
+	if m != nil {
+		return m.Exemplar
+	}
+	return nil
+}
+
 type Quantile struct {
-	Quantile         *float64 `protobuf:"fixed64,1,opt,name=quantile" json:"quantile,omitempty"`
-	Value            *float64 `protobuf:"fixed64,2,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	Quantile             *float64 `protobuf:"fixed64,1,opt,name=quantile" json:"quantile,omitempty"`
+	Value                *float64 `protobuf:"fixed64,2,opt,name=value" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
 }
 
 func (m *Quantile) Reset()         { *m = Quantile{} }
 func (m *Quantile) String() string { return proto.CompactTextString(m) }
 func (*Quantile) ProtoMessage()    {}
+func (*Quantile) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{3}
+}
+
+func (m *Quantile) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Quantile.Unmarshal(m, b)
+}
+func (m *Quantile) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Quantile.Marshal(b, m, deterministic)
+}
+func (m *Quantile) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Quantile.Merge(m, src)
+}
+func (m *Quantile) XXX_Size() int {
+	return xxx_messageInfo_Quantile.Size(m)
+}
+func (m *Quantile) XXX_DiscardUnknown() {
+	xxx_messageInfo_Quantile.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Quantile proto.InternalMessageInfo
 
 func (m *Quantile) GetQuantile() float64 {
 	if m != nil && m.Quantile != nil {
@@ -152,15 +251,38 @@ func (m *Quantile) GetValue() float64 {
 }
 
 type Summary struct {
-	SampleCount      *uint64     `protobuf:"varint,1,opt,name=sample_count" json:"sample_count,omitempty"`
-	SampleSum        *float64    `protobuf:"fixed64,2,opt,name=sample_sum" json:"sample_sum,omitempty"`
-	Quantile         []*Quantile `protobuf:"bytes,3,rep,name=quantile" json:"quantile,omitempty"`
-	XXX_unrecognized []byte      `json:"-"`
+	SampleCount          *uint64     `protobuf:"varint,1,opt,name=sample_count,json=sampleCount" json:"sample_count,omitempty"`
+	SampleSum            *float64    `protobuf:"fixed64,2,opt,name=sample_sum,json=sampleSum" json:"sample_sum,omitempty"`
+	Quantile             []*Quantile `protobuf:"bytes,3,rep,name=quantile" json:"quantile,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}    `json:"-"`
+	XXX_unrecognized     []byte      `json:"-"`
+	XXX_sizecache        int32       `json:"-"`
 }
 
 func (m *Summary) Reset()         { *m = Summary{} }
 func (m *Summary) String() string { return proto.CompactTextString(m) }
 func (*Summary) ProtoMessage()    {}
+func (*Summary) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{4}
+}
+
+func (m *Summary) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Summary.Unmarshal(m, b)
+}
+func (m *Summary) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Summary.Marshal(b, m, deterministic)
+}
+func (m *Summary) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Summary.Merge(m, src)
+}
+func (m *Summary) XXX_Size() int {
+	return xxx_messageInfo_Summary.Size(m)
+}
+func (m *Summary) XXX_DiscardUnknown() {
+	xxx_messageInfo_Summary.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Summary proto.InternalMessageInfo
 
 func (m *Summary) GetSampleCount() uint64 {
 	if m != nil && m.SampleCount != nil {
@@ -184,13 +306,36 @@ func (m *Summary) GetQuantile() []*Quantile {
 }
 
 type Untyped struct {
-	Value            *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	Value                *float64 `protobuf:"fixed64,1,opt,name=value" json:"value,omitempty"`
+	XXX_NoUnkeyedLiteral struct{} `json:"-"`
+	XXX_unrecognized     []byte   `json:"-"`
+	XXX_sizecache        int32    `json:"-"`
 }
 
 func (m *Untyped) Reset()         { *m = Untyped{} }
 func (m *Untyped) String() string { return proto.CompactTextString(m) }
 func (*Untyped) ProtoMessage()    {}
+func (*Untyped) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{5}
+}
+
+func (m *Untyped) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Untyped.Unmarshal(m, b)
+}
+func (m *Untyped) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Untyped.Marshal(b, m, deterministic)
+}
+func (m *Untyped) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Untyped.Merge(m, src)
+}
+func (m *Untyped) XXX_Size() int {
+	return xxx_messageInfo_Untyped.Size(m)
+}
+func (m *Untyped) XXX_DiscardUnknown() {
+	xxx_messageInfo_Untyped.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Untyped proto.InternalMessageInfo
 
 func (m *Untyped) GetValue() float64 {
 	if m != nil && m.Value != nil {
@@ -200,15 +345,38 @@ func (m *Untyped) GetValue() float64 {
 }
 
 type Histogram struct {
-	SampleCount      *uint64   `protobuf:"varint,1,opt,name=sample_count" json:"sample_count,omitempty"`
-	SampleSum        *float64  `protobuf:"fixed64,2,opt,name=sample_sum" json:"sample_sum,omitempty"`
-	Bucket           []*Bucket `protobuf:"bytes,3,rep,name=bucket" json:"bucket,omitempty"`
-	XXX_unrecognized []byte    `json:"-"`
+	SampleCount          *uint64   `protobuf:"varint,1,opt,name=sample_count,json=sampleCount" json:"sample_count,omitempty"`
+	SampleSum            *float64  `protobuf:"fixed64,2,opt,name=sample_sum,json=sampleSum" json:"sample_sum,omitempty"`
+	Bucket               []*Bucket `protobuf:"bytes,3,rep,name=bucket" json:"bucket,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}  `json:"-"`
+	XXX_unrecognized     []byte    `json:"-"`
+	XXX_sizecache        int32     `json:"-"`
 }
 
 func (m *Histogram) Reset()         { *m = Histogram{} }
 func (m *Histogram) String() string { return proto.CompactTextString(m) }
 func (*Histogram) ProtoMessage()    {}
+func (*Histogram) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{6}
+}
+
+func (m *Histogram) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Histogram.Unmarshal(m, b)
+}
+func (m *Histogram) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Histogram.Marshal(b, m, deterministic)
+}
+func (m *Histogram) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Histogram.Merge(m, src)
+}
+func (m *Histogram) XXX_Size() int {
+	return xxx_messageInfo_Histogram.Size(m)
+}
+func (m *Histogram) XXX_DiscardUnknown() {
+	xxx_messageInfo_Histogram.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Histogram proto.InternalMessageInfo
 
 func (m *Histogram) GetSampleCount() uint64 {
 	if m != nil && m.SampleCount != nil {
@@ -232,14 +400,38 @@ func (m *Histogram) GetBucket() []*Bucket {
 }
 
 type Bucket struct {
-	CumulativeCount  *uint64  `protobuf:"varint,1,opt,name=cumulative_count" json:"cumulative_count,omitempty"`
-	UpperBound       *float64 `protobuf:"fixed64,2,opt,name=upper_bound" json:"upper_bound,omitempty"`
-	XXX_unrecognized []byte   `json:"-"`
+	CumulativeCount      *uint64   `protobuf:"varint,1,opt,name=cumulative_count,json=cumulativeCount" json:"cumulative_count,omitempty"`
+	UpperBound           *float64  `protobuf:"fixed64,2,opt,name=upper_bound,json=upperBound" json:"upper_bound,omitempty"`
+	Exemplar             *Exemplar `protobuf:"bytes,3,opt,name=exemplar" json:"exemplar,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}  `json:"-"`
+	XXX_unrecognized     []byte    `json:"-"`
+	XXX_sizecache        int32     `json:"-"`
 }
 
 func (m *Bucket) Reset()         { *m = Bucket{} }
 func (m *Bucket) String() string { return proto.CompactTextString(m) }
 func (*Bucket) ProtoMessage()    {}
+func (*Bucket) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{7}
+}
+
+func (m *Bucket) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Bucket.Unmarshal(m, b)
+}
+func (m *Bucket) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Bucket.Marshal(b, m, deterministic)
+}
+func (m *Bucket) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Bucket.Merge(m, src)
+}
+func (m *Bucket) XXX_Size() int {
+	return xxx_messageInfo_Bucket.Size(m)
+}
+func (m *Bucket) XXX_DiscardUnknown() {
+	xxx_messageInfo_Bucket.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Bucket proto.InternalMessageInfo
 
 func (m *Bucket) GetCumulativeCount() uint64 {
 	if m != nil && m.CumulativeCount != nil {
@@ -255,20 +447,105 @@ func (m *Bucket) GetUpperBound() float64 {
 	return 0
 }
 
+func (m *Bucket) GetExemplar() *Exemplar {
+	if m != nil {
+		return m.Exemplar
+	}
+	return nil
+}
+
+type Exemplar struct {
+	Label                []*LabelPair         `protobuf:"bytes,1,rep,name=label" json:"label,omitempty"`
+	Value                *float64             `protobuf:"fixed64,2,opt,name=value" json:"value,omitempty"`
+	Timestamp            *timestamp.Timestamp `protobuf:"bytes,3,opt,name=timestamp" json:"timestamp,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}             `json:"-"`
+	XXX_unrecognized     []byte               `json:"-"`
+	XXX_sizecache        int32                `json:"-"`
+}
+
+func (m *Exemplar) Reset()         { *m = Exemplar{} }
+func (m *Exemplar) String() string { return proto.CompactTextString(m) }
+func (*Exemplar) ProtoMessage()    {}
+func (*Exemplar) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{8}
+}
+
+func (m *Exemplar) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Exemplar.Unmarshal(m, b)
+}
+func (m *Exemplar) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Exemplar.Marshal(b, m, deterministic)
+}
+func (m *Exemplar) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Exemplar.Merge(m, src)
+}
+func (m *Exemplar) XXX_Size() int {
+	return xxx_messageInfo_Exemplar.Size(m)
+}
+func (m *Exemplar) XXX_DiscardUnknown() {
+	xxx_messageInfo_Exemplar.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Exemplar proto.InternalMessageInfo
+
+func (m *Exemplar) GetLabel() []*LabelPair {
+	if m != nil {
+		return m.Label
+	}
+	return nil
+}
+
+func (m *Exemplar) GetValue() float64 {
+	if m != nil && m.Value != nil {
+		return *m.Value
+	}
+	return 0
+}
+
+func (m *Exemplar) GetTimestamp() *timestamp.Timestamp {
+	if m != nil {
+		return m.Timestamp
+	}
+	return nil
+}
+
 type Metric struct {
-	Label            []*LabelPair `protobuf:"bytes,1,rep,name=label" json:"label,omitempty"`
-	Gauge            *Gauge       `protobuf:"bytes,2,opt,name=gauge" json:"gauge,omitempty"`
-	Counter          *Counter     `protobuf:"bytes,3,opt,name=counter" json:"counter,omitempty"`
-	Summary          *Summary     `protobuf:"bytes,4,opt,name=summary" json:"summary,omitempty"`
-	Untyped          *Untyped     `protobuf:"bytes,5,opt,name=untyped" json:"untyped,omitempty"`
-	Histogram        *Histogram   `protobuf:"bytes,7,opt,name=histogram" json:"histogram,omitempty"`
-	TimestampMs      *int64       `protobuf:"varint,6,opt,name=timestamp_ms" json:"timestamp_ms,omitempty"`
-	XXX_unrecognized []byte       `json:"-"`
+	Label                []*LabelPair `protobuf:"bytes,1,rep,name=label" json:"label,omitempty"`
+	Gauge                *Gauge       `protobuf:"bytes,2,opt,name=gauge" json:"gauge,omitempty"`
+	Counter              *Counter     `protobuf:"bytes,3,opt,name=counter" json:"counter,omitempty"`
+	Summary              *Summary     `protobuf:"bytes,4,opt,name=summary" json:"summary,omitempty"`
+	Untyped              *Untyped     `protobuf:"bytes,5,opt,name=untyped" json:"untyped,omitempty"`
+	Histogram            *Histogram   `protobuf:"bytes,7,opt,name=histogram" json:"histogram,omitempty"`
+	TimestampMs          *int64       `protobuf:"varint,6,opt,name=timestamp_ms,json=timestampMs" json:"timestamp_ms,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}     `json:"-"`
+	XXX_unrecognized     []byte       `json:"-"`
+	XXX_sizecache        int32        `json:"-"`
 }
 
 func (m *Metric) Reset()         { *m = Metric{} }
 func (m *Metric) String() string { return proto.CompactTextString(m) }
 func (*Metric) ProtoMessage()    {}
+func (*Metric) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{9}
+}
+
+func (m *Metric) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_Metric.Unmarshal(m, b)
+}
+func (m *Metric) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_Metric.Marshal(b, m, deterministic)
+}
+func (m *Metric) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_Metric.Merge(m, src)
+}
+func (m *Metric) XXX_Size() int {
+	return xxx_messageInfo_Metric.Size(m)
+}
+func (m *Metric) XXX_DiscardUnknown() {
+	xxx_messageInfo_Metric.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_Metric proto.InternalMessageInfo
 
 func (m *Metric) GetLabel() []*LabelPair {
 	if m != nil {
@@ -320,16 +597,39 @@ func (m *Metric) GetTimestampMs() int64 {
 }
 
 type MetricFamily struct {
-	Name             *string     `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
-	Help             *string     `protobuf:"bytes,2,opt,name=help" json:"help,omitempty"`
-	Type             *MetricType `protobuf:"varint,3,opt,name=type,enum=io.prometheus.client.MetricType" json:"type,omitempty"`
-	Metric           []*Metric   `protobuf:"bytes,4,rep,name=metric" json:"metric,omitempty"`
-	XXX_unrecognized []byte      `json:"-"`
+	Name                 *string     `protobuf:"bytes,1,opt,name=name" json:"name,omitempty"`
+	Help                 *string     `protobuf:"bytes,2,opt,name=help" json:"help,omitempty"`
+	Type                 *MetricType `protobuf:"varint,3,opt,name=type,enum=io.prometheus.client.MetricType" json:"type,omitempty"`
+	Metric               []*Metric   `protobuf:"bytes,4,rep,name=metric" json:"metric,omitempty"`
+	XXX_NoUnkeyedLiteral struct{}    `json:"-"`
+	XXX_unrecognized     []byte      `json:"-"`
+	XXX_sizecache        int32       `json:"-"`
 }
 
 func (m *MetricFamily) Reset()         { *m = MetricFamily{} }
 func (m *MetricFamily) String() string { return proto.CompactTextString(m) }
 func (*MetricFamily) ProtoMessage()    {}
+func (*MetricFamily) Descriptor() ([]byte, []int) {
+	return fileDescriptor_6039342a2ba47b72, []int{10}
+}
+
+func (m *MetricFamily) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_MetricFamily.Unmarshal(m, b)
+}
+func (m *MetricFamily) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_MetricFamily.Marshal(b, m, deterministic)
+}
+func (m *MetricFamily) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_MetricFamily.Merge(m, src)
+}
+func (m *MetricFamily) XXX_Size() int {
+	return xxx_messageInfo_MetricFamily.Size(m)
+}
+func (m *MetricFamily) XXX_DiscardUnknown() {
+	xxx_messageInfo_MetricFamily.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_MetricFamily proto.InternalMessageInfo
 
 func (m *MetricFamily) GetName() string {
 	if m != nil && m.Name != nil {
@@ -361,4 +661,63 @@ func (m *MetricFamily) GetMetric() []*Metric {
 
 func init() {
 	proto.RegisterEnum("io.prometheus.client.MetricType", MetricType_name, MetricType_value)
+	proto.RegisterType((*LabelPair)(nil), "io.prometheus.client.LabelPair")
+	proto.RegisterType((*Gauge)(nil), "io.prometheus.client.Gauge")
+	proto.RegisterType((*Counter)(nil), "io.prometheus.client.Counter")
+	proto.RegisterType((*Quantile)(nil), "io.prometheus.client.Quantile")
+	proto.RegisterType((*Summary)(nil), "io.prometheus.client.Summary")
+	proto.RegisterType((*Untyped)(nil), "io.prometheus.client.Untyped")
+	proto.RegisterType((*Histogram)(nil), "io.prometheus.client.Histogram")
+	proto.RegisterType((*Bucket)(nil), "io.prometheus.client.Bucket")
+	proto.RegisterType((*Exemplar)(nil), "io.prometheus.client.Exemplar")
+	proto.RegisterType((*Metric)(nil), "io.prometheus.client.Metric")
+	proto.RegisterType((*MetricFamily)(nil), "io.prometheus.client.MetricFamily")
+}
+
+func init() { proto.RegisterFile("metrics.proto", fileDescriptor_6039342a2ba47b72) }
+
+var fileDescriptor_6039342a2ba47b72 = []byte{
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+	0xbb, 0xd1, 0x33, 0x76, 0x6a, 0xb8, 0x5d, 0xd4, 0x46, 0x99, 0xf3, 0xc3, 0x80, 0x75, 0xf5, 0x07,
+	0x5e, 0x79, 0x34, 0x8c, 0x56, 0x95, 0xcf, 0x19, 0x02, 0x73, 0x41, 0xa2, 0x44, 0xbf, 0x66, 0x72,
+	0x8d, 0xf6, 0xc0, 0x14, 0x1a, 0xe5, 0x15, 0xfe, 0xbf, 0xdb, 0xab, 0x56, 0xa5, 0x26, 0x4f, 0x56,
+	0x09, 0xc1, 0x12, 0x2d, 0xd2, 0xa4, 0x5e, 0x60, 0xdb, 0xbc, 0x2d, 0x4d, 0x8a, 0x87, 0x35, 0xf6,
+	0xd1, 0x08, 0xa0, 0x9c, 0x84, 0xda, 0xd0, 0x3c, 0x3e, 0x9b, 0x9e, 0x4e, 0x06, 0xb8, 0xf3, 0x1f,
+	0xb2, 0xa0, 0x3e, 0x3c, 0x9c, 0x0e, 0x07, 0x1d, 0x43, 0xd4, 0xc7, 0xd3, 0xd1, 0xe8, 0x10, 0x5f,
+	0x74, 0xd6, 0xc4, 0x66, 0x7a, 0x3a, 0xb9, 0x38, 0x1f, 0xbc, 0xec, 0xd4, 0xd0, 0x06, 0x58, 0x27,
+	0xaf, 0xc7, 0x93, 0xb3, 0x21, 0x3e, 0x1c, 0x75, 0xcc, 0x23, 0x0c, 0x95, 0xef, 0xfe, 0xbb, 0x83,
+	0x20, 0x64, 0x0b, 0x3e, 0x77, 0xfd, 0x98, 0xf6, 0xcb, 0x6e, 0x5f, 0x75, 0x67, 0x34, 0xbe, 0x24,
+	0x51, 0x3f, 0x88, 0x9f, 0x85, 0xf1, 0xac, 0xec, 0xce, 0x54, 0xf7, 0x57, 0x00, 0x00, 0x00, 0xff,
+	0xff, 0xd0, 0x84, 0x91, 0x73, 0x59, 0x06, 0x00, 0x00,
 }

vendor/github.com/prometheus/common/AUTHORS.md

@@ -1,11 +0,0 @@
-Maintainers of this repository:
-
-* Fabian Reinartz <fabian@soundcloud.com>
-
-The following individuals have contributed code to this repository
-(listed in alphabetical order):
-
-* Björn Rabenstein <beorn@soundcloud.com>
-* Fabian Reinartz <fabian@soundcloud.com>
-* Julius Volz <julius.volz@gmail.com>
-* Miguel Molina <hi@mvader.me>

vendor/github.com/prometheus/common/expfmt/decode.go

@@ -31,6 +31,7 @@ type Decoder interface {
 	Decode(*dto.MetricFamily) error
 }
 
+// DecodeOptions contains options used by the Decoder and in sample extraction.
 type DecodeOptions struct {
 	// Timestamp is added to each value from the stream that has no explicit timestamp set.
 	Timestamp model.Time
@@ -142,6 +143,8 @@ func (d *textDecoder) Decode(v *dto.MetricFamily) error {
 	return nil
 }
 
+// SampleDecoder wraps a Decoder to extract samples from the metric families
+// decoded by the wrapped Decoder.
 type SampleDecoder struct {
 	Dec  Decoder
 	Opts *DecodeOptions
@@ -149,37 +152,51 @@ type SampleDecoder struct {
 	f dto.MetricFamily
 }
 
+// Decode calls the Decode method of the wrapped Decoder and then extracts the
+// samples from the decoded MetricFamily into the provided model.Vector.
 func (sd *SampleDecoder) Decode(s *model.Vector) error {
-	if err := sd.Dec.Decode(&sd.f); err != nil {
+	err := sd.Dec.Decode(&sd.f)
+	if err != nil {
 		return err
 	}
-	*s = extractSamples(&sd.f, sd.Opts)
-	return nil
+	*s, err = extractSamples(&sd.f, sd.Opts)
+	return err
 }
 
-// Extract samples builds a slice of samples from the provided metric families.
-func ExtractSamples(o *DecodeOptions, fams ...*dto.MetricFamily) model.Vector {
-	var all model.Vector
+// ExtractSamples builds a slice of samples from the provided metric
+// families. If an error occurs during sample extraction, it continues to
+// extract from the remaining metric families. The returned error is the last
+// error that has occurred.
+func ExtractSamples(o *DecodeOptions, fams ...*dto.MetricFamily) (model.Vector, error) {
+	var (
+		all     model.Vector
+		lastErr error
+	)
 	for _, f := range fams {
-		all = append(all, extractSamples(f, o)...)
+		some, err := extractSamples(f, o)
+		if err != nil {
+			lastErr = err
+			continue
+		}
+		all = append(all, some...)
 	}
-	return all
+	return all, lastErr
 }
 
-func extractSamples(f *dto.MetricFamily, o *DecodeOptions) model.Vector {
+func extractSamples(f *dto.MetricFamily, o *DecodeOptions) (model.Vector, error) {
 	switch f.GetType() {
 	case dto.MetricType_COUNTER:
-		return extractCounter(o, f)
+		return extractCounter(o, f), nil
 	case dto.MetricType_GAUGE:
-		return extractGauge(o, f)
+		return extractGauge(o, f), nil
 	case dto.MetricType_SUMMARY:
-		return extractSummary(o, f)
+		return extractSummary(o, f), nil
 	case dto.MetricType_UNTYPED:
-		return extractUntyped(o, f)
+		return extractUntyped(o, f), nil
 	case dto.MetricType_HISTOGRAM:
-		return extractHistogram(o, f)
+		return extractHistogram(o, f), nil
 	}
-	panic("expfmt.extractSamples: unknown metric family type")
+	return nil, fmt.Errorf("expfmt.extractSamples: unknown metric family type %v", f.GetType())
 }
 
 func extractCounter(o *DecodeOptions, f *dto.MetricFamily) model.Vector {

vendor/github.com/prometheus/common/expfmt/encode.go

@@ -18,7 +18,7 @@ import (
 	"io"
 	"net/http"
 
-	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/proto" //nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/matttproud/golang_protobuf_extensions/pbutil"
 	"github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg"
 
@@ -30,17 +30,38 @@ type Encoder interface {
 	Encode(*dto.MetricFamily) error
 }
 
-type encoder func(*dto.MetricFamily) error
-
-func (e encoder) Encode(v *dto.MetricFamily) error {
-	return e(v)
+// Closer is implemented by Encoders that need to be closed to finalize
+// encoding. (For example, OpenMetrics needs a final `# EOF` line.)
+//
+// Note that all Encoder implementations returned from this package implement
+// Closer, too, even if the Close call is a no-op. This happens in preparation
+// for adding a Close method to the Encoder interface directly in a (mildly
+// breaking) release in the future.
+type Closer interface {
+	Close() error
 }
 
-// Negotiate returns the Content-Type based on the given Accept header.
-// If no appropriate accepted type is found, FmtText is returned.
+type encoderCloser struct {
+	encode func(*dto.MetricFamily) error
+	close  func() error
+}
+
+func (ec encoderCloser) Encode(v *dto.MetricFamily) error {
+	return ec.encode(v)
+}
+
+func (ec encoderCloser) Close() error {
+	return ec.close()
+}
+
+// Negotiate returns the Content-Type based on the given Accept header. If no
+// appropriate accepted type is found, FmtText is returned (which is the
+// Prometheus text format). This function will never negotiate FmtOpenMetrics,
+// as the support is still experimental. To include the option to negotiate
+// FmtOpenMetrics, use NegotiateOpenMetrics.
 func Negotiate(h http.Header) Format {
 	for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
-		// Check for protocol buffer
+		ver := ac.Params["version"]
 		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
 			switch ac.Params["encoding"] {
 			case "delimited":
@@ -51,8 +72,6 @@ func Negotiate(h http.Header) Format {
 				return FmtProtoCompact
 			}
 		}
-		// Check for text format.
-		ver := ac.Params["version"]
 		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
 			return FmtText
 		}
@@ -60,29 +79,84 @@ func Negotiate(h http.Header) Format {
 	return FmtText
 }
 
-// NewEncoder returns a new encoder based on content type negotiation.
+// NegotiateIncludingOpenMetrics works like Negotiate but includes
+// FmtOpenMetrics as an option for the result. Note that this function is
+// temporary and will disappear once FmtOpenMetrics is fully supported and as
+// such may be negotiated by the normal Negotiate function.
+func NegotiateIncludingOpenMetrics(h http.Header) Format {
+	for _, ac := range goautoneg.ParseAccept(h.Get(hdrAccept)) {
+		ver := ac.Params["version"]
+		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
+			switch ac.Params["encoding"] {
+			case "delimited":
+				return FmtProtoDelim
+			case "text":
+				return FmtProtoText
+			case "compact-text":
+				return FmtProtoCompact
+			}
+		}
+		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
+			return FmtText
+		}
+		if ac.Type+"/"+ac.SubType == OpenMetricsType && (ver == OpenMetricsVersion || ver == "") {
+			return FmtOpenMetrics
+		}
+	}
+	return FmtText
+}
+
+// NewEncoder returns a new encoder based on content type negotiation. All
+// Encoder implementations returned by NewEncoder also implement Closer, and
+// callers should always call the Close method. It is currently only required
+// for FmtOpenMetrics, but a future (breaking) release will add the Close method
+// to the Encoder interface directly. The current version of the Encoder
+// interface is kept for backwards compatibility.
 func NewEncoder(w io.Writer, format Format) Encoder {
 	switch format {
 	case FmtProtoDelim:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := pbutil.WriteDelimited(w, v)
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := pbutil.WriteDelimited(w, v)
+				return err
+			},
+			close: func() error { return nil },
+		}
 	case FmtProtoCompact:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := fmt.Fprintln(w, v.String())
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := fmt.Fprintln(w, v.String())
+				return err
+			},
+			close: func() error { return nil },
+		}
 	case FmtProtoText:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := fmt.Fprintln(w, proto.MarshalTextString(v))
+				return err
+			},
+			close: func() error { return nil },
+		}
 	case FmtText:
-		return encoder(func(v *dto.MetricFamily) error {
-			_, err := MetricFamilyToText(w, v)
-			return err
-		})
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := MetricFamilyToText(w, v)
+				return err
+			},
+			close: func() error { return nil },
+		}
+	case FmtOpenMetrics:
+		return encoderCloser{
+			encode: func(v *dto.MetricFamily) error {
+				_, err := MetricFamilyToOpenMetrics(w, v)
+				return err
+			},
+			close: func() error {
+				_, err := FinalizeOpenMetrics(w)
+				return err
+			},
+		}
 	}
-	panic("expfmt.NewEncoder: unknown format")
+	panic(fmt.Errorf("expfmt.NewEncoder: unknown format %q", format))
 }

vendor/github.com/prometheus/common/expfmt/expfmt.go

@@ -11,27 +11,28 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// A package for reading and writing Prometheus metrics.
+// Package expfmt contains tools for reading and writing Prometheus metrics.
 package expfmt
 
+// Format specifies the HTTP content type of the different wire protocols.
 type Format string
 
+// Constants to assemble the Content-Type values for the different wire protocols.
 const (
-	TextVersion = "0.0.4"
-
-	ProtoType     = `application/vnd.google.protobuf`
-	ProtoProtocol = `io.prometheus.client.MetricFamily`
-	ProtoFmt      = ProtoType + "; proto=" + ProtoProtocol + ";"
+	TextVersion        = "0.0.4"
+	ProtoType          = `application/vnd.google.protobuf`
+	ProtoProtocol      = `io.prometheus.client.MetricFamily`
+	ProtoFmt           = ProtoType + "; proto=" + ProtoProtocol + ";"
+	OpenMetricsType    = `application/openmetrics-text`
+	OpenMetricsVersion = "0.0.1"
 
 	// The Content-Type values for the different wire protocols.
 	FmtUnknown      Format = `<unknown>`
-	FmtText         Format = `text/plain; version=` + TextVersion
+	FmtText         Format = `text/plain; version=` + TextVersion + `; charset=utf-8`
 	FmtProtoDelim   Format = ProtoFmt + ` encoding=delimited`
 	FmtProtoText    Format = ProtoFmt + ` encoding=text`
 	FmtProtoCompact Format = ProtoFmt + ` encoding=compact-text`
-
-	// fmtJSON2 is hidden as it is deprecated.
-	fmtJSON2 Format = `application/json; version=0.0.2`
+	FmtOpenMetrics  Format = OpenMetricsType + `; version=` + OpenMetricsVersion + `; charset=utf-8`
 )
 
 const (

vendor/github.com/prometheus/common/expfmt/openmetrics_create.go

@@ -0,0 +1,527 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package expfmt
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"math"
+	"strconv"
+	"strings"
+
+	"github.com/golang/protobuf/ptypes"
+	"github.com/prometheus/common/model"
+
+	dto "github.com/prometheus/client_model/go"
+)
+
+// MetricFamilyToOpenMetrics converts a MetricFamily proto message into the
+// OpenMetrics text format and writes the resulting lines to 'out'. It returns
+// the number of bytes written and any error encountered. The output will have
+// the same order as the input, no further sorting is performed. Furthermore,
+// this function assumes the input is already sanitized and does not perform any
+// sanity checks. If the input contains duplicate metrics or invalid metric or
+// label names, the conversion will result in invalid text format output.
+//
+// This function fulfills the type 'expfmt.encoder'.
+//
+// Note that OpenMetrics requires a final `# EOF` line. Since this function acts
+// on individual metric families, it is the responsibility of the caller to
+// append this line to 'out' once all metric families have been written.
+// Conveniently, this can be done by calling FinalizeOpenMetrics.
+//
+// The output should be fully OpenMetrics compliant. However, there are a few
+// missing features and peculiarities to avoid complications when switching from
+// Prometheus to OpenMetrics or vice versa:
+//
+// - Counters are expected to have the `_total` suffix in their metric name. In
+//   the output, the suffix will be truncated from the `# TYPE` and `# HELP`
+//   line. A counter with a missing `_total` suffix is not an error. However,
+//   its type will be set to `unknown` in that case to avoid invalid OpenMetrics
+//   output.
+//
+// - No support for the following (optional) features: `# UNIT` line, `_created`
+//   line, info type, stateset type, gaugehistogram type.
+//
+// - The size of exemplar labels is not checked (i.e. it's possible to create
+//   exemplars that are larger than allowed by the OpenMetrics specification).
+//
+// - The value of Counters is not checked. (OpenMetrics doesn't allow counters
+//   with a `NaN` value.)
+func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily) (written int, err error) {
+	name := in.GetName()
+	if name == "" {
+		return 0, fmt.Errorf("MetricFamily has no name: %s", in)
+	}
+
+	// Try the interface upgrade. If it doesn't work, we'll use a
+	// bufio.Writer from the sync.Pool.
+	w, ok := out.(enhancedWriter)
+	if !ok {
+		b := bufPool.Get().(*bufio.Writer)
+		b.Reset(out)
+		w = b
+		defer func() {
+			bErr := b.Flush()
+			if err == nil {
+				err = bErr
+			}
+			bufPool.Put(b)
+		}()
+	}
+
+	var (
+		n          int
+		metricType = in.GetType()
+		shortName  = name
+	)
+	if metricType == dto.MetricType_COUNTER && strings.HasSuffix(shortName, "_total") {
+		shortName = name[:len(name)-6]
+	}
+
+	// Comments, first HELP, then TYPE.
+	if in.Help != nil {
+		n, err = w.WriteString("# HELP ")
+		written += n
+		if err != nil {
+			return
+		}
+		n, err = w.WriteString(shortName)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return
+		}
+		n, err = writeEscapedString(w, *in.Help, true)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte('\n')
+		written++
+		if err != nil {
+			return
+		}
+	}
+	n, err = w.WriteString("# TYPE ")
+	written += n
+	if err != nil {
+		return
+	}
+	n, err = w.WriteString(shortName)
+	written += n
+	if err != nil {
+		return
+	}
+	switch metricType {
+	case dto.MetricType_COUNTER:
+		if strings.HasSuffix(name, "_total") {
+			n, err = w.WriteString(" counter\n")
+		} else {
+			n, err = w.WriteString(" unknown\n")
+		}
+	case dto.MetricType_GAUGE:
+		n, err = w.WriteString(" gauge\n")
+	case dto.MetricType_SUMMARY:
+		n, err = w.WriteString(" summary\n")
+	case dto.MetricType_UNTYPED:
+		n, err = w.WriteString(" unknown\n")
+	case dto.MetricType_HISTOGRAM:
+		n, err = w.WriteString(" histogram\n")
+	default:
+		return written, fmt.Errorf("unknown metric type %s", metricType.String())
+	}
+	written += n
+	if err != nil {
+		return
+	}
+
+	// Finally the samples, one line for each.
+	for _, metric := range in.Metric {
+		switch metricType {
+		case dto.MetricType_COUNTER:
+			if metric.Counter == nil {
+				return written, fmt.Errorf(
+					"expected counter in metric %s %s", name, metric,
+				)
+			}
+			// Note that we have ensured above that either the name
+			// ends on `_total` or that the rendered type is
+			// `unknown`. Therefore, no `_total` must be added here.
+			n, err = writeOpenMetricsSample(
+				w, name, "", metric, "", 0,
+				metric.Counter.GetValue(), 0, false,
+				metric.Counter.Exemplar,
+			)
+		case dto.MetricType_GAUGE:
+			if metric.Gauge == nil {
+				return written, fmt.Errorf(
+					"expected gauge in metric %s %s", name, metric,
+				)
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "", metric, "", 0,
+				metric.Gauge.GetValue(), 0, false,
+				nil,
+			)
+		case dto.MetricType_UNTYPED:
+			if metric.Untyped == nil {
+				return written, fmt.Errorf(
+					"expected untyped in metric %s %s", name, metric,
+				)
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "", metric, "", 0,
+				metric.Untyped.GetValue(), 0, false,
+				nil,
+			)
+		case dto.MetricType_SUMMARY:
+			if metric.Summary == nil {
+				return written, fmt.Errorf(
+					"expected summary in metric %s %s", name, metric,
+				)
+			}
+			for _, q := range metric.Summary.Quantile {
+				n, err = writeOpenMetricsSample(
+					w, name, "", metric,
+					model.QuantileLabel, q.GetQuantile(),
+					q.GetValue(), 0, false,
+					nil,
+				)
+				written += n
+				if err != nil {
+					return
+				}
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_sum", metric, "", 0,
+				metric.Summary.GetSampleSum(), 0, false,
+				nil,
+			)
+			written += n
+			if err != nil {
+				return
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_count", metric, "", 0,
+				0, metric.Summary.GetSampleCount(), true,
+				nil,
+			)
+		case dto.MetricType_HISTOGRAM:
+			if metric.Histogram == nil {
+				return written, fmt.Errorf(
+					"expected histogram in metric %s %s", name, metric,
+				)
+			}
+			infSeen := false
+			for _, b := range metric.Histogram.Bucket {
+				n, err = writeOpenMetricsSample(
+					w, name, "_bucket", metric,
+					model.BucketLabel, b.GetUpperBound(),
+					0, b.GetCumulativeCount(), true,
+					b.Exemplar,
+				)
+				written += n
+				if err != nil {
+					return
+				}
+				if math.IsInf(b.GetUpperBound(), +1) {
+					infSeen = true
+				}
+			}
+			if !infSeen {
+				n, err = writeOpenMetricsSample(
+					w, name, "_bucket", metric,
+					model.BucketLabel, math.Inf(+1),
+					0, metric.Histogram.GetSampleCount(), true,
+					nil,
+				)
+				written += n
+				if err != nil {
+					return
+				}
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_sum", metric, "", 0,
+				metric.Histogram.GetSampleSum(), 0, false,
+				nil,
+			)
+			written += n
+			if err != nil {
+				return
+			}
+			n, err = writeOpenMetricsSample(
+				w, name, "_count", metric, "", 0,
+				0, metric.Histogram.GetSampleCount(), true,
+				nil,
+			)
+		default:
+			return written, fmt.Errorf(
+				"unexpected type in metric %s %s", name, metric,
+			)
+		}
+		written += n
+		if err != nil {
+			return
+		}
+	}
+	return
+}
+
+// FinalizeOpenMetrics writes the final `# EOF\n` line required by OpenMetrics.
+func FinalizeOpenMetrics(w io.Writer) (written int, err error) {
+	return w.Write([]byte("# EOF\n"))
+}
+
+// writeOpenMetricsSample writes a single sample in OpenMetrics text format to
+// w, given the metric name, the metric proto message itself, optionally an
+// additional label name with a float64 value (use empty string as label name if
+// not required), the value (optionally as float64 or uint64, determined by
+// useIntValue), and optionally an exemplar (use nil if not required). The
+// function returns the number of bytes written and any error encountered.
+func writeOpenMetricsSample(
+	w enhancedWriter,
+	name, suffix string,
+	metric *dto.Metric,
+	additionalLabelName string, additionalLabelValue float64,
+	floatValue float64, intValue uint64, useIntValue bool,
+	exemplar *dto.Exemplar,
+) (int, error) {
+	var written int
+	n, err := w.WriteString(name)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if suffix != "" {
+		n, err = w.WriteString(suffix)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	n, err = writeOpenMetricsLabelPairs(
+		w, metric.Label, additionalLabelName, additionalLabelValue,
+	)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	err = w.WriteByte(' ')
+	written++
+	if err != nil {
+		return written, err
+	}
+	if useIntValue {
+		n, err = writeUint(w, intValue)
+	} else {
+		n, err = writeOpenMetricsFloat(w, floatValue)
+	}
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if metric.TimestampMs != nil {
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return written, err
+		}
+		// TODO(beorn7): Format this directly without converting to a float first.
+		n, err = writeOpenMetricsFloat(w, float64(*metric.TimestampMs)/1000)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	if exemplar != nil {
+		n, err = writeExemplar(w, exemplar)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	err = w.WriteByte('\n')
+	written++
+	if err != nil {
+		return written, err
+	}
+	return written, nil
+}
+
+// writeOpenMetricsLabelPairs works like writeOpenMetrics but formats the float
+// in OpenMetrics style.
+func writeOpenMetricsLabelPairs(
+	w enhancedWriter,
+	in []*dto.LabelPair,
+	additionalLabelName string, additionalLabelValue float64,
+) (int, error) {
+	if len(in) == 0 && additionalLabelName == "" {
+		return 0, nil
+	}
+	var (
+		written   int
+		separator byte = '{'
+	)
+	for _, lp := range in {
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(lp.GetName())
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeEscapedString(w, lp.GetValue(), true)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
+		separator = ','
+	}
+	if additionalLabelName != "" {
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(additionalLabelName)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeOpenMetricsFloat(w, additionalLabelValue)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
+	}
+	err := w.WriteByte('}')
+	written++
+	if err != nil {
+		return written, err
+	}
+	return written, nil
+}
+
+// writeExemplar writes the provided exemplar in OpenMetrics format to w. The
+// function returns the number of bytes written and any error encountered.
+func writeExemplar(w enhancedWriter, e *dto.Exemplar) (int, error) {
+	written := 0
+	n, err := w.WriteString(" # ")
+	written += n
+	if err != nil {
+		return written, err
+	}
+	n, err = writeOpenMetricsLabelPairs(w, e.Label, "", 0)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	err = w.WriteByte(' ')
+	written++
+	if err != nil {
+		return written, err
+	}
+	n, err = writeOpenMetricsFloat(w, e.GetValue())
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if e.Timestamp != nil {
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return written, err
+		}
+		ts, err := ptypes.Timestamp((*e).Timestamp)
+		if err != nil {
+			return written, err
+		}
+		// TODO(beorn7): Format this directly from components of ts to
+		// avoid overflow/underflow and precision issues of the float
+		// conversion.
+		n, err = writeOpenMetricsFloat(w, float64(ts.UnixNano())/1e9)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	return written, nil
+}
+
+// writeOpenMetricsFloat works like writeFloat but appends ".0" if the resulting
+// number would otherwise contain neither a "." nor an "e".
+func writeOpenMetricsFloat(w enhancedWriter, f float64) (int, error) {
+	switch {
+	case f == 1:
+		return w.WriteString("1.0")
+	case f == 0:
+		return w.WriteString("0.0")
+	case f == -1:
+		return w.WriteString("-1.0")
+	case math.IsNaN(f):
+		return w.WriteString("NaN")
+	case math.IsInf(f, +1):
+		return w.WriteString("+Inf")
+	case math.IsInf(f, -1):
+		return w.WriteString("-Inf")
+	default:
+		bp := numBufPool.Get().(*[]byte)
+		*bp = strconv.AppendFloat((*bp)[:0], f, 'g', -1, 64)
+		if !bytes.ContainsAny(*bp, "e.") {
+			*bp = append(*bp, '.', '0')
+		}
+		written, err := w.Write(*bp)
+		numBufPool.Put(bp)
+		return written, err
+	}
+}
+
+// writeUint is like writeInt just for uint64.
+func writeUint(w enhancedWriter, u uint64) (int, error) {
+	bp := numBufPool.Get().(*[]byte)
+	*bp = strconv.AppendUint((*bp)[:0], u, 10)
+	written, err := w.Write(*bp)
+	numBufPool.Put(bp)
+	return written, err
+}

vendor/github.com/prometheus/common/expfmt/text_create.go

@@ -14,52 +14,140 @@
 package expfmt
 
 import (
+	"bufio"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"math"
+	"strconv"
 	"strings"
+	"sync"
+
+	"github.com/prometheus/common/model"
 
 	dto "github.com/prometheus/client_model/go"
-	"github.com/prometheus/common/model"
+)
+
+// enhancedWriter has all the enhanced write functions needed here. bufio.Writer
+// implements it.
+type enhancedWriter interface {
+	io.Writer
+	WriteRune(r rune) (n int, err error)
+	WriteString(s string) (n int, err error)
+	WriteByte(c byte) error
+}
+
+const (
+	initialNumBufSize = 24
+)
+
+var (
+	bufPool = sync.Pool{
+		New: func() interface{} {
+			return bufio.NewWriter(ioutil.Discard)
+		},
+	}
+	numBufPool = sync.Pool{
+		New: func() interface{} {
+			b := make([]byte, 0, initialNumBufSize)
+			return &b
+		},
+	}
 )
 
 // MetricFamilyToText converts a MetricFamily proto message into text format and
 // writes the resulting lines to 'out'. It returns the number of bytes written
-// and any error encountered.  This function does not perform checks on the
-// content of the metric and label names, i.e. invalid metric or label names
+// and any error encountered. The output will have the same order as the input,
+// no further sorting is performed. Furthermore, this function assumes the input
+// is already sanitized and does not perform any sanity checks. If the input
+// contains duplicate metrics or invalid metric or label names, the conversion
 // will result in invalid text format output.
+//
 // This method fulfills the type 'prometheus.encoder'.
-func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
-	var written int
-
+func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (written int, err error) {
 	// Fail-fast checks.
 	if len(in.Metric) == 0 {
-		return written, fmt.Errorf("MetricFamily has no metrics: %s", in)
+		return 0, fmt.Errorf("MetricFamily has no metrics: %s", in)
 	}
 	name := in.GetName()
 	if name == "" {
-		return written, fmt.Errorf("MetricFamily has no name: %s", in)
+		return 0, fmt.Errorf("MetricFamily has no name: %s", in)
 	}
 
+	// Try the interface upgrade. If it doesn't work, we'll use a
+	// bufio.Writer from the sync.Pool.
+	w, ok := out.(enhancedWriter)
+	if !ok {
+		b := bufPool.Get().(*bufio.Writer)
+		b.Reset(out)
+		w = b
+		defer func() {
+			bErr := b.Flush()
+			if err == nil {
+				err = bErr
+			}
+			bufPool.Put(b)
+		}()
+	}
+
+	var n int
+
 	// Comments, first HELP, then TYPE.
 	if in.Help != nil {
-		n, err := fmt.Fprintf(
-			out, "# HELP %s %s\n",
-			name, escapeString(*in.Help, false),
-		)
+		n, err = w.WriteString("# HELP ")
 		written += n
 		if err != nil {
-			return written, err
+			return
+		}
+		n, err = w.WriteString(name)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return
+		}
+		n, err = writeEscapedString(w, *in.Help, false)
+		written += n
+		if err != nil {
+			return
+		}
+		err = w.WriteByte('\n')
+		written++
+		if err != nil {
+			return
 		}
 	}
-	metricType := in.GetType()
-	n, err := fmt.Fprintf(
-		out, "# TYPE %s %s\n",
-		name, strings.ToLower(metricType.String()),
-	)
+	n, err = w.WriteString("# TYPE ")
 	written += n
 	if err != nil {
-		return written, err
+		return
+	}
+	n, err = w.WriteString(name)
+	written += n
+	if err != nil {
+		return
+	}
+	metricType := in.GetType()
+	switch metricType {
+	case dto.MetricType_COUNTER:
+		n, err = w.WriteString(" counter\n")
+	case dto.MetricType_GAUGE:
+		n, err = w.WriteString(" gauge\n")
+	case dto.MetricType_SUMMARY:
+		n, err = w.WriteString(" summary\n")
+	case dto.MetricType_UNTYPED:
+		n, err = w.WriteString(" untyped\n")
+	case dto.MetricType_HISTOGRAM:
+		n, err = w.WriteString(" histogram\n")
+	default:
+		return written, fmt.Errorf("unknown metric type %s", metricType.String())
+	}
+	written += n
+	if err != nil {
+		return
 	}
 
 	// Finally the samples, one line for each.
@@ -72,9 +160,8 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 				)
 			}
 			n, err = writeSample(
-				name, metric, "", "",
+				w, name, "", metric, "", 0,
 				metric.Counter.GetValue(),
-				out,
 			)
 		case dto.MetricType_GAUGE:
 			if metric.Gauge == nil {
@@ -83,9 +170,8 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 				)
 			}
 			n, err = writeSample(
-				name, metric, "", "",
+				w, name, "", metric, "", 0,
 				metric.Gauge.GetValue(),
-				out,
 			)
 		case dto.MetricType_UNTYPED:
 			if metric.Untyped == nil {
@@ -94,9 +180,8 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 				)
 			}
 			n, err = writeSample(
-				name, metric, "", "",
+				w, name, "", metric, "", 0,
 				metric.Untyped.GetValue(),
-				out,
 			)
 		case dto.MetricType_SUMMARY:
 			if metric.Summary == nil {
@@ -106,29 +191,26 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 			}
 			for _, q := range metric.Summary.Quantile {
 				n, err = writeSample(
-					name, metric,
-					model.QuantileLabel, fmt.Sprint(q.GetQuantile()),
+					w, name, "", metric,
+					model.QuantileLabel, q.GetQuantile(),
 					q.GetValue(),
-					out,
 				)
 				written += n
 				if err != nil {
-					return written, err
+					return
 				}
 			}
 			n, err = writeSample(
-				name+"_sum", metric, "", "",
+				w, name, "_sum", metric, "", 0,
 				metric.Summary.GetSampleSum(),
-				out,
 			)
-			if err != nil {
-				return written, err
-			}
 			written += n
+			if err != nil {
+				return
+			}
 			n, err = writeSample(
-				name+"_count", metric, "", "",
+				w, name, "_count", metric, "", 0,
 				float64(metric.Summary.GetSampleCount()),
-				out,
 			)
 		case dto.MetricType_HISTOGRAM:
 			if metric.Histogram == nil {
@@ -137,46 +219,42 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 				)
 			}
 			infSeen := false
-			for _, q := range metric.Histogram.Bucket {
+			for _, b := range metric.Histogram.Bucket {
 				n, err = writeSample(
-					name+"_bucket", metric,
-					model.BucketLabel, fmt.Sprint(q.GetUpperBound()),
-					float64(q.GetCumulativeCount()),
-					out,
+					w, name, "_bucket", metric,
+					model.BucketLabel, b.GetUpperBound(),
+					float64(b.GetCumulativeCount()),
 				)
 				written += n
 				if err != nil {
-					return written, err
+					return
 				}
-				if math.IsInf(q.GetUpperBound(), +1) {
+				if math.IsInf(b.GetUpperBound(), +1) {
 					infSeen = true
 				}
 			}
 			if !infSeen {
 				n, err = writeSample(
-					name+"_bucket", metric,
-					model.BucketLabel, "+Inf",
+					w, name, "_bucket", metric,
+					model.BucketLabel, math.Inf(+1),
 					float64(metric.Histogram.GetSampleCount()),
-					out,
 				)
-				if err != nil {
-					return written, err
-				}
 				written += n
+				if err != nil {
+					return
+				}
 			}
 			n, err = writeSample(
-				name+"_sum", metric, "", "",
+				w, name, "_sum", metric, "", 0,
 				metric.Histogram.GetSampleSum(),
-				out,
 			)
-			if err != nil {
-				return written, err
-			}
 			written += n
+			if err != nil {
+				return
+			}
 			n, err = writeSample(
-				name+"_count", metric, "", "",
+				w, name, "_count", metric, "", 0,
 				float64(metric.Histogram.GetSampleCount()),
-				out,
 			)
 		default:
 			return written, fmt.Errorf(
@@ -185,116 +263,203 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 		}
 		written += n
 		if err != nil {
-			return written, err
+			return
 		}
 	}
-	return written, nil
+	return
 }
 
-// writeSample writes a single sample in text format to out, given the metric
+// writeSample writes a single sample in text format to w, given the metric
 // name, the metric proto message itself, optionally an additional label name
-// and value (use empty strings if not required), and the value. The function
-// returns the number of bytes written and any error encountered.
+// with a float64 value (use empty string as label name if not required), and
+// the value. The function returns the number of bytes written and any error
+// encountered.
 func writeSample(
-	name string,
+	w enhancedWriter,
+	name, suffix string,
 	metric *dto.Metric,
-	additionalLabelName, additionalLabelValue string,
+	additionalLabelName string, additionalLabelValue float64,
 	value float64,
-	out io.Writer,
 ) (int, error) {
 	var written int
-	n, err := fmt.Fprint(out, name)
+	n, err := w.WriteString(name)
 	written += n
 	if err != nil {
 		return written, err
 	}
-	n, err = labelPairsToText(
-		metric.Label,
-		additionalLabelName, additionalLabelValue,
-		out,
-	)
-	written += n
-	if err != nil {
-		return written, err
-	}
-	n, err = fmt.Fprintf(out, " %v", value)
-	written += n
-	if err != nil {
-		return written, err
-	}
-	if metric.TimestampMs != nil {
-		n, err = fmt.Fprintf(out, " %v", *metric.TimestampMs)
+	if suffix != "" {
+		n, err = w.WriteString(suffix)
 		written += n
 		if err != nil {
 			return written, err
 		}
 	}
-	n, err = out.Write([]byte{'\n'})
+	n, err = writeLabelPairs(
+		w, metric.Label, additionalLabelName, additionalLabelValue,
+	)
 	written += n
 	if err != nil {
 		return written, err
 	}
+	err = w.WriteByte(' ')
+	written++
+	if err != nil {
+		return written, err
+	}
+	n, err = writeFloat(w, value)
+	written += n
+	if err != nil {
+		return written, err
+	}
+	if metric.TimestampMs != nil {
+		err = w.WriteByte(' ')
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err = writeInt(w, *metric.TimestampMs)
+		written += n
+		if err != nil {
+			return written, err
+		}
+	}
+	err = w.WriteByte('\n')
+	written++
+	if err != nil {
+		return written, err
+	}
 	return written, nil
 }
 
-// labelPairsToText converts a slice of LabelPair proto messages plus the
+// writeLabelPairs converts a slice of LabelPair proto messages plus the
 // explicitly given additional label pair into text formatted as required by the
-// text format and writes it to 'out'. An empty slice in combination with an
-// empty string 'additionalLabelName' results in nothing being
-// written. Otherwise, the label pairs are written, escaped as required by the
-// text format, and enclosed in '{...}'. The function returns the number of
-// bytes written and any error encountered.
-func labelPairsToText(
+// text format and writes it to 'w'. An empty slice in combination with an empty
+// string 'additionalLabelName' results in nothing being written. Otherwise, the
+// label pairs are written, escaped as required by the text format, and enclosed
+// in '{...}'. The function returns the number of bytes written and any error
+// encountered.
+func writeLabelPairs(
+	w enhancedWriter,
 	in []*dto.LabelPair,
-	additionalLabelName, additionalLabelValue string,
-	out io.Writer,
+	additionalLabelName string, additionalLabelValue float64,
 ) (int, error) {
 	if len(in) == 0 && additionalLabelName == "" {
 		return 0, nil
 	}
-	var written int
-	separator := '{'
+	var (
+		written   int
+		separator byte = '{'
+	)
 	for _, lp := range in {
-		n, err := fmt.Fprintf(
-			out, `%c%s="%s"`,
-			separator, lp.GetName(), escapeString(lp.GetValue(), true),
-		)
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(lp.GetName())
 		written += n
 		if err != nil {
 			return written, err
 		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeEscapedString(w, lp.GetValue(), true)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
 		separator = ','
 	}
 	if additionalLabelName != "" {
-		n, err := fmt.Fprintf(
-			out, `%c%s="%s"`,
-			separator, additionalLabelName,
-			escapeString(additionalLabelValue, true),
-		)
+		err := w.WriteByte(separator)
+		written++
+		if err != nil {
+			return written, err
+		}
+		n, err := w.WriteString(additionalLabelName)
 		written += n
 		if err != nil {
 			return written, err
 		}
+		n, err = w.WriteString(`="`)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		n, err = writeFloat(w, additionalLabelValue)
+		written += n
+		if err != nil {
+			return written, err
+		}
+		err = w.WriteByte('"')
+		written++
+		if err != nil {
+			return written, err
+		}
 	}
-	n, err := out.Write([]byte{'}'})
-	written += n
+	err := w.WriteByte('}')
+	written++
 	if err != nil {
 		return written, err
 	}
 	return written, nil
 }
 
+// writeEscapedString replaces '\' by '\\', new line character by '\n', and - if
+// includeDoubleQuote is true - '"' by '\"'.
 var (
-	escape                = strings.NewReplacer("\\", `\\`, "\n", `\n`)
-	escapeWithDoubleQuote = strings.NewReplacer("\\", `\\`, "\n", `\n`, "\"", `\"`)
+	escaper       = strings.NewReplacer("\\", `\\`, "\n", `\n`)
+	quotedEscaper = strings.NewReplacer("\\", `\\`, "\n", `\n`, "\"", `\"`)
 )
 
-// escapeString replaces '\' by '\\', new line character by '\n', and - if
-// includeDoubleQuote is true - '"' by '\"'.
-func escapeString(v string, includeDoubleQuote bool) string {
+func writeEscapedString(w enhancedWriter, v string, includeDoubleQuote bool) (int, error) {
 	if includeDoubleQuote {
-		return escapeWithDoubleQuote.Replace(v)
+		return quotedEscaper.WriteString(w, v)
 	}
+	return escaper.WriteString(w, v)
+}
 
-	return escape.Replace(v)
+// writeFloat is equivalent to fmt.Fprint with a float64 argument but hardcodes
+// a few common cases for increased efficiency. For non-hardcoded cases, it uses
+// strconv.AppendFloat to avoid allocations, similar to writeInt.
+func writeFloat(w enhancedWriter, f float64) (int, error) {
+	switch {
+	case f == 1:
+		return 1, w.WriteByte('1')
+	case f == 0:
+		return 1, w.WriteByte('0')
+	case f == -1:
+		return w.WriteString("-1")
+	case math.IsNaN(f):
+		return w.WriteString("NaN")
+	case math.IsInf(f, +1):
+		return w.WriteString("+Inf")
+	case math.IsInf(f, -1):
+		return w.WriteString("-Inf")
+	default:
+		bp := numBufPool.Get().(*[]byte)
+		*bp = strconv.AppendFloat((*bp)[:0], f, 'g', -1, 64)
+		written, err := w.Write(*bp)
+		numBufPool.Put(bp)
+		return written, err
+	}
+}
+
+// writeInt is equivalent to fmt.Fprint with an int64 argument but uses
+// strconv.AppendInt with a byte slice taken from a sync.Pool to avoid
+// allocations.
+func writeInt(w enhancedWriter, i int64) (int, error) {
+	bp := numBufPool.Get().(*[]byte)
+	*bp = strconv.AppendInt((*bp)[:0], i, 10)
+	written, err := w.Write(*bp)
+	numBufPool.Put(bp)
+	return written, err
 }

vendor/github.com/prometheus/common/expfmt/text_parse.go

@@ -24,7 +24,7 @@ import (
 
 	dto "github.com/prometheus/client_model/go"
 
-	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/proto" //nolint:staticcheck // Ignore SA1019. Need to keep deprecated package for compatibility.
 	"github.com/prometheus/common/model"
 )
 
@@ -47,7 +47,7 @@ func (e ParseError) Error() string {
 }
 
 // TextParser is used to parse the simple and flat text-based exchange format. Its
-// nil value is ready to use.
+// zero value is ready to use.
 type TextParser struct {
 	metricFamiliesByName map[string]*dto.MetricFamily
 	buf                  *bufio.Reader // Where the parsed input is read through.
@@ -299,6 +299,17 @@ func (p *TextParser) startLabelName() stateFn {
 		p.parseError(fmt.Sprintf("expected '=' after label name, found %q", p.currentByte))
 		return nil
 	}
+	// Check for duplicate label names.
+	labels := make(map[string]struct{})
+	for _, l := range p.currentMetric.Label {
+		lName := l.GetName()
+		if _, exists := labels[lName]; !exists {
+			labels[lName] = struct{}{}
+		} else {
+			p.parseError(fmt.Sprintf("duplicate label names for metric %q", p.currentMF.GetName()))
+			return nil
+		}
+	}
 	return p.startLabelValue
 }
 
@@ -315,13 +326,17 @@ func (p *TextParser) startLabelValue() stateFn {
 	if p.readTokenAsLabelValue(); p.err != nil {
 		return nil
 	}
+	if !model.LabelValue(p.currentToken.String()).IsValid() {
+		p.parseError(fmt.Sprintf("invalid label value %q", p.currentToken.String()))
+		return nil
+	}
 	p.currentLabelPair.Value = proto.String(p.currentToken.String())
 	// Special treatment of summaries:
 	// - Quantile labels are special, will result in dto.Quantile later.
 	// - Other labels have to be added to currentLabels for signature calculation.
 	if p.currentMF.GetType() == dto.MetricType_SUMMARY {
 		if p.currentLabelPair.GetName() == model.QuantileLabel {
-			if p.currentQuantile, p.err = strconv.ParseFloat(p.currentLabelPair.GetValue(), 64); p.err != nil {
+			if p.currentQuantile, p.err = parseFloat(p.currentLabelPair.GetValue()); p.err != nil {
 				// Create a more helpful error message.
 				p.parseError(fmt.Sprintf("expected float as value for 'quantile' label, got %q", p.currentLabelPair.GetValue()))
 				return nil
@@ -333,7 +348,7 @@ func (p *TextParser) startLabelValue() stateFn {
 	// Similar special treatment of histograms.
 	if p.currentMF.GetType() == dto.MetricType_HISTOGRAM {
 		if p.currentLabelPair.GetName() == model.BucketLabel {
-			if p.currentBucket, p.err = strconv.ParseFloat(p.currentLabelPair.GetValue(), 64); p.err != nil {
+			if p.currentBucket, p.err = parseFloat(p.currentLabelPair.GetValue()); p.err != nil {
 				// Create a more helpful error message.
 				p.parseError(fmt.Sprintf("expected float as value for 'le' label, got %q", p.currentLabelPair.GetValue()))
 				return nil
@@ -355,7 +370,7 @@ func (p *TextParser) startLabelValue() stateFn {
 		}
 		return p.readingValue
 	default:
-		p.parseError(fmt.Sprintf("unexpected end of label value %q", p.currentLabelPair.Value))
+		p.parseError(fmt.Sprintf("unexpected end of label value %q", p.currentLabelPair.GetValue()))
 		return nil
 	}
 }
@@ -388,7 +403,7 @@ func (p *TextParser) readingValue() stateFn {
 	if p.readTokenUntilWhitespace(); p.err != nil {
 		return nil // Unexpected end of input.
 	}
-	value, err := strconv.ParseFloat(p.currentToken.String(), 64)
+	value, err := parseFloat(p.currentToken.String())
 	if err != nil {
 		// Create a more helpful error message.
 		p.parseError(fmt.Sprintf("expected float as value, got %q", p.currentToken.String()))
@@ -552,8 +567,8 @@ func (p *TextParser) readTokenUntilWhitespace() {
 // byte considered is the byte already read (now in p.currentByte).  The first
 // newline byte encountered is still copied into p.currentByte, but not into
 // p.currentToken. If recognizeEscapeSequence is true, two escape sequences are
-// recognized: '\\' tranlates into '\', and '\n' into a line-feed character. All
-// other escape sequences are invalid and cause an error.
+// recognized: '\\' translates into '\', and '\n' into a line-feed character.
+// All other escape sequences are invalid and cause an error.
 func (p *TextParser) readTokenUntilNewline(recognizeEscapeSequence bool) {
 	p.currentToken.Reset()
 	escaped := false
@@ -751,3 +766,10 @@ func histogramMetricName(name string) string {
 		return name
 	}
 }
+
+func parseFloat(s string) (float64, error) {
+	if strings.ContainsAny(s, "pP_") {
+		return 0, fmt.Errorf("unsupported character in float")
+	}
+	return strconv.ParseFloat(s, 64)
+}

vendor/github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg/autoneg.go

@@ -1,12 +1,12 @@
 /*
+Copyright (c) 2011, Open Knowledge Foundation Ltd.
+All rights reserved.
+
 HTTP Content-Type Autonegotiation.
 
 The functions in this package implement the behaviour specified in
 http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
 
-Copyright (c) 2011, Open Knowledge Foundation Ltd.
-All rights reserved.
-
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:

vendor/github.com/prometheus/common/model/fnv.go

@@ -20,7 +20,7 @@ const (
 	prime64  = 1099511628211
 )
 
-// hashNew initializies a new fnv64a hash value.
+// hashNew initializes a new fnv64a hash value.
 func hashNew() uint64 {
 	return offset64
 }

vendor/github.com/prometheus/common/model/labels.go

@@ -45,6 +45,14 @@ const (
 	// scrape a target.
 	MetricsPathLabel = "__metrics_path__"
 
+	// ScrapeIntervalLabel is the name of the label that holds the scrape interval
+	// used to scrape a target.
+	ScrapeIntervalLabel = "__scrape_interval__"
+
+	// ScrapeTimeoutLabel is the name of the label that holds the scrape
+	// timeout used to scrape a target.
+	ScrapeTimeoutLabel = "__scrape_timeout__"
+
 	// ReservedLabelPrefix is a prefix which is not legal in user-supplied
 	// label names.
 	ReservedLabelPrefix = "__"
@@ -80,14 +88,18 @@ const (
 	QuantileLabel = "quantile"
 )
 
-// LabelNameRE is a regular expression matching valid label names.
+// LabelNameRE is a regular expression matching valid label names. Note that the
+// IsValid method of LabelName performs the same check but faster than a match
+// with this regular expression.
 var LabelNameRE = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$")
 
 // A LabelName is a key for a LabelSet or Metric.  It has a value associated
 // therewith.
 type LabelName string
 
-// IsValid is true iff the label name matches the pattern of LabelNameRE.
+// IsValid is true iff the label name matches the pattern of LabelNameRE. This
+// method, however, does not use LabelNameRE for the check but a much faster
+// hardcoded implementation.
 func (ln LabelName) IsValid() bool {
 	if len(ln) == 0 {
 		return false
@@ -106,7 +118,7 @@ func (ln *LabelName) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	if err := unmarshal(&s); err != nil {
 		return err
 	}
-	if !LabelNameRE.MatchString(s) {
+	if !LabelName(s).IsValid() {
 		return fmt.Errorf("%q is not a valid label name", s)
 	}
 	*ln = LabelName(s)
@@ -119,7 +131,7 @@ func (ln *LabelName) UnmarshalJSON(b []byte) error {
 	if err := json.Unmarshal(b, &s); err != nil {
 		return err
 	}
-	if !LabelNameRE.MatchString(s) {
+	if !LabelName(s).IsValid() {
 		return fmt.Errorf("%q is not a valid label name", s)
 	}
 	*ln = LabelName(s)

vendor/github.com/prometheus/common/model/labelset.go

@@ -160,7 +160,7 @@ func (l *LabelSet) UnmarshalJSON(b []byte) error {
 	// LabelName as a string and does not call its UnmarshalJSON method.
 	// Thus, we have to replicate the behavior here.
 	for ln := range m {
-		if !LabelNameRE.MatchString(string(ln)) {
+		if !ln.IsValid() {
 			return fmt.Errorf("%q is not a valid label name", ln)
 		}
 	}

vendor/github.com/prometheus/common/model/metric.go

@@ -21,8 +21,10 @@ import (
 )
 
 var (
-	separator    = []byte{0}
-	MetricNameRE = regexp.MustCompile(`^[a-zA-Z_][a-zA-Z0-9_:]*$`)
+	// MetricNameRE is a regular expression matching valid metric
+	// names. Note that the IsValidMetricName function performs the same
+	// check but faster than a match with this regular expression.
+	MetricNameRE = regexp.MustCompile(`^[a-zA-Z_:][a-zA-Z0-9_:]*$`)
 )
 
 // A Metric is similar to a LabelSet, but the key difference is that a Metric is
@@ -41,7 +43,7 @@ func (m Metric) Before(o Metric) bool {
 
 // Clone returns a copy of the Metric.
 func (m Metric) Clone() Metric {
-	clone := Metric{}
+	clone := make(Metric, len(m))
 	for k, v := range m {
 		clone[k] = v
 	}
@@ -85,6 +87,8 @@ func (m Metric) FastFingerprint() Fingerprint {
 }
 
 // IsValidMetricName returns true iff name matches the pattern of MetricNameRE.
+// This function, however, does not use MetricNameRE for the check but a much
+// faster hardcoded implementation.
 func IsValidMetricName(n LabelValue) bool {
 	if len(n) == 0 {
 		return false

vendor/github.com/prometheus/common/model/silence.go

@@ -59,8 +59,8 @@ func (m *Matcher) Validate() error {
 	return nil
 }
 
-// Silence defines the representation of a silence definiton
-// in the Prometheus eco-system.
+// Silence defines the representation of a silence definition in the Prometheus
+// eco-system.
 type Silence struct {
 	ID uint64 `json:"id,omitempty"`
 

vendor/github.com/prometheus/common/model/time.go

@@ -14,6 +14,8 @@
 package model
 
 import (
+	"encoding/json"
+	"errors"
 	"fmt"
 	"math"
 	"regexp"
@@ -43,7 +45,7 @@ const (
 // (1970-01-01 00:00 UTC) excluding leap seconds.
 type Time int64
 
-// Interval describes and interval between two timestamps.
+// Interval describes an interval between two timestamps.
 type Interval struct {
 	Start, End Time
 }
@@ -150,7 +152,13 @@ func (t *Time) UnmarshalJSON(b []byte) error {
 			return err
 		}
 
-		*t = Time(v + va)
+		// If the value was something like -0.1 the negative is lost in the
+		// parsing because of the leading zero, this ensures that we capture it.
+		if len(p[0]) > 0 && p[0][0] == '-' && v+va > 0 {
+			*t = Time(v+va) * -1
+		} else {
+			*t = Time(v + va)
+		}
 
 	default:
 		return fmt.Errorf("invalid time %q", string(b))
@@ -163,70 +171,130 @@ func (t *Time) UnmarshalJSON(b []byte) error {
 // This type should not propagate beyond the scope of input/output processing.
 type Duration time.Duration
 
-var durationRE = regexp.MustCompile("^([0-9]+)(y|w|d|h|m|s|ms)$")
+// Set implements pflag/flag.Value
+func (d *Duration) Set(s string) error {
+	var err error
+	*d, err = ParseDuration(s)
+	return err
+}
 
-// StringToDuration parses a string into a time.Duration, assuming that a year
+// Type implements pflag.Value
+func (d *Duration) Type() string {
+	return "duration"
+}
+
+var durationRE = regexp.MustCompile("^(([0-9]+)y)?(([0-9]+)w)?(([0-9]+)d)?(([0-9]+)h)?(([0-9]+)m)?(([0-9]+)s)?(([0-9]+)ms)?$")
+
+// ParseDuration parses a string into a time.Duration, assuming that a year
 // always has 365d, a week always has 7d, and a day always has 24h.
 func ParseDuration(durationStr string) (Duration, error) {
+	switch durationStr {
+	case "0":
+		// Allow 0 without a unit.
+		return 0, nil
+	case "":
+		return 0, fmt.Errorf("empty duration string")
+	}
 	matches := durationRE.FindStringSubmatch(durationStr)
-	if len(matches) != 3 {
+	if matches == nil {
 		return 0, fmt.Errorf("not a valid duration string: %q", durationStr)
 	}
-	var (
-		n, _ = strconv.Atoi(matches[1])
-		dur  = time.Duration(n) * time.Millisecond
-	)
-	switch unit := matches[2]; unit {
-	case "y":
-		dur *= 1000 * 60 * 60 * 24 * 365
-	case "w":
-		dur *= 1000 * 60 * 60 * 24 * 7
-	case "d":
-		dur *= 1000 * 60 * 60 * 24
-	case "h":
-		dur *= 1000 * 60 * 60
-	case "m":
-		dur *= 1000 * 60
-	case "s":
-		dur *= 1000
-	case "ms":
-		// Value already correct
-	default:
-		return 0, fmt.Errorf("invalid time unit in duration string: %q", unit)
+	var dur time.Duration
+
+	// Parse the match at pos `pos` in the regex and use `mult` to turn that
+	// into ms, then add that value to the total parsed duration.
+	var overflowErr error
+	m := func(pos int, mult time.Duration) {
+		if matches[pos] == "" {
+			return
+		}
+		n, _ := strconv.Atoi(matches[pos])
+
+		// Check if the provided duration overflows time.Duration (> ~ 290years).
+		if n > int((1<<63-1)/mult/time.Millisecond) {
+			overflowErr = errors.New("duration out of range")
+		}
+		d := time.Duration(n) * time.Millisecond
+		dur += d * mult
+
+		if dur < 0 {
+			overflowErr = errors.New("duration out of range")
+		}
 	}
-	return Duration(dur), nil
+
+	m(2, 1000*60*60*24*365) // y
+	m(4, 1000*60*60*24*7)   // w
+	m(6, 1000*60*60*24)     // d
+	m(8, 1000*60*60)        // h
+	m(10, 1000*60)          // m
+	m(12, 1000)             // s
+	m(14, 1)                // ms
+
+	return Duration(dur), overflowErr
 }
 
 func (d Duration) String() string {
 	var (
-		ms   = int64(time.Duration(d) / time.Millisecond)
-		unit = "ms"
+		ms = int64(time.Duration(d) / time.Millisecond)
+		r  = ""
 	)
-	factors := map[string]int64{
-		"y":  1000 * 60 * 60 * 24 * 365,
-		"w":  1000 * 60 * 60 * 24 * 7,
-		"d":  1000 * 60 * 60 * 24,
-		"h":  1000 * 60 * 60,
-		"m":  1000 * 60,
-		"s":  1000,
-		"ms": 1,
+	if ms == 0 {
+		return "0s"
 	}
 
-	switch int64(0) {
-	case ms % factors["y"]:
-		unit = "y"
-	case ms % factors["w"]:
-		unit = "w"
-	case ms % factors["d"]:
-		unit = "d"
-	case ms % factors["h"]:
-		unit = "h"
-	case ms % factors["m"]:
-		unit = "m"
-	case ms % factors["s"]:
-		unit = "s"
+	f := func(unit string, mult int64, exact bool) {
+		if exact && ms%mult != 0 {
+			return
+		}
+		if v := ms / mult; v > 0 {
+			r += fmt.Sprintf("%d%s", v, unit)
+			ms -= v * mult
+		}
 	}
-	return fmt.Sprintf("%v%v", ms/factors[unit], unit)
+
+	// Only format years and weeks if the remainder is zero, as it is often
+	// easier to read 90d than 12w6d.
+	f("y", 1000*60*60*24*365, true)
+	f("w", 1000*60*60*24*7, true)
+
+	f("d", 1000*60*60*24, false)
+	f("h", 1000*60*60, false)
+	f("m", 1000*60, false)
+	f("s", 1000, false)
+	f("ms", 1, false)
+
+	return r
+}
+
+// MarshalJSON implements the json.Marshaler interface.
+func (d Duration) MarshalJSON() ([]byte, error) {
+	return json.Marshal(d.String())
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+func (d *Duration) UnmarshalJSON(bytes []byte) error {
+	var s string
+	if err := json.Unmarshal(bytes, &s); err != nil {
+		return err
+	}
+	dur, err := ParseDuration(s)
+	if err != nil {
+		return err
+	}
+	*d = dur
+	return nil
+}
+
+// MarshalText implements the encoding.TextMarshaler interface.
+func (d *Duration) MarshalText() ([]byte, error) {
+	return []byte(d.String()), nil
+}
+
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
+func (d *Duration) UnmarshalText(text []byte) error {
+	var err error
+	*d, err = ParseDuration(string(text))
+	return err
 }
 
 // MarshalYAML implements the yaml.Marshaler interface.

vendor/github.com/prometheus/common/model/value.go

@@ -22,6 +22,22 @@ import (
 	"strings"
 )
 
+var (
+	// ZeroSamplePair is the pseudo zero-value of SamplePair used to signal a
+	// non-existing sample pair. It is a SamplePair with timestamp Earliest and
+	// value 0.0. Note that the natural zero value of SamplePair has a timestamp
+	// of 0, which is possible to appear in a real SamplePair and thus not
+	// suitable to signal a non-existing SamplePair.
+	ZeroSamplePair = SamplePair{Timestamp: Earliest}
+
+	// ZeroSample is the pseudo zero-value of Sample used to signal a
+	// non-existing sample. It is a Sample with timestamp Earliest, value 0.0,
+	// and metric nil. Note that the natural zero value of Sample has a timestamp
+	// of 0, which is possible to appear in a real Sample and thus not suitable
+	// to signal a non-existing Sample.
+	ZeroSample = Sample{Timestamp: Earliest}
+)
+
 // A SampleValue is a representation of a value for a given sample at a given
 // time.
 type SampleValue float64
@@ -84,7 +100,7 @@ func (s *SamplePair) UnmarshalJSON(b []byte) error {
 }
 
 // Equal returns true if this SamplePair and o have equal Values and equal
-// Timestamps. The sematics of Value equality is defined by SampleValue.Equal.
+// Timestamps. The semantics of Value equality is defined by SampleValue.Equal.
 func (s *SamplePair) Equal(o *SamplePair) bool {
 	return s == o || (s.Value.Equal(o.Value) && s.Timestamp.Equal(o.Timestamp))
 }
@@ -101,7 +117,7 @@ type Sample struct {
 }
 
 // Equal compares first the metrics, then the timestamp, then the value. The
-// sematics of value equality is defined by SampleValue.Equal.
+// semantics of value equality is defined by SampleValue.Equal.
 func (s *Sample) Equal(o *Sample) bool {
 	if s == o {
 		return true
@@ -113,11 +129,8 @@ func (s *Sample) Equal(o *Sample) bool {
 	if !s.Timestamp.Equal(o.Timestamp) {
 		return false
 	}
-	if s.Value.Equal(o.Value) {
-		return false
-	}
 
-	return true
+	return s.Value.Equal(o.Value)
 }
 
 func (s Sample) String() string {

vendor/github.com/prometheus/procfs/.gitignore

@@ -0,0 +1 @@
+/fixtures/

vendor/github.com/prometheus/procfs/.golangci.yml

@@ -0,0 +1,4 @@
+---
+linters:
+  enable:
+  - golint

vendor/github.com/prometheus/procfs/.travis.yml

@@ -1,5 +0,0 @@
-sudo: false
-language: go
-go:
-    - 1.5
-    - 1.6

vendor/github.com/prometheus/procfs/AUTHORS.md

@@ -1,20 +0,0 @@
-The Prometheus project was started by Matt T. Proud (emeritus) and
-Julius Volz in 2012.
-
-Maintainers of this repository:
-
-* Tobias Schmidt <ts@soundcloud.com>
-
-The following individuals have contributed code to this repository
-(listed in alphabetical order):
-
-* Armen Baghumian <abaghumian@noggin.com.au>
-* Bjoern Rabenstein <beorn@soundcloud.com>
-* David Cournapeau <cournape@gmail.com>
-* Ji-Hoon, Seol <jihoon.seol@gmail.com>
-* Jonas Große Sundrup <cherti@letopolis.de>
-* Julius Volz <julius.volz@gmail.com>
-* Matthias Rampke <mr@soundcloud.com>
-* Nicky Gerritsen <nicky@streamone.nl>
-* Rémi Audebert <contact@halfr.net>
-* Tobias Schmidt <tobidt@gmail.com>

vendor/github.com/prometheus/procfs/CODE_OF_CONDUCT.md

@@ -0,0 +1,3 @@
+## Prometheus Community Code of Conduct
+
+Prometheus follows the [CNCF Code of Conduct](https://github.com/cncf/foundation/blob/master/code-of-conduct.md).

vendor/github.com/prometheus/procfs/CONTRIBUTING.md

@@ -2,17 +2,120 @@
 
 Prometheus uses GitHub to manage reviews of pull requests.
 
-* If you have a trivial fix or improvement, go ahead and create a pull
-  request, addressing (with `@...`) one or more of the maintainers
-  (see [AUTHORS.md](AUTHORS.md)) in the description of the pull request.
+* If you are a new contributor see: [Steps to Contribute](#steps-to-contribute)
+
+* If you have a trivial fix or improvement, go ahead and create a pull request,
+  addressing (with `@...`) a suitable maintainer of this repository (see
+  [MAINTAINERS.md](MAINTAINERS.md)) in the description of the pull request.
 
 * If you plan to do something more involved, first discuss your ideas
   on our [mailing list](https://groups.google.com/forum/?fromgroups#!forum/prometheus-developers).
   This will avoid unnecessary work and surely give you and us a good deal
-  of inspiration.
+  of inspiration. Also please see our [non-goals issue](https://github.com/prometheus/docs/issues/149) on areas that the Prometheus community doesn't plan to work on.
 
 * Relevant coding style guidelines are the [Go Code Review
   Comments](https://code.google.com/p/go-wiki/wiki/CodeReviewComments)
   and the _Formatting and style_ section of Peter Bourgon's [Go: Best
   Practices for Production
-  Environments](http://peter.bourgon.org/go-in-production/#formatting-and-style).
+  Environments](https://peter.bourgon.org/go-in-production/#formatting-and-style).
+
+* Be sure to sign off on the [DCO](https://github.com/probot/dco#how-it-works)
+
+## Steps to Contribute
+
+Should you wish to work on an issue, please claim it first by commenting on the GitHub issue that you want to work on it. This is to prevent duplicated efforts from contributors on the same issue.
+
+Please check the [`help-wanted`](https://github.com/prometheus/procfs/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22) label to find issues that are good for getting started. If you have questions about one of the issues, with or without the tag, please comment on them and one of the maintainers will clarify it. For a quicker response, contact us over [IRC](https://prometheus.io/community).
+
+For quickly compiling and testing your changes do:
+```
+make test         # Make sure all the tests pass before you commit and push :)
+```
+
+We use [`golangci-lint`](https://github.com/golangci/golangci-lint) for linting the code. If it reports an issue and you think that the warning needs to be disregarded or is a false-positive, you can add a special comment `//nolint:linter1[,linter2,...]` before the offending line. Use this sparingly though, fixing the code to comply with the linter's recommendation is in general the preferred course of action.
+
+## Pull Request Checklist
+
+* Branch from the master branch and, if needed, rebase to the current master branch before submitting your pull request. If it doesn't merge cleanly with master you may be asked to rebase your changes.
+
+* Commits should be as small as possible, while ensuring that each commit is correct independently (i.e., each commit should compile and pass tests).
+
+* If your patch is not getting reviewed or you need a specific person to review it, you can @-reply a reviewer asking for a review in the pull request or a comment, or you can ask for a review on IRC channel [#prometheus](https://webchat.freenode.net/?channels=#prometheus) on irc.freenode.net (for the easiest start, [join via Riot](https://riot.im/app/#/room/#prometheus:matrix.org)).
+
+* Add tests relevant to the fixed bug or new feature.
+
+## Dependency management
+
+The Prometheus project uses [Go modules](https://golang.org/cmd/go/#hdr-Modules__module_versions__and_more) to manage dependencies on external packages. This requires a working Go environment with version 1.12 or greater installed.
+
+All dependencies are vendored in the `vendor/` directory.
+
+To add or update a new dependency, use the `go get` command:
+
+```bash
+# Pick the latest tagged release.
+go get example.com/some/module/pkg
+
+# Pick a specific version.
+go get example.com/some/module/pkg@vX.Y.Z
+```
+
+Tidy up the `go.mod` and `go.sum` files and copy the new/updated dependency to the `vendor/` directory:
+
+
+```bash
+# The GO111MODULE variable can be omitted when the code isn't located in GOPATH.
+GO111MODULE=on go mod tidy
+
+GO111MODULE=on go mod vendor
+```
+
+You have to commit the changes to `go.mod`, `go.sum` and the `vendor/` directory before submitting the pull request.
+
+
+## API Implementation Guidelines
+
+### Naming and Documentation
+
+Public functions and structs should normally be named according to the file(s) being read and parsed.  For example, 
+the `fs.BuddyInfo()` function reads the file `/proc/buddyinfo`.  In addition, the godoc for each public function
+should contain the path to the file(s) being read and a URL of the linux kernel documentation describing the file(s).
+
+### Reading vs. Parsing
+
+Most functionality in this library consists of reading files and then parsing the text into structured data.  In most
+cases reading and parsing should be separated into different functions/methods with a public `fs.Thing()` method and 
+a private `parseThing(r Reader)` function.  This provides a logical separation and allows parsing to be tested
+directly without the need to read from the filesystem.  Using a `Reader` argument is preferred over other data types
+such as `string` or `*File` because it provides the most flexibility regarding the data source.  When a set of files 
+in a directory needs to be parsed, then a `path` string parameter to the parse function can be used instead.
+
+### /proc and /sys filesystem I/O 
+
+The `proc` and `sys` filesystems are pseudo file systems and work a bit differently from standard disk I/O.  
+Many of the files are changing continuously and the data being read can in some cases change between subsequent 
+reads in the same file.  Also, most of the files are relatively small (less than a few KBs), and system calls
+to the `stat` function will often return the wrong size.  Therefore, for most files it's recommended to read the 
+full file in a single operation using an internal utility function called `util.ReadFileNoStat`.
+This function is similar to `ioutil.ReadFile`, but it avoids the system call to `stat` to get the current size of
+the file.
+
+Note that parsing the file's contents can still be performed one line at a time.  This is done by first reading 
+the full file, and then using a scanner on the `[]byte` or `string` containing the data.
+
+```
+    data, err := util.ReadFileNoStat("/proc/cpuinfo")
+    if err != nil {
+        return err
+    }
+    reader := bytes.NewReader(data)
+    scanner := bufio.NewScanner(reader)
+```
+
+The `/sys` filesystem contains many very small files which contain only a single numeric or text value.  These files
+can be read using an internal function called `util.SysReadFile` which is similar to `ioutil.ReadFile` but does
+not bother to check the size of the file before reading.
+```
+    data, err := util.SysReadFile("/sys/class/power_supply/BAT0/capacity")
+```
+

vendor/github.com/prometheus/procfs/MAINTAINERS.md

@@ -0,0 +1,2 @@
+* Johannes 'fish' Ziemke <github@freigeist.org> @discordianfish
+* Paul Gier <pgier@redhat.com> @pgier

vendor/github.com/prometheus/procfs/Makefile

@@ -1,6 +1,31 @@
-ci:
-	! gofmt -l *.go | read nothing
-	go vet
-	go test -v ./...
-	go get github.com/golang/lint/golint
-	golint *.go
+# Copyright 2018 The Prometheus Authors
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+include Makefile.common
+
+%/.unpacked: %.ttar
+	@echo ">> extracting fixtures"
+	./ttar -C $(dir $*) -x -f $*.ttar
+	touch $@
+
+fixtures: fixtures/.unpacked
+
+update_fixtures:
+	rm -vf fixtures/.unpacked
+	./ttar -c -f fixtures.ttar fixtures/
+
+.PHONY: build
+build:
+
+.PHONY: test
+test: fixtures/.unpacked common-test

vendor/github.com/prometheus/procfs/Makefile.common

@@ -0,0 +1,311 @@
+# Copyright 2018 The Prometheus Authors
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# A common Makefile that includes rules to be reused in different prometheus projects.
+# !!! Open PRs only against the prometheus/prometheus/Makefile.common repository!
+
+# Example usage :
+# Create the main Makefile in the root project directory.
+# include Makefile.common
+# customTarget:
+# 	@echo ">> Running customTarget"
+#
+
+# Ensure GOBIN is not set during build so that promu is installed to the correct path
+unexport GOBIN
+
+GO           ?= go
+GOFMT        ?= $(GO)fmt
+FIRST_GOPATH := $(firstword $(subst :, ,$(shell $(GO) env GOPATH)))
+GOOPTS       ?=
+GOHOSTOS     ?= $(shell $(GO) env GOHOSTOS)
+GOHOSTARCH   ?= $(shell $(GO) env GOHOSTARCH)
+
+GO_VERSION        ?= $(shell $(GO) version)
+GO_VERSION_NUMBER ?= $(word 3, $(GO_VERSION))
+PRE_GO_111        ?= $(shell echo $(GO_VERSION_NUMBER) | grep -E 'go1\.(10|[0-9])\.')
+
+GOVENDOR :=
+GO111MODULE :=
+ifeq (, $(PRE_GO_111))
+	ifneq (,$(wildcard go.mod))
+		# Enforce Go modules support just in case the directory is inside GOPATH (and for Travis CI).
+		GO111MODULE := on
+
+		ifneq (,$(wildcard vendor))
+			# Always use the local vendor/ directory to satisfy the dependencies.
+			GOOPTS := $(GOOPTS) -mod=vendor
+		endif
+	endif
+else
+	ifneq (,$(wildcard go.mod))
+		ifneq (,$(wildcard vendor))
+$(warning This repository requires Go >= 1.11 because of Go modules)
+$(warning Some recipes may not work as expected as the current Go runtime is '$(GO_VERSION_NUMBER)')
+		endif
+	else
+		# This repository isn't using Go modules (yet).
+		GOVENDOR := $(FIRST_GOPATH)/bin/govendor
+	endif
+endif
+PROMU        := $(FIRST_GOPATH)/bin/promu
+pkgs          = ./...
+
+ifeq (arm, $(GOHOSTARCH))
+	GOHOSTARM ?= $(shell GOARM= $(GO) env GOARM)
+	GO_BUILD_PLATFORM ?= $(GOHOSTOS)-$(GOHOSTARCH)v$(GOHOSTARM)
+else
+	GO_BUILD_PLATFORM ?= $(GOHOSTOS)-$(GOHOSTARCH)
+endif
+
+GOTEST := $(GO) test
+GOTEST_DIR :=
+ifneq ($(CIRCLE_JOB),)
+ifneq ($(shell which gotestsum),)
+	GOTEST_DIR := test-results
+	GOTEST := gotestsum --junitfile $(GOTEST_DIR)/unit-tests.xml --
+endif
+endif
+
+PROMU_VERSION ?= 0.12.0
+PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_VERSION)/promu-$(PROMU_VERSION).$(GO_BUILD_PLATFORM).tar.gz
+
+GOLANGCI_LINT :=
+GOLANGCI_LINT_OPTS ?=
+GOLANGCI_LINT_VERSION ?= v1.39.0
+# golangci-lint only supports linux, darwin and windows platforms on i386/amd64.
+# windows isn't included here because of the path separator being different.
+ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux darwin))
+	ifeq ($(GOHOSTARCH),$(filter $(GOHOSTARCH),amd64 i386))
+		GOLANGCI_LINT := $(FIRST_GOPATH)/bin/golangci-lint
+	endif
+endif
+
+PREFIX                  ?= $(shell pwd)
+BIN_DIR                 ?= $(shell pwd)
+DOCKER_IMAGE_TAG        ?= $(subst /,-,$(shell git rev-parse --abbrev-ref HEAD))
+DOCKERFILE_PATH         ?= ./Dockerfile
+DOCKERBUILD_CONTEXT     ?= ./
+DOCKER_REPO             ?= prom
+
+DOCKER_ARCHS            ?= amd64
+
+BUILD_DOCKER_ARCHS = $(addprefix common-docker-,$(DOCKER_ARCHS))
+PUBLISH_DOCKER_ARCHS = $(addprefix common-docker-publish-,$(DOCKER_ARCHS))
+TAG_DOCKER_ARCHS = $(addprefix common-docker-tag-latest-,$(DOCKER_ARCHS))
+
+ifeq ($(GOHOSTARCH),amd64)
+        ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux freebsd darwin windows))
+                # Only supported on amd64
+                test-flags := -race
+        endif
+endif
+
+# This rule is used to forward a target like "build" to "common-build".  This
+# allows a new "build" target to be defined in a Makefile which includes this
+# one and override "common-build" without override warnings.
+%: common-% ;
+
+.PHONY: common-all
+common-all: precheck style check_license lint yamllint unused build test
+
+.PHONY: common-style
+common-style:
+	@echo ">> checking code style"
+	@fmtRes=$$($(GOFMT) -d $$(find . -path ./vendor -prune -o -name '*.go' -print)); \
+	if [ -n "$${fmtRes}" ]; then \
+		echo "gofmt checking failed!"; echo "$${fmtRes}"; echo; \
+		echo "Please ensure you are using $$($(GO) version) for formatting code."; \
+		exit 1; \
+	fi
+
+.PHONY: common-check_license
+common-check_license:
+	@echo ">> checking license header"
+	@licRes=$$(for file in $$(find . -type f -iname '*.go' ! -path './vendor/*') ; do \
+               awk 'NR<=3' $$file | grep -Eq "(Copyright|generated|GENERATED)" || echo $$file; \
+       done); \
+       if [ -n "$${licRes}" ]; then \
+               echo "license header checking failed:"; echo "$${licRes}"; \
+               exit 1; \
+       fi
+
+.PHONY: common-deps
+common-deps:
+	@echo ">> getting dependencies"
+ifdef GO111MODULE
+	GO111MODULE=$(GO111MODULE) $(GO) mod download
+else
+	$(GO) get $(GOOPTS) -t ./...
+endif
+
+.PHONY: update-go-deps
+update-go-deps:
+	@echo ">> updating Go dependencies"
+	@for m in $$($(GO) list -mod=readonly -m -f '{{ if and (not .Indirect) (not .Main)}}{{.Path}}{{end}}' all); do \
+		$(GO) get $$m; \
+	done
+	GO111MODULE=$(GO111MODULE) $(GO) mod tidy
+ifneq (,$(wildcard vendor))
+	GO111MODULE=$(GO111MODULE) $(GO) mod vendor
+endif
+
+.PHONY: common-test-short
+common-test-short: $(GOTEST_DIR)
+	@echo ">> running short tests"
+	GO111MODULE=$(GO111MODULE) $(GOTEST) -short $(GOOPTS) $(pkgs)
+
+.PHONY: common-test
+common-test: $(GOTEST_DIR)
+	@echo ">> running all tests"
+	GO111MODULE=$(GO111MODULE) $(GOTEST) $(test-flags) $(GOOPTS) $(pkgs)
+
+$(GOTEST_DIR):
+	@mkdir -p $@
+
+.PHONY: common-format
+common-format:
+	@echo ">> formatting code"
+	GO111MODULE=$(GO111MODULE) $(GO) fmt $(pkgs)
+
+.PHONY: common-vet
+common-vet:
+	@echo ">> vetting code"
+	GO111MODULE=$(GO111MODULE) $(GO) vet $(GOOPTS) $(pkgs)
+
+.PHONY: common-lint
+common-lint: $(GOLANGCI_LINT)
+ifdef GOLANGCI_LINT
+	@echo ">> running golangci-lint"
+ifdef GO111MODULE
+# 'go list' needs to be executed before staticcheck to prepopulate the modules cache.
+# Otherwise staticcheck might fail randomly for some reason not yet explained.
+	GO111MODULE=$(GO111MODULE) $(GO) list -e -compiled -test=true -export=false -deps=true -find=false -tags= -- ./... > /dev/null
+	GO111MODULE=$(GO111MODULE) $(GOLANGCI_LINT) run $(GOLANGCI_LINT_OPTS) $(pkgs)
+else
+	$(GOLANGCI_LINT) run $(pkgs)
+endif
+endif
+
+.PHONY: common-yamllint
+common-yamllint:
+	@echo ">> running yamllint on all YAML files in the repository"
+ifeq (, $(shell which yamllint))
+	@echo "yamllint not installed so skipping"
+else
+	yamllint .
+endif
+
+# For backward-compatibility.
+.PHONY: common-staticcheck
+common-staticcheck: lint
+
+.PHONY: common-unused
+common-unused: $(GOVENDOR)
+ifdef GOVENDOR
+	@echo ">> running check for unused packages"
+	@$(GOVENDOR) list +unused | grep . && exit 1 || echo 'No unused packages'
+else
+ifdef GO111MODULE
+	@echo ">> running check for unused/missing packages in go.mod"
+	GO111MODULE=$(GO111MODULE) $(GO) mod tidy
+ifeq (,$(wildcard vendor))
+	@git diff --exit-code -- go.sum go.mod
+else
+	@echo ">> running check for unused packages in vendor/"
+	GO111MODULE=$(GO111MODULE) $(GO) mod vendor
+	@git diff --exit-code -- go.sum go.mod vendor/
+endif
+endif
+endif
+
+.PHONY: common-build
+common-build: promu
+	@echo ">> building binaries"
+	GO111MODULE=$(GO111MODULE) $(PROMU) build --prefix $(PREFIX) $(PROMU_BINARIES)
+
+.PHONY: common-tarball
+common-tarball: promu
+	@echo ">> building release tarball"
+	$(PROMU) tarball --prefix $(PREFIX) $(BIN_DIR)
+
+.PHONY: common-docker $(BUILD_DOCKER_ARCHS)
+common-docker: $(BUILD_DOCKER_ARCHS)
+$(BUILD_DOCKER_ARCHS): common-docker-%:
+	docker build -t "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:$(DOCKER_IMAGE_TAG)" \
+		-f $(DOCKERFILE_PATH) \
+		--build-arg ARCH="$*" \
+		--build-arg OS="linux" \
+		$(DOCKERBUILD_CONTEXT)
+
+.PHONY: common-docker-publish $(PUBLISH_DOCKER_ARCHS)
+common-docker-publish: $(PUBLISH_DOCKER_ARCHS)
+$(PUBLISH_DOCKER_ARCHS): common-docker-publish-%:
+	docker push "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:$(DOCKER_IMAGE_TAG)"
+
+DOCKER_MAJOR_VERSION_TAG = $(firstword $(subst ., ,$(shell cat VERSION)))
+.PHONY: common-docker-tag-latest $(TAG_DOCKER_ARCHS)
+common-docker-tag-latest: $(TAG_DOCKER_ARCHS)
+$(TAG_DOCKER_ARCHS): common-docker-tag-latest-%:
+	docker tag "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:$(DOCKER_IMAGE_TAG)" "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:latest"
+	docker tag "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:$(DOCKER_IMAGE_TAG)" "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$*:v$(DOCKER_MAJOR_VERSION_TAG)"
+
+.PHONY: common-docker-manifest
+common-docker-manifest:
+	DOCKER_CLI_EXPERIMENTAL=enabled docker manifest create -a "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME):$(DOCKER_IMAGE_TAG)" $(foreach ARCH,$(DOCKER_ARCHS),$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME)-linux-$(ARCH):$(DOCKER_IMAGE_TAG))
+	DOCKER_CLI_EXPERIMENTAL=enabled docker manifest push "$(DOCKER_REPO)/$(DOCKER_IMAGE_NAME):$(DOCKER_IMAGE_TAG)"
+
+.PHONY: promu
+promu: $(PROMU)
+
+$(PROMU):
+	$(eval PROMU_TMP := $(shell mktemp -d))
+	curl -s -L $(PROMU_URL) | tar -xvzf - -C $(PROMU_TMP)
+	mkdir -p $(FIRST_GOPATH)/bin
+	cp $(PROMU_TMP)/promu-$(PROMU_VERSION).$(GO_BUILD_PLATFORM)/promu $(FIRST_GOPATH)/bin/promu
+	rm -r $(PROMU_TMP)
+
+.PHONY: proto
+proto:
+	@echo ">> generating code from proto files"
+	@./scripts/genproto.sh
+
+ifdef GOLANGCI_LINT
+$(GOLANGCI_LINT):
+	mkdir -p $(FIRST_GOPATH)/bin
+	curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/$(GOLANGCI_LINT_VERSION)/install.sh \
+		| sed -e '/install -d/d' \
+		| sh -s -- -b $(FIRST_GOPATH)/bin $(GOLANGCI_LINT_VERSION)
+endif
+
+ifdef GOVENDOR
+.PHONY: $(GOVENDOR)
+$(GOVENDOR):
+	GOOS= GOARCH= $(GO) get -u github.com/kardianos/govendor
+endif
+
+.PHONY: precheck
+precheck::
+
+define PRECHECK_COMMAND_template =
+precheck:: $(1)_precheck
+
+PRECHECK_COMMAND_$(1) ?= $(1) $$(strip $$(PRECHECK_OPTIONS_$(1)))
+.PHONY: $(1)_precheck
+$(1)_precheck:
+	@if ! $$(PRECHECK_COMMAND_$(1)) 1>/dev/null 2>&1; then \
+		echo "Execution of '$$(PRECHECK_COMMAND_$(1))' command failed. Is $(1) installed?"; \
+		exit 1; \
+	fi
+endef

vendor/github.com/prometheus/procfs/README.md

@@ -1,10 +1,61 @@
 # procfs
 
-This procfs package provides functions to retrieve system, kernel and process
-metrics from the pseudo-filesystem proc.
+This package provides functions to retrieve system, kernel, and process
+metrics from the pseudo-filesystems /proc and /sys.
 
 *WARNING*: This package is a work in progress. Its API may still break in
 backwards-incompatible ways without warnings. Use it at your own risk.
 
-[![GoDoc](https://godoc.org/github.com/prometheus/procfs?status.png)](https://godoc.org/github.com/prometheus/procfs)
-[![Build Status](https://travis-ci.org/prometheus/procfs.svg?branch=master)](https://travis-ci.org/prometheus/procfs)
+[![Go Reference](https://pkg.go.dev/badge/github.com/prometheus/procfs.svg)](https://pkg.go.dev/github.com/prometheus/procfs)
+[![CircleCI](https://circleci.com/gh/prometheus/procfs/tree/master.svg?style=svg)](https://circleci.com/gh/prometheus/procfs/tree/master)
+[![Go Report Card](https://goreportcard.com/badge/github.com/prometheus/procfs)](https://goreportcard.com/report/github.com/prometheus/procfs)
+
+## Usage
+
+The procfs library is organized by packages based on whether the gathered data is coming from
+/proc, /sys, or both.  Each package contains an `FS` type which represents the path to either /proc, 
+/sys, or both.  For example, cpu statistics are gathered from
+`/proc/stat` and are available via the root procfs package.  First, the proc filesystem mount
+point is initialized, and then the stat information is read.
+
+```go
+fs, err := procfs.NewFS("/proc")
+stats, err := fs.Stat()
+```
+
+Some sub-packages such as `blockdevice`, require access to both the proc and sys filesystems.
+
+```go
+    fs, err := blockdevice.NewFS("/proc", "/sys")
+    stats, err := fs.ProcDiskstats()
+```
+
+## Package Organization
+
+The packages in this project are organized according to (1) whether the data comes from the `/proc` or
+`/sys` filesystem and (2) the type of information being retrieved.  For example, most process information
+can be gathered from the functions in the root `procfs` package.  Information about block devices such as disk drives
+is available in the `blockdevices` sub-package.
+
+## Building and Testing
+
+The procfs library is intended to be built as part of another application, so there are no distributable binaries.  
+However, most of the API includes unit tests which can be run with `make test`.
+
+### Updating Test Fixtures
+
+The procfs library includes a set of test fixtures which include many example files from
+the `/proc` and `/sys` filesystems.  These fixtures are included as a [ttar](https://github.com/ideaship/ttar) file
+which is extracted automatically during testing.  To add/update the test fixtures, first
+ensure the `fixtures` directory is up to date by removing the existing directory and then
+extracting the ttar file using `make fixtures/.unpacked` or just `make test`.
+
+```bash
+rm -rf fixtures
+make test
+```
+
+Next, make the required changes to the extracted files in the `fixtures` directory.  When
+the changes are complete, run `make update_fixtures` to create a new `fixtures.ttar` file
+based on the updated `fixtures` directory.  And finally, verify the changes using
+`git diff fixtures.ttar`.

vendor/github.com/prometheus/procfs/SECURITY.md

@@ -0,0 +1,6 @@
+# Reporting a security issue
+
+The Prometheus security policy, including how to report vulnerabilities, can be
+found here:
+
+https://prometheus.io/docs/operating/security/

vendor/github.com/prometheus/procfs/arp.go

@@ -0,0 +1,85 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net"
+	"strings"
+)
+
+// ARPEntry contains a single row of the columnar data represented in
+// /proc/net/arp.
+type ARPEntry struct {
+	// IP address
+	IPAddr net.IP
+	// MAC address
+	HWAddr net.HardwareAddr
+	// Name of the device
+	Device string
+}
+
+// GatherARPEntries retrieves all the ARP entries, parse the relevant columns,
+// and then return a slice of ARPEntry's.
+func (fs FS) GatherARPEntries() ([]ARPEntry, error) {
+	data, err := ioutil.ReadFile(fs.proc.Path("net/arp"))
+	if err != nil {
+		return nil, fmt.Errorf("error reading arp %q: %w", fs.proc.Path("net/arp"), err)
+	}
+
+	return parseARPEntries(data)
+}
+
+func parseARPEntries(data []byte) ([]ARPEntry, error) {
+	lines := strings.Split(string(data), "\n")
+	entries := make([]ARPEntry, 0)
+	var err error
+	const (
+		expectedDataWidth   = 6
+		expectedHeaderWidth = 9
+	)
+	for _, line := range lines {
+		columns := strings.Fields(line)
+		width := len(columns)
+
+		if width == expectedHeaderWidth || width == 0 {
+			continue
+		} else if width == expectedDataWidth {
+			entry, err := parseARPEntry(columns)
+			if err != nil {
+				return []ARPEntry{}, fmt.Errorf("failed to parse ARP entry: %w", err)
+			}
+			entries = append(entries, entry)
+		} else {
+			return []ARPEntry{}, fmt.Errorf("%d columns were detected, but %d were expected", width, expectedDataWidth)
+		}
+
+	}
+
+	return entries, err
+}
+
+func parseARPEntry(columns []string) (ARPEntry, error) {
+	ip := net.ParseIP(columns[0])
+	mac := net.HardwareAddr(columns[3])
+
+	entry := ARPEntry{
+		IPAddr: ip,
+		HWAddr: mac,
+		Device: columns[5],
+	}
+
+	return entry, nil
+}

vendor/github.com/prometheus/procfs/buddyinfo.go

@@ -0,0 +1,85 @@
+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// A BuddyInfo is the details parsed from /proc/buddyinfo.
+// The data is comprised of an array of free fragments of each size.
+// The sizes are 2^n*PAGE_SIZE, where n is the array index.
+type BuddyInfo struct {
+	Node  string
+	Zone  string
+	Sizes []float64
+}
+
+// BuddyInfo reads the buddyinfo statistics from the specified `proc` filesystem.
+func (fs FS) BuddyInfo() ([]BuddyInfo, error) {
+	file, err := os.Open(fs.proc.Path("buddyinfo"))
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	return parseBuddyInfo(file)
+}
+
+func parseBuddyInfo(r io.Reader) ([]BuddyInfo, error) {
+	var (
+		buddyInfo   = []BuddyInfo{}
+		scanner     = bufio.NewScanner(r)
+		bucketCount = -1
+	)
+
+	for scanner.Scan() {
+		var err error
+		line := scanner.Text()
+		parts := strings.Fields(line)
+
+		if len(parts) < 4 {
+			return nil, fmt.Errorf("invalid number of fields when parsing buddyinfo")
+		}
+
+		node := strings.TrimRight(parts[1], ",")
+		zone := strings.TrimRight(parts[3], ",")
+		arraySize := len(parts[4:])
+
+		if bucketCount == -1 {
+			bucketCount = arraySize
+		} else {
+			if bucketCount != arraySize {
+				return nil, fmt.Errorf("mismatch in number of buddyinfo buckets, previous count %d, new count %d", bucketCount, arraySize)
+			}
+		}
+
+		sizes := make([]float64, arraySize)
+		for i := 0; i < arraySize; i++ {
+			sizes[i], err = strconv.ParseFloat(parts[i+4], 64)
+			if err != nil {
+				return nil, fmt.Errorf("invalid value in buddyinfo: %w", err)
+			}
+		}
+
+		buddyInfo = append(buddyInfo, BuddyInfo{node, zone, sizes})
+	}
+
+	return buddyInfo, scanner.Err()
+}

vendor/github.com/prometheus/procfs/cmdline.go

@@ -0,0 +1,30 @@
+// Copyright 2021 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// CmdLine returns the command line of the kernel.
+func (fs FS) CmdLine() ([]string, error) {
+	data, err := util.ReadFileNoStat(fs.proc.Path("cmdline"))
+	if err != nil {
+		return nil, err
+	}
+
+	return strings.Fields(string(data)), nil
+}

vendor/github.com/prometheus/procfs/cpuinfo.go

@@ -0,0 +1,481 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// CPUInfo contains general information about a system CPU found in /proc/cpuinfo
+type CPUInfo struct {
+	Processor       uint
+	VendorID        string
+	CPUFamily       string
+	Model           string
+	ModelName       string
+	Stepping        string
+	Microcode       string
+	CPUMHz          float64
+	CacheSize       string
+	PhysicalID      string
+	Siblings        uint
+	CoreID          string
+	CPUCores        uint
+	APICID          string
+	InitialAPICID   string
+	FPU             string
+	FPUException    string
+	CPUIDLevel      uint
+	WP              string
+	Flags           []string
+	Bugs            []string
+	BogoMips        float64
+	CLFlushSize     uint
+	CacheAlignment  uint
+	AddressSizes    string
+	PowerManagement string
+}
+
+var (
+	cpuinfoClockRegexp          = regexp.MustCompile(`([\d.]+)`)
+	cpuinfoS390XProcessorRegexp = regexp.MustCompile(`^processor\s+(\d+):.*`)
+)
+
+// CPUInfo returns information about current system CPUs.
+// See https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+func (fs FS) CPUInfo() ([]CPUInfo, error) {
+	data, err := util.ReadFileNoStat(fs.proc.Path("cpuinfo"))
+	if err != nil {
+		return nil, err
+	}
+	return parseCPUInfo(data)
+}
+
+func parseCPUInfoX86(info []byte) ([]CPUInfo, error) {
+	scanner := bufio.NewScanner(bytes.NewReader(info))
+
+	// find the first "processor" line
+	firstLine := firstNonEmptyLine(scanner)
+	if !strings.HasPrefix(firstLine, "processor") || !strings.Contains(firstLine, ":") {
+		return nil, fmt.Errorf("invalid cpuinfo file: %q", firstLine)
+	}
+	field := strings.SplitN(firstLine, ": ", 2)
+	v, err := strconv.ParseUint(field[1], 0, 32)
+	if err != nil {
+		return nil, err
+	}
+	firstcpu := CPUInfo{Processor: uint(v)}
+	cpuinfo := []CPUInfo{firstcpu}
+	i := 0
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.Contains(line, ":") {
+			continue
+		}
+		field := strings.SplitN(line, ": ", 2)
+		switch strings.TrimSpace(field[0]) {
+		case "processor":
+			cpuinfo = append(cpuinfo, CPUInfo{}) // start of the next processor
+			i++
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].Processor = uint(v)
+		case "vendor", "vendor_id":
+			cpuinfo[i].VendorID = field[1]
+		case "cpu family":
+			cpuinfo[i].CPUFamily = field[1]
+		case "model":
+			cpuinfo[i].Model = field[1]
+		case "model name":
+			cpuinfo[i].ModelName = field[1]
+		case "stepping":
+			cpuinfo[i].Stepping = field[1]
+		case "microcode":
+			cpuinfo[i].Microcode = field[1]
+		case "cpu MHz":
+			v, err := strconv.ParseFloat(field[1], 64)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CPUMHz = v
+		case "cache size":
+			cpuinfo[i].CacheSize = field[1]
+		case "physical id":
+			cpuinfo[i].PhysicalID = field[1]
+		case "siblings":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].Siblings = uint(v)
+		case "core id":
+			cpuinfo[i].CoreID = field[1]
+		case "cpu cores":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CPUCores = uint(v)
+		case "apicid":
+			cpuinfo[i].APICID = field[1]
+		case "initial apicid":
+			cpuinfo[i].InitialAPICID = field[1]
+		case "fpu":
+			cpuinfo[i].FPU = field[1]
+		case "fpu_exception":
+			cpuinfo[i].FPUException = field[1]
+		case "cpuid level":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CPUIDLevel = uint(v)
+		case "wp":
+			cpuinfo[i].WP = field[1]
+		case "flags":
+			cpuinfo[i].Flags = strings.Fields(field[1])
+		case "bugs":
+			cpuinfo[i].Bugs = strings.Fields(field[1])
+		case "bogomips":
+			v, err := strconv.ParseFloat(field[1], 64)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].BogoMips = v
+		case "clflush size":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CLFlushSize = uint(v)
+		case "cache_alignment":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CacheAlignment = uint(v)
+		case "address sizes":
+			cpuinfo[i].AddressSizes = field[1]
+		case "power management":
+			cpuinfo[i].PowerManagement = field[1]
+		}
+	}
+	return cpuinfo, nil
+}
+
+func parseCPUInfoARM(info []byte) ([]CPUInfo, error) {
+	scanner := bufio.NewScanner(bytes.NewReader(info))
+
+	firstLine := firstNonEmptyLine(scanner)
+	match, _ := regexp.MatchString("^[Pp]rocessor", firstLine)
+	if !match || !strings.Contains(firstLine, ":") {
+		return nil, fmt.Errorf("invalid cpuinfo file: %q", firstLine)
+	}
+	field := strings.SplitN(firstLine, ": ", 2)
+	cpuinfo := []CPUInfo{}
+	featuresLine := ""
+	commonCPUInfo := CPUInfo{}
+	i := 0
+	if strings.TrimSpace(field[0]) == "Processor" {
+		commonCPUInfo = CPUInfo{ModelName: field[1]}
+		i = -1
+	} else {
+		v, err := strconv.ParseUint(field[1], 0, 32)
+		if err != nil {
+			return nil, err
+		}
+		firstcpu := CPUInfo{Processor: uint(v)}
+		cpuinfo = []CPUInfo{firstcpu}
+	}
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.Contains(line, ":") {
+			continue
+		}
+		field := strings.SplitN(line, ": ", 2)
+		switch strings.TrimSpace(field[0]) {
+		case "processor":
+			cpuinfo = append(cpuinfo, commonCPUInfo) // start of the next processor
+			i++
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].Processor = uint(v)
+		case "BogoMIPS":
+			if i == -1 {
+				cpuinfo = append(cpuinfo, commonCPUInfo) // There is only one processor
+				i++
+				cpuinfo[i].Processor = 0
+			}
+			v, err := strconv.ParseFloat(field[1], 64)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].BogoMips = v
+		case "Features":
+			featuresLine = line
+		case "model name":
+			cpuinfo[i].ModelName = field[1]
+		}
+	}
+	fields := strings.SplitN(featuresLine, ": ", 2)
+	for i := range cpuinfo {
+		cpuinfo[i].Flags = strings.Fields(fields[1])
+	}
+	return cpuinfo, nil
+
+}
+
+func parseCPUInfoS390X(info []byte) ([]CPUInfo, error) {
+	scanner := bufio.NewScanner(bytes.NewReader(info))
+
+	firstLine := firstNonEmptyLine(scanner)
+	if !strings.HasPrefix(firstLine, "vendor_id") || !strings.Contains(firstLine, ":") {
+		return nil, fmt.Errorf("invalid cpuinfo file: %q", firstLine)
+	}
+	field := strings.SplitN(firstLine, ": ", 2)
+	cpuinfo := []CPUInfo{}
+	commonCPUInfo := CPUInfo{VendorID: field[1]}
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.Contains(line, ":") {
+			continue
+		}
+		field := strings.SplitN(line, ": ", 2)
+		switch strings.TrimSpace(field[0]) {
+		case "bogomips per cpu":
+			v, err := strconv.ParseFloat(field[1], 64)
+			if err != nil {
+				return nil, err
+			}
+			commonCPUInfo.BogoMips = v
+		case "features":
+			commonCPUInfo.Flags = strings.Fields(field[1])
+		}
+		if strings.HasPrefix(line, "processor") {
+			match := cpuinfoS390XProcessorRegexp.FindStringSubmatch(line)
+			if len(match) < 2 {
+				return nil, fmt.Errorf("invalid cpuinfo file: %q", firstLine)
+			}
+			cpu := commonCPUInfo
+			v, err := strconv.ParseUint(match[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpu.Processor = uint(v)
+			cpuinfo = append(cpuinfo, cpu)
+		}
+		if strings.HasPrefix(line, "cpu number") {
+			break
+		}
+	}
+
+	i := 0
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.Contains(line, ":") {
+			continue
+		}
+		field := strings.SplitN(line, ": ", 2)
+		switch strings.TrimSpace(field[0]) {
+		case "cpu number":
+			i++
+		case "cpu MHz dynamic":
+			clock := cpuinfoClockRegexp.FindString(strings.TrimSpace(field[1]))
+			v, err := strconv.ParseFloat(clock, 64)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CPUMHz = v
+		case "physical id":
+			cpuinfo[i].PhysicalID = field[1]
+		case "core id":
+			cpuinfo[i].CoreID = field[1]
+		case "cpu cores":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CPUCores = uint(v)
+		case "siblings":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].Siblings = uint(v)
+		}
+	}
+
+	return cpuinfo, nil
+}
+
+func parseCPUInfoMips(info []byte) ([]CPUInfo, error) {
+	scanner := bufio.NewScanner(bytes.NewReader(info))
+
+	// find the first "processor" line
+	firstLine := firstNonEmptyLine(scanner)
+	if !strings.HasPrefix(firstLine, "system type") || !strings.Contains(firstLine, ":") {
+		return nil, fmt.Errorf("invalid cpuinfo file: %q", firstLine)
+	}
+	field := strings.SplitN(firstLine, ": ", 2)
+	cpuinfo := []CPUInfo{}
+	systemType := field[1]
+
+	i := 0
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.Contains(line, ":") {
+			continue
+		}
+		field := strings.SplitN(line, ": ", 2)
+		switch strings.TrimSpace(field[0]) {
+		case "processor":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			i = int(v)
+			cpuinfo = append(cpuinfo, CPUInfo{}) // start of the next processor
+			cpuinfo[i].Processor = uint(v)
+			cpuinfo[i].VendorID = systemType
+		case "cpu model":
+			cpuinfo[i].ModelName = field[1]
+		case "BogoMIPS":
+			v, err := strconv.ParseFloat(field[1], 64)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].BogoMips = v
+		}
+	}
+	return cpuinfo, nil
+}
+
+func parseCPUInfoPPC(info []byte) ([]CPUInfo, error) {
+	scanner := bufio.NewScanner(bytes.NewReader(info))
+
+	firstLine := firstNonEmptyLine(scanner)
+	if !strings.HasPrefix(firstLine, "processor") || !strings.Contains(firstLine, ":") {
+		return nil, fmt.Errorf("invalid cpuinfo file: %q", firstLine)
+	}
+	field := strings.SplitN(firstLine, ": ", 2)
+	v, err := strconv.ParseUint(field[1], 0, 32)
+	if err != nil {
+		return nil, err
+	}
+	firstcpu := CPUInfo{Processor: uint(v)}
+	cpuinfo := []CPUInfo{firstcpu}
+	i := 0
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.Contains(line, ":") {
+			continue
+		}
+		field := strings.SplitN(line, ": ", 2)
+		switch strings.TrimSpace(field[0]) {
+		case "processor":
+			cpuinfo = append(cpuinfo, CPUInfo{}) // start of the next processor
+			i++
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].Processor = uint(v)
+		case "cpu":
+			cpuinfo[i].VendorID = field[1]
+		case "clock":
+			clock := cpuinfoClockRegexp.FindString(strings.TrimSpace(field[1]))
+			v, err := strconv.ParseFloat(clock, 64)
+			if err != nil {
+				return nil, err
+			}
+			cpuinfo[i].CPUMHz = v
+		}
+	}
+	return cpuinfo, nil
+}
+
+func parseCPUInfoRISCV(info []byte) ([]CPUInfo, error) {
+	scanner := bufio.NewScanner(bytes.NewReader(info))
+
+	firstLine := firstNonEmptyLine(scanner)
+	if !strings.HasPrefix(firstLine, "processor") || !strings.Contains(firstLine, ":") {
+		return nil, fmt.Errorf("invalid cpuinfo file: %q", firstLine)
+	}
+	field := strings.SplitN(firstLine, ": ", 2)
+	v, err := strconv.ParseUint(field[1], 0, 32)
+	if err != nil {
+		return nil, err
+	}
+	firstcpu := CPUInfo{Processor: uint(v)}
+	cpuinfo := []CPUInfo{firstcpu}
+	i := 0
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if !strings.Contains(line, ":") {
+			continue
+		}
+		field := strings.SplitN(line, ": ", 2)
+		switch strings.TrimSpace(field[0]) {
+		case "processor":
+			v, err := strconv.ParseUint(field[1], 0, 32)
+			if err != nil {
+				return nil, err
+			}
+			i = int(v)
+			cpuinfo = append(cpuinfo, CPUInfo{}) // start of the next processor
+			cpuinfo[i].Processor = uint(v)
+		case "hart":
+			cpuinfo[i].CoreID = field[1]
+		case "isa":
+			cpuinfo[i].ModelName = field[1]
+		}
+	}
+	return cpuinfo, nil
+}
+
+func parseCPUInfoDummy(_ []byte) ([]CPUInfo, error) { // nolint:unused,deadcode
+	return nil, errors.New("not implemented")
+}
+
+// firstNonEmptyLine advances the scanner to the first non-empty line
+// and returns the contents of that line
+func firstNonEmptyLine(scanner *bufio.Scanner) string {
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.TrimSpace(line) != "" {
+			return line
+		}
+	}
+	return ""
+}

vendor/github.com/prometheus/procfs/cpuinfo_armx.go

@@ -0,0 +1,19 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+// +build arm arm64
+
+package procfs
+
+var parseCPUInfo = parseCPUInfoARM

vendor/github.com/prometheus/procfs/cpuinfo_mipsx.go

@@ -0,0 +1,19 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+// +build mips mipsle mips64 mips64le
+
+package procfs
+
+var parseCPUInfo = parseCPUInfoMips

vendor/github.com/prometheus/procfs/cpuinfo_others.go

@@ -0,0 +1,19 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+// +build !386,!amd64,!arm,!arm64,!mips,!mips64,!mips64le,!mipsle,!ppc64,!ppc64le,!riscv64,!s390x
+
+package procfs
+
+var parseCPUInfo = parseCPUInfoDummy

vendor/github.com/prometheus/procfs/cpuinfo_ppcx.go

@@ -0,0 +1,19 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+// +build ppc64 ppc64le
+
+package procfs
+
+var parseCPUInfo = parseCPUInfoPPC

vendor/github.com/prometheus/procfs/cpuinfo_riscvx.go

@@ -0,0 +1,19 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+// +build riscv riscv64
+
+package procfs
+
+var parseCPUInfo = parseCPUInfoRISCV

vendor/github.com/prometheus/procfs/cpuinfo_s390x.go

@@ -0,0 +1,18 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+
+package procfs
+
+var parseCPUInfo = parseCPUInfoS390X

vendor/github.com/prometheus/procfs/cpuinfo_x86.go

@@ -0,0 +1,19 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux
+// +build 386 amd64
+
+package procfs
+
+var parseCPUInfo = parseCPUInfoX86

vendor/github.com/prometheus/procfs/crypto.go

@@ -0,0 +1,153 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// Crypto holds info parsed from /proc/crypto.
+type Crypto struct {
+	Alignmask   *uint64
+	Async       bool
+	Blocksize   *uint64
+	Chunksize   *uint64
+	Ctxsize     *uint64
+	Digestsize  *uint64
+	Driver      string
+	Geniv       string
+	Internal    string
+	Ivsize      *uint64
+	Maxauthsize *uint64
+	MaxKeysize  *uint64
+	MinKeysize  *uint64
+	Module      string
+	Name        string
+	Priority    *int64
+	Refcnt      *int64
+	Seedsize    *uint64
+	Selftest    string
+	Type        string
+	Walksize    *uint64
+}
+
+// Crypto parses an crypto-file (/proc/crypto) and returns a slice of
+// structs containing the relevant info.  More information available here:
+// https://kernel.readthedocs.io/en/sphinx-samples/crypto-API.html
+func (fs FS) Crypto() ([]Crypto, error) {
+	path := fs.proc.Path("crypto")
+	b, err := util.ReadFileNoStat(path)
+	if err != nil {
+		return nil, fmt.Errorf("error reading crypto %q: %w", path, err)
+	}
+
+	crypto, err := parseCrypto(bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("error parsing crypto %q: %w", path, err)
+	}
+
+	return crypto, nil
+}
+
+// parseCrypto parses a /proc/crypto stream into Crypto elements.
+func parseCrypto(r io.Reader) ([]Crypto, error) {
+	var out []Crypto
+
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		text := s.Text()
+		switch {
+		case strings.HasPrefix(text, "name"):
+			// Each crypto element begins with its name.
+			out = append(out, Crypto{})
+		case text == "":
+			continue
+		}
+
+		kv := strings.Split(text, ":")
+		if len(kv) != 2 {
+			return nil, fmt.Errorf("malformed crypto line: %q", text)
+		}
+
+		k := strings.TrimSpace(kv[0])
+		v := strings.TrimSpace(kv[1])
+
+		// Parse the key/value pair into the currently focused element.
+		c := &out[len(out)-1]
+		if err := c.parseKV(k, v); err != nil {
+			return nil, err
+		}
+	}
+
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+
+	return out, nil
+}
+
+// parseKV parses a key/value pair into the appropriate field of c.
+func (c *Crypto) parseKV(k, v string) error {
+	vp := util.NewValueParser(v)
+
+	switch k {
+	case "async":
+		// Interpret literal yes as true.
+		c.Async = v == "yes"
+	case "blocksize":
+		c.Blocksize = vp.PUInt64()
+	case "chunksize":
+		c.Chunksize = vp.PUInt64()
+	case "digestsize":
+		c.Digestsize = vp.PUInt64()
+	case "driver":
+		c.Driver = v
+	case "geniv":
+		c.Geniv = v
+	case "internal":
+		c.Internal = v
+	case "ivsize":
+		c.Ivsize = vp.PUInt64()
+	case "maxauthsize":
+		c.Maxauthsize = vp.PUInt64()
+	case "max keysize":
+		c.MaxKeysize = vp.PUInt64()
+	case "min keysize":
+		c.MinKeysize = vp.PUInt64()
+	case "module":
+		c.Module = v
+	case "name":
+		c.Name = v
+	case "priority":
+		c.Priority = vp.PInt64()
+	case "refcnt":
+		c.Refcnt = vp.PInt64()
+	case "seedsize":
+		c.Seedsize = vp.PUInt64()
+	case "selftest":
+		c.Selftest = v
+	case "type":
+		c.Type = v
+	case "walksize":
+		c.Walksize = vp.PUInt64()
+	}
+
+	return vp.Err()
+}

vendor/github.com/prometheus/procfs/doc.go

@@ -31,7 +31,7 @@
 //    		log.Fatalf("could not get process: %s", err)
 //    	}
 //
-//    	stat, err := p.NewStat()
+//    	stat, err := p.Stat()
 //    	if err != nil {
 //    		log.Fatalf("could not get process stat: %s", err)
 //    	}

vendor/github.com/prometheus/procfs/fs.go

@@ -1,33 +1,43 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
-	"fmt"
-	"os"
-	"path"
+	"github.com/prometheus/procfs/internal/fs"
 )
 
-// FS represents the pseudo-filesystem proc, which provides an interface to
+// FS represents the pseudo-filesystem sys, which provides an interface to
 // kernel data structures.
-type FS string
+type FS struct {
+	proc fs.FS
+}
 
 // DefaultMountPoint is the common mount point of the proc filesystem.
-const DefaultMountPoint = "/proc"
+const DefaultMountPoint = fs.DefaultProcMountPoint
 
-// NewFS returns a new FS mounted under the given mountPoint. It will error
-// if the mount point can't be read.
+// NewDefaultFS returns a new proc FS mounted under the default proc mountPoint.
+// It will error if the mount point directory can't be read or is a file.
+func NewDefaultFS() (FS, error) {
+	return NewFS(DefaultMountPoint)
+}
+
+// NewFS returns a new proc FS mounted under the given proc mountPoint. It will error
+// if the mount point directory can't be read or is a file.
 func NewFS(mountPoint string) (FS, error) {
-	info, err := os.Stat(mountPoint)
+	fs, err := fs.NewFS(mountPoint)
 	if err != nil {
-		return "", fmt.Errorf("could not read %s: %s", mountPoint, err)
+		return FS{}, err
 	}
-	if !info.IsDir() {
-		return "", fmt.Errorf("mount point %s is not a directory", mountPoint)
-	}
-
-	return FS(mountPoint), nil
-}
-
-// Path returns the path of the given subsystem relative to the procfs root.
-func (fs FS) Path(p ...string) string {
-	return path.Join(append([]string{string(fs)}, p...)...)
+	return FS{fs}, nil
 }

vendor/github.com/prometheus/procfs/fscache.go

@@ -0,0 +1,422 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// Fscacheinfo represents fscache statistics.
+type Fscacheinfo struct {
+	// Number of index cookies allocated
+	IndexCookiesAllocated uint64
+	// data storage cookies allocated
+	DataStorageCookiesAllocated uint64
+	// Number of special cookies allocated
+	SpecialCookiesAllocated uint64
+	// Number of objects allocated
+	ObjectsAllocated uint64
+	// Number of object allocation failures
+	ObjectAllocationsFailure uint64
+	// Number of objects that reached the available state
+	ObjectsAvailable uint64
+	// Number of objects that reached the dead state
+	ObjectsDead uint64
+	// Number of objects that didn't have a coherency check
+	ObjectsWithoutCoherencyCheck uint64
+	// Number of objects that passed a coherency check
+	ObjectsWithCoherencyCheck uint64
+	// Number of objects that needed a coherency data update
+	ObjectsNeedCoherencyCheckUpdate uint64
+	// Number of objects that were declared obsolete
+	ObjectsDeclaredObsolete uint64
+	// Number of pages marked as being cached
+	PagesMarkedAsBeingCached uint64
+	// Number of uncache page requests seen
+	UncachePagesRequestSeen uint64
+	// Number of acquire cookie requests seen
+	AcquireCookiesRequestSeen uint64
+	// Number of acq reqs given a NULL parent
+	AcquireRequestsWithNullParent uint64
+	// Number of acq reqs rejected due to no cache available
+	AcquireRequestsRejectedNoCacheAvailable uint64
+	// Number of acq reqs succeeded
+	AcquireRequestsSucceeded uint64
+	// Number of acq reqs rejected due to error
+	AcquireRequestsRejectedDueToError uint64
+	// Number of acq reqs failed on ENOMEM
+	AcquireRequestsFailedDueToEnomem uint64
+	// Number of lookup calls made on cache backends
+	LookupsNumber uint64
+	// Number of negative lookups made
+	LookupsNegative uint64
+	// Number of positive lookups made
+	LookupsPositive uint64
+	// Number of objects created by lookup
+	ObjectsCreatedByLookup uint64
+	// Number of lookups timed out and requeued
+	LookupsTimedOutAndRequed uint64
+	InvalidationsNumber      uint64
+	InvalidationsRunning     uint64
+	// Number of update cookie requests seen
+	UpdateCookieRequestSeen uint64
+	// Number of upd reqs given a NULL parent
+	UpdateRequestsWithNullParent uint64
+	// Number of upd reqs granted CPU time
+	UpdateRequestsRunning uint64
+	// Number of relinquish cookie requests seen
+	RelinquishCookiesRequestSeen uint64
+	// Number of rlq reqs given a NULL parent
+	RelinquishCookiesWithNullParent uint64
+	// Number of rlq reqs waited on completion of creation
+	RelinquishRequestsWaitingCompleteCreation uint64
+	// Relinqs rtr
+	RelinquishRetries uint64
+	// Number of attribute changed requests seen
+	AttributeChangedRequestsSeen uint64
+	// Number of attr changed requests queued
+	AttributeChangedRequestsQueued uint64
+	// Number of attr changed rejected -ENOBUFS
+	AttributeChangedRejectDueToEnobufs uint64
+	// Number of attr changed failed -ENOMEM
+	AttributeChangedFailedDueToEnomem uint64
+	// Number of attr changed ops given CPU time
+	AttributeChangedOps uint64
+	// Number of allocation requests seen
+	AllocationRequestsSeen uint64
+	// Number of successful alloc reqs
+	AllocationOkRequests uint64
+	// Number of alloc reqs that waited on lookup completion
+	AllocationWaitingOnLookup uint64
+	// Number of alloc reqs rejected -ENOBUFS
+	AllocationsRejectedDueToEnobufs uint64
+	// Number of alloc reqs aborted -ERESTARTSYS
+	AllocationsAbortedDueToErestartsys uint64
+	// Number of alloc reqs submitted
+	AllocationOperationsSubmitted uint64
+	// Number of alloc reqs waited for CPU time
+	AllocationsWaitedForCPU uint64
+	// Number of alloc reqs aborted due to object death
+	AllocationsAbortedDueToObjectDeath uint64
+	// Number of retrieval (read) requests seen
+	RetrievalsReadRequests uint64
+	// Number of successful retr reqs
+	RetrievalsOk uint64
+	// Number of retr reqs that waited on lookup completion
+	RetrievalsWaitingLookupCompletion uint64
+	// Number of retr reqs returned -ENODATA
+	RetrievalsReturnedEnodata uint64
+	// Number of retr reqs rejected -ENOBUFS
+	RetrievalsRejectedDueToEnobufs uint64
+	// Number of retr reqs aborted -ERESTARTSYS
+	RetrievalsAbortedDueToErestartsys uint64
+	// Number of retr reqs failed -ENOMEM
+	RetrievalsFailedDueToEnomem uint64
+	// Number of retr reqs submitted
+	RetrievalsRequests uint64
+	// Number of retr reqs waited for CPU time
+	RetrievalsWaitingCPU uint64
+	// Number of retr reqs aborted due to object death
+	RetrievalsAbortedDueToObjectDeath uint64
+	// Number of storage (write) requests seen
+	StoreWriteRequests uint64
+	// Number of successful store reqs
+	StoreSuccessfulRequests uint64
+	// Number of store reqs on a page already pending storage
+	StoreRequestsOnPendingStorage uint64
+	// Number of store reqs rejected -ENOBUFS
+	StoreRequestsRejectedDueToEnobufs uint64
+	// Number of store reqs failed -ENOMEM
+	StoreRequestsFailedDueToEnomem uint64
+	// Number of store reqs submitted
+	StoreRequestsSubmitted uint64
+	// Number of store reqs granted CPU time
+	StoreRequestsRunning uint64
+	// Number of pages given store req processing time
+	StorePagesWithRequestsProcessing uint64
+	// Number of store reqs deleted from tracking tree
+	StoreRequestsDeleted uint64
+	// Number of store reqs over store limit
+	StoreRequestsOverStoreLimit uint64
+	// Number of release reqs against pages with no pending store
+	ReleaseRequestsAgainstPagesWithNoPendingStorage uint64
+	// Number of release reqs against pages stored by time lock granted
+	ReleaseRequestsAgainstPagesStoredByTimeLockGranted uint64
+	// Number of release reqs ignored due to in-progress store
+	ReleaseRequestsIgnoredDueToInProgressStore uint64
+	// Number of page stores cancelled due to release req
+	PageStoresCancelledByReleaseRequests uint64
+	VmscanWaiting                        uint64
+	// Number of times async ops added to pending queues
+	OpsPending uint64
+	// Number of times async ops given CPU time
+	OpsRunning uint64
+	// Number of times async ops queued for processing
+	OpsEnqueued uint64
+	// Number of async ops cancelled
+	OpsCancelled uint64
+	// Number of async ops rejected due to object lookup/create failure
+	OpsRejected uint64
+	// Number of async ops initialised
+	OpsInitialised uint64
+	// Number of async ops queued for deferred release
+	OpsDeferred uint64
+	// Number of async ops released (should equal ini=N when idle)
+	OpsReleased uint64
+	// Number of deferred-release async ops garbage collected
+	OpsGarbageCollected uint64
+	// Number of in-progress alloc_object() cache ops
+	CacheopAllocationsinProgress uint64
+	// Number of in-progress lookup_object() cache ops
+	CacheopLookupObjectInProgress uint64
+	// Number of in-progress lookup_complete() cache ops
+	CacheopLookupCompleteInPorgress uint64
+	// Number of in-progress grab_object() cache ops
+	CacheopGrabObjectInProgress uint64
+	CacheopInvalidations        uint64
+	// Number of in-progress update_object() cache ops
+	CacheopUpdateObjectInProgress uint64
+	// Number of in-progress drop_object() cache ops
+	CacheopDropObjectInProgress uint64
+	// Number of in-progress put_object() cache ops
+	CacheopPutObjectInProgress uint64
+	// Number of in-progress attr_changed() cache ops
+	CacheopAttributeChangeInProgress uint64
+	// Number of in-progress sync_cache() cache ops
+	CacheopSyncCacheInProgress uint64
+	// Number of in-progress read_or_alloc_page() cache ops
+	CacheopReadOrAllocPageInProgress uint64
+	// Number of in-progress read_or_alloc_pages() cache ops
+	CacheopReadOrAllocPagesInProgress uint64
+	// Number of in-progress allocate_page() cache ops
+	CacheopAllocatePageInProgress uint64
+	// Number of in-progress allocate_pages() cache ops
+	CacheopAllocatePagesInProgress uint64
+	// Number of in-progress write_page() cache ops
+	CacheopWritePagesInProgress uint64
+	// Number of in-progress uncache_page() cache ops
+	CacheopUncachePagesInProgress uint64
+	// Number of in-progress dissociate_pages() cache ops
+	CacheopDissociatePagesInProgress uint64
+	// Number of object lookups/creations rejected due to lack of space
+	CacheevLookupsAndCreationsRejectedLackSpace uint64
+	// Number of stale objects deleted
+	CacheevStaleObjectsDeleted uint64
+	// Number of objects retired when relinquished
+	CacheevRetiredWhenReliquished uint64
+	// Number of objects culled
+	CacheevObjectsCulled uint64
+}
+
+// Fscacheinfo returns information about current fscache statistics.
+// See https://www.kernel.org/doc/Documentation/filesystems/caching/fscache.txt
+func (fs FS) Fscacheinfo() (Fscacheinfo, error) {
+	b, err := util.ReadFileNoStat(fs.proc.Path("fs/fscache/stats"))
+	if err != nil {
+		return Fscacheinfo{}, err
+	}
+
+	m, err := parseFscacheinfo(bytes.NewReader(b))
+	if err != nil {
+		return Fscacheinfo{}, fmt.Errorf("failed to parse Fscacheinfo: %w", err)
+	}
+
+	return *m, nil
+}
+
+func setFSCacheFields(fields []string, setFields ...*uint64) error {
+	var err error
+	if len(fields) < len(setFields) {
+		return fmt.Errorf("Insufficient number of fields, expected %v, got %v", len(setFields), len(fields))
+	}
+
+	for i := range setFields {
+		*setFields[i], err = strconv.ParseUint(strings.Split(fields[i], "=")[1], 0, 64)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func parseFscacheinfo(r io.Reader) (*Fscacheinfo, error) {
+	var m Fscacheinfo
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		fields := strings.Fields(s.Text())
+		if len(fields) < 2 {
+			return nil, fmt.Errorf("malformed Fscacheinfo line: %q", s.Text())
+		}
+
+		switch fields[0] {
+		case "Cookies:":
+			err := setFSCacheFields(fields[1:], &m.IndexCookiesAllocated, &m.DataStorageCookiesAllocated,
+				&m.SpecialCookiesAllocated)
+			if err != nil {
+				return &m, err
+			}
+		case "Objects:":
+			err := setFSCacheFields(fields[1:], &m.ObjectsAllocated, &m.ObjectAllocationsFailure,
+				&m.ObjectsAvailable, &m.ObjectsDead)
+			if err != nil {
+				return &m, err
+			}
+		case "ChkAux":
+			err := setFSCacheFields(fields[2:], &m.ObjectsWithoutCoherencyCheck, &m.ObjectsWithCoherencyCheck,
+				&m.ObjectsNeedCoherencyCheckUpdate, &m.ObjectsDeclaredObsolete)
+			if err != nil {
+				return &m, err
+			}
+		case "Pages":
+			err := setFSCacheFields(fields[2:], &m.PagesMarkedAsBeingCached, &m.UncachePagesRequestSeen)
+			if err != nil {
+				return &m, err
+			}
+		case "Acquire:":
+			err := setFSCacheFields(fields[1:], &m.AcquireCookiesRequestSeen, &m.AcquireRequestsWithNullParent,
+				&m.AcquireRequestsRejectedNoCacheAvailable, &m.AcquireRequestsSucceeded, &m.AcquireRequestsRejectedDueToError,
+				&m.AcquireRequestsFailedDueToEnomem)
+			if err != nil {
+				return &m, err
+			}
+		case "Lookups:":
+			err := setFSCacheFields(fields[1:], &m.LookupsNumber, &m.LookupsNegative, &m.LookupsPositive,
+				&m.ObjectsCreatedByLookup, &m.LookupsTimedOutAndRequed)
+			if err != nil {
+				return &m, err
+			}
+		case "Invals":
+			err := setFSCacheFields(fields[2:], &m.InvalidationsNumber, &m.InvalidationsRunning)
+			if err != nil {
+				return &m, err
+			}
+		case "Updates:":
+			err := setFSCacheFields(fields[1:], &m.UpdateCookieRequestSeen, &m.UpdateRequestsWithNullParent,
+				&m.UpdateRequestsRunning)
+			if err != nil {
+				return &m, err
+			}
+		case "Relinqs:":
+			err := setFSCacheFields(fields[1:], &m.RelinquishCookiesRequestSeen, &m.RelinquishCookiesWithNullParent,
+				&m.RelinquishRequestsWaitingCompleteCreation, &m.RelinquishRetries)
+			if err != nil {
+				return &m, err
+			}
+		case "AttrChg:":
+			err := setFSCacheFields(fields[1:], &m.AttributeChangedRequestsSeen, &m.AttributeChangedRequestsQueued,
+				&m.AttributeChangedRejectDueToEnobufs, &m.AttributeChangedFailedDueToEnomem, &m.AttributeChangedOps)
+			if err != nil {
+				return &m, err
+			}
+		case "Allocs":
+			if strings.Split(fields[2], "=")[0] == "n" {
+				err := setFSCacheFields(fields[2:], &m.AllocationRequestsSeen, &m.AllocationOkRequests,
+					&m.AllocationWaitingOnLookup, &m.AllocationsRejectedDueToEnobufs, &m.AllocationsAbortedDueToErestartsys)
+				if err != nil {
+					return &m, err
+				}
+			} else {
+				err := setFSCacheFields(fields[2:], &m.AllocationOperationsSubmitted, &m.AllocationsWaitedForCPU,
+					&m.AllocationsAbortedDueToObjectDeath)
+				if err != nil {
+					return &m, err
+				}
+			}
+		case "Retrvls:":
+			if strings.Split(fields[1], "=")[0] == "n" {
+				err := setFSCacheFields(fields[1:], &m.RetrievalsReadRequests, &m.RetrievalsOk, &m.RetrievalsWaitingLookupCompletion,
+					&m.RetrievalsReturnedEnodata, &m.RetrievalsRejectedDueToEnobufs, &m.RetrievalsAbortedDueToErestartsys,
+					&m.RetrievalsFailedDueToEnomem)
+				if err != nil {
+					return &m, err
+				}
+			} else {
+				err := setFSCacheFields(fields[1:], &m.RetrievalsRequests, &m.RetrievalsWaitingCPU, &m.RetrievalsAbortedDueToObjectDeath)
+				if err != nil {
+					return &m, err
+				}
+			}
+		case "Stores":
+			if strings.Split(fields[2], "=")[0] == "n" {
+				err := setFSCacheFields(fields[2:], &m.StoreWriteRequests, &m.StoreSuccessfulRequests,
+					&m.StoreRequestsOnPendingStorage, &m.StoreRequestsRejectedDueToEnobufs, &m.StoreRequestsFailedDueToEnomem)
+				if err != nil {
+					return &m, err
+				}
+			} else {
+				err := setFSCacheFields(fields[2:], &m.StoreRequestsSubmitted, &m.StoreRequestsRunning,
+					&m.StorePagesWithRequestsProcessing, &m.StoreRequestsDeleted, &m.StoreRequestsOverStoreLimit)
+				if err != nil {
+					return &m, err
+				}
+			}
+		case "VmScan":
+			err := setFSCacheFields(fields[2:], &m.ReleaseRequestsAgainstPagesWithNoPendingStorage,
+				&m.ReleaseRequestsAgainstPagesStoredByTimeLockGranted, &m.ReleaseRequestsIgnoredDueToInProgressStore,
+				&m.PageStoresCancelledByReleaseRequests, &m.VmscanWaiting)
+			if err != nil {
+				return &m, err
+			}
+		case "Ops":
+			if strings.Split(fields[2], "=")[0] == "pend" {
+				err := setFSCacheFields(fields[2:], &m.OpsPending, &m.OpsRunning, &m.OpsEnqueued, &m.OpsCancelled, &m.OpsRejected)
+				if err != nil {
+					return &m, err
+				}
+			} else {
+				err := setFSCacheFields(fields[2:], &m.OpsInitialised, &m.OpsDeferred, &m.OpsReleased, &m.OpsGarbageCollected)
+				if err != nil {
+					return &m, err
+				}
+			}
+		case "CacheOp:":
+			if strings.Split(fields[1], "=")[0] == "alo" {
+				err := setFSCacheFields(fields[1:], &m.CacheopAllocationsinProgress, &m.CacheopLookupObjectInProgress,
+					&m.CacheopLookupCompleteInPorgress, &m.CacheopGrabObjectInProgress)
+				if err != nil {
+					return &m, err
+				}
+			} else if strings.Split(fields[1], "=")[0] == "inv" {
+				err := setFSCacheFields(fields[1:], &m.CacheopInvalidations, &m.CacheopUpdateObjectInProgress,
+					&m.CacheopDropObjectInProgress, &m.CacheopPutObjectInProgress, &m.CacheopAttributeChangeInProgress,
+					&m.CacheopSyncCacheInProgress)
+				if err != nil {
+					return &m, err
+				}
+			} else {
+				err := setFSCacheFields(fields[1:], &m.CacheopReadOrAllocPageInProgress, &m.CacheopReadOrAllocPagesInProgress,
+					&m.CacheopAllocatePageInProgress, &m.CacheopAllocatePagesInProgress, &m.CacheopWritePagesInProgress,
+					&m.CacheopUncachePagesInProgress, &m.CacheopDissociatePagesInProgress)
+				if err != nil {
+					return &m, err
+				}
+			}
+		case "CacheEv:":
+			err := setFSCacheFields(fields[1:], &m.CacheevLookupsAndCreationsRejectedLackSpace, &m.CacheevStaleObjectsDeleted,
+				&m.CacheevRetiredWhenReliquished, &m.CacheevObjectsCulled)
+			if err != nil {
+				return &m, err
+			}
+		}
+	}
+
+	return &m, nil
+}

vendor/github.com/prometheus/procfs/go.mod

@@ -0,0 +1,9 @@
+module github.com/prometheus/procfs
+
+go 1.13
+
+require (
+	github.com/google/go-cmp v0.5.4
+	golang.org/x/sync v0.0.0-20201207232520-09787c993a3a
+	golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c
+)

vendor/github.com/prometheus/procfs/go.sum

@@ -0,0 +1,8 @@
+github.com/google/go-cmp v0.5.4 h1:L8R9j+yAqZuZjsqh/z+F1NCffTKKLShY6zXTItVIZ8M=
+github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+golang.org/x/sync v0.0.0-20201207232520-09787c993a3a h1:DcqTD9SDLc+1P/r1EmRBwnVsrOwW+kk2vWf9n+1sGhs=
+golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c h1:VwygUrnw9jn88c4u8GD3rZQbqrP/tgas88tPUbBxQrk=
+golang.org/x/sys v0.0.0-20210124154548-22da62e12c0c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

vendor/github.com/prometheus/procfs/internal/fs/fs.go

@@ -0,0 +1,55 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fs
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+const (
+	// DefaultProcMountPoint is the common mount point of the proc filesystem.
+	DefaultProcMountPoint = "/proc"
+
+	// DefaultSysMountPoint is the common mount point of the sys filesystem.
+	DefaultSysMountPoint = "/sys"
+
+	// DefaultConfigfsMountPoint is the common mount point of the configfs
+	DefaultConfigfsMountPoint = "/sys/kernel/config"
+)
+
+// FS represents a pseudo-filesystem, normally /proc or /sys, which provides an
+// interface to kernel data structures.
+type FS string
+
+// NewFS returns a new FS mounted under the given mountPoint. It will error
+// if the mount point can't be read.
+func NewFS(mountPoint string) (FS, error) {
+	info, err := os.Stat(mountPoint)
+	if err != nil {
+		return "", fmt.Errorf("could not read %q: %w", mountPoint, err)
+	}
+	if !info.IsDir() {
+		return "", fmt.Errorf("mount point %q is not a directory", mountPoint)
+	}
+
+	return FS(mountPoint), nil
+}
+
+// Path appends the given path elements to the filesystem path, adding separators
+// as necessary.
+func (fs FS) Path(p ...string) string {
+	return filepath.Join(append([]string{string(fs)}, p...)...)
+}

vendor/github.com/prometheus/procfs/internal/util/parse.go

@@ -0,0 +1,97 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package util
+
+import (
+	"io/ioutil"
+	"strconv"
+	"strings"
+)
+
+// ParseUint32s parses a slice of strings into a slice of uint32s.
+func ParseUint32s(ss []string) ([]uint32, error) {
+	us := make([]uint32, 0, len(ss))
+	for _, s := range ss {
+		u, err := strconv.ParseUint(s, 10, 32)
+		if err != nil {
+			return nil, err
+		}
+
+		us = append(us, uint32(u))
+	}
+
+	return us, nil
+}
+
+// ParseUint64s parses a slice of strings into a slice of uint64s.
+func ParseUint64s(ss []string) ([]uint64, error) {
+	us := make([]uint64, 0, len(ss))
+	for _, s := range ss {
+		u, err := strconv.ParseUint(s, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		us = append(us, u)
+	}
+
+	return us, nil
+}
+
+// ParsePInt64s parses a slice of strings into a slice of int64 pointers.
+func ParsePInt64s(ss []string) ([]*int64, error) {
+	us := make([]*int64, 0, len(ss))
+	for _, s := range ss {
+		u, err := strconv.ParseInt(s, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		us = append(us, &u)
+	}
+
+	return us, nil
+}
+
+// ReadUintFromFile reads a file and attempts to parse a uint64 from it.
+func ReadUintFromFile(path string) (uint64, error) {
+	data, err := ioutil.ReadFile(path)
+	if err != nil {
+		return 0, err
+	}
+	return strconv.ParseUint(strings.TrimSpace(string(data)), 10, 64)
+}
+
+// ReadIntFromFile reads a file and attempts to parse a int64 from it.
+func ReadIntFromFile(path string) (int64, error) {
+	data, err := ioutil.ReadFile(path)
+	if err != nil {
+		return 0, err
+	}
+	return strconv.ParseInt(strings.TrimSpace(string(data)), 10, 64)
+}
+
+// ParseBool parses a string into a boolean pointer.
+func ParseBool(b string) *bool {
+	var truth bool
+	switch b {
+	case "enabled":
+		truth = true
+	case "disabled":
+		truth = false
+	default:
+		return nil
+	}
+	return &truth
+}

vendor/github.com/prometheus/procfs/internal/util/readfile.go

@@ -0,0 +1,38 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package util
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+)
+
+// ReadFileNoStat uses ioutil.ReadAll to read contents of entire file.
+// This is similar to ioutil.ReadFile but without the call to os.Stat, because
+// many files in /proc and /sys report incorrect file sizes (either 0 or 4096).
+// Reads a max file size of 512kB.  For files larger than this, a scanner
+// should be used.
+func ReadFileNoStat(filename string) ([]byte, error) {
+	const maxBufferSize = 1024 * 512
+
+	f, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	reader := io.LimitReader(f, maxBufferSize)
+	return ioutil.ReadAll(reader)
+}

vendor/github.com/prometheus/procfs/internal/util/sysreadfile.go

@@ -0,0 +1,48 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux,!appengine
+
+package util
+
+import (
+	"bytes"
+	"os"
+	"syscall"
+)
+
+// SysReadFile is a simplified ioutil.ReadFile that invokes syscall.Read directly.
+// https://github.com/prometheus/node_exporter/pull/728/files
+//
+// Note that this function will not read files larger than 128 bytes.
+func SysReadFile(file string) (string, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	// On some machines, hwmon drivers are broken and return EAGAIN.  This causes
+	// Go's ioutil.ReadFile implementation to poll forever.
+	//
+	// Since we either want to read data or bail immediately, do the simplest
+	// possible read using syscall directly.
+	const sysFileBufferSize = 128
+	b := make([]byte, sysFileBufferSize)
+	n, err := syscall.Read(int(f.Fd()), b)
+	if err != nil {
+		return "", err
+	}
+
+	return string(bytes.TrimSpace(b[:n])), nil
+}

vendor/github.com/prometheus/procfs/internal/util/sysreadfile_compat.go

@@ -0,0 +1,26 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build linux,appengine !linux
+
+package util
+
+import (
+	"fmt"
+)
+
+// SysReadFile is here implemented as a noop for builds that do not support
+// the read syscall. For example Windows, or Linux on Google App Engine.
+func SysReadFile(file string) (string, error) {
+	return "", fmt.Errorf("not supported on this platform")
+}

vendor/github.com/prometheus/procfs/internal/util/valueparser.go

@@ -0,0 +1,91 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package util
+
+import (
+	"strconv"
+)
+
+// TODO(mdlayher): util packages are an anti-pattern and this should be moved
+// somewhere else that is more focused in the future.
+
+// A ValueParser enables parsing a single string into a variety of data types
+// in a concise and safe way. The Err method must be invoked after invoking
+// any other methods to ensure a value was successfully parsed.
+type ValueParser struct {
+	v   string
+	err error
+}
+
+// NewValueParser creates a ValueParser using the input string.
+func NewValueParser(v string) *ValueParser {
+	return &ValueParser{v: v}
+}
+
+// Int interprets the underlying value as an int and returns that value.
+func (vp *ValueParser) Int() int { return int(vp.int64()) }
+
+// PInt64 interprets the underlying value as an int64 and returns a pointer to
+// that value.
+func (vp *ValueParser) PInt64() *int64 {
+	if vp.err != nil {
+		return nil
+	}
+
+	v := vp.int64()
+	return &v
+}
+
+// int64 interprets the underlying value as an int64 and returns that value.
+// TODO: export if/when necessary.
+func (vp *ValueParser) int64() int64 {
+	if vp.err != nil {
+		return 0
+	}
+
+	// A base value of zero makes ParseInt infer the correct base using the
+	// string's prefix, if any.
+	const base = 0
+	v, err := strconv.ParseInt(vp.v, base, 64)
+	if err != nil {
+		vp.err = err
+		return 0
+	}
+
+	return v
+}
+
+// PUInt64 interprets the underlying value as an uint64 and returns a pointer to
+// that value.
+func (vp *ValueParser) PUInt64() *uint64 {
+	if vp.err != nil {
+		return nil
+	}
+
+	// A base value of zero makes ParseInt infer the correct base using the
+	// string's prefix, if any.
+	const base = 0
+	v, err := strconv.ParseUint(vp.v, base, 64)
+	if err != nil {
+		vp.err = err
+		return nil
+	}
+
+	return &v
+}
+
+// Err returns the last error, if any, encountered by the ValueParser.
+func (vp *ValueParser) Err() error {
+	return vp.err
+}

vendor/github.com/prometheus/procfs/ipvs.go

@@ -1,7 +1,21 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
 	"bufio"
+	"bytes"
 	"encoding/hex"
 	"errors"
 	"fmt"
@@ -11,6 +25,8 @@ import (
 	"os"
 	"strconv"
 	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
 )
 
 // IPVSStats holds IPVS statistics, as exposed by the kernel in `/proc/net/ip_vs_stats`.
@@ -31,14 +47,16 @@ type IPVSStats struct {
 type IPVSBackendStatus struct {
 	// The local (virtual) IP address.
 	LocalAddress net.IP
-	// The local (virtual) port.
-	LocalPort uint16
-	// The transport protocol (TCP, UDP).
-	Proto string
 	// The remote (real) IP address.
 	RemoteAddress net.IP
+	// The local (virtual) port.
+	LocalPort uint16
 	// The remote (real) port.
 	RemotePort uint16
+	// The local firewall mark
+	LocalMark string
+	// The transport protocol (TCP, UDP).
+	Proto string
 	// The current number of active connections for this virtual/real address pair.
 	ActiveConn uint64
 	// The current number of inactive connections for this virtual/real address pair.
@@ -47,29 +65,18 @@ type IPVSBackendStatus struct {
 	Weight uint64
 }
 
-// NewIPVSStats reads the IPVS statistics.
-func NewIPVSStats() (IPVSStats, error) {
-	fs, err := NewFS(DefaultMountPoint)
+// IPVSStats reads the IPVS statistics from the specified `proc` filesystem.
+func (fs FS) IPVSStats() (IPVSStats, error) {
+	data, err := util.ReadFileNoStat(fs.proc.Path("net/ip_vs_stats"))
 	if err != nil {
 		return IPVSStats{}, err
 	}
 
-	return fs.NewIPVSStats()
-}
-
-// NewIPVSStats reads the IPVS statistics from the specified `proc` filesystem.
-func (fs FS) NewIPVSStats() (IPVSStats, error) {
-	file, err := os.Open(fs.Path("net/ip_vs_stats"))
-	if err != nil {
-		return IPVSStats{}, err
-	}
-	defer file.Close()
-
-	return parseIPVSStats(file)
+	return parseIPVSStats(bytes.NewReader(data))
 }
 
 // parseIPVSStats performs the actual parsing of `ip_vs_stats`.
-func parseIPVSStats(file io.Reader) (IPVSStats, error) {
+func parseIPVSStats(r io.Reader) (IPVSStats, error) {
 	var (
 		statContent []byte
 		statLines   []string
@@ -77,7 +84,7 @@ func parseIPVSStats(file io.Reader) (IPVSStats, error) {
 		stats       IPVSStats
 	)
 
-	statContent, err := ioutil.ReadAll(file)
+	statContent, err := ioutil.ReadAll(r)
 	if err != nil {
 		return IPVSStats{}, err
 	}
@@ -116,19 +123,9 @@ func parseIPVSStats(file io.Reader) (IPVSStats, error) {
 	return stats, nil
 }
 
-// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs.
-func NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
-	fs, err := NewFS(DefaultMountPoint)
-	if err != nil {
-		return []IPVSBackendStatus{}, err
-	}
-
-	return fs.NewIPVSBackendStatus()
-}
-
-// NewIPVSBackendStatus reads and returns the status of all (virtual,real) server pairs from the specified `proc` filesystem.
-func (fs FS) NewIPVSBackendStatus() ([]IPVSBackendStatus, error) {
-	file, err := os.Open(fs.Path("net/ip_vs"))
+// IPVSBackendStatus reads and returns the status of all (virtual,real) server pairs from the specified `proc` filesystem.
+func (fs FS) IPVSBackendStatus() ([]IPVSBackendStatus, error) {
+	file, err := os.Open(fs.proc.Path("net/ip_vs"))
 	if err != nil {
 		return nil, err
 	}
@@ -142,13 +139,14 @@ func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
 		status       []IPVSBackendStatus
 		scanner      = bufio.NewScanner(file)
 		proto        string
+		localMark    string
 		localAddress net.IP
 		localPort    uint16
 		err          error
 	)
 
 	for scanner.Scan() {
-		fields := strings.Fields(string(scanner.Text()))
+		fields := strings.Fields(scanner.Text())
 		if len(fields) == 0 {
 			continue
 		}
@@ -160,10 +158,19 @@ func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
 				continue
 			}
 			proto = fields[0]
+			localMark = ""
 			localAddress, localPort, err = parseIPPort(fields[1])
 			if err != nil {
 				return nil, err
 			}
+		case fields[0] == "FWM":
+			if len(fields) < 2 {
+				continue
+			}
+			proto = fields[0]
+			localMark = fields[1]
+			localAddress = nil
+			localPort = 0
 		case fields[0] == "->":
 			if len(fields) < 6 {
 				continue
@@ -187,6 +194,7 @@ func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
 			status = append(status, IPVSBackendStatus{
 				LocalAddress:  localAddress,
 				LocalPort:     localPort,
+				LocalMark:     localMark,
 				RemoteAddress: remoteAddress,
 				RemotePort:    remotePort,
 				Proto:         proto,
@@ -200,22 +208,31 @@ func parseIPVSBackendStatus(file io.Reader) ([]IPVSBackendStatus, error) {
 }
 
 func parseIPPort(s string) (net.IP, uint16, error) {
-	tmp := strings.SplitN(s, ":", 2)
+	var (
+		ip  net.IP
+		err error
+	)
 
-	if len(tmp) != 2 {
-		return nil, 0, fmt.Errorf("invalid IP:Port: %s", s)
+	switch len(s) {
+	case 13:
+		ip, err = hex.DecodeString(s[0:8])
+		if err != nil {
+			return nil, 0, err
+		}
+	case 46:
+		ip = net.ParseIP(s[1:40])
+		if ip == nil {
+			return nil, 0, fmt.Errorf("invalid IPv6 address: %s", s[1:40])
+		}
+	default:
+		return nil, 0, fmt.Errorf("unexpected IP:Port: %s", s)
 	}
 
-	if len(tmp[0]) != 8 && len(tmp[0]) != 32 {
-		return nil, 0, fmt.Errorf("invalid IP: %s", tmp[0])
+	portString := s[len(s)-4:]
+	if len(portString) != 4 {
+		return nil, 0, fmt.Errorf("unexpected port string format: %s", portString)
 	}
-
-	ip, err := hex.DecodeString(tmp[0])
-	if err != nil {
-		return nil, 0, err
-	}
-
-	port, err := strconv.ParseUint(tmp[1], 16, 16)
+	port, err := strconv.ParseUint(portString, 16, 16)
 	if err != nil {
 		return nil, 0, err
 	}

vendor/github.com/prometheus/procfs/kernel_random.go

@@ -0,0 +1,62 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// +build !windows
+
+package procfs
+
+import (
+	"os"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// KernelRandom contains information about to the kernel's random number generator.
+type KernelRandom struct {
+	// EntropyAvaliable gives the available entropy, in bits.
+	EntropyAvaliable *uint64
+	// PoolSize gives the size of the entropy pool, in bits.
+	PoolSize *uint64
+	// URandomMinReseedSeconds is the number of seconds after which the DRNG will be reseeded.
+	URandomMinReseedSeconds *uint64
+	// WriteWakeupThreshold the number of bits of entropy below which we wake up processes
+	// that do a select(2) or poll(2) for write access to /dev/random.
+	WriteWakeupThreshold *uint64
+	// ReadWakeupThreshold is the number of bits of entropy required for waking up processes that sleep
+	// waiting for entropy from /dev/random.
+	ReadWakeupThreshold *uint64
+}
+
+// KernelRandom returns values from /proc/sys/kernel/random.
+func (fs FS) KernelRandom() (KernelRandom, error) {
+	random := KernelRandom{}
+
+	for file, p := range map[string]**uint64{
+		"entropy_avail":           &random.EntropyAvaliable,
+		"poolsize":                &random.PoolSize,
+		"urandom_min_reseed_secs": &random.URandomMinReseedSeconds,
+		"write_wakeup_threshold":  &random.WriteWakeupThreshold,
+		"read_wakeup_threshold":   &random.ReadWakeupThreshold,
+	} {
+		val, err := util.ReadUintFromFile(fs.proc.Path("sys", "kernel", "random", file))
+		if os.IsNotExist(err) {
+			continue
+		}
+		if err != nil {
+			return random, err
+		}
+		*p = &val
+	}
+
+	return random, nil
+}

vendor/github.com/prometheus/procfs/loadavg.go

@@ -0,0 +1,62 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// LoadAvg represents an entry in /proc/loadavg
+type LoadAvg struct {
+	Load1  float64
+	Load5  float64
+	Load15 float64
+}
+
+// LoadAvg returns loadavg from /proc.
+func (fs FS) LoadAvg() (*LoadAvg, error) {
+	path := fs.proc.Path("loadavg")
+
+	data, err := util.ReadFileNoStat(path)
+	if err != nil {
+		return nil, err
+	}
+	return parseLoad(data)
+}
+
+// Parse /proc loadavg and return 1m, 5m and 15m.
+func parseLoad(loadavgBytes []byte) (*LoadAvg, error) {
+	loads := make([]float64, 3)
+	parts := strings.Fields(string(loadavgBytes))
+	if len(parts) < 3 {
+		return nil, fmt.Errorf("malformed loadavg line: too few fields in loadavg string: %q", string(loadavgBytes))
+	}
+
+	var err error
+	for i, load := range parts[0:3] {
+		loads[i], err = strconv.ParseFloat(load, 64)
+		if err != nil {
+			return nil, fmt.Errorf("could not parse load %q: %w", load, err)
+		}
+	}
+	return &LoadAvg{
+		Load1:  loads[0],
+		Load5:  loads[1],
+		Load15: loads[2],
+	}, nil
+}

vendor/github.com/prometheus/procfs/mdstat.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package procfs
 
 import (
@@ -9,8 +22,12 @@ import (
 )
 
 var (
-	statuslineRE = regexp.MustCompile(`(\d+) blocks .*\[(\d+)/(\d+)\] \[[U_]+\]`)
-	buildlineRE  = regexp.MustCompile(`\((\d+)/\d+\)`)
+	statusLineRE         = regexp.MustCompile(`(\d+) blocks .*\[(\d+)/(\d+)\] \[([U_]+)\]`)
+	recoveryLineBlocksRE = regexp.MustCompile(`\((\d+)/\d+\)`)
+	recoveryLinePctRE    = regexp.MustCompile(`= (.+)%`)
+	recoveryLineFinishRE = regexp.MustCompile(`finish=(.+)min`)
+	recoveryLineSpeedRE  = regexp.MustCompile(`speed=(.+)[A-Z]`)
+	componentDeviceRE    = regexp.MustCompile(`(.*)\[\d+\]`)
 )
 
 // MDStat holds info parsed from /proc/mdstat.
@@ -21,118 +38,225 @@ type MDStat struct {
 	ActivityState string
 	// Number of active disks.
 	DisksActive int64
-	// Total number of disks the device consists of.
+	// Total number of disks the device requires.
 	DisksTotal int64
+	// Number of failed disks.
+	DisksFailed int64
+	// Number of "down" disks. (the _ indicator in the status line)
+	DisksDown int64
+	// Spare disks in the device.
+	DisksSpare int64
 	// Number of blocks the device holds.
 	BlocksTotal int64
 	// Number of blocks on the device that are in sync.
 	BlocksSynced int64
+	// progress percentage of current sync
+	BlocksSyncedPct float64
+	// estimated finishing time for current sync (in minutes)
+	BlocksSyncedFinishTime float64
+	// current sync speed (in Kilobytes/sec)
+	BlocksSyncedSpeed float64
+	// Name of md component devices
+	Devices []string
 }
 
-// ParseMDStat parses an mdstat-file and returns a struct with the relevant infos.
-func (fs FS) ParseMDStat() (mdstates []MDStat, err error) {
-	mdStatusFilePath := fs.Path("mdstat")
-	content, err := ioutil.ReadFile(mdStatusFilePath)
+// MDStat parses an mdstat-file (/proc/mdstat) and returns a slice of
+// structs containing the relevant info.  More information available here:
+// https://raid.wiki.kernel.org/index.php/Mdstat
+func (fs FS) MDStat() ([]MDStat, error) {
+	data, err := ioutil.ReadFile(fs.proc.Path("mdstat"))
 	if err != nil {
-		return []MDStat{}, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
+		return nil, err
 	}
+	mdstat, err := parseMDStat(data)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing mdstat %q: %w", fs.proc.Path("mdstat"), err)
+	}
+	return mdstat, nil
+}
 
-	mdStates := []MDStat{}
-	lines := strings.Split(string(content), "\n")
-	for i, l := range lines {
-		if l == "" {
-			continue
-		}
-		if l[0] == ' ' {
-			continue
-		}
-		if strings.HasPrefix(l, "Personalities") || strings.HasPrefix(l, "unused") {
+// parseMDStat parses data from mdstat file (/proc/mdstat) and returns a slice of
+// structs containing the relevant info.
+func parseMDStat(mdStatData []byte) ([]MDStat, error) {
+	mdStats := []MDStat{}
+	lines := strings.Split(string(mdStatData), "\n")
+
+	for i, line := range lines {
+		if strings.TrimSpace(line) == "" || line[0] == ' ' ||
+			strings.HasPrefix(line, "Personalities") ||
+			strings.HasPrefix(line, "unused") {
 			continue
 		}
 
-		mainLine := strings.Split(l, " ")
-		if len(mainLine) < 3 {
-			return mdStates, fmt.Errorf("error parsing mdline: %s", l)
+		deviceFields := strings.Fields(line)
+		if len(deviceFields) < 3 {
+			return nil, fmt.Errorf("not enough fields in mdline (expected at least 3): %s", line)
 		}
-		mdName := mainLine[0]
-		activityState := mainLine[2]
+		mdName := deviceFields[0] // mdx
+		state := deviceFields[2]  // active or inactive
 
 		if len(lines) <= i+3 {
-			return mdStates, fmt.Errorf(
-				"error parsing %s: too few lines for md device %s",
-				mdStatusFilePath,
-				mdName,
-			)
+			return nil, fmt.Errorf("error parsing %q: too few lines for md device", mdName)
 		}
 
-		active, total, size, err := evalStatusline(lines[i+1])
+		// Failed disks have the suffix (F) & Spare disks have the suffix (S).
+		fail := int64(strings.Count(line, "(F)"))
+		spare := int64(strings.Count(line, "(S)"))
+		active, total, down, size, err := evalStatusLine(lines[i], lines[i+1])
+
 		if err != nil {
-			return mdStates, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
+			return nil, fmt.Errorf("error parsing md device lines: %w", err)
 		}
 
-		// j is the line number of the syncing-line.
-		j := i + 2
+		syncLineIdx := i + 2
 		if strings.Contains(lines[i+2], "bitmap") { // skip bitmap line
-			j = i + 3
+			syncLineIdx++
 		}
 
 		// If device is syncing at the moment, get the number of currently
 		// synced bytes, otherwise that number equals the size of the device.
 		syncedBlocks := size
-		if strings.Contains(lines[j], "recovery") || strings.Contains(lines[j], "resync") {
-			syncedBlocks, err = evalBuildline(lines[j])
-			if err != nil {
-				return mdStates, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
+		speed := float64(0)
+		finish := float64(0)
+		pct := float64(0)
+		recovering := strings.Contains(lines[syncLineIdx], "recovery")
+		resyncing := strings.Contains(lines[syncLineIdx], "resync")
+		checking := strings.Contains(lines[syncLineIdx], "check")
+
+		// Append recovery and resyncing state info.
+		if recovering || resyncing || checking {
+			if recovering {
+				state = "recovering"
+			} else if checking {
+				state = "checking"
+			} else {
+				state = "resyncing"
+			}
+
+			// Handle case when resync=PENDING or resync=DELAYED.
+			if strings.Contains(lines[syncLineIdx], "PENDING") ||
+				strings.Contains(lines[syncLineIdx], "DELAYED") {
+				syncedBlocks = 0
+			} else {
+				syncedBlocks, pct, finish, speed, err = evalRecoveryLine(lines[syncLineIdx])
+				if err != nil {
+					return nil, fmt.Errorf("error parsing sync line in md device %q: %w", mdName, err)
+				}
 			}
 		}
 
-		mdStates = append(mdStates, MDStat{
-			Name:          mdName,
-			ActivityState: activityState,
-			DisksActive:   active,
-			DisksTotal:    total,
-			BlocksTotal:   size,
-			BlocksSynced:  syncedBlocks,
+		mdStats = append(mdStats, MDStat{
+			Name:                   mdName,
+			ActivityState:          state,
+			DisksActive:            active,
+			DisksFailed:            fail,
+			DisksDown:              down,
+			DisksSpare:             spare,
+			DisksTotal:             total,
+			BlocksTotal:            size,
+			BlocksSynced:           syncedBlocks,
+			BlocksSyncedPct:        pct,
+			BlocksSyncedFinishTime: finish,
+			BlocksSyncedSpeed:      speed,
+			Devices:                evalComponentDevices(deviceFields),
 		})
 	}
 
-	return mdStates, nil
+	return mdStats, nil
 }
 
-func evalStatusline(statusline string) (active, total, size int64, err error) {
-	matches := statuslineRE.FindStringSubmatch(statusline)
-	if len(matches) != 4 {
-		return 0, 0, 0, fmt.Errorf("unexpected statusline: %s", statusline)
+func evalStatusLine(deviceLine, statusLine string) (active, total, down, size int64, err error) {
+
+	sizeStr := strings.Fields(statusLine)[0]
+	size, err = strconv.ParseInt(sizeStr, 10, 64)
+	if err != nil {
+		return 0, 0, 0, 0, fmt.Errorf("unexpected statusLine %q: %w", statusLine, err)
 	}
 
-	size, err = strconv.ParseInt(matches[1], 10, 64)
-	if err != nil {
-		return 0, 0, 0, fmt.Errorf("unexpected statusline %s: %s", statusline, err)
+	if strings.Contains(deviceLine, "raid0") || strings.Contains(deviceLine, "linear") {
+		// In the device deviceLine, only disks have a number associated with them in [].
+		total = int64(strings.Count(deviceLine, "["))
+		return total, total, 0, size, nil
+	}
+
+	if strings.Contains(deviceLine, "inactive") {
+		return 0, 0, 0, size, nil
+	}
+
+	matches := statusLineRE.FindStringSubmatch(statusLine)
+	if len(matches) != 5 {
+		return 0, 0, 0, 0, fmt.Errorf("couldn't find all the substring matches: %s", statusLine)
 	}
 
 	total, err = strconv.ParseInt(matches[2], 10, 64)
 	if err != nil {
-		return 0, 0, 0, fmt.Errorf("unexpected statusline %s: %s", statusline, err)
+		return 0, 0, 0, 0, fmt.Errorf("unexpected statusLine %q: %w", statusLine, err)
 	}
 
 	active, err = strconv.ParseInt(matches[3], 10, 64)
 	if err != nil {
-		return 0, 0, 0, fmt.Errorf("unexpected statusline %s: %s", statusline, err)
+		return 0, 0, 0, 0, fmt.Errorf("unexpected statusLine %q: %w", statusLine, err)
 	}
+	down = int64(strings.Count(matches[4], "_"))
 
-	return active, total, size, nil
+	return active, total, down, size, nil
 }
 
-func evalBuildline(buildline string) (syncedBlocks int64, err error) {
-	matches := buildlineRE.FindStringSubmatch(buildline)
+func evalRecoveryLine(recoveryLine string) (syncedBlocks int64, pct float64, finish float64, speed float64, err error) {
+	matches := recoveryLineBlocksRE.FindStringSubmatch(recoveryLine)
 	if len(matches) != 2 {
-		return 0, fmt.Errorf("unexpected buildline: %s", buildline)
+		return 0, 0, 0, 0, fmt.Errorf("unexpected recoveryLine: %s", recoveryLine)
 	}
 
 	syncedBlocks, err = strconv.ParseInt(matches[1], 10, 64)
 	if err != nil {
-		return 0, fmt.Errorf("%s in buildline: %s", err, buildline)
+		return 0, 0, 0, 0, fmt.Errorf("error parsing int from recoveryLine %q: %w", recoveryLine, err)
 	}
 
-	return syncedBlocks, nil
+	// Get percentage complete
+	matches = recoveryLinePctRE.FindStringSubmatch(recoveryLine)
+	if len(matches) != 2 {
+		return syncedBlocks, 0, 0, 0, fmt.Errorf("unexpected recoveryLine matching percentage: %s", recoveryLine)
+	}
+	pct, err = strconv.ParseFloat(strings.TrimSpace(matches[1]), 64)
+	if err != nil {
+		return syncedBlocks, 0, 0, 0, fmt.Errorf("error parsing float from recoveryLine %q: %w", recoveryLine, err)
+	}
+
+	// Get time expected left to complete
+	matches = recoveryLineFinishRE.FindStringSubmatch(recoveryLine)
+	if len(matches) != 2 {
+		return syncedBlocks, pct, 0, 0, fmt.Errorf("unexpected recoveryLine matching est. finish time: %s", recoveryLine)
+	}
+	finish, err = strconv.ParseFloat(matches[1], 64)
+	if err != nil {
+		return syncedBlocks, pct, 0, 0, fmt.Errorf("error parsing float from recoveryLine %q: %w", recoveryLine, err)
+	}
+
+	// Get recovery speed
+	matches = recoveryLineSpeedRE.FindStringSubmatch(recoveryLine)
+	if len(matches) != 2 {
+		return syncedBlocks, pct, finish, 0, fmt.Errorf("unexpected recoveryLine matching speed: %s", recoveryLine)
+	}
+	speed, err = strconv.ParseFloat(matches[1], 64)
+	if err != nil {
+		return syncedBlocks, pct, finish, 0, fmt.Errorf("error parsing float from recoveryLine %q: %w", recoveryLine, err)
+	}
+
+	return syncedBlocks, pct, finish, speed, nil
+}
+
+func evalComponentDevices(deviceFields []string) []string {
+	mdComponentDevices := make([]string, 0)
+	if len(deviceFields) > 3 {
+		for _, field := range deviceFields[4:] {
+			match := componentDeviceRE.FindStringSubmatch(field)
+			if match == nil {
+				continue
+			}
+			mdComponentDevices = append(mdComponentDevices, match[1])
+		}
+	}
+
+	return mdComponentDevices
 }

vendor/github.com/prometheus/procfs/meminfo.go

@@ -0,0 +1,277 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// Meminfo represents memory statistics.
+type Meminfo struct {
+	// Total usable ram (i.e. physical ram minus a few reserved
+	// bits and the kernel binary code)
+	MemTotal *uint64
+	// The sum of LowFree+HighFree
+	MemFree *uint64
+	// An estimate of how much memory is available for starting
+	// new applications, without swapping. Calculated from
+	// MemFree, SReclaimable, the size of the file LRU lists, and
+	// the low watermarks in each zone.  The estimate takes into
+	// account that the system needs some page cache to function
+	// well, and that not all reclaimable slab will be
+	// reclaimable, due to items being in use. The impact of those
+	// factors will vary from system to system.
+	MemAvailable *uint64
+	// Relatively temporary storage for raw disk blocks shouldn't
+	// get tremendously large (20MB or so)
+	Buffers *uint64
+	Cached  *uint64
+	// Memory that once was swapped out, is swapped back in but
+	// still also is in the swapfile (if memory is needed it
+	// doesn't need to be swapped out AGAIN because it is already
+	// in the swapfile. This saves I/O)
+	SwapCached *uint64
+	// Memory that has been used more recently and usually not
+	// reclaimed unless absolutely necessary.
+	Active *uint64
+	// Memory which has been less recently used.  It is more
+	// eligible to be reclaimed for other purposes
+	Inactive     *uint64
+	ActiveAnon   *uint64
+	InactiveAnon *uint64
+	ActiveFile   *uint64
+	InactiveFile *uint64
+	Unevictable  *uint64
+	Mlocked      *uint64
+	// total amount of swap space available
+	SwapTotal *uint64
+	// Memory which has been evicted from RAM, and is temporarily
+	// on the disk
+	SwapFree *uint64
+	// Memory which is waiting to get written back to the disk
+	Dirty *uint64
+	// Memory which is actively being written back to the disk
+	Writeback *uint64
+	// Non-file backed pages mapped into userspace page tables
+	AnonPages *uint64
+	// files which have been mapped, such as libraries
+	Mapped *uint64
+	Shmem  *uint64
+	// in-kernel data structures cache
+	Slab *uint64
+	// Part of Slab, that might be reclaimed, such as caches
+	SReclaimable *uint64
+	// Part of Slab, that cannot be reclaimed on memory pressure
+	SUnreclaim  *uint64
+	KernelStack *uint64
+	// amount of memory dedicated to the lowest level of page
+	// tables.
+	PageTables *uint64
+	// NFS pages sent to the server, but not yet committed to
+	// stable storage
+	NFSUnstable *uint64
+	// Memory used for block device "bounce buffers"
+	Bounce *uint64
+	// Memory used by FUSE for temporary writeback buffers
+	WritebackTmp *uint64
+	// Based on the overcommit ratio ('vm.overcommit_ratio'),
+	// this is the total amount of  memory currently available to
+	// be allocated on the system. This limit is only adhered to
+	// if strict overcommit accounting is enabled (mode 2 in
+	// 'vm.overcommit_memory').
+	// The CommitLimit is calculated with the following formula:
+	// CommitLimit = ([total RAM pages] - [total huge TLB pages]) *
+	//                overcommit_ratio / 100 + [total swap pages]
+	// For example, on a system with 1G of physical RAM and 7G
+	// of swap with a `vm.overcommit_ratio` of 30 it would
+	// yield a CommitLimit of 7.3G.
+	// For more details, see the memory overcommit documentation
+	// in vm/overcommit-accounting.
+	CommitLimit *uint64
+	// The amount of memory presently allocated on the system.
+	// The committed memory is a sum of all of the memory which
+	// has been allocated by processes, even if it has not been
+	// "used" by them as of yet. A process which malloc()'s 1G
+	// of memory, but only touches 300M of it will show up as
+	// using 1G. This 1G is memory which has been "committed" to
+	// by the VM and can be used at any time by the allocating
+	// application. With strict overcommit enabled on the system
+	// (mode 2 in 'vm.overcommit_memory'),allocations which would
+	// exceed the CommitLimit (detailed above) will not be permitted.
+	// This is useful if one needs to guarantee that processes will
+	// not fail due to lack of memory once that memory has been
+	// successfully allocated.
+	CommittedAS *uint64
+	// total size of vmalloc memory area
+	VmallocTotal *uint64
+	// amount of vmalloc area which is used
+	VmallocUsed *uint64
+	// largest contiguous block of vmalloc area which is free
+	VmallocChunk      *uint64
+	HardwareCorrupted *uint64
+	AnonHugePages     *uint64
+	ShmemHugePages    *uint64
+	ShmemPmdMapped    *uint64
+	CmaTotal          *uint64
+	CmaFree           *uint64
+	HugePagesTotal    *uint64
+	HugePagesFree     *uint64
+	HugePagesRsvd     *uint64
+	HugePagesSurp     *uint64
+	Hugepagesize      *uint64
+	DirectMap4k       *uint64
+	DirectMap2M       *uint64
+	DirectMap1G       *uint64
+}
+
+// Meminfo returns an information about current kernel/system memory statistics.
+// See https://www.kernel.org/doc/Documentation/filesystems/proc.txt
+func (fs FS) Meminfo() (Meminfo, error) {
+	b, err := util.ReadFileNoStat(fs.proc.Path("meminfo"))
+	if err != nil {
+		return Meminfo{}, err
+	}
+
+	m, err := parseMemInfo(bytes.NewReader(b))
+	if err != nil {
+		return Meminfo{}, fmt.Errorf("failed to parse meminfo: %w", err)
+	}
+
+	return *m, nil
+}
+
+func parseMemInfo(r io.Reader) (*Meminfo, error) {
+	var m Meminfo
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		// Each line has at least a name and value; we ignore the unit.
+		fields := strings.Fields(s.Text())
+		if len(fields) < 2 {
+			return nil, fmt.Errorf("malformed meminfo line: %q", s.Text())
+		}
+
+		v, err := strconv.ParseUint(fields[1], 0, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		switch fields[0] {
+		case "MemTotal:":
+			m.MemTotal = &v
+		case "MemFree:":
+			m.MemFree = &v
+		case "MemAvailable:":
+			m.MemAvailable = &v
+		case "Buffers:":
+			m.Buffers = &v
+		case "Cached:":
+			m.Cached = &v
+		case "SwapCached:":
+			m.SwapCached = &v
+		case "Active:":
+			m.Active = &v
+		case "Inactive:":
+			m.Inactive = &v
+		case "Active(anon):":
+			m.ActiveAnon = &v
+		case "Inactive(anon):":
+			m.InactiveAnon = &v
+		case "Active(file):":
+			m.ActiveFile = &v
+		case "Inactive(file):":
+			m.InactiveFile = &v
+		case "Unevictable:":
+			m.Unevictable = &v
+		case "Mlocked:":
+			m.Mlocked = &v
+		case "SwapTotal:":
+			m.SwapTotal = &v
+		case "SwapFree:":
+			m.SwapFree = &v
+		case "Dirty:":
+			m.Dirty = &v
+		case "Writeback:":
+			m.Writeback = &v
+		case "AnonPages:":
+			m.AnonPages = &v
+		case "Mapped:":
+			m.Mapped = &v
+		case "Shmem:":
+			m.Shmem = &v
+		case "Slab:":
+			m.Slab = &v
+		case "SReclaimable:":
+			m.SReclaimable = &v
+		case "SUnreclaim:":
+			m.SUnreclaim = &v
+		case "KernelStack:":
+			m.KernelStack = &v
+		case "PageTables:":
+			m.PageTables = &v
+		case "NFS_Unstable:":
+			m.NFSUnstable = &v
+		case "Bounce:":
+			m.Bounce = &v
+		case "WritebackTmp:":
+			m.WritebackTmp = &v
+		case "CommitLimit:":
+			m.CommitLimit = &v
+		case "Committed_AS:":
+			m.CommittedAS = &v
+		case "VmallocTotal:":
+			m.VmallocTotal = &v
+		case "VmallocUsed:":
+			m.VmallocUsed = &v
+		case "VmallocChunk:":
+			m.VmallocChunk = &v
+		case "HardwareCorrupted:":
+			m.HardwareCorrupted = &v
+		case "AnonHugePages:":
+			m.AnonHugePages = &v
+		case "ShmemHugePages:":
+			m.ShmemHugePages = &v
+		case "ShmemPmdMapped:":
+			m.ShmemPmdMapped = &v
+		case "CmaTotal:":
+			m.CmaTotal = &v
+		case "CmaFree:":
+			m.CmaFree = &v
+		case "HugePages_Total:":
+			m.HugePagesTotal = &v
+		case "HugePages_Free:":
+			m.HugePagesFree = &v
+		case "HugePages_Rsvd:":
+			m.HugePagesRsvd = &v
+		case "HugePages_Surp:":
+			m.HugePagesSurp = &v
+		case "Hugepagesize:":
+			m.Hugepagesize = &v
+		case "DirectMap4k:":
+			m.DirectMap4k = &v
+		case "DirectMap2M:":
+			m.DirectMap2M = &v
+		case "DirectMap1G:":
+			m.DirectMap1G = &v
+		}
+	}
+
+	return &m, nil
+}

vendor/github.com/prometheus/procfs/mountinfo.go

@@ -0,0 +1,180 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// A MountInfo is a type that describes the details, options
+// for each mount, parsed from /proc/self/mountinfo.
+// The fields described in each entry of /proc/self/mountinfo
+// is described in the following man page.
+// http://man7.org/linux/man-pages/man5/proc.5.html
+type MountInfo struct {
+	// Unique ID for the mount
+	MountID int
+	// The ID of the parent mount
+	ParentID int
+	// The value of `st_dev` for the files on this FS
+	MajorMinorVer string
+	// The pathname of the directory in the FS that forms
+	// the root for this mount
+	Root string
+	// The pathname of the mount point relative to the root
+	MountPoint string
+	// Mount options
+	Options map[string]string
+	// Zero or more optional fields
+	OptionalFields map[string]string
+	// The Filesystem type
+	FSType string
+	// FS specific information or "none"
+	Source string
+	// Superblock options
+	SuperOptions map[string]string
+}
+
+// Reads each line of the mountinfo file, and returns a list of formatted MountInfo structs.
+func parseMountInfo(info []byte) ([]*MountInfo, error) {
+	mounts := []*MountInfo{}
+	scanner := bufio.NewScanner(bytes.NewReader(info))
+	for scanner.Scan() {
+		mountString := scanner.Text()
+		parsedMounts, err := parseMountInfoString(mountString)
+		if err != nil {
+			return nil, err
+		}
+		mounts = append(mounts, parsedMounts)
+	}
+
+	err := scanner.Err()
+	return mounts, err
+}
+
+// Parses a mountinfo file line, and converts it to a MountInfo struct.
+// An important check here is to see if the hyphen separator, as if it does not exist,
+// it means that the line is malformed.
+func parseMountInfoString(mountString string) (*MountInfo, error) {
+	var err error
+
+	mountInfo := strings.Split(mountString, " ")
+	mountInfoLength := len(mountInfo)
+	if mountInfoLength < 10 {
+		return nil, fmt.Errorf("couldn't find enough fields in mount string: %s", mountString)
+	}
+
+	if mountInfo[mountInfoLength-4] != "-" {
+		return nil, fmt.Errorf("couldn't find separator in expected field: %s", mountInfo[mountInfoLength-4])
+	}
+
+	mount := &MountInfo{
+		MajorMinorVer:  mountInfo[2],
+		Root:           mountInfo[3],
+		MountPoint:     mountInfo[4],
+		Options:        mountOptionsParser(mountInfo[5]),
+		OptionalFields: nil,
+		FSType:         mountInfo[mountInfoLength-3],
+		Source:         mountInfo[mountInfoLength-2],
+		SuperOptions:   mountOptionsParser(mountInfo[mountInfoLength-1]),
+	}
+
+	mount.MountID, err = strconv.Atoi(mountInfo[0])
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse mount ID")
+	}
+	mount.ParentID, err = strconv.Atoi(mountInfo[1])
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse parent ID")
+	}
+	// Has optional fields, which is a space separated list of values.
+	// Example: shared:2 master:7
+	if mountInfo[6] != "" {
+		mount.OptionalFields, err = mountOptionsParseOptionalFields(mountInfo[6 : mountInfoLength-4])
+		if err != nil {
+			return nil, err
+		}
+	}
+	return mount, nil
+}
+
+// mountOptionsIsValidField checks a string against a valid list of optional fields keys.
+func mountOptionsIsValidField(s string) bool {
+	switch s {
+	case
+		"shared",
+		"master",
+		"propagate_from",
+		"unbindable":
+		return true
+	}
+	return false
+}
+
+// mountOptionsParseOptionalFields parses a list of optional fields strings into a double map of strings.
+func mountOptionsParseOptionalFields(o []string) (map[string]string, error) {
+	optionalFields := make(map[string]string)
+	for _, field := range o {
+		optionSplit := strings.SplitN(field, ":", 2)
+		value := ""
+		if len(optionSplit) == 2 {
+			value = optionSplit[1]
+		}
+		if mountOptionsIsValidField(optionSplit[0]) {
+			optionalFields[optionSplit[0]] = value
+		}
+	}
+	return optionalFields, nil
+}
+
+// mountOptionsParser parses the mount options, superblock options.
+func mountOptionsParser(mountOptions string) map[string]string {
+	opts := make(map[string]string)
+	options := strings.Split(mountOptions, ",")
+	for _, opt := range options {
+		splitOption := strings.Split(opt, "=")
+		if len(splitOption) < 2 {
+			key := splitOption[0]
+			opts[key] = ""
+		} else {
+			key, value := splitOption[0], splitOption[1]
+			opts[key] = value
+		}
+	}
+	return opts
+}
+
+// GetMounts retrieves mountinfo information from `/proc/self/mountinfo`.
+func GetMounts() ([]*MountInfo, error) {
+	data, err := util.ReadFileNoStat("/proc/self/mountinfo")
+	if err != nil {
+		return nil, err
+	}
+	return parseMountInfo(data)
+}
+
+// GetProcMounts retrieves mountinfo information from a processes' `/proc/<pid>/mountinfo`.
+func GetProcMounts(pid int) ([]*MountInfo, error) {
+	data, err := util.ReadFileNoStat(fmt.Sprintf("/proc/%d/mountinfo", pid))
+	if err != nil {
+		return nil, err
+	}
+	return parseMountInfo(data)
+}

vendor/github.com/prometheus/procfs/mountstats.go

@@ -0,0 +1,638 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+// While implementing parsing of /proc/[pid]/mountstats, this blog was used
+// heavily as a reference:
+//   https://utcc.utoronto.ca/~cks/space/blog/linux/NFSMountstatsIndex
+//
+// Special thanks to Chris Siebenmann for all of his posts explaining the
+// various statistics available for NFS.
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Constants shared between multiple functions.
+const (
+	deviceEntryLen = 8
+
+	fieldBytesLen  = 8
+	fieldEventsLen = 27
+
+	statVersion10 = "1.0"
+	statVersion11 = "1.1"
+
+	fieldTransport10TCPLen = 10
+	fieldTransport10UDPLen = 7
+
+	fieldTransport11TCPLen = 13
+	fieldTransport11UDPLen = 10
+)
+
+// A Mount is a device mount parsed from /proc/[pid]/mountstats.
+type Mount struct {
+	// Name of the device.
+	Device string
+	// The mount point of the device.
+	Mount string
+	// The filesystem type used by the device.
+	Type string
+	// If available additional statistics related to this Mount.
+	// Use a type assertion to determine if additional statistics are available.
+	Stats MountStats
+}
+
+// A MountStats is a type which contains detailed statistics for a specific
+// type of Mount.
+type MountStats interface {
+	mountStats()
+}
+
+// A MountStatsNFS is a MountStats implementation for NFSv3 and v4 mounts.
+type MountStatsNFS struct {
+	// The version of statistics provided.
+	StatVersion string
+	// The mount options of the NFS mount.
+	Opts map[string]string
+	// The age of the NFS mount.
+	Age time.Duration
+	// Statistics related to byte counters for various operations.
+	Bytes NFSBytesStats
+	// Statistics related to various NFS event occurrences.
+	Events NFSEventsStats
+	// Statistics broken down by filesystem operation.
+	Operations []NFSOperationStats
+	// Statistics about the NFS RPC transport.
+	Transport NFSTransportStats
+}
+
+// mountStats implements MountStats.
+func (m MountStatsNFS) mountStats() {}
+
+// A NFSBytesStats contains statistics about the number of bytes read and written
+// by an NFS client to and from an NFS server.
+type NFSBytesStats struct {
+	// Number of bytes read using the read() syscall.
+	Read uint64
+	// Number of bytes written using the write() syscall.
+	Write uint64
+	// Number of bytes read using the read() syscall in O_DIRECT mode.
+	DirectRead uint64
+	// Number of bytes written using the write() syscall in O_DIRECT mode.
+	DirectWrite uint64
+	// Number of bytes read from the NFS server, in total.
+	ReadTotal uint64
+	// Number of bytes written to the NFS server, in total.
+	WriteTotal uint64
+	// Number of pages read directly via mmap()'d files.
+	ReadPages uint64
+	// Number of pages written directly via mmap()'d files.
+	WritePages uint64
+}
+
+// A NFSEventsStats contains statistics about NFS event occurrences.
+type NFSEventsStats struct {
+	// Number of times cached inode attributes are re-validated from the server.
+	InodeRevalidate uint64
+	// Number of times cached dentry nodes are re-validated from the server.
+	DnodeRevalidate uint64
+	// Number of times an inode cache is cleared.
+	DataInvalidate uint64
+	// Number of times cached inode attributes are invalidated.
+	AttributeInvalidate uint64
+	// Number of times files or directories have been open()'d.
+	VFSOpen uint64
+	// Number of times a directory lookup has occurred.
+	VFSLookup uint64
+	// Number of times permissions have been checked.
+	VFSAccess uint64
+	// Number of updates (and potential writes) to pages.
+	VFSUpdatePage uint64
+	// Number of pages read directly via mmap()'d files.
+	VFSReadPage uint64
+	// Number of times a group of pages have been read.
+	VFSReadPages uint64
+	// Number of pages written directly via mmap()'d files.
+	VFSWritePage uint64
+	// Number of times a group of pages have been written.
+	VFSWritePages uint64
+	// Number of times directory entries have been read with getdents().
+	VFSGetdents uint64
+	// Number of times attributes have been set on inodes.
+	VFSSetattr uint64
+	// Number of pending writes that have been forcefully flushed to the server.
+	VFSFlush uint64
+	// Number of times fsync() has been called on directories and files.
+	VFSFsync uint64
+	// Number of times locking has been attempted on a file.
+	VFSLock uint64
+	// Number of times files have been closed and released.
+	VFSFileRelease uint64
+	// Unknown.  Possibly unused.
+	CongestionWait uint64
+	// Number of times files have been truncated.
+	Truncation uint64
+	// Number of times a file has been grown due to writes beyond its existing end.
+	WriteExtension uint64
+	// Number of times a file was removed while still open by another process.
+	SillyRename uint64
+	// Number of times the NFS server gave less data than expected while reading.
+	ShortRead uint64
+	// Number of times the NFS server wrote less data than expected while writing.
+	ShortWrite uint64
+	// Number of times the NFS server indicated EJUKEBOX; retrieving data from
+	// offline storage.
+	JukeboxDelay uint64
+	// Number of NFS v4.1+ pNFS reads.
+	PNFSRead uint64
+	// Number of NFS v4.1+ pNFS writes.
+	PNFSWrite uint64
+}
+
+// A NFSOperationStats contains statistics for a single operation.
+type NFSOperationStats struct {
+	// The name of the operation.
+	Operation string
+	// Number of requests performed for this operation.
+	Requests uint64
+	// Number of times an actual RPC request has been transmitted for this operation.
+	Transmissions uint64
+	// Number of times a request has had a major timeout.
+	MajorTimeouts uint64
+	// Number of bytes sent for this operation, including RPC headers and payload.
+	BytesSent uint64
+	// Number of bytes received for this operation, including RPC headers and payload.
+	BytesReceived uint64
+	// Duration all requests spent queued for transmission before they were sent.
+	CumulativeQueueMilliseconds uint64
+	// Duration it took to get a reply back after the request was transmitted.
+	CumulativeTotalResponseMilliseconds uint64
+	// Duration from when a request was enqueued to when it was completely handled.
+	CumulativeTotalRequestMilliseconds uint64
+	// The count of operations that complete with tk_status < 0.  These statuses usually indicate error conditions.
+	Errors uint64
+}
+
+// A NFSTransportStats contains statistics for the NFS mount RPC requests and
+// responses.
+type NFSTransportStats struct {
+	// The transport protocol used for the NFS mount.
+	Protocol string
+	// The local port used for the NFS mount.
+	Port uint64
+	// Number of times the client has had to establish a connection from scratch
+	// to the NFS server.
+	Bind uint64
+	// Number of times the client has made a TCP connection to the NFS server.
+	Connect uint64
+	// Duration (in jiffies, a kernel internal unit of time) the NFS mount has
+	// spent waiting for connections to the server to be established.
+	ConnectIdleTime uint64
+	// Duration since the NFS mount last saw any RPC traffic.
+	IdleTimeSeconds uint64
+	// Number of RPC requests for this mount sent to the NFS server.
+	Sends uint64
+	// Number of RPC responses for this mount received from the NFS server.
+	Receives uint64
+	// Number of times the NFS server sent a response with a transaction ID
+	// unknown to this client.
+	BadTransactionIDs uint64
+	// A running counter, incremented on each request as the current difference
+	// ebetween sends and receives.
+	CumulativeActiveRequests uint64
+	// A running counter, incremented on each request by the current backlog
+	// queue size.
+	CumulativeBacklog uint64
+
+	// Stats below only available with stat version 1.1.
+
+	// Maximum number of simultaneously active RPC requests ever used.
+	MaximumRPCSlotsUsed uint64
+	// A running counter, incremented on each request as the current size of the
+	// sending queue.
+	CumulativeSendingQueue uint64
+	// A running counter, incremented on each request as the current size of the
+	// pending queue.
+	CumulativePendingQueue uint64
+}
+
+// parseMountStats parses a /proc/[pid]/mountstats file and returns a slice
+// of Mount structures containing detailed information about each mount.
+// If available, statistics for each mount are parsed as well.
+func parseMountStats(r io.Reader) ([]*Mount, error) {
+	const (
+		device            = "device"
+		statVersionPrefix = "statvers="
+
+		nfs3Type = "nfs"
+		nfs4Type = "nfs4"
+	)
+
+	var mounts []*Mount
+
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		// Only look for device entries in this function
+		ss := strings.Fields(string(s.Bytes()))
+		if len(ss) == 0 || ss[0] != device {
+			continue
+		}
+
+		m, err := parseMount(ss)
+		if err != nil {
+			return nil, err
+		}
+
+		// Does this mount also possess statistics information?
+		if len(ss) > deviceEntryLen {
+			// Only NFSv3 and v4 are supported for parsing statistics
+			if m.Type != nfs3Type && m.Type != nfs4Type {
+				return nil, fmt.Errorf("cannot parse MountStats for fstype %q", m.Type)
+			}
+
+			statVersion := strings.TrimPrefix(ss[8], statVersionPrefix)
+
+			stats, err := parseMountStatsNFS(s, statVersion)
+			if err != nil {
+				return nil, err
+			}
+
+			m.Stats = stats
+		}
+
+		mounts = append(mounts, m)
+	}
+
+	return mounts, s.Err()
+}
+
+// parseMount parses an entry in /proc/[pid]/mountstats in the format:
+//   device [device] mounted on [mount] with fstype [type]
+func parseMount(ss []string) (*Mount, error) {
+	if len(ss) < deviceEntryLen {
+		return nil, fmt.Errorf("invalid device entry: %v", ss)
+	}
+
+	// Check for specific words appearing at specific indices to ensure
+	// the format is consistent with what we expect
+	format := []struct {
+		i int
+		s string
+	}{
+		{i: 0, s: "device"},
+		{i: 2, s: "mounted"},
+		{i: 3, s: "on"},
+		{i: 5, s: "with"},
+		{i: 6, s: "fstype"},
+	}
+
+	for _, f := range format {
+		if ss[f.i] != f.s {
+			return nil, fmt.Errorf("invalid device entry: %v", ss)
+		}
+	}
+
+	return &Mount{
+		Device: ss[1],
+		Mount:  ss[4],
+		Type:   ss[7],
+	}, nil
+}
+
+// parseMountStatsNFS parses a MountStatsNFS by scanning additional information
+// related to NFS statistics.
+func parseMountStatsNFS(s *bufio.Scanner, statVersion string) (*MountStatsNFS, error) {
+	// Field indicators for parsing specific types of data
+	const (
+		fieldOpts       = "opts:"
+		fieldAge        = "age:"
+		fieldBytes      = "bytes:"
+		fieldEvents     = "events:"
+		fieldPerOpStats = "per-op"
+		fieldTransport  = "xprt:"
+	)
+
+	stats := &MountStatsNFS{
+		StatVersion: statVersion,
+	}
+
+	for s.Scan() {
+		ss := strings.Fields(string(s.Bytes()))
+		if len(ss) == 0 {
+			break
+		}
+
+		switch ss[0] {
+		case fieldOpts:
+			if len(ss) < 2 {
+				return nil, fmt.Errorf("not enough information for NFS stats: %v", ss)
+			}
+			if stats.Opts == nil {
+				stats.Opts = map[string]string{}
+			}
+			for _, opt := range strings.Split(ss[1], ",") {
+				split := strings.Split(opt, "=")
+				if len(split) == 2 {
+					stats.Opts[split[0]] = split[1]
+				} else {
+					stats.Opts[opt] = ""
+				}
+			}
+		case fieldAge:
+			if len(ss) < 2 {
+				return nil, fmt.Errorf("not enough information for NFS stats: %v", ss)
+			}
+			// Age integer is in seconds
+			d, err := time.ParseDuration(ss[1] + "s")
+			if err != nil {
+				return nil, err
+			}
+
+			stats.Age = d
+		case fieldBytes:
+			if len(ss) < 2 {
+				return nil, fmt.Errorf("not enough information for NFS stats: %v", ss)
+			}
+			bstats, err := parseNFSBytesStats(ss[1:])
+			if err != nil {
+				return nil, err
+			}
+
+			stats.Bytes = *bstats
+		case fieldEvents:
+			if len(ss) < 2 {
+				return nil, fmt.Errorf("not enough information for NFS stats: %v", ss)
+			}
+			estats, err := parseNFSEventsStats(ss[1:])
+			if err != nil {
+				return nil, err
+			}
+
+			stats.Events = *estats
+		case fieldTransport:
+			if len(ss) < 3 {
+				return nil, fmt.Errorf("not enough information for NFS transport stats: %v", ss)
+			}
+
+			tstats, err := parseNFSTransportStats(ss[1:], statVersion)
+			if err != nil {
+				return nil, err
+			}
+
+			stats.Transport = *tstats
+		}
+
+		// When encountering "per-operation statistics", we must break this
+		// loop and parse them separately to ensure we can terminate parsing
+		// before reaching another device entry; hence why this 'if' statement
+		// is not just another switch case
+		if ss[0] == fieldPerOpStats {
+			break
+		}
+	}
+
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+
+	// NFS per-operation stats appear last before the next device entry
+	perOpStats, err := parseNFSOperationStats(s)
+	if err != nil {
+		return nil, err
+	}
+
+	stats.Operations = perOpStats
+
+	return stats, nil
+}
+
+// parseNFSBytesStats parses a NFSBytesStats line using an input set of
+// integer fields.
+func parseNFSBytesStats(ss []string) (*NFSBytesStats, error) {
+	if len(ss) != fieldBytesLen {
+		return nil, fmt.Errorf("invalid NFS bytes stats: %v", ss)
+	}
+
+	ns := make([]uint64, 0, fieldBytesLen)
+	for _, s := range ss {
+		n, err := strconv.ParseUint(s, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		ns = append(ns, n)
+	}
+
+	return &NFSBytesStats{
+		Read:        ns[0],
+		Write:       ns[1],
+		DirectRead:  ns[2],
+		DirectWrite: ns[3],
+		ReadTotal:   ns[4],
+		WriteTotal:  ns[5],
+		ReadPages:   ns[6],
+		WritePages:  ns[7],
+	}, nil
+}
+
+// parseNFSEventsStats parses a NFSEventsStats line using an input set of
+// integer fields.
+func parseNFSEventsStats(ss []string) (*NFSEventsStats, error) {
+	if len(ss) != fieldEventsLen {
+		return nil, fmt.Errorf("invalid NFS events stats: %v", ss)
+	}
+
+	ns := make([]uint64, 0, fieldEventsLen)
+	for _, s := range ss {
+		n, err := strconv.ParseUint(s, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		ns = append(ns, n)
+	}
+
+	return &NFSEventsStats{
+		InodeRevalidate:     ns[0],
+		DnodeRevalidate:     ns[1],
+		DataInvalidate:      ns[2],
+		AttributeInvalidate: ns[3],
+		VFSOpen:             ns[4],
+		VFSLookup:           ns[5],
+		VFSAccess:           ns[6],
+		VFSUpdatePage:       ns[7],
+		VFSReadPage:         ns[8],
+		VFSReadPages:        ns[9],
+		VFSWritePage:        ns[10],
+		VFSWritePages:       ns[11],
+		VFSGetdents:         ns[12],
+		VFSSetattr:          ns[13],
+		VFSFlush:            ns[14],
+		VFSFsync:            ns[15],
+		VFSLock:             ns[16],
+		VFSFileRelease:      ns[17],
+		CongestionWait:      ns[18],
+		Truncation:          ns[19],
+		WriteExtension:      ns[20],
+		SillyRename:         ns[21],
+		ShortRead:           ns[22],
+		ShortWrite:          ns[23],
+		JukeboxDelay:        ns[24],
+		PNFSRead:            ns[25],
+		PNFSWrite:           ns[26],
+	}, nil
+}
+
+// parseNFSOperationStats parses a slice of NFSOperationStats by scanning
+// additional information about per-operation statistics until an empty
+// line is reached.
+func parseNFSOperationStats(s *bufio.Scanner) ([]NFSOperationStats, error) {
+	const (
+		// Minimum number of expected fields in each per-operation statistics set
+		minFields = 9
+	)
+
+	var ops []NFSOperationStats
+
+	for s.Scan() {
+		ss := strings.Fields(string(s.Bytes()))
+		if len(ss) == 0 {
+			// Must break when reading a blank line after per-operation stats to
+			// enable top-level function to parse the next device entry
+			break
+		}
+
+		if len(ss) < minFields {
+			return nil, fmt.Errorf("invalid NFS per-operations stats: %v", ss)
+		}
+
+		// Skip string operation name for integers
+		ns := make([]uint64, 0, minFields-1)
+		for _, st := range ss[1:] {
+			n, err := strconv.ParseUint(st, 10, 64)
+			if err != nil {
+				return nil, err
+			}
+
+			ns = append(ns, n)
+		}
+
+		opStats := NFSOperationStats{
+			Operation:                           strings.TrimSuffix(ss[0], ":"),
+			Requests:                            ns[0],
+			Transmissions:                       ns[1],
+			MajorTimeouts:                       ns[2],
+			BytesSent:                           ns[3],
+			BytesReceived:                       ns[4],
+			CumulativeQueueMilliseconds:         ns[5],
+			CumulativeTotalResponseMilliseconds: ns[6],
+			CumulativeTotalRequestMilliseconds:  ns[7],
+		}
+
+		if len(ns) > 8 {
+			opStats.Errors = ns[8]
+		}
+
+		ops = append(ops, opStats)
+	}
+
+	return ops, s.Err()
+}
+
+// parseNFSTransportStats parses a NFSTransportStats line using an input set of
+// integer fields matched to a specific stats version.
+func parseNFSTransportStats(ss []string, statVersion string) (*NFSTransportStats, error) {
+	// Extract the protocol field. It is the only string value in the line
+	protocol := ss[0]
+	ss = ss[1:]
+
+	switch statVersion {
+	case statVersion10:
+		var expectedLength int
+		if protocol == "tcp" {
+			expectedLength = fieldTransport10TCPLen
+		} else if protocol == "udp" {
+			expectedLength = fieldTransport10UDPLen
+		} else {
+			return nil, fmt.Errorf("invalid NFS protocol \"%s\" in stats 1.0 statement: %v", protocol, ss)
+		}
+		if len(ss) != expectedLength {
+			return nil, fmt.Errorf("invalid NFS transport stats 1.0 statement: %v", ss)
+		}
+	case statVersion11:
+		var expectedLength int
+		if protocol == "tcp" {
+			expectedLength = fieldTransport11TCPLen
+		} else if protocol == "udp" {
+			expectedLength = fieldTransport11UDPLen
+		} else {
+			return nil, fmt.Errorf("invalid NFS protocol \"%s\" in stats 1.1 statement: %v", protocol, ss)
+		}
+		if len(ss) != expectedLength {
+			return nil, fmt.Errorf("invalid NFS transport stats 1.1 statement: %v", ss)
+		}
+	default:
+		return nil, fmt.Errorf("unrecognized NFS transport stats version: %q", statVersion)
+	}
+
+	// Allocate enough for v1.1 stats since zero value for v1.1 stats will be okay
+	// in a v1.0 response. Since the stat length is bigger for TCP stats, we use
+	// the TCP length here.
+	//
+	// Note: slice length must be set to length of v1.1 stats to avoid a panic when
+	// only v1.0 stats are present.
+	// See: https://github.com/prometheus/node_exporter/issues/571.
+	ns := make([]uint64, fieldTransport11TCPLen)
+	for i, s := range ss {
+		n, err := strconv.ParseUint(s, 10, 64)
+		if err != nil {
+			return nil, err
+		}
+
+		ns[i] = n
+	}
+
+	// The fields differ depending on the transport protocol (TCP or UDP)
+	// From https://utcc.utoronto.ca/%7Ecks/space/blog/linux/NFSMountstatsXprt
+	//
+	// For the udp RPC transport there is no connection count, connect idle time,
+	// or idle time (fields #3, #4, and #5); all other fields are the same. So
+	// we set them to 0 here.
+	if protocol == "udp" {
+		ns = append(ns[:2], append(make([]uint64, 3), ns[2:]...)...)
+	}
+
+	return &NFSTransportStats{
+		Protocol:                 protocol,
+		Port:                     ns[0],
+		Bind:                     ns[1],
+		Connect:                  ns[2],
+		ConnectIdleTime:          ns[3],
+		IdleTimeSeconds:          ns[4],
+		Sends:                    ns[5],
+		Receives:                 ns[6],
+		BadTransactionIDs:        ns[7],
+		CumulativeActiveRequests: ns[8],
+		CumulativeBacklog:        ns[9],
+		MaximumRPCSlotsUsed:      ns[10],
+		CumulativeSendingQueue:   ns[11],
+		CumulativePendingQueue:   ns[12],
+	}, nil
+}

vendor/github.com/prometheus/procfs/net_conntrackstat.go

@@ -0,0 +1,153 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// A ConntrackStatEntry represents one line from net/stat/nf_conntrack
+// and contains netfilter conntrack statistics at one CPU core
+type ConntrackStatEntry struct {
+	Entries       uint64
+	Found         uint64
+	Invalid       uint64
+	Ignore        uint64
+	Insert        uint64
+	InsertFailed  uint64
+	Drop          uint64
+	EarlyDrop     uint64
+	SearchRestart uint64
+}
+
+// ConntrackStat retrieves netfilter's conntrack statistics, split by CPU cores
+func (fs FS) ConntrackStat() ([]ConntrackStatEntry, error) {
+	return readConntrackStat(fs.proc.Path("net", "stat", "nf_conntrack"))
+}
+
+// Parses a slice of ConntrackStatEntries from the given filepath
+func readConntrackStat(path string) ([]ConntrackStatEntry, error) {
+	// This file is small and can be read with one syscall.
+	b, err := util.ReadFileNoStat(path)
+	if err != nil {
+		// Do not wrap this error so the caller can detect os.IsNotExist and
+		// similar conditions.
+		return nil, err
+	}
+
+	stat, err := parseConntrackStat(bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("failed to read conntrack stats from %q: %w", path, err)
+	}
+
+	return stat, nil
+}
+
+// Reads the contents of a conntrack statistics file and parses a slice of ConntrackStatEntries
+func parseConntrackStat(r io.Reader) ([]ConntrackStatEntry, error) {
+	var entries []ConntrackStatEntry
+
+	scanner := bufio.NewScanner(r)
+	scanner.Scan()
+	for scanner.Scan() {
+		fields := strings.Fields(scanner.Text())
+		conntrackEntry, err := parseConntrackStatEntry(fields)
+		if err != nil {
+			return nil, err
+		}
+		entries = append(entries, *conntrackEntry)
+	}
+
+	return entries, nil
+}
+
+// Parses a ConntrackStatEntry from given array of fields
+func parseConntrackStatEntry(fields []string) (*ConntrackStatEntry, error) {
+	if len(fields) != 17 {
+		return nil, fmt.Errorf("invalid conntrackstat entry, missing fields")
+	}
+	entry := &ConntrackStatEntry{}
+
+	entries, err := parseConntrackStatField(fields[0])
+	if err != nil {
+		return nil, err
+	}
+	entry.Entries = entries
+
+	found, err := parseConntrackStatField(fields[2])
+	if err != nil {
+		return nil, err
+	}
+	entry.Found = found
+
+	invalid, err := parseConntrackStatField(fields[4])
+	if err != nil {
+		return nil, err
+	}
+	entry.Invalid = invalid
+
+	ignore, err := parseConntrackStatField(fields[5])
+	if err != nil {
+		return nil, err
+	}
+	entry.Ignore = ignore
+
+	insert, err := parseConntrackStatField(fields[8])
+	if err != nil {
+		return nil, err
+	}
+	entry.Insert = insert
+
+	insertFailed, err := parseConntrackStatField(fields[9])
+	if err != nil {
+		return nil, err
+	}
+	entry.InsertFailed = insertFailed
+
+	drop, err := parseConntrackStatField(fields[10])
+	if err != nil {
+		return nil, err
+	}
+	entry.Drop = drop
+
+	earlyDrop, err := parseConntrackStatField(fields[11])
+	if err != nil {
+		return nil, err
+	}
+	entry.EarlyDrop = earlyDrop
+
+	searchRestart, err := parseConntrackStatField(fields[16])
+	if err != nil {
+		return nil, err
+	}
+	entry.SearchRestart = searchRestart
+
+	return entry, nil
+}
+
+// Parses a uint64 from given hex in string
+func parseConntrackStatField(field string) (uint64, error) {
+	val, err := strconv.ParseUint(field, 16, 64)
+	if err != nil {
+		return 0, fmt.Errorf("couldn't parse %q field: %w", field, err)
+	}
+	return val, err
+}

vendor/github.com/prometheus/procfs/net_dev.go

@@ -0,0 +1,205 @@
+// Copyright 2018 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"errors"
+	"os"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+// NetDevLine is single line parsed from /proc/net/dev or /proc/[pid]/net/dev.
+type NetDevLine struct {
+	Name         string `json:"name"`          // The name of the interface.
+	RxBytes      uint64 `json:"rx_bytes"`      // Cumulative count of bytes received.
+	RxPackets    uint64 `json:"rx_packets"`    // Cumulative count of packets received.
+	RxErrors     uint64 `json:"rx_errors"`     // Cumulative count of receive errors encountered.
+	RxDropped    uint64 `json:"rx_dropped"`    // Cumulative count of packets dropped while receiving.
+	RxFIFO       uint64 `json:"rx_fifo"`       // Cumulative count of FIFO buffer errors.
+	RxFrame      uint64 `json:"rx_frame"`      // Cumulative count of packet framing errors.
+	RxCompressed uint64 `json:"rx_compressed"` // Cumulative count of compressed packets received by the device driver.
+	RxMulticast  uint64 `json:"rx_multicast"`  // Cumulative count of multicast frames received by the device driver.
+	TxBytes      uint64 `json:"tx_bytes"`      // Cumulative count of bytes transmitted.
+	TxPackets    uint64 `json:"tx_packets"`    // Cumulative count of packets transmitted.
+	TxErrors     uint64 `json:"tx_errors"`     // Cumulative count of transmit errors encountered.
+	TxDropped    uint64 `json:"tx_dropped"`    // Cumulative count of packets dropped while transmitting.
+	TxFIFO       uint64 `json:"tx_fifo"`       // Cumulative count of FIFO buffer errors.
+	TxCollisions uint64 `json:"tx_collisions"` // Cumulative count of collisions detected on the interface.
+	TxCarrier    uint64 `json:"tx_carrier"`    // Cumulative count of carrier losses detected by the device driver.
+	TxCompressed uint64 `json:"tx_compressed"` // Cumulative count of compressed packets transmitted by the device driver.
+}
+
+// NetDev is parsed from /proc/net/dev or /proc/[pid]/net/dev. The map keys
+// are interface names.
+type NetDev map[string]NetDevLine
+
+// NetDev returns kernel/system statistics read from /proc/net/dev.
+func (fs FS) NetDev() (NetDev, error) {
+	return newNetDev(fs.proc.Path("net/dev"))
+}
+
+// NetDev returns kernel/system statistics read from /proc/[pid]/net/dev.
+func (p Proc) NetDev() (NetDev, error) {
+	return newNetDev(p.path("net/dev"))
+}
+
+// newNetDev creates a new NetDev from the contents of the given file.
+func newNetDev(file string) (NetDev, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return NetDev{}, err
+	}
+	defer f.Close()
+
+	netDev := NetDev{}
+	s := bufio.NewScanner(f)
+	for n := 0; s.Scan(); n++ {
+		// Skip the 2 header lines.
+		if n < 2 {
+			continue
+		}
+
+		line, err := netDev.parseLine(s.Text())
+		if err != nil {
+			return netDev, err
+		}
+
+		netDev[line.Name] = *line
+	}
+
+	return netDev, s.Err()
+}
+
+// parseLine parses a single line from the /proc/net/dev file. Header lines
+// must be filtered prior to calling this method.
+func (netDev NetDev) parseLine(rawLine string) (*NetDevLine, error) {
+	parts := strings.SplitN(rawLine, ":", 2)
+	if len(parts) != 2 {
+		return nil, errors.New("invalid net/dev line, missing colon")
+	}
+	fields := strings.Fields(strings.TrimSpace(parts[1]))
+
+	var err error
+	line := &NetDevLine{}
+
+	// Interface Name
+	line.Name = strings.TrimSpace(parts[0])
+	if line.Name == "" {
+		return nil, errors.New("invalid net/dev line, empty interface name")
+	}
+
+	// RX
+	line.RxBytes, err = strconv.ParseUint(fields[0], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxPackets, err = strconv.ParseUint(fields[1], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxErrors, err = strconv.ParseUint(fields[2], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxDropped, err = strconv.ParseUint(fields[3], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxFIFO, err = strconv.ParseUint(fields[4], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxFrame, err = strconv.ParseUint(fields[5], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxCompressed, err = strconv.ParseUint(fields[6], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.RxMulticast, err = strconv.ParseUint(fields[7], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+
+	// TX
+	line.TxBytes, err = strconv.ParseUint(fields[8], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxPackets, err = strconv.ParseUint(fields[9], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxErrors, err = strconv.ParseUint(fields[10], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxDropped, err = strconv.ParseUint(fields[11], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxFIFO, err = strconv.ParseUint(fields[12], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxCollisions, err = strconv.ParseUint(fields[13], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxCarrier, err = strconv.ParseUint(fields[14], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.TxCompressed, err = strconv.ParseUint(fields[15], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+
+	return line, nil
+}
+
+// Total aggregates the values across interfaces and returns a new NetDevLine.
+// The Name field will be a sorted comma separated list of interface names.
+func (netDev NetDev) Total() NetDevLine {
+	total := NetDevLine{}
+
+	names := make([]string, 0, len(netDev))
+	for _, ifc := range netDev {
+		names = append(names, ifc.Name)
+		total.RxBytes += ifc.RxBytes
+		total.RxPackets += ifc.RxPackets
+		total.RxErrors += ifc.RxErrors
+		total.RxDropped += ifc.RxDropped
+		total.RxFIFO += ifc.RxFIFO
+		total.RxFrame += ifc.RxFrame
+		total.RxCompressed += ifc.RxCompressed
+		total.RxMulticast += ifc.RxMulticast
+		total.TxBytes += ifc.TxBytes
+		total.TxPackets += ifc.TxPackets
+		total.TxErrors += ifc.TxErrors
+		total.TxDropped += ifc.TxDropped
+		total.TxFIFO += ifc.TxFIFO
+		total.TxCollisions += ifc.TxCollisions
+		total.TxCarrier += ifc.TxCarrier
+		total.TxCompressed += ifc.TxCompressed
+	}
+	sort.Strings(names)
+	total.Name = strings.Join(names, ", ")
+
+	return total
+}

vendor/github.com/prometheus/procfs/net_ip_socket.go

@@ -0,0 +1,226 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"encoding/hex"
+	"fmt"
+	"io"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const (
+	// readLimit is used by io.LimitReader while reading the content of the
+	// /proc/net/udp{,6} files. The number of lines inside such a file is dynamic
+	// as each line represents a single used socket.
+	// In theory, the number of available sockets is 65535 (2^16 - 1) per IP.
+	// With e.g. 150 Byte per line and the maximum number of 65535,
+	// the reader needs to handle 150 Byte * 65535 =~ 10 MB for a single IP.
+	readLimit = 4294967296 // Byte -> 4 GiB
+)
+
+// this contains generic data structures for both udp and tcp sockets
+type (
+	// NetIPSocket represents the contents of /proc/net/{t,u}dp{,6} file without the header.
+	NetIPSocket []*netIPSocketLine
+
+	// NetIPSocketSummary provides already computed values like the total queue lengths or
+	// the total number of used sockets. In contrast to NetIPSocket it does not collect
+	// the parsed lines into a slice.
+	NetIPSocketSummary struct {
+		// TxQueueLength shows the total queue length of all parsed tx_queue lengths.
+		TxQueueLength uint64
+		// RxQueueLength shows the total queue length of all parsed rx_queue lengths.
+		RxQueueLength uint64
+		// UsedSockets shows the total number of parsed lines representing the
+		// number of used sockets.
+		UsedSockets uint64
+	}
+
+	// netIPSocketLine represents the fields parsed from a single line
+	// in /proc/net/{t,u}dp{,6}. Fields which are not used by IPSocket are skipped.
+	// For the proc file format details, see https://linux.die.net/man/5/proc.
+	netIPSocketLine struct {
+		Sl        uint64
+		LocalAddr net.IP
+		LocalPort uint64
+		RemAddr   net.IP
+		RemPort   uint64
+		St        uint64
+		TxQueue   uint64
+		RxQueue   uint64
+		UID       uint64
+		Inode     uint64
+	}
+)
+
+func newNetIPSocket(file string) (NetIPSocket, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	var netIPSocket NetIPSocket
+
+	lr := io.LimitReader(f, readLimit)
+	s := bufio.NewScanner(lr)
+	s.Scan() // skip first line with headers
+	for s.Scan() {
+		fields := strings.Fields(s.Text())
+		line, err := parseNetIPSocketLine(fields)
+		if err != nil {
+			return nil, err
+		}
+		netIPSocket = append(netIPSocket, line)
+	}
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+	return netIPSocket, nil
+}
+
+// newNetIPSocketSummary creates a new NetIPSocket{,6} from the contents of the given file.
+func newNetIPSocketSummary(file string) (*NetIPSocketSummary, error) {
+	f, err := os.Open(file)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	var netIPSocketSummary NetIPSocketSummary
+
+	lr := io.LimitReader(f, readLimit)
+	s := bufio.NewScanner(lr)
+	s.Scan() // skip first line with headers
+	for s.Scan() {
+		fields := strings.Fields(s.Text())
+		line, err := parseNetIPSocketLine(fields)
+		if err != nil {
+			return nil, err
+		}
+		netIPSocketSummary.TxQueueLength += line.TxQueue
+		netIPSocketSummary.RxQueueLength += line.RxQueue
+		netIPSocketSummary.UsedSockets++
+	}
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+	return &netIPSocketSummary, nil
+}
+
+// the /proc/net/{t,u}dp{,6} files are network byte order for ipv4 and for ipv6 the address is four words consisting of four bytes each. In each of those four words the four bytes are written in reverse order.
+
+func parseIP(hexIP string) (net.IP, error) {
+	var byteIP []byte
+	byteIP, err := hex.DecodeString(hexIP)
+	if err != nil {
+		return nil, fmt.Errorf("cannot parse address field in socket line %q", hexIP)
+	}
+	switch len(byteIP) {
+	case 4:
+		return net.IP{byteIP[3], byteIP[2], byteIP[1], byteIP[0]}, nil
+	case 16:
+		i := net.IP{
+			byteIP[3], byteIP[2], byteIP[1], byteIP[0],
+			byteIP[7], byteIP[6], byteIP[5], byteIP[4],
+			byteIP[11], byteIP[10], byteIP[9], byteIP[8],
+			byteIP[15], byteIP[14], byteIP[13], byteIP[12],
+		}
+		return i, nil
+	default:
+		return nil, fmt.Errorf("Unable to parse IP %s", hexIP)
+	}
+}
+
+// parseNetIPSocketLine parses a single line, represented by a list of fields.
+func parseNetIPSocketLine(fields []string) (*netIPSocketLine, error) {
+	line := &netIPSocketLine{}
+	if len(fields) < 10 {
+		return nil, fmt.Errorf(
+			"cannot parse net socket line as it has less then 10 columns %q",
+			strings.Join(fields, " "),
+		)
+	}
+	var err error // parse error
+
+	// sl
+	s := strings.Split(fields[0], ":")
+	if len(s) != 2 {
+		return nil, fmt.Errorf("cannot parse sl field in socket line %q", fields[0])
+	}
+
+	if line.Sl, err = strconv.ParseUint(s[0], 0, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse sl value in socket line: %w", err)
+	}
+	// local_address
+	l := strings.Split(fields[1], ":")
+	if len(l) != 2 {
+		return nil, fmt.Errorf("cannot parse local_address field in socket line %q", fields[1])
+	}
+	if line.LocalAddr, err = parseIP(l[0]); err != nil {
+		return nil, err
+	}
+	if line.LocalPort, err = strconv.ParseUint(l[1], 16, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse local_address port value in socket line: %w", err)
+	}
+
+	// remote_address
+	r := strings.Split(fields[2], ":")
+	if len(r) != 2 {
+		return nil, fmt.Errorf("cannot parse rem_address field in socket line %q", fields[1])
+	}
+	if line.RemAddr, err = parseIP(r[0]); err != nil {
+		return nil, err
+	}
+	if line.RemPort, err = strconv.ParseUint(r[1], 16, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse rem_address port value in socket line: %w", err)
+	}
+
+	// st
+	if line.St, err = strconv.ParseUint(fields[3], 16, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse st value in socket line: %w", err)
+	}
+
+	// tx_queue and rx_queue
+	q := strings.Split(fields[4], ":")
+	if len(q) != 2 {
+		return nil, fmt.Errorf(
+			"cannot parse tx/rx queues in socket line as it has a missing colon %q",
+			fields[4],
+		)
+	}
+	if line.TxQueue, err = strconv.ParseUint(q[0], 16, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse tx_queue value in socket line: %w", err)
+	}
+	if line.RxQueue, err = strconv.ParseUint(q[1], 16, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse rx_queue value in socket line: %w", err)
+	}
+
+	// uid
+	if line.UID, err = strconv.ParseUint(fields[7], 0, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse uid value in socket line: %w", err)
+	}
+
+	// inode
+	if line.Inode, err = strconv.ParseUint(fields[9], 0, 64); err != nil {
+		return nil, fmt.Errorf("cannot parse inode value in socket line: %w", err)
+	}
+
+	return line, nil
+}

vendor/github.com/prometheus/procfs/net_protocols.go

@@ -0,0 +1,180 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// NetProtocolStats stores the contents from /proc/net/protocols
+type NetProtocolStats map[string]NetProtocolStatLine
+
+// NetProtocolStatLine contains a single line parsed from /proc/net/protocols. We
+// only care about the first six columns as the rest are not likely to change
+// and only serve to provide a set of capabilities for each protocol.
+type NetProtocolStatLine struct {
+	Name         string // 0 The name of the protocol
+	Size         uint64 // 1 The size, in bytes, of a given protocol structure. e.g. sizeof(struct tcp_sock) or sizeof(struct unix_sock)
+	Sockets      int64  // 2 Number of sockets in use by this protocol
+	Memory       int64  // 3 Number of 4KB pages allocated by all sockets of this protocol
+	Pressure     int    // 4 This is either yes, no, or NI (not implemented). For the sake of simplicity we treat NI as not experiencing memory pressure.
+	MaxHeader    uint64 // 5 Protocol specific max header size
+	Slab         bool   // 6 Indicates whether or not memory is allocated from the SLAB
+	ModuleName   string // 7 The name of the module that implemented this protocol or "kernel" if not from a module
+	Capabilities NetProtocolCapabilities
+}
+
+// NetProtocolCapabilities contains a list of capabilities for each protocol
+type NetProtocolCapabilities struct {
+	Close               bool // 8
+	Connect             bool // 9
+	Disconnect          bool // 10
+	Accept              bool // 11
+	IoCtl               bool // 12
+	Init                bool // 13
+	Destroy             bool // 14
+	Shutdown            bool // 15
+	SetSockOpt          bool // 16
+	GetSockOpt          bool // 17
+	SendMsg             bool // 18
+	RecvMsg             bool // 19
+	SendPage            bool // 20
+	Bind                bool // 21
+	BacklogRcv          bool // 22
+	Hash                bool // 23
+	UnHash              bool // 24
+	GetPort             bool // 25
+	EnterMemoryPressure bool // 26
+}
+
+// NetProtocols reads stats from /proc/net/protocols and returns a map of
+// PortocolStatLine entries. As of this writing no official Linux Documentation
+// exists, however the source is fairly self-explanatory and the format seems
+// stable since its introduction in 2.6.12-rc2
+// Linux 2.6.12-rc2 - https://elixir.bootlin.com/linux/v2.6.12-rc2/source/net/core/sock.c#L1452
+// Linux 5.10 - https://elixir.bootlin.com/linux/v5.10.4/source/net/core/sock.c#L3586
+func (fs FS) NetProtocols() (NetProtocolStats, error) {
+	data, err := util.ReadFileNoStat(fs.proc.Path("net/protocols"))
+	if err != nil {
+		return NetProtocolStats{}, err
+	}
+	return parseNetProtocols(bufio.NewScanner(bytes.NewReader(data)))
+}
+
+func parseNetProtocols(s *bufio.Scanner) (NetProtocolStats, error) {
+	nps := NetProtocolStats{}
+
+	// Skip the header line
+	s.Scan()
+
+	for s.Scan() {
+		line, err := nps.parseLine(s.Text())
+		if err != nil {
+			return NetProtocolStats{}, err
+		}
+
+		nps[line.Name] = *line
+	}
+	return nps, nil
+}
+
+func (ps NetProtocolStats) parseLine(rawLine string) (*NetProtocolStatLine, error) {
+	line := &NetProtocolStatLine{Capabilities: NetProtocolCapabilities{}}
+	var err error
+	const enabled = "yes"
+	const disabled = "no"
+
+	fields := strings.Fields(rawLine)
+	line.Name = fields[0]
+	line.Size, err = strconv.ParseUint(fields[1], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.Sockets, err = strconv.ParseInt(fields[2], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	line.Memory, err = strconv.ParseInt(fields[3], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	if fields[4] == enabled {
+		line.Pressure = 1
+	} else if fields[4] == disabled {
+		line.Pressure = 0
+	} else {
+		line.Pressure = -1
+	}
+	line.MaxHeader, err = strconv.ParseUint(fields[5], 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	if fields[6] == enabled {
+		line.Slab = true
+	} else if fields[6] == disabled {
+		line.Slab = false
+	} else {
+		return nil, fmt.Errorf("unable to parse capability for protocol: %s", line.Name)
+	}
+	line.ModuleName = fields[7]
+
+	err = line.Capabilities.parseCapabilities(fields[8:])
+	if err != nil {
+		return nil, err
+	}
+
+	return line, nil
+}
+
+func (pc *NetProtocolCapabilities) parseCapabilities(capabilities []string) error {
+	// The capabilities are all bools so we can loop over to map them
+	capabilityFields := [...]*bool{
+		&pc.Close,
+		&pc.Connect,
+		&pc.Disconnect,
+		&pc.Accept,
+		&pc.IoCtl,
+		&pc.Init,
+		&pc.Destroy,
+		&pc.Shutdown,
+		&pc.SetSockOpt,
+		&pc.GetSockOpt,
+		&pc.SendMsg,
+		&pc.RecvMsg,
+		&pc.SendPage,
+		&pc.Bind,
+		&pc.BacklogRcv,
+		&pc.Hash,
+		&pc.UnHash,
+		&pc.GetPort,
+		&pc.EnterMemoryPressure,
+	}
+
+	for i := 0; i < len(capabilities); i++ {
+		if capabilities[i] == "y" {
+			*capabilityFields[i] = true
+		} else if capabilities[i] == "n" {
+			*capabilityFields[i] = false
+		} else {
+			return fmt.Errorf("unable to parse capability block for protocol: position %d", i)
+		}
+	}
+	return nil
+}

vendor/github.com/prometheus/procfs/net_sockstat.go

@@ -0,0 +1,163 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// A NetSockstat contains the output of /proc/net/sockstat{,6} for IPv4 or IPv6,
+// respectively.
+type NetSockstat struct {
+	// Used is non-nil for IPv4 sockstat results, but nil for IPv6.
+	Used      *int
+	Protocols []NetSockstatProtocol
+}
+
+// A NetSockstatProtocol contains statistics about a given socket protocol.
+// Pointer fields indicate that the value may or may not be present on any
+// given protocol.
+type NetSockstatProtocol struct {
+	Protocol string
+	InUse    int
+	Orphan   *int
+	TW       *int
+	Alloc    *int
+	Mem      *int
+	Memory   *int
+}
+
+// NetSockstat retrieves IPv4 socket statistics.
+func (fs FS) NetSockstat() (*NetSockstat, error) {
+	return readSockstat(fs.proc.Path("net", "sockstat"))
+}
+
+// NetSockstat6 retrieves IPv6 socket statistics.
+//
+// If IPv6 is disabled on this kernel, the returned error can be checked with
+// os.IsNotExist.
+func (fs FS) NetSockstat6() (*NetSockstat, error) {
+	return readSockstat(fs.proc.Path("net", "sockstat6"))
+}
+
+// readSockstat opens and parses a NetSockstat from the input file.
+func readSockstat(name string) (*NetSockstat, error) {
+	// This file is small and can be read with one syscall.
+	b, err := util.ReadFileNoStat(name)
+	if err != nil {
+		// Do not wrap this error so the caller can detect os.IsNotExist and
+		// similar conditions.
+		return nil, err
+	}
+
+	stat, err := parseSockstat(bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("failed to read sockstats from %q: %w", name, err)
+	}
+
+	return stat, nil
+}
+
+// parseSockstat reads the contents of a sockstat file and parses a NetSockstat.
+func parseSockstat(r io.Reader) (*NetSockstat, error) {
+	var stat NetSockstat
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		// Expect a minimum of a protocol and one key/value pair.
+		fields := strings.Split(s.Text(), " ")
+		if len(fields) < 3 {
+			return nil, fmt.Errorf("malformed sockstat line: %q", s.Text())
+		}
+
+		// The remaining fields are key/value pairs.
+		kvs, err := parseSockstatKVs(fields[1:])
+		if err != nil {
+			return nil, fmt.Errorf("error parsing sockstat key/value pairs from %q: %w", s.Text(), err)
+		}
+
+		// The first field is the protocol. We must trim its colon suffix.
+		proto := strings.TrimSuffix(fields[0], ":")
+		switch proto {
+		case "sockets":
+			// Special case: IPv4 has a sockets "used" key/value pair that we
+			// embed at the top level of the structure.
+			used := kvs["used"]
+			stat.Used = &used
+		default:
+			// Parse all other lines as individual protocols.
+			nsp := parseSockstatProtocol(kvs)
+			nsp.Protocol = proto
+			stat.Protocols = append(stat.Protocols, nsp)
+		}
+	}
+
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+
+	return &stat, nil
+}
+
+// parseSockstatKVs parses a string slice into a map of key/value pairs.
+func parseSockstatKVs(kvs []string) (map[string]int, error) {
+	if len(kvs)%2 != 0 {
+		return nil, errors.New("odd number of fields in key/value pairs")
+	}
+
+	// Iterate two values at a time to gather key/value pairs.
+	out := make(map[string]int, len(kvs)/2)
+	for i := 0; i < len(kvs); i += 2 {
+		vp := util.NewValueParser(kvs[i+1])
+		out[kvs[i]] = vp.Int()
+
+		if err := vp.Err(); err != nil {
+			return nil, err
+		}
+	}
+
+	return out, nil
+}
+
+// parseSockstatProtocol parses a NetSockstatProtocol from the input kvs map.
+func parseSockstatProtocol(kvs map[string]int) NetSockstatProtocol {
+	var nsp NetSockstatProtocol
+	for k, v := range kvs {
+		// Capture the range variable to ensure we get unique pointers for
+		// each of the optional fields.
+		v := v
+		switch k {
+		case "inuse":
+			nsp.InUse = v
+		case "orphan":
+			nsp.Orphan = &v
+		case "tw":
+			nsp.TW = &v
+		case "alloc":
+			nsp.Alloc = &v
+		case "mem":
+			nsp.Mem = &v
+		case "memory":
+			nsp.Memory = &v
+		}
+	}
+
+	return nsp
+}

vendor/github.com/prometheus/procfs/net_softnet.go

@@ -0,0 +1,102 @@
+// Copyright 2019 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// For the proc file format details,
+// See:
+// * Linux 2.6.23 https://elixir.bootlin.com/linux/v2.6.23/source/net/core/dev.c#L2343
+// * Linux 4.17 https://elixir.bootlin.com/linux/v4.17/source/net/core/net-procfs.c#L162
+// and https://elixir.bootlin.com/linux/v4.17/source/include/linux/netdevice.h#L2810.
+
+// SoftnetStat contains a single row of data from /proc/net/softnet_stat
+type SoftnetStat struct {
+	// Number of processed packets
+	Processed uint32
+	// Number of dropped packets
+	Dropped uint32
+	// Number of times processing packets ran out of quota
+	TimeSqueezed uint32
+}
+
+var softNetProcFile = "net/softnet_stat"
+
+// NetSoftnetStat reads data from /proc/net/softnet_stat.
+func (fs FS) NetSoftnetStat() ([]SoftnetStat, error) {
+	b, err := util.ReadFileNoStat(fs.proc.Path(softNetProcFile))
+	if err != nil {
+		return nil, err
+	}
+
+	entries, err := parseSoftnet(bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse /proc/net/softnet_stat: %w", err)
+	}
+
+	return entries, nil
+}
+
+func parseSoftnet(r io.Reader) ([]SoftnetStat, error) {
+	const minColumns = 9
+
+	s := bufio.NewScanner(r)
+
+	var stats []SoftnetStat
+	for s.Scan() {
+		columns := strings.Fields(s.Text())
+		width := len(columns)
+
+		if width < minColumns {
+			return nil, fmt.Errorf("%d columns were detected, but at least %d were expected", width, minColumns)
+		}
+
+		// We only parse the first three columns at the moment.
+		us, err := parseHexUint32s(columns[0:3])
+		if err != nil {
+			return nil, err
+		}
+
+		stats = append(stats, SoftnetStat{
+			Processed:    us[0],
+			Dropped:      us[1],
+			TimeSqueezed: us[2],
+		})
+	}
+
+	return stats, nil
+}
+
+func parseHexUint32s(ss []string) ([]uint32, error) {
+	us := make([]uint32, 0, len(ss))
+	for _, s := range ss {
+		u, err := strconv.ParseUint(s, 16, 32)
+		if err != nil {
+			return nil, err
+		}
+
+		us = append(us, uint32(u))
+	}
+
+	return us, nil
+}

vendor/github.com/prometheus/procfs/net_tcp.go

@@ -0,0 +1,64 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+type (
+	// NetTCP represents the contents of /proc/net/tcp{,6} file without the header.
+	NetTCP []*netIPSocketLine
+
+	// NetTCPSummary provides already computed values like the total queue lengths or
+	// the total number of used sockets. In contrast to NetTCP it does not collect
+	// the parsed lines into a slice.
+	NetTCPSummary NetIPSocketSummary
+)
+
+// NetTCP returns the IPv4 kernel/networking statistics for TCP datagrams
+// read from /proc/net/tcp.
+func (fs FS) NetTCP() (NetTCP, error) {
+	return newNetTCP(fs.proc.Path("net/tcp"))
+}
+
+// NetTCP6 returns the IPv6 kernel/networking statistics for TCP datagrams
+// read from /proc/net/tcp6.
+func (fs FS) NetTCP6() (NetTCP, error) {
+	return newNetTCP(fs.proc.Path("net/tcp6"))
+}
+
+// NetTCPSummary returns already computed statistics like the total queue lengths
+// for TCP datagrams read from /proc/net/tcp.
+func (fs FS) NetTCPSummary() (*NetTCPSummary, error) {
+	return newNetTCPSummary(fs.proc.Path("net/tcp"))
+}
+
+// NetTCP6Summary returns already computed statistics like the total queue lengths
+// for TCP datagrams read from /proc/net/tcp6.
+func (fs FS) NetTCP6Summary() (*NetTCPSummary, error) {
+	return newNetTCPSummary(fs.proc.Path("net/tcp6"))
+}
+
+// newNetTCP creates a new NetTCP{,6} from the contents of the given file.
+func newNetTCP(file string) (NetTCP, error) {
+	n, err := newNetIPSocket(file)
+	n1 := NetTCP(n)
+	return n1, err
+}
+
+func newNetTCPSummary(file string) (*NetTCPSummary, error) {
+	n, err := newNetIPSocketSummary(file)
+	if n == nil {
+		return nil, err
+	}
+	n1 := NetTCPSummary(*n)
+	return &n1, err
+}

vendor/github.com/prometheus/procfs/net_udp.go

@@ -0,0 +1,64 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+type (
+	// NetUDP represents the contents of /proc/net/udp{,6} file without the header.
+	NetUDP []*netIPSocketLine
+
+	// NetUDPSummary provides already computed values like the total queue lengths or
+	// the total number of used sockets. In contrast to NetUDP it does not collect
+	// the parsed lines into a slice.
+	NetUDPSummary NetIPSocketSummary
+)
+
+// NetUDP returns the IPv4 kernel/networking statistics for UDP datagrams
+// read from /proc/net/udp.
+func (fs FS) NetUDP() (NetUDP, error) {
+	return newNetUDP(fs.proc.Path("net/udp"))
+}
+
+// NetUDP6 returns the IPv6 kernel/networking statistics for UDP datagrams
+// read from /proc/net/udp6.
+func (fs FS) NetUDP6() (NetUDP, error) {
+	return newNetUDP(fs.proc.Path("net/udp6"))
+}
+
+// NetUDPSummary returns already computed statistics like the total queue lengths
+// for UDP datagrams read from /proc/net/udp.
+func (fs FS) NetUDPSummary() (*NetUDPSummary, error) {
+	return newNetUDPSummary(fs.proc.Path("net/udp"))
+}
+
+// NetUDP6Summary returns already computed statistics like the total queue lengths
+// for UDP datagrams read from /proc/net/udp6.
+func (fs FS) NetUDP6Summary() (*NetUDPSummary, error) {
+	return newNetUDPSummary(fs.proc.Path("net/udp6"))
+}
+
+// newNetUDP creates a new NetUDP{,6} from the contents of the given file.
+func newNetUDP(file string) (NetUDP, error) {
+	n, err := newNetIPSocket(file)
+	n1 := NetUDP(n)
+	return n1, err
+}
+
+func newNetUDPSummary(file string) (*NetUDPSummary, error) {
+	n, err := newNetIPSocketSummary(file)
+	if n == nil {
+		return nil, err
+	}
+	n1 := NetUDPSummary(*n)
+	return &n1, err
+}