init

.drone.yml

@@ -0,0 +1,19 @@
+workspace:
+  base: /go
+  path: src/github.com/umputun/remark
+
+pipeline:
+  
+  build:
+    image: golang:1.9-alpine
+    commands:
+      - apk add --no-cache --update tzdata && cp /usr/share/zoneinfo/America/Chicago /etc/localtime 
+      - cd app
+      - go get -v ./...
+      - go test -v ./...
+      
+  docker:
+    image: plugins/docker
+    repo: umputun/remark
+    secrets: [ docker_username, docker_password ]
+    tags: ${DRONE_REPO_BRANCH}

.gitignore

@@ -1,14 +1,5 @@
-# Binaries for programs and plugins
-*.exe
-*.dll
-*.so
-*.dylib
-
-# Test binary, build with `go test -c`
-*.test
-
-# Output of the go coverage tool, specifically when used with LiteIDE
-*.out
-
-# Project-local glide cache, RE: https://github.com/Masterminds/glide/issues/736
-.glide/
+*.cov
+.cover
+target
+/logs/
+/target/

Dockerfile

@@ -0,0 +1,32 @@
+FROM umputun/baseimage:buildgo-latest as build
+
+ADD . /go/src/github.com/umputun/remark
+WORKDIR /go/src/github.com/umputun/remark
+
+RUN cd app && go test -v $(go list -e ./... | grep -v vendor)
+
+RUN gometalinter --disable-all --deadline=300s --vendor --enable=vet --enable=vetshadow --enable=golint \
+    --enable=staticcheck --enable=ineffassign --enable=goconst --enable=errcheck --enable=unconvert \
+    --enable=deadcode  --enable=gosimple --enable=gas -tests ./...
+
+RUN /script/checkvendor.sh
+RUN mkdir -p target && /script/coverage.sh
+
+RUN go build -o remark -ldflags "-X main.revision=$(git rev-parse --abbrev-ref HEAD)-$(git describe --abbrev=7 --always --tags)-$(date +%Y%m%d-%H:%M:%S)" ./app
+
+# Run
+FROM umputun/baseimage:micro-latest
+
+RUN apk add --update ca-certificates && update-ca-certificates
+
+COPY --from=build /go/src/github.com/umputun/remark/remark /srv/
+
+RUN chown -R umputun:umputun /srv
+
+USER umputun
+
+WORKDIR /srv
+EXPOSE 8080
+
+CMD ["/srv/remark"]
+ENTRYPOINT ["/init.sh"]

README.md

@@ -1,2 +1,9 @@
 # remark
-comment engine
+
+description
+
+## API
+
+## command line parameters
+
+## configuration

app/main.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/hashicorp/logutils"
+	"github.com/jessevdk/go-flags"
+
+	"github.com/umputun/remark/app/rest"
+)
+
+var opts struct {
+	Mongo       []string `short:"m" long:"mongo" env:"MONGO" default:"mongo" description:"mongo host:port" env-delim:","`
+	MongoPasswd string   `short:"p" long:"mongo-password" env:"MONGO_PASSWD" default:"" description:"mongo password"`
+	MongoDelay  int      `long:"mongo-delay" env:"MONGO_DELAY" default:"0" description:"mongo initial delay"`
+
+	Dbg bool `long:"dbg" env:"DEBUG" description:"debug mode"`
+}
+
+var revision = "unknown"
+
+func main() {
+	fmt.Printf("remark %s\n", revision)
+	if _, err := flags.Parse(&opts); err != nil {
+		log.Fatal(err)
+	}
+	setupLog(opts.Dbg)
+	log.Print("[INFO] started remark")
+
+	srv := rest.Server{
+		Version: revision,
+	}
+	srv.Run()
+}
+
+func setupLog(dbg bool) {
+	filter := &logutils.LevelFilter{
+		Levels:   []logutils.LogLevel{"DEBUG", "INFO", "WARN", "ERROR"},
+		MinLevel: logutils.LogLevel("INFO"),
+		Writer:   os.Stdout,
+	}
+
+	log.SetFlags(log.Ldate | log.Ltime)
+
+	if dbg {
+		log.SetFlags(log.Ldate | log.Ltime | log.Lmicroseconds | log.Lshortfile)
+		filter.MinLevel = logutils.LogLevel("DEBUG")
+	}
+	log.SetOutput(filter)
+}

app/rest/middleware.go

@@ -0,0 +1,104 @@
+package rest
+
+import (
+	"log"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/didip/tollbooth"
+	"github.com/go-chi/render"
+)
+
+var org = "Umputun"
+
+// JSON is a map alias, just for convenience
+type JSON map[string]interface{}
+
+// Limiter middleware defines max recs/sec for given client. Client detected as a combination
+// of source IP, auth key and user agent.  Requests rejected with 429 status code.
+func Limiter(recSec int, excludeIps ...string) func(http.Handler) http.Handler {
+
+	return func(h http.Handler) http.Handler {
+		l := tollbooth.NewLimiter(int64(recSec), time.Second)
+
+		fn := func(w http.ResponseWriter, r *http.Request) {
+
+			for _, exclIP := range excludeIps {
+				if strings.HasPrefix(r.RemoteAddr, exclIP) {
+					h.ServeHTTP(w, r)
+					return
+				}
+			}
+
+			keys := []string{
+				r.Header.Get("Authorization"),
+				r.Header.Get("X-Forwarded-For"),
+				r.Header.Get("X-Real-IP"),
+				r.Header.Get("RemoteAddr"),
+				r.Header.Get("User-Agent"),
+			}
+
+			if httpError := tollbooth.LimitByKeys(l, keys); httpError != nil {
+				render.Status(r, httpError.StatusCode)
+				render.JSON(w, r, JSON{"error": httpError.Message})
+				return
+			}
+			h.ServeHTTP(w, r)
+		}
+		return http.HandlerFunc(fn)
+	}
+}
+
+// AppInfo adds custom app-info to header
+func AppInfo(app string, version string) func(http.Handler) http.Handler {
+	f := func(h http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			w.Header().Set("Org", org)
+			w.Header().Set("App-Name", app)
+			w.Header().Set("App-Version", version)
+			if mhost := os.Getenv("MHOST"); mhost != "" {
+				w.Header().Set("Host", mhost)
+			}
+			h.ServeHTTP(w, r)
+		}
+		return http.HandlerFunc(fn)
+	}
+	return f
+}
+
+// Ping middleware response with pong. Stops chain if ping request detected
+func Ping(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+
+		if r.Method == "GET" && strings.HasSuffix(strings.ToLower(r.URL.Path), "/ping") {
+			w.Header().Set("Content-Type", "text/plain")
+			w.WriteHeader(http.StatusOK)
+			if _, err := w.Write([]byte("pong")); err != nil {
+				log.Printf("[WARN] can't send pong, %s", err)
+			}
+			return
+		}
+		next.ServeHTTP(w, r)
+	}
+	return http.HandlerFunc(fn)
+}
+
+// Recoverer is a middleware that recovers from panics, logs the panic and returns a HTTP 500 status if possible.
+func Recoverer(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		defer func() {
+			if rvr := recover(); rvr != nil {
+
+				log.Printf("[ERROR] request panic, %v", rvr)
+
+				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+			}
+		}()
+
+		next.ServeHTTP(w, r)
+	}
+
+	return http.HandlerFunc(fn)
+}

app/rest/server.go

@@ -0,0 +1,41 @@
+package rest
+
+import (
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/go-chi/chi"
+	"github.com/go-chi/chi/middleware"
+	"github.com/go-chi/render"
+)
+
+// Server is a rest access server
+type Server struct {
+	Version string
+}
+
+// Run the lister and request's router, activate rest server
+func (s *Server) Run() {
+	log.Print("[INFO] activate rest server")
+	router := chi.NewRouter()
+	router.Use(middleware.RealIP, Recoverer)
+	router.Use(middleware.Throttle(100), middleware.Timeout(60*time.Second))
+	router.Use(Limiter(10), AppInfo("remark", s.Version), Ping)
+
+	router.Route("/blah", func(r chi.Router) {
+		r.Get("/{id}", s.getBlahCtrl)
+	})
+
+	log.Fatal(http.ListenAndServe(":8080", router))
+}
+
+// GET /blah/:id?foo=bar
+func (s *Server) getBlahCtrl(w http.ResponseWriter, r *http.Request) {
+	id := chi.URLParam(r, "id")
+	foo := r.URL.Query().Get("foo")
+	log.Printf("[INFO] request for id=%s, foo=%s", id, foo)
+
+	render.Status(r, http.StatusAccepted)
+	render.JSON(w, r, JSON{"data": "something"})
+}

app/store/bolt.go

@@ -0,0 +1,199 @@
+package store
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/boltdb/bolt"
+	"github.com/pkg/errors"
+)
+
+// BoltDB implements store.Interface. Each instance represents one site.
+// Keys built as pid-id. Each url (post) makes it's own bucket
+// In addition there is a bucket "last" with reference to other buckets+keys to all cross-posts last comment extraction.
+// Thread safe.
+type BoltDB struct {
+	*bolt.DB
+}
+
+var lastBucketName = "last"
+
+// NewBoltDB makes persistent boltdb-based store
+func NewBoltDB(dbFile string) (*BoltDB, error) {
+	log.Printf("[INFO] bolt store, %s", dbFile)
+	result := BoltDB{}
+	db, err := bolt.Open(dbFile, 0600, &bolt.Options{Timeout: 1 * time.Second})
+	if err != nil {
+		return nil, err
+	}
+	result.DB = db
+	return &result, err
+}
+
+// Create saves new comment to store
+func (b *BoltDB) Create(comment Comment) error {
+
+	comment.ID = time.Now().UnixNano()
+
+	return b.Update(func(tx *bolt.Tx) error {
+		bucket, e := tx.CreateBucketIfNotExists([]byte(comment.Locator.URL))
+		if e != nil {
+			return errors.Wrapf(e, "can't make bucket", comment.Locator.URL)
+		}
+
+		// check if key already in store, reject doubles
+		key := b.keyFromComment(comment)
+		if bucket.Get(key) != nil {
+			return errors.Errorf("key %s already in store", string(key))
+		}
+
+		// serialise comment to json's []byte for bolt and save
+		jdata, jerr := json.Marshal(&comment)
+		if jerr != nil {
+			return errors.Wrap(jerr, "can't marshal comment")
+		}
+
+		if err := bucket.Put(key, jdata); err != nil {
+			return errors.Wrapf(err, "failed to put key %s", string(key))
+		}
+
+		// add reference to comment to "last" bucket
+		bucket, e = tx.CreateBucketIfNotExists([]byte(lastBucketName))
+		if e != nil {
+			return errors.Wrapf(e, "can't make bucket %s", lastBucketName)
+		}
+
+		rv := refFromComment(comment)
+		e = bucket.Put([]byte(fmt.Sprintf("%d", time.Now().UnixNano())), []byte(rv.value()))
+		if e != nil {
+			return errors.Wrapf(e, "can't put reference %s to %s", rv.value(), lastBucketName)
+		}
+
+		return nil
+	})
+}
+
+// Delete removed comment by url and id from the store
+func (b *BoltDB) Delete(url string, id int64) error {
+
+	return b.Update(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket([]byte(url))
+		if bucket == nil {
+			return errors.Errorf("no bucket %s in store", url)
+		}
+		key := []byte(fmt.Sprintf("%12d", id))
+		if err := bucket.Delete(key); err != nil {
+			errors.Wrapf(err, "can't delete key %s from bucket %s", key, url)
+		}
+		return nil
+	})
+}
+
+// Find comments for post
+func (b *BoltDB) Find(request Request) ([]Comment, error) {
+	res := []Comment{}
+
+	err := b.View(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket([]byte(request.Locator.URL))
+		if bucket == nil {
+			return errors.Errorf("no bucket %s in store", request.Locator.URL)
+		}
+
+		return bucket.ForEach(func(k, v []byte) error {
+			comment := Comment{}
+			if e := json.Unmarshal(v, &comment); e != nil {
+				return errors.Wrap(e, "failed to unmarshal")
+			}
+			res = append(res, comment)
+			return nil
+		})
+	})
+
+	return res, err
+}
+
+// Last returns up to max last comments for given locator
+func (b *BoltDB) Last(locator Locator, max int) (result []Comment, err error) {
+
+	err = b.View(func(tx *bolt.Tx) error {
+		lastBk := tx.Bucket([]byte(lastBucketName))
+		if lastBk == nil {
+			return errors.Errorf("no bucket %s in store", lastBucketName)
+		}
+
+		c := lastBk.Cursor()
+		for k, v := c.Last(); k != nil; k, v = c.Prev() {
+			url, id, err := refFromValue(v).parse()
+			if err != nil {
+				return err
+			}
+			urlBk := tx.Bucket([]byte(url))
+			if urlBk == nil {
+				return errors.Errorf("no bucket %s in store", url)
+			}
+			commentVal := urlBk.Get(b.keyFromValue(id))
+			if commentVal == nil {
+				return errors.Errorf("no comment for %d in store %s", id, url)
+			}
+
+			comment := Comment{}
+			if e := json.Unmarshal(commentVal, &comment); e != nil {
+				return errors.Wrap(e, "failed to unmarshal")
+			}
+			result = append(result, comment)
+		}
+		return nil
+	})
+
+	return result, err
+}
+
+func (b *BoltDB) keyFromComment(comment Comment) []byte {
+	return []byte(fmt.Sprintf("%12d", comment.ID))
+}
+
+func (b *BoltDB) keyFromValue(id int64) []byte {
+	return []byte(fmt.Sprintf("%12d", id))
+}
+
+// buckets returns list of buckets, which is list of all commented posts
+func (b BoltDB) buckets() (result []string) {
+
+	b.View(func(tx *bolt.Tx) error {
+		return tx.ForEach(func(name []byte, _ *bolt.Bucket) error {
+			result = append(result, string(name))
+			return nil
+		})
+	})
+	return result
+}
+
+type ref string
+
+func refFromComment(comment Comment) *ref {
+	result := ref(fmt.Sprintf("%s!!%d", comment.Locator.URL, comment.ID))
+	return &result
+}
+
+func refFromValue(val []byte) *ref {
+	result := ref(string(val))
+	return &result
+}
+
+func (r ref) value() string { return string(r) }
+
+func (r ref) parse() (url string, id int64, err error) {
+	elems := strings.Split(string(r), "!!")
+	if len(elems) < 2 {
+		return "", 0, errors.Errorf("can't parse ref %s", r)
+	}
+	url = elems[0]
+	if id, err = strconv.ParseInt(elems[1], 10, 64); err != nil {
+		return "", 0, errors.Wrapf(err, "can't extract id from ref %s", r)
+	}
+	return url, id, nil
+}

app/store/bolt_test.go

@@ -0,0 +1,63 @@
+package store
+
+import (
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+var testDb = "/tmp/test-remark.db"
+
+func TestBoltDB_CreateAndFind(t *testing.T) {
+	defer os.Remove(testDb)
+
+	b, err := NewBoltDB(testDb)
+	assert.Nil(t, err)
+
+	comment := Comment{Text: "some text", Timestamp: time.Date(2017, 12, 20, 15, 18, 22, 0, time.Local),
+		Locator: Locator{URL: "https://radio-t.com", SiteID: "radio-t"}, User: User{ID: "user1", Name: "user name"}}
+	err = b.Create(comment)
+	assert.Nil(t, err)
+
+	comment = Comment{Text: "some text2", Timestamp: time.Date(2017, 12, 20, 15, 18, 23, 0, time.Local),
+		Locator: Locator{URL: "https://radio-t.com", SiteID: "radio-t"}, User: User{ID: "user1", Name: "user name"}}
+	err = b.Create(comment)
+	assert.Nil(t, err)
+
+	res, err := b.Find(Request{Locator: Locator{URL: "https://radio-t.com"}})
+	assert.Nil(t, err)
+	assert.Equal(t, 2, len(res))
+	assert.Equal(t, "some text", res[0].Text)
+	assert.Equal(t, "user1", res[0].User.ID)
+}
+
+func TestBoltDB_Delete(t *testing.T) {
+	defer os.Remove(testDb)
+
+	b, err := NewBoltDB(testDb)
+	assert.Nil(t, err)
+
+	comment := Comment{Text: "some text", Timestamp: time.Date(2017, 12, 20, 15, 18, 22, 0, time.Local),
+		Locator: Locator{URL: "https://radio-t.com", SiteID: "radio-t"}, User: User{ID: "user1", Name: "user name"}}
+	err = b.Create(comment)
+	assert.Nil(t, err)
+
+	comment = Comment{Text: "some text2", Timestamp: time.Date(2017, 12, 20, 15, 18, 23, 0, time.Local),
+		Locator: Locator{URL: "https://radio-t.com", SiteID: "radio-t"}, User: User{ID: "user1", Name: "user name"}}
+	err = b.Create(comment)
+	assert.Nil(t, err)
+
+	res, err := b.Find(Request{Locator: Locator{URL: "https://radio-t.com"}})
+	assert.Nil(t, err)
+	assert.Equal(t, 2, len(res))
+
+	err = b.Delete("https://radio-t.com", res[0].ID)
+	assert.Nil(t, err)
+
+	res, err = b.Find(Request{Locator: Locator{URL: "https://radio-t.com"}})
+	assert.Nil(t, err)
+	assert.Equal(t, 1, len(res))
+	assert.Equal(t, "some text2", res[0].Text)
+}

app/store/store.go

@@ -0,0 +1,46 @@
+package store
+
+import "time"
+
+// Comment represents a single comment with reference to its parent
+type Comment struct {
+	ID       int64 `json:"id"`
+	ParentID int64 `json:"pid"`
+
+	Text string `json:"text"`
+
+	User User `json:"user"`
+
+	Locator   Locator   `json:"locator"`
+	Score     int       `json:"score"`
+	Timestamp time.Time `json:"time"`
+}
+
+// Locator keeps site and url of the post
+type Locator struct {
+	SiteID string `json:"site"`
+	URL    string `json:"url"`
+}
+
+// User holds user-related info
+type User struct {
+	Name string `json:"name"`
+	ID   string `json:"id"`
+	IP   string `json:"-"`
+}
+
+// Request is a container for all finds
+type Request struct {
+	Locator Locator `json:"locator"`
+	Sort    string  `json:"sort"`
+	Offset  int     `json:"offset"`
+	Limit   int     `json:"limit"`
+}
+
+// Interface defines basic CRUD for comments
+type Interface interface {
+	Create(comment Comment) error
+	Delete(id string) error
+	Find(request Request) ([]Comment, error)
+	Last(locator Locator, max int) []Comment
+}

docker-compose.yml

@@ -0,0 +1,19 @@
+version: '2'
+
+services:
+
+    remark:
+        image: umputun/remark:develop
+        container_name: "remark"
+        hostname: "remark"
+        restart: always
+
+        logging:
+          driver: json-file
+          options:
+              max-size: "10m"
+              max-file: "5"
+
+        environment:
+            - MHOST=${MHOST}
+

vendor/github.com/boltdb/bolt/LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2013 Ben Johnson
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/boltdb/bolt/Makefile

@@ -0,0 +1,18 @@
+BRANCH=`git rev-parse --abbrev-ref HEAD`
+COMMIT=`git rev-parse --short HEAD`
+GOLDFLAGS="-X main.branch $(BRANCH) -X main.commit $(COMMIT)"
+
+default: build
+
+race:
+	@go test -v -race -test.run="TestSimulate_(100op|1000op)"
+
+# go get github.com/kisielk/errcheck
+errcheck:
+	@errcheck -ignorepkg=bytes -ignore=os:Remove github.com/boltdb/bolt
+
+test: 
+	@go test -v -cover .
+	@go test -v ./cmd/bolt
+
+.PHONY: fmt test

vendor/github.com/boltdb/bolt/README.md

@@ -0,0 +1,915 @@
+Bolt [![Coverage Status](https://coveralls.io/repos/boltdb/bolt/badge.svg?branch=master)](https://coveralls.io/r/boltdb/bolt?branch=master) [![GoDoc](https://godoc.org/github.com/boltdb/bolt?status.svg)](https://godoc.org/github.com/boltdb/bolt) ![Version](https://img.shields.io/badge/version-1.2.1-green.svg)
+====
+
+Bolt is a pure Go key/value store inspired by [Howard Chu's][hyc_symas]
+[LMDB project][lmdb]. The goal of the project is to provide a simple,
+fast, and reliable database for projects that don't require a full database
+server such as Postgres or MySQL.
+
+Since Bolt is meant to be used as such a low-level piece of functionality,
+simplicity is key. The API will be small and only focus on getting values
+and setting values. That's it.
+
+[hyc_symas]: https://twitter.com/hyc_symas
+[lmdb]: http://symas.com/mdb/
+
+## Project Status
+
+Bolt is stable, the API is fixed, and the file format is fixed. Full unit
+test coverage and randomized black box testing are used to ensure database
+consistency and thread safety. Bolt is currently used in high-load production
+environments serving databases as large as 1TB. Many companies such as
+Shopify and Heroku use Bolt-backed services every day.
+
+## Table of Contents
+
+- [Getting Started](#getting-started)
+  - [Installing](#installing)
+  - [Opening a database](#opening-a-database)
+  - [Transactions](#transactions)
+    - [Read-write transactions](#read-write-transactions)
+    - [Read-only transactions](#read-only-transactions)
+    - [Batch read-write transactions](#batch-read-write-transactions)
+    - [Managing transactions manually](#managing-transactions-manually)
+  - [Using buckets](#using-buckets)
+  - [Using key/value pairs](#using-keyvalue-pairs)
+  - [Autoincrementing integer for the bucket](#autoincrementing-integer-for-the-bucket)
+  - [Iterating over keys](#iterating-over-keys)
+    - [Prefix scans](#prefix-scans)
+    - [Range scans](#range-scans)
+    - [ForEach()](#foreach)
+  - [Nested buckets](#nested-buckets)
+  - [Database backups](#database-backups)
+  - [Statistics](#statistics)
+  - [Read-Only Mode](#read-only-mode)
+  - [Mobile Use (iOS/Android)](#mobile-use-iosandroid)
+- [Resources](#resources)
+- [Comparison with other databases](#comparison-with-other-databases)
+  - [Postgres, MySQL, & other relational databases](#postgres-mysql--other-relational-databases)
+  - [LevelDB, RocksDB](#leveldb-rocksdb)
+  - [LMDB](#lmdb)
+- [Caveats & Limitations](#caveats--limitations)
+- [Reading the Source](#reading-the-source)
+- [Other Projects Using Bolt](#other-projects-using-bolt)
+
+## Getting Started
+
+### Installing
+
+To start using Bolt, install Go and run `go get`:
+
+```sh
+$ go get github.com/boltdb/bolt/...
+```
+
+This will retrieve the library and install the `bolt` command line utility into
+your `$GOBIN` path.
+
+
+### Opening a database
+
+The top-level object in Bolt is a `DB`. It is represented as a single file on
+your disk and represents a consistent snapshot of your data.
+
+To open your database, simply use the `bolt.Open()` function:
+
+```go
+package main
+
+import (
+	"log"
+
+	"github.com/boltdb/bolt"
+)
+
+func main() {
+	// Open the my.db data file in your current directory.
+	// It will be created if it doesn't exist.
+	db, err := bolt.Open("my.db", 0600, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer db.Close()
+
+	...
+}
+```
+
+Please note that Bolt obtains a file lock on the data file so multiple processes
+cannot open the same database at the same time. Opening an already open Bolt
+database will cause it to hang until the other process closes it. To prevent
+an indefinite wait you can pass a timeout option to the `Open()` function:
+
+```go
+db, err := bolt.Open("my.db", 0600, &bolt.Options{Timeout: 1 * time.Second})
+```
+
+
+### Transactions
+
+Bolt allows only one read-write transaction at a time but allows as many
+read-only transactions as you want at a time. Each transaction has a consistent
+view of the data as it existed when the transaction started.
+
+Individual transactions and all objects created from them (e.g. buckets, keys)
+are not thread safe. To work with data in multiple goroutines you must start
+a transaction for each one or use locking to ensure only one goroutine accesses
+a transaction at a time. Creating transaction from the `DB` is thread safe.
+
+Read-only transactions and read-write transactions should not depend on one
+another and generally shouldn't be opened simultaneously in the same goroutine.
+This can cause a deadlock as the read-write transaction needs to periodically
+re-map the data file but it cannot do so while a read-only transaction is open.
+
+
+#### Read-write transactions
+
+To start a read-write transaction, you can use the `DB.Update()` function:
+
+```go
+err := db.Update(func(tx *bolt.Tx) error {
+	...
+	return nil
+})
+```
+
+Inside the closure, you have a consistent view of the database. You commit the
+transaction by returning `nil` at the end. You can also rollback the transaction
+at any point by returning an error. All database operations are allowed inside
+a read-write transaction.
+
+Always check the return error as it will report any disk failures that can cause
+your transaction to not complete. If you return an error within your closure
+it will be passed through.
+
+
+#### Read-only transactions
+
+To start a read-only transaction, you can use the `DB.View()` function:
+
+```go
+err := db.View(func(tx *bolt.Tx) error {
+	...
+	return nil
+})
+```
+
+You also get a consistent view of the database within this closure, however,
+no mutating operations are allowed within a read-only transaction. You can only
+retrieve buckets, retrieve values, and copy the database within a read-only
+transaction.
+
+
+#### Batch read-write transactions
+
+Each `DB.Update()` waits for disk to commit the writes. This overhead
+can be minimized by combining multiple updates with the `DB.Batch()`
+function:
+
+```go
+err := db.Batch(func(tx *bolt.Tx) error {
+	...
+	return nil
+})
+```
+
+Concurrent Batch calls are opportunistically combined into larger
+transactions. Batch is only useful when there are multiple goroutines
+calling it.
+
+The trade-off is that `Batch` can call the given
+function multiple times, if parts of the transaction fail. The
+function must be idempotent and side effects must take effect only
+after a successful return from `DB.Batch()`.
+
+For example: don't display messages from inside the function, instead
+set variables in the enclosing scope:
+
+```go
+var id uint64
+err := db.Batch(func(tx *bolt.Tx) error {
+	// Find last key in bucket, decode as bigendian uint64, increment
+	// by one, encode back to []byte, and add new key.
+	...
+	id = newValue
+	return nil
+})
+if err != nil {
+	return ...
+}
+fmt.Println("Allocated ID %d", id)
+```
+
+
+#### Managing transactions manually
+
+The `DB.View()` and `DB.Update()` functions are wrappers around the `DB.Begin()`
+function. These helper functions will start the transaction, execute a function,
+and then safely close your transaction if an error is returned. This is the
+recommended way to use Bolt transactions.
+
+However, sometimes you may want to manually start and end your transactions.
+You can use the `DB.Begin()` function directly but **please** be sure to close
+the transaction.
+
+```go
+// Start a writable transaction.
+tx, err := db.Begin(true)
+if err != nil {
+    return err
+}
+defer tx.Rollback()
+
+// Use the transaction...
+_, err := tx.CreateBucket([]byte("MyBucket"))
+if err != nil {
+    return err
+}
+
+// Commit the transaction and check for error.
+if err := tx.Commit(); err != nil {
+    return err
+}
+```
+
+The first argument to `DB.Begin()` is a boolean stating if the transaction
+should be writable.
+
+
+### Using buckets
+
+Buckets are collections of key/value pairs within the database. All keys in a
+bucket must be unique. You can create a bucket using the `DB.CreateBucket()`
+function:
+
+```go
+db.Update(func(tx *bolt.Tx) error {
+	b, err := tx.CreateBucket([]byte("MyBucket"))
+	if err != nil {
+		return fmt.Errorf("create bucket: %s", err)
+	}
+	return nil
+})
+```
+
+You can also create a bucket only if it doesn't exist by using the
+`Tx.CreateBucketIfNotExists()` function. It's a common pattern to call this
+function for all your top-level buckets after you open your database so you can
+guarantee that they exist for future transactions.
+
+To delete a bucket, simply call the `Tx.DeleteBucket()` function.
+
+
+### Using key/value pairs
+
+To save a key/value pair to a bucket, use the `Bucket.Put()` function:
+
+```go
+db.Update(func(tx *bolt.Tx) error {
+	b := tx.Bucket([]byte("MyBucket"))
+	err := b.Put([]byte("answer"), []byte("42"))
+	return err
+})
+```
+
+This will set the value of the `"answer"` key to `"42"` in the `MyBucket`
+bucket. To retrieve this value, we can use the `Bucket.Get()` function:
+
+```go
+db.View(func(tx *bolt.Tx) error {
+	b := tx.Bucket([]byte("MyBucket"))
+	v := b.Get([]byte("answer"))
+	fmt.Printf("The answer is: %s\n", v)
+	return nil
+})
+```
+
+The `Get()` function does not return an error because its operation is
+guaranteed to work (unless there is some kind of system failure). If the key
+exists then it will return its byte slice value. If it doesn't exist then it
+will return `nil`. It's important to note that you can have a zero-length value
+set to a key which is different than the key not existing.
+
+Use the `Bucket.Delete()` function to delete a key from the bucket.
+
+Please note that values returned from `Get()` are only valid while the
+transaction is open. If you need to use a value outside of the transaction
+then you must use `copy()` to copy it to another byte slice.
+
+
+### Autoincrementing integer for the bucket
+By using the `NextSequence()` function, you can let Bolt determine a sequence
+which can be used as the unique identifier for your key/value pairs. See the
+example below.
+
+```go
+// CreateUser saves u to the store. The new user ID is set on u once the data is persisted.
+func (s *Store) CreateUser(u *User) error {
+    return s.db.Update(func(tx *bolt.Tx) error {
+        // Retrieve the users bucket.
+        // This should be created when the DB is first opened.
+        b := tx.Bucket([]byte("users"))
+
+        // Generate ID for the user.
+        // This returns an error only if the Tx is closed or not writeable.
+        // That can't happen in an Update() call so I ignore the error check.
+        id, _ := b.NextSequence()
+        u.ID = int(id)
+
+        // Marshal user data into bytes.
+        buf, err := json.Marshal(u)
+        if err != nil {
+            return err
+        }
+
+        // Persist bytes to users bucket.
+        return b.Put(itob(u.ID), buf)
+    })
+}
+
+// itob returns an 8-byte big endian representation of v.
+func itob(v int) []byte {
+    b := make([]byte, 8)
+    binary.BigEndian.PutUint64(b, uint64(v))
+    return b
+}
+
+type User struct {
+    ID int
+    ...
+}
+```
+
+### Iterating over keys
+
+Bolt stores its keys in byte-sorted order within a bucket. This makes sequential
+iteration over these keys extremely fast. To iterate over keys we'll use a
+`Cursor`:
+
+```go
+db.View(func(tx *bolt.Tx) error {
+	// Assume bucket exists and has keys
+	b := tx.Bucket([]byte("MyBucket"))
+
+	c := b.Cursor()
+
+	for k, v := c.First(); k != nil; k, v = c.Next() {
+		fmt.Printf("key=%s, value=%s\n", k, v)
+	}
+
+	return nil
+})
+```
+
+The cursor allows you to move to a specific point in the list of keys and move
+forward or backward through the keys one at a time.
+
+The following functions are available on the cursor:
+
+```
+First()  Move to the first key.
+Last()   Move to the last key.
+Seek()   Move to a specific key.
+Next()   Move to the next key.
+Prev()   Move to the previous key.
+```
+
+Each of those functions has a return signature of `(key []byte, value []byte)`.
+When you have iterated to the end of the cursor then `Next()` will return a
+`nil` key.  You must seek to a position using `First()`, `Last()`, or `Seek()`
+before calling `Next()` or `Prev()`. If you do not seek to a position then
+these functions will return a `nil` key.
+
+During iteration, if the key is non-`nil` but the value is `nil`, that means
+the key refers to a bucket rather than a value.  Use `Bucket.Bucket()` to
+access the sub-bucket.
+
+
+#### Prefix scans
+
+To iterate over a key prefix, you can combine `Seek()` and `bytes.HasPrefix()`:
+
+```go
+db.View(func(tx *bolt.Tx) error {
+	// Assume bucket exists and has keys
+	c := tx.Bucket([]byte("MyBucket")).Cursor()
+
+	prefix := []byte("1234")
+	for k, v := c.Seek(prefix); k != nil && bytes.HasPrefix(k, prefix); k, v = c.Next() {
+		fmt.Printf("key=%s, value=%s\n", k, v)
+	}
+
+	return nil
+})
+```
+
+#### Range scans
+
+Another common use case is scanning over a range such as a time range. If you
+use a sortable time encoding such as RFC3339 then you can query a specific
+date range like this:
+
+```go
+db.View(func(tx *bolt.Tx) error {
+	// Assume our events bucket exists and has RFC3339 encoded time keys.
+	c := tx.Bucket([]byte("Events")).Cursor()
+
+	// Our time range spans the 90's decade.
+	min := []byte("1990-01-01T00:00:00Z")
+	max := []byte("2000-01-01T00:00:00Z")
+
+	// Iterate over the 90's.
+	for k, v := c.Seek(min); k != nil && bytes.Compare(k, max) <= 0; k, v = c.Next() {
+		fmt.Printf("%s: %s\n", k, v)
+	}
+
+	return nil
+})
+```
+
+Note that, while RFC3339 is sortable, the Golang implementation of RFC3339Nano does not use a fixed number of digits after the decimal point and is therefore not sortable.
+
+
+#### ForEach()
+
+You can also use the function `ForEach()` if you know you'll be iterating over
+all the keys in a bucket:
+
+```go
+db.View(func(tx *bolt.Tx) error {
+	// Assume bucket exists and has keys
+	b := tx.Bucket([]byte("MyBucket"))
+
+	b.ForEach(func(k, v []byte) error {
+		fmt.Printf("key=%s, value=%s\n", k, v)
+		return nil
+	})
+	return nil
+})
+```
+
+Please note that keys and values in `ForEach()` are only valid while
+the transaction is open. If you need to use a key or value outside of
+the transaction, you must use `copy()` to copy it to another byte
+slice.
+
+### Nested buckets
+
+You can also store a bucket in a key to create nested buckets. The API is the
+same as the bucket management API on the `DB` object:
+
+```go
+func (*Bucket) CreateBucket(key []byte) (*Bucket, error)
+func (*Bucket) CreateBucketIfNotExists(key []byte) (*Bucket, error)
+func (*Bucket) DeleteBucket(key []byte) error
+```
+
+Say you had a multi-tenant application where the root level bucket was the account bucket. Inside of this bucket was a sequence of accounts which themselves are buckets. And inside the sequence bucket you could have many buckets pertaining to the Account itself (Users, Notes, etc) isolating the information into logical groupings.
+
+```go
+
+// createUser creates a new user in the given account.
+func createUser(accountID int, u *User) error {
+    // Start the transaction.
+    tx, err := db.Begin(true)
+    if err != nil {
+        return err
+    }
+    defer tx.Rollback()
+
+    // Retrieve the root bucket for the account.
+    // Assume this has already been created when the account was set up.
+    root := tx.Bucket([]byte(strconv.FormatUint(accountID, 10)))
+
+    // Setup the users bucket.
+    bkt, err := root.CreateBucketIfNotExists([]byte("USERS"))
+    if err != nil {
+        return err
+    }
+
+    // Generate an ID for the new user.
+    userID, err := bkt.NextSequence()
+    if err != nil {
+        return err
+    }
+    u.ID = userID
+
+    // Marshal and save the encoded user.
+    if buf, err := json.Marshal(u); err != nil {
+        return err
+    } else if err := bkt.Put([]byte(strconv.FormatUint(u.ID, 10)), buf); err != nil {
+        return err
+    }
+
+    // Commit the transaction.
+    if err := tx.Commit(); err != nil {
+        return err
+    }
+
+    return nil
+}
+
+```
+
+
+
+
+### Database backups
+
+Bolt is a single file so it's easy to backup. You can use the `Tx.WriteTo()`
+function to write a consistent view of the database to a writer. If you call
+this from a read-only transaction, it will perform a hot backup and not block
+your other database reads and writes.
+
+By default, it will use a regular file handle which will utilize the operating
+system's page cache. See the [`Tx`](https://godoc.org/github.com/boltdb/bolt#Tx)
+documentation for information about optimizing for larger-than-RAM datasets.
+
+One common use case is to backup over HTTP so you can use tools like `cURL` to
+do database backups:
+
+```go
+func BackupHandleFunc(w http.ResponseWriter, req *http.Request) {
+	err := db.View(func(tx *bolt.Tx) error {
+		w.Header().Set("Content-Type", "application/octet-stream")
+		w.Header().Set("Content-Disposition", `attachment; filename="my.db"`)
+		w.Header().Set("Content-Length", strconv.Itoa(int(tx.Size())))
+		_, err := tx.WriteTo(w)
+		return err
+	})
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+}
+```
+
+Then you can backup using this command:
+
+```sh
+$ curl http://localhost/backup > my.db
+```
+
+Or you can open your browser to `http://localhost/backup` and it will download
+automatically.
+
+If you want to backup to another file you can use the `Tx.CopyFile()` helper
+function.
+
+
+### Statistics
+
+The database keeps a running count of many of the internal operations it
+performs so you can better understand what's going on. By grabbing a snapshot
+of these stats at two points in time we can see what operations were performed
+in that time range.
+
+For example, we could start a goroutine to log stats every 10 seconds:
+
+```go
+go func() {
+	// Grab the initial stats.
+	prev := db.Stats()
+
+	for {
+		// Wait for 10s.
+		time.Sleep(10 * time.Second)
+
+		// Grab the current stats and diff them.
+		stats := db.Stats()
+		diff := stats.Sub(&prev)
+
+		// Encode stats to JSON and print to STDERR.
+		json.NewEncoder(os.Stderr).Encode(diff)
+
+		// Save stats for the next loop.
+		prev = stats
+	}
+}()
+```
+
+It's also useful to pipe these stats to a service such as statsd for monitoring
+or to provide an HTTP endpoint that will perform a fixed-length sample.
+
+
+### Read-Only Mode
+
+Sometimes it is useful to create a shared, read-only Bolt database. To this,
+set the `Options.ReadOnly` flag when opening your database. Read-only mode
+uses a shared lock to allow multiple processes to read from the database but
+it will block any processes from opening the database in read-write mode.
+
+```go
+db, err := bolt.Open("my.db", 0666, &bolt.Options{ReadOnly: true})
+if err != nil {
+	log.Fatal(err)
+}
+```
+
+### Mobile Use (iOS/Android)
+
+Bolt is able to run on mobile devices by leveraging the binding feature of the
+[gomobile](https://github.com/golang/mobile) tool. Create a struct that will
+contain your database logic and a reference to a `*bolt.DB` with a initializing
+constructor that takes in a filepath where the database file will be stored.
+Neither Android nor iOS require extra permissions or cleanup from using this method.
+
+```go
+func NewBoltDB(filepath string) *BoltDB {
+	db, err := bolt.Open(filepath+"/demo.db", 0600, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	return &BoltDB{db}
+}
+
+type BoltDB struct {
+	db *bolt.DB
+	...
+}
+
+func (b *BoltDB) Path() string {
+	return b.db.Path()
+}
+
+func (b *BoltDB) Close() {
+	b.db.Close()
+}
+```
+
+Database logic should be defined as methods on this wrapper struct.
+
+To initialize this struct from the native language (both platforms now sync
+their local storage to the cloud. These snippets disable that functionality for the
+database file):
+
+#### Android
+
+```java
+String path;
+if (android.os.Build.VERSION.SDK_INT >=android.os.Build.VERSION_CODES.LOLLIPOP){
+    path = getNoBackupFilesDir().getAbsolutePath();
+} else{
+    path = getFilesDir().getAbsolutePath();
+}
+Boltmobiledemo.BoltDB boltDB = Boltmobiledemo.NewBoltDB(path)
+```
+
+#### iOS
+
+```objc
+- (void)demo {
+    NSString* path = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory,
+                                                          NSUserDomainMask,
+                                                          YES) objectAtIndex:0];
+	GoBoltmobiledemoBoltDB * demo = GoBoltmobiledemoNewBoltDB(path);
+	[self addSkipBackupAttributeToItemAtPath:demo.path];
+	//Some DB Logic would go here
+	[demo close];
+}
+
+- (BOOL)addSkipBackupAttributeToItemAtPath:(NSString *) filePathString
+{
+    NSURL* URL= [NSURL fileURLWithPath: filePathString];
+    assert([[NSFileManager defaultManager] fileExistsAtPath: [URL path]]);
+
+    NSError *error = nil;
+    BOOL success = [URL setResourceValue: [NSNumber numberWithBool: YES]
+                                  forKey: NSURLIsExcludedFromBackupKey error: &error];
+    if(!success){
+        NSLog(@"Error excluding %@ from backup %@", [URL lastPathComponent], error);
+    }
+    return success;
+}
+
+```
+
+## Resources
+
+For more information on getting started with Bolt, check out the following articles:
+
+* [Intro to BoltDB: Painless Performant Persistence](http://npf.io/2014/07/intro-to-boltdb-painless-performant-persistence/) by [Nate Finch](https://github.com/natefinch).
+* [Bolt -- an embedded key/value database for Go](https://www.progville.com/go/bolt-embedded-db-golang/) by Progville
+
+
+## Comparison with other databases
+
+### Postgres, MySQL, & other relational databases
+
+Relational databases structure data into rows and are only accessible through
+the use of SQL. This approach provides flexibility in how you store and query
+your data but also incurs overhead in parsing and planning SQL statements. Bolt
+accesses all data by a byte slice key. This makes Bolt fast to read and write
+data by key but provides no built-in support for joining values together.
+
+Most relational databases (with the exception of SQLite) are standalone servers
+that run separately from your application. This gives your systems
+flexibility to connect multiple application servers to a single database
+server but also adds overhead in serializing and transporting data over the
+network. Bolt runs as a library included in your application so all data access
+has to go through your application's process. This brings data closer to your
+application but limits multi-process access to the data.
+
+
+### LevelDB, RocksDB
+
+LevelDB and its derivatives (RocksDB, HyperLevelDB) are similar to Bolt in that
+they are libraries bundled into the application, however, their underlying
+structure is a log-structured merge-tree (LSM tree). An LSM tree optimizes
+random writes by using a write ahead log and multi-tiered, sorted files called
+SSTables. Bolt uses a B+tree internally and only a single file. Both approaches
+have trade-offs.
+
+If you require a high random write throughput (>10,000 w/sec) or you need to use
+spinning disks then LevelDB could be a good choice. If your application is
+read-heavy or does a lot of range scans then Bolt could be a good choice.
+
+One other important consideration is that LevelDB does not have transactions.
+It supports batch writing of key/values pairs and it supports read snapshots
+but it will not give you the ability to do a compare-and-swap operation safely.
+Bolt supports fully serializable ACID transactions.
+
+
+### LMDB
+
+Bolt was originally a port of LMDB so it is architecturally similar. Both use
+a B+tree, have ACID semantics with fully serializable transactions, and support
+lock-free MVCC using a single writer and multiple readers.
+
+The two projects have somewhat diverged. LMDB heavily focuses on raw performance
+while Bolt has focused on simplicity and ease of use. For example, LMDB allows
+several unsafe actions such as direct writes for the sake of performance. Bolt
+opts to disallow actions which can leave the database in a corrupted state. The
+only exception to this in Bolt is `DB.NoSync`.
+
+There are also a few differences in API. LMDB requires a maximum mmap size when
+opening an `mdb_env` whereas Bolt will handle incremental mmap resizing
+automatically. LMDB overloads the getter and setter functions with multiple
+flags whereas Bolt splits these specialized cases into their own functions.
+
+
+## Caveats & Limitations
+
+It's important to pick the right tool for the job and Bolt is no exception.
+Here are a few things to note when evaluating and using Bolt:
+
+* Bolt is good for read intensive workloads. Sequential write performance is
+  also fast but random writes can be slow. You can use `DB.Batch()` or add a
+  write-ahead log to help mitigate this issue.
+
+* Bolt uses a B+tree internally so there can be a lot of random page access.
+  SSDs provide a significant performance boost over spinning disks.
+
+* Try to avoid long running read transactions. Bolt uses copy-on-write so
+  old pages cannot be reclaimed while an old transaction is using them.
+
+* Byte slices returned from Bolt are only valid during a transaction. Once the
+  transaction has been committed or rolled back then the memory they point to
+  can be reused by a new page or can be unmapped from virtual memory and you'll
+  see an `unexpected fault address` panic when accessing it.
+
+* Bolt uses an exclusive write lock on the database file so it cannot be
+  shared by multiple processes.
+
+* Be careful when using `Bucket.FillPercent`. Setting a high fill percent for
+  buckets that have random inserts will cause your database to have very poor
+  page utilization.
+
+* Use larger buckets in general. Smaller buckets causes poor page utilization
+  once they become larger than the page size (typically 4KB).
+
+* Bulk loading a lot of random writes into a new bucket can be slow as the
+  page will not split until the transaction is committed. Randomly inserting
+  more than 100,000 key/value pairs into a single new bucket in a single
+  transaction is not advised.
+
+* Bolt uses a memory-mapped file so the underlying operating system handles the
+  caching of the data. Typically, the OS will cache as much of the file as it
+  can in memory and will release memory as needed to other processes. This means
+  that Bolt can show very high memory usage when working with large databases.
+  However, this is expected and the OS will release memory as needed. Bolt can
+  handle databases much larger than the available physical RAM, provided its
+  memory-map fits in the process virtual address space. It may be problematic
+  on 32-bits systems.
+
+* The data structures in the Bolt database are memory mapped so the data file
+  will be endian specific. This means that you cannot copy a Bolt file from a
+  little endian machine to a big endian machine and have it work. For most
+  users this is not a concern since most modern CPUs are little endian.
+
+* Because of the way pages are laid out on disk, Bolt cannot truncate data files
+  and return free pages back to the disk. Instead, Bolt maintains a free list
+  of unused pages within its data file. These free pages can be reused by later
+  transactions. This works well for many use cases as databases generally tend
+  to grow. However, it's important to note that deleting large chunks of data
+  will not allow you to reclaim that space on disk.
+
+  For more information on page allocation, [see this comment][page-allocation].
+
+[page-allocation]: https://github.com/boltdb/bolt/issues/308#issuecomment-74811638
+
+
+## Reading the Source
+
+Bolt is a relatively small code base (<3KLOC) for an embedded, serializable,
+transactional key/value database so it can be a good starting point for people
+interested in how databases work.
+
+The best places to start are the main entry points into Bolt:
+
+- `Open()` - Initializes the reference to the database. It's responsible for
+  creating the database if it doesn't exist, obtaining an exclusive lock on the
+  file, reading the meta pages, & memory-mapping the file.
+
+- `DB.Begin()` - Starts a read-only or read-write transaction depending on the
+  value of the `writable` argument. This requires briefly obtaining the "meta"
+  lock to keep track of open transactions. Only one read-write transaction can
+  exist at a time so the "rwlock" is acquired during the life of a read-write
+  transaction.
+
+- `Bucket.Put()` - Writes a key/value pair into a bucket. After validating the
+  arguments, a cursor is used to traverse the B+tree to the page and position
+  where they key & value will be written. Once the position is found, the bucket
+  materializes the underlying page and the page's parent pages into memory as
+  "nodes". These nodes are where mutations occur during read-write transactions.
+  These changes get flushed to disk during commit.
+
+- `Bucket.Get()` - Retrieves a key/value pair from a bucket. This uses a cursor
+  to move to the page & position of a key/value pair. During a read-only
+  transaction, the key and value data is returned as a direct reference to the
+  underlying mmap file so there's no allocation overhead. For read-write
+  transactions, this data may reference the mmap file or one of the in-memory
+  node values.
+
+- `Cursor` - This object is simply for traversing the B+tree of on-disk pages
+  or in-memory nodes. It can seek to a specific key, move to the first or last
+  value, or it can move forward or backward. The cursor handles the movement up
+  and down the B+tree transparently to the end user.
+
+- `Tx.Commit()` - Converts the in-memory dirty nodes and the list of free pages
+  into pages to be written to disk. Writing to disk then occurs in two phases.
+  First, the dirty pages are written to disk and an `fsync()` occurs. Second, a
+  new meta page with an incremented transaction ID is written and another
+  `fsync()` occurs. This two phase write ensures that partially written data
+  pages are ignored in the event of a crash since the meta page pointing to them
+  is never written. Partially written meta pages are invalidated because they
+  are written with a checksum.
+
+If you have additional notes that could be helpful for others, please submit
+them via pull request.
+
+
+## Other Projects Using Bolt
+
+Below is a list of public, open source projects that use Bolt:
+
+* [BoltDbWeb](https://github.com/evnix/boltdbweb) - A web based GUI for BoltDB files.
+* [Operation Go: A Routine Mission](http://gocode.io) - An online programming game for Golang using Bolt for user accounts and a leaderboard.
+* [Bazil](https://bazil.org/) - A file system that lets your data reside where it is most convenient for it to reside.
+* [DVID](https://github.com/janelia-flyem/dvid) - Added Bolt as optional storage engine and testing it against Basho-tuned leveldb.
+* [Skybox Analytics](https://github.com/skybox/skybox) - A standalone funnel analysis tool for web analytics.
+* [Scuttlebutt](https://github.com/benbjohnson/scuttlebutt) - Uses Bolt to store and process all Twitter mentions of GitHub projects.
+* [Wiki](https://github.com/peterhellberg/wiki) - A tiny wiki using Goji, BoltDB and Blackfriday.
+* [ChainStore](https://github.com/pressly/chainstore) - Simple key-value interface to a variety of storage engines organized as a chain of operations.
+* [MetricBase](https://github.com/msiebuhr/MetricBase) - Single-binary version of Graphite.
+* [Gitchain](https://github.com/gitchain/gitchain) - Decentralized, peer-to-peer Git repositories aka "Git meets Bitcoin".
+* [event-shuttle](https://github.com/sclasen/event-shuttle) - A Unix system service to collect and reliably deliver messages to Kafka.
+* [ipxed](https://github.com/kelseyhightower/ipxed) - Web interface and api for ipxed.
+* [BoltStore](https://github.com/yosssi/boltstore) - Session store using Bolt.
+* [photosite/session](https://godoc.org/bitbucket.org/kardianos/photosite/session) - Sessions for a photo viewing site.
+* [LedisDB](https://github.com/siddontang/ledisdb) - A high performance NoSQL, using Bolt as optional storage.
+* [ipLocator](https://github.com/AndreasBriese/ipLocator) - A fast ip-geo-location-server using bolt with bloom filters.
+* [cayley](https://github.com/google/cayley) - Cayley is an open-source graph database using Bolt as optional backend.
+* [bleve](http://www.blevesearch.com/) - A pure Go search engine similar to ElasticSearch that uses Bolt as the default storage backend.
+* [tentacool](https://github.com/optiflows/tentacool) - REST api server to manage system stuff (IP, DNS, Gateway...) on a linux server.
+* [Seaweed File System](https://github.com/chrislusf/seaweedfs) - Highly scalable distributed key~file system with O(1) disk read.
+* [InfluxDB](https://influxdata.com) - Scalable datastore for metrics, events, and real-time analytics.
+* [Freehold](http://tshannon.bitbucket.org/freehold/) - An open, secure, and lightweight platform for your files and data.
+* [Prometheus Annotation Server](https://github.com/oliver006/prom_annotation_server) - Annotation server for PromDash & Prometheus service monitoring system.
+* [Consul](https://github.com/hashicorp/consul) - Consul is service discovery and configuration made easy. Distributed, highly available, and datacenter-aware.
+* [Kala](https://github.com/ajvb/kala) - Kala is a modern job scheduler optimized to run on a single node. It is persistent, JSON over HTTP API, ISO 8601 duration notation, and dependent jobs.
+* [drive](https://github.com/odeke-em/drive) - drive is an unofficial Google Drive command line client for \*NIX operating systems.
+* [stow](https://github.com/djherbis/stow) -  a persistence manager for objects
+  backed by boltdb.
+* [buckets](https://github.com/joyrexus/buckets) - a bolt wrapper streamlining
+  simple tx and key scans.
+* [mbuckets](https://github.com/abhigupta912/mbuckets) - A Bolt wrapper that allows easy operations on multi level (nested) buckets.
+* [Request Baskets](https://github.com/darklynx/request-baskets) - A web service to collect arbitrary HTTP requests and inspect them via REST API or simple web UI, similar to [RequestBin](http://requestb.in/) service
+* [Go Report Card](https://goreportcard.com/) - Go code quality report cards as a (free and open source) service.
+* [Boltdb Boilerplate](https://github.com/bobintornado/boltdb-boilerplate) - Boilerplate wrapper around bolt aiming to make simple calls one-liners.
+* [lru](https://github.com/crowdriff/lru) - Easy to use Bolt-backed Least-Recently-Used (LRU) read-through cache with chainable remote stores.
+* [Storm](https://github.com/asdine/storm) - Simple and powerful ORM for BoltDB.
+* [GoWebApp](https://github.com/josephspurrier/gowebapp) - A basic MVC web application in Go using BoltDB.
+* [SimpleBolt](https://github.com/xyproto/simplebolt) - A simple way to use BoltDB. Deals mainly with strings.
+* [Algernon](https://github.com/xyproto/algernon) - A HTTP/2 web server with built-in support for Lua. Uses BoltDB as the default database backend.
+* [MuLiFS](https://github.com/dankomiocevic/mulifs) - Music Library Filesystem creates a filesystem to organise your music files.
+* [GoShort](https://github.com/pankajkhairnar/goShort) - GoShort is a URL shortener written in Golang and BoltDB for persistent key/value storage and for routing it's using high performent HTTPRouter.
+* [torrent](https://github.com/anacrolix/torrent) - Full-featured BitTorrent client package and utilities in Go. BoltDB is a storage backend in development.
+* [gopherpit](https://github.com/gopherpit/gopherpit) - A web service to manage Go remote import paths with custom domains
+* [bolter](https://github.com/hasit/bolter) - Command-line app for viewing BoltDB file in your terminal.
+* [btcwallet](https://github.com/btcsuite/btcwallet) - A bitcoin wallet.
+* [dcrwallet](https://github.com/decred/dcrwallet) - A wallet for the Decred cryptocurrency.
+* [Ironsmith](https://github.com/timshannon/ironsmith) - A simple, script-driven continuous integration (build - > test -> release) tool, with no external dependencies
+* [BoltHold](https://github.com/timshannon/bolthold) - An embeddable NoSQL store for Go types built on BoltDB
+
+If you are using Bolt in a project please send a pull request to add it to the list.

vendor/github.com/boltdb/bolt/appveyor.yml

@@ -0,0 +1,18 @@
+version: "{build}"
+
+os: Windows Server 2012 R2
+
+clone_folder: c:\gopath\src\github.com\boltdb\bolt
+
+environment:
+  GOPATH: c:\gopath
+
+install:
+  - echo %PATH%
+  - echo %GOPATH%
+  - go version
+  - go env
+  - go get -v -t ./...
+
+build_script:
+  - go test -v ./...

vendor/github.com/boltdb/bolt/bolt_386.go

@@ -0,0 +1,10 @@
+package bolt
+
+// maxMapSize represents the largest mmap size supported by Bolt.
+const maxMapSize = 0x7FFFFFFF // 2GB
+
+// maxAllocSize is the size used when creating array pointers.
+const maxAllocSize = 0xFFFFFFF
+
+// Are unaligned load/stores broken on this arch?
+var brokenUnaligned = false

vendor/github.com/boltdb/bolt/bolt_amd64.go

@@ -0,0 +1,10 @@
+package bolt
+
+// maxMapSize represents the largest mmap size supported by Bolt.
+const maxMapSize = 0xFFFFFFFFFFFF // 256TB
+
+// maxAllocSize is the size used when creating array pointers.
+const maxAllocSize = 0x7FFFFFFF
+
+// Are unaligned load/stores broken on this arch?
+var brokenUnaligned = false

vendor/github.com/boltdb/bolt/bolt_arm.go

@@ -0,0 +1,28 @@
+package bolt
+
+import "unsafe"
+
+// maxMapSize represents the largest mmap size supported by Bolt.
+const maxMapSize = 0x7FFFFFFF // 2GB
+
+// maxAllocSize is the size used when creating array pointers.
+const maxAllocSize = 0xFFFFFFF
+
+// Are unaligned load/stores broken on this arch?
+var brokenUnaligned bool
+
+func init() {
+	// Simple check to see whether this arch handles unaligned load/stores
+	// correctly.
+
+	// ARM9 and older devices require load/stores to be from/to aligned
+	// addresses. If not, the lower 2 bits are cleared and that address is
+	// read in a jumbled up order.
+
+	// See http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka15414.html
+
+	raw := [6]byte{0xfe, 0xef, 0x11, 0x22, 0x22, 0x11}
+	val := *(*uint32)(unsafe.Pointer(uintptr(unsafe.Pointer(&raw)) + 2))
+
+	brokenUnaligned = val != 0x11222211
+}

vendor/github.com/boltdb/bolt/bolt_arm64.go

@@ -0,0 +1,12 @@
+// +build arm64
+
+package bolt
+
+// maxMapSize represents the largest mmap size supported by Bolt.
+const maxMapSize = 0xFFFFFFFFFFFF // 256TB
+
+// maxAllocSize is the size used when creating array pointers.
+const maxAllocSize = 0x7FFFFFFF
+
+// Are unaligned load/stores broken on this arch?
+var brokenUnaligned = false

vendor/github.com/boltdb/bolt/bolt_linux.go

@@ -0,0 +1,10 @@
+package bolt
+
+import (
+	"syscall"
+)
+
+// fdatasync flushes written data to a file descriptor.
+func fdatasync(db *DB) error {
+	return syscall.Fdatasync(int(db.file.Fd()))
+}

vendor/github.com/boltdb/bolt/bolt_openbsd.go

@@ -0,0 +1,27 @@
+package bolt
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const (
+	msAsync      = 1 << iota // perform asynchronous writes
+	msSync                   // perform synchronous writes
+	msInvalidate             // invalidate cached data
+)
+
+func msync(db *DB) error {
+	_, _, errno := syscall.Syscall(syscall.SYS_MSYNC, uintptr(unsafe.Pointer(db.data)), uintptr(db.datasz), msInvalidate)
+	if errno != 0 {
+		return errno
+	}
+	return nil
+}
+
+func fdatasync(db *DB) error {
+	if db.data != nil {
+		return msync(db)
+	}
+	return db.file.Sync()
+}

vendor/github.com/boltdb/bolt/bolt_ppc.go

@@ -0,0 +1,9 @@
+// +build ppc
+
+package bolt
+
+// maxMapSize represents the largest mmap size supported by Bolt.
+const maxMapSize = 0x7FFFFFFF // 2GB
+
+// maxAllocSize is the size used when creating array pointers.
+const maxAllocSize = 0xFFFFFFF

vendor/github.com/boltdb/bolt/bolt_ppc64.go

@@ -0,0 +1,12 @@
+// +build ppc64
+
+package bolt
+
+// maxMapSize represents the largest mmap size supported by Bolt.
+const maxMapSize = 0xFFFFFFFFFFFF // 256TB
+
+// maxAllocSize is the size used when creating array pointers.
+const maxAllocSize = 0x7FFFFFFF
+
+// Are unaligned load/stores broken on this arch?
+var brokenUnaligned = false

vendor/github.com/boltdb/bolt/bolt_ppc64le.go

@@ -0,0 +1,12 @@
+// +build ppc64le
+
+package bolt
+
+// maxMapSize represents the largest mmap size supported by Bolt.
+const maxMapSize = 0xFFFFFFFFFFFF // 256TB
+
+// maxAllocSize is the size used when creating array pointers.
+const maxAllocSize = 0x7FFFFFFF
+
+// Are unaligned load/stores broken on this arch?
+var brokenUnaligned = false

vendor/github.com/boltdb/bolt/bolt_s390x.go

@@ -0,0 +1,12 @@
+// +build s390x
+
+package bolt
+
+// maxMapSize represents the largest mmap size supported by Bolt.
+const maxMapSize = 0xFFFFFFFFFFFF // 256TB
+
+// maxAllocSize is the size used when creating array pointers.
+const maxAllocSize = 0x7FFFFFFF
+
+// Are unaligned load/stores broken on this arch?
+var brokenUnaligned = false

vendor/github.com/boltdb/bolt/bolt_unix.go

@@ -0,0 +1,89 @@
+// +build !windows,!plan9,!solaris
+
+package bolt
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+	"time"
+	"unsafe"
+)
+
+// flock acquires an advisory lock on a file descriptor.
+func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) error {
+	var t time.Time
+	for {
+		// If we're beyond our timeout then return an error.
+		// This can only occur after we've attempted a flock once.
+		if t.IsZero() {
+			t = time.Now()
+		} else if timeout > 0 && time.Since(t) > timeout {
+			return ErrTimeout
+		}
+		flag := syscall.LOCK_SH
+		if exclusive {
+			flag = syscall.LOCK_EX
+		}
+
+		// Otherwise attempt to obtain an exclusive lock.
+		err := syscall.Flock(int(db.file.Fd()), flag|syscall.LOCK_NB)
+		if err == nil {
+			return nil
+		} else if err != syscall.EWOULDBLOCK {
+			return err
+		}
+
+		// Wait for a bit and try again.
+		time.Sleep(50 * time.Millisecond)
+	}
+}
+
+// funlock releases an advisory lock on a file descriptor.
+func funlock(db *DB) error {
+	return syscall.Flock(int(db.file.Fd()), syscall.LOCK_UN)
+}
+
+// mmap memory maps a DB's data file.
+func mmap(db *DB, sz int) error {
+	// Map the data file to memory.
+	b, err := syscall.Mmap(int(db.file.Fd()), 0, sz, syscall.PROT_READ, syscall.MAP_SHARED|db.MmapFlags)
+	if err != nil {
+		return err
+	}
+
+	// Advise the kernel that the mmap is accessed randomly.
+	if err := madvise(b, syscall.MADV_RANDOM); err != nil {
+		return fmt.Errorf("madvise: %s", err)
+	}
+
+	// Save the original byte slice and convert to a byte array pointer.
+	db.dataref = b
+	db.data = (*[maxMapSize]byte)(unsafe.Pointer(&b[0]))
+	db.datasz = sz
+	return nil
+}
+
+// munmap unmaps a DB's data file from memory.
+func munmap(db *DB) error {
+	// Ignore the unmap if we have no mapped data.
+	if db.dataref == nil {
+		return nil
+	}
+
+	// Unmap using the original byte slice.
+	err := syscall.Munmap(db.dataref)
+	db.dataref = nil
+	db.data = nil
+	db.datasz = 0
+	return err
+}
+
+// NOTE: This function is copied from stdlib because it is not available on darwin.
+func madvise(b []byte, advice int) (err error) {
+	_, _, e1 := syscall.Syscall(syscall.SYS_MADVISE, uintptr(unsafe.Pointer(&b[0])), uintptr(len(b)), uintptr(advice))
+	if e1 != 0 {
+		err = e1
+	}
+	return
+}

vendor/github.com/boltdb/bolt/bolt_unix_solaris.go

@@ -0,0 +1,90 @@
+package bolt
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+	"time"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// flock acquires an advisory lock on a file descriptor.
+func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) error {
+	var t time.Time
+	for {
+		// If we're beyond our timeout then return an error.
+		// This can only occur after we've attempted a flock once.
+		if t.IsZero() {
+			t = time.Now()
+		} else if timeout > 0 && time.Since(t) > timeout {
+			return ErrTimeout
+		}
+		var lock syscall.Flock_t
+		lock.Start = 0
+		lock.Len = 0
+		lock.Pid = 0
+		lock.Whence = 0
+		lock.Pid = 0
+		if exclusive {
+			lock.Type = syscall.F_WRLCK
+		} else {
+			lock.Type = syscall.F_RDLCK
+		}
+		err := syscall.FcntlFlock(db.file.Fd(), syscall.F_SETLK, &lock)
+		if err == nil {
+			return nil
+		} else if err != syscall.EAGAIN {
+			return err
+		}
+
+		// Wait for a bit and try again.
+		time.Sleep(50 * time.Millisecond)
+	}
+}
+
+// funlock releases an advisory lock on a file descriptor.
+func funlock(db *DB) error {
+	var lock syscall.Flock_t
+	lock.Start = 0
+	lock.Len = 0
+	lock.Type = syscall.F_UNLCK
+	lock.Whence = 0
+	return syscall.FcntlFlock(uintptr(db.file.Fd()), syscall.F_SETLK, &lock)
+}
+
+// mmap memory maps a DB's data file.
+func mmap(db *DB, sz int) error {
+	// Map the data file to memory.
+	b, err := unix.Mmap(int(db.file.Fd()), 0, sz, syscall.PROT_READ, syscall.MAP_SHARED|db.MmapFlags)
+	if err != nil {
+		return err
+	}
+
+	// Advise the kernel that the mmap is accessed randomly.
+	if err := unix.Madvise(b, syscall.MADV_RANDOM); err != nil {
+		return fmt.Errorf("madvise: %s", err)
+	}
+
+	// Save the original byte slice and convert to a byte array pointer.
+	db.dataref = b
+	db.data = (*[maxMapSize]byte)(unsafe.Pointer(&b[0]))
+	db.datasz = sz
+	return nil
+}
+
+// munmap unmaps a DB's data file from memory.
+func munmap(db *DB) error {
+	// Ignore the unmap if we have no mapped data.
+	if db.dataref == nil {
+		return nil
+	}
+
+	// Unmap using the original byte slice.
+	err := unix.Munmap(db.dataref)
+	db.dataref = nil
+	db.data = nil
+	db.datasz = 0
+	return err
+}

vendor/github.com/boltdb/bolt/bolt_windows.go

@@ -0,0 +1,144 @@
+package bolt
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+	"time"
+	"unsafe"
+)
+
+// LockFileEx code derived from golang build filemutex_windows.go @ v1.5.1
+var (
+	modkernel32      = syscall.NewLazyDLL("kernel32.dll")
+	procLockFileEx   = modkernel32.NewProc("LockFileEx")
+	procUnlockFileEx = modkernel32.NewProc("UnlockFileEx")
+)
+
+const (
+	lockExt = ".lock"
+
+	// see https://msdn.microsoft.com/en-us/library/windows/desktop/aa365203(v=vs.85).aspx
+	flagLockExclusive       = 2
+	flagLockFailImmediately = 1
+
+	// see https://msdn.microsoft.com/en-us/library/windows/desktop/ms681382(v=vs.85).aspx
+	errLockViolation syscall.Errno = 0x21
+)
+
+func lockFileEx(h syscall.Handle, flags, reserved, locklow, lockhigh uint32, ol *syscall.Overlapped) (err error) {
+	r, _, err := procLockFileEx.Call(uintptr(h), uintptr(flags), uintptr(reserved), uintptr(locklow), uintptr(lockhigh), uintptr(unsafe.Pointer(ol)))
+	if r == 0 {
+		return err
+	}
+	return nil
+}
+
+func unlockFileEx(h syscall.Handle, reserved, locklow, lockhigh uint32, ol *syscall.Overlapped) (err error) {
+	r, _, err := procUnlockFileEx.Call(uintptr(h), uintptr(reserved), uintptr(locklow), uintptr(lockhigh), uintptr(unsafe.Pointer(ol)), 0)
+	if r == 0 {
+		return err
+	}
+	return nil
+}
+
+// fdatasync flushes written data to a file descriptor.
+func fdatasync(db *DB) error {
+	return db.file.Sync()
+}
+
+// flock acquires an advisory lock on a file descriptor.
+func flock(db *DB, mode os.FileMode, exclusive bool, timeout time.Duration) error {
+	// Create a separate lock file on windows because a process
+	// cannot share an exclusive lock on the same file. This is
+	// needed during Tx.WriteTo().
+	f, err := os.OpenFile(db.path+lockExt, os.O_CREATE, mode)
+	if err != nil {
+		return err
+	}
+	db.lockfile = f
+
+	var t time.Time
+	for {
+		// If we're beyond our timeout then return an error.
+		// This can only occur after we've attempted a flock once.
+		if t.IsZero() {
+			t = time.Now()
+		} else if timeout > 0 && time.Since(t) > timeout {
+			return ErrTimeout
+		}
+
+		var flag uint32 = flagLockFailImmediately
+		if exclusive {
+			flag |= flagLockExclusive
+		}
+
+		err := lockFileEx(syscall.Handle(db.lockfile.Fd()), flag, 0, 1, 0, &syscall.Overlapped{})
+		if err == nil {
+			return nil
+		} else if err != errLockViolation {
+			return err
+		}
+
+		// Wait for a bit and try again.
+		time.Sleep(50 * time.Millisecond)
+	}
+}
+
+// funlock releases an advisory lock on a file descriptor.
+func funlock(db *DB) error {
+	err := unlockFileEx(syscall.Handle(db.lockfile.Fd()), 0, 1, 0, &syscall.Overlapped{})
+	db.lockfile.Close()
+	os.Remove(db.path + lockExt)
+	return err
+}
+
+// mmap memory maps a DB's data file.
+// Based on: https://github.com/edsrzf/mmap-go
+func mmap(db *DB, sz int) error {
+	if !db.readOnly {
+		// Truncate the database to the size of the mmap.
+		if err := db.file.Truncate(int64(sz)); err != nil {
+			return fmt.Errorf("truncate: %s", err)
+		}
+	}
+
+	// Open a file mapping handle.
+	sizelo := uint32(sz >> 32)
+	sizehi := uint32(sz) & 0xffffffff
+	h, errno := syscall.CreateFileMapping(syscall.Handle(db.file.Fd()), nil, syscall.PAGE_READONLY, sizelo, sizehi, nil)
+	if h == 0 {
+		return os.NewSyscallError("CreateFileMapping", errno)
+	}
+
+	// Create the memory map.
+	addr, errno := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, uintptr(sz))
+	if addr == 0 {
+		return os.NewSyscallError("MapViewOfFile", errno)
+	}
+
+	// Close mapping handle.
+	if err := syscall.CloseHandle(syscall.Handle(h)); err != nil {
+		return os.NewSyscallError("CloseHandle", err)
+	}
+
+	// Convert to a byte array.
+	db.data = ((*[maxMapSize]byte)(unsafe.Pointer(addr)))
+	db.datasz = sz
+
+	return nil
+}
+
+// munmap unmaps a pointer from a file.
+// Based on: https://github.com/edsrzf/mmap-go
+func munmap(db *DB) error {
+	if db.data == nil {
+		return nil
+	}
+
+	addr := (uintptr)(unsafe.Pointer(&db.data[0]))
+	if err := syscall.UnmapViewOfFile(addr); err != nil {
+		return os.NewSyscallError("UnmapViewOfFile", err)
+	}
+	return nil
+}

vendor/github.com/boltdb/bolt/boltsync_unix.go

@@ -0,0 +1,8 @@
+// +build !windows,!plan9,!linux,!openbsd
+
+package bolt
+
+// fdatasync flushes written data to a file descriptor.
+func fdatasync(db *DB) error {
+	return db.file.Sync()
+}

vendor/github.com/boltdb/bolt/bucket.go

@@ -0,0 +1,777 @@
+package bolt
+
+import (
+	"bytes"
+	"fmt"
+	"unsafe"
+)
+
+const (
+	// MaxKeySize is the maximum length of a key, in bytes.
+	MaxKeySize = 32768
+
+	// MaxValueSize is the maximum length of a value, in bytes.
+	MaxValueSize = (1 << 31) - 2
+)
+
+const (
+	maxUint = ^uint(0)
+	minUint = 0
+	maxInt  = int(^uint(0) >> 1)
+	minInt  = -maxInt - 1
+)
+
+const bucketHeaderSize = int(unsafe.Sizeof(bucket{}))
+
+const (
+	minFillPercent = 0.1
+	maxFillPercent = 1.0
+)
+
+// DefaultFillPercent is the percentage that split pages are filled.
+// This value can be changed by setting Bucket.FillPercent.
+const DefaultFillPercent = 0.5
+
+// Bucket represents a collection of key/value pairs inside the database.
+type Bucket struct {
+	*bucket
+	tx       *Tx                // the associated transaction
+	buckets  map[string]*Bucket // subbucket cache
+	page     *page              // inline page reference
+	rootNode *node              // materialized node for the root page.
+	nodes    map[pgid]*node     // node cache
+
+	// Sets the threshold for filling nodes when they split. By default,
+	// the bucket will fill to 50% but it can be useful to increase this
+	// amount if you know that your write workloads are mostly append-only.
+	//
+	// This is non-persisted across transactions so it must be set in every Tx.
+	FillPercent float64
+}
+
+// bucket represents the on-file representation of a bucket.
+// This is stored as the "value" of a bucket key. If the bucket is small enough,
+// then its root page can be stored inline in the "value", after the bucket
+// header. In the case of inline buckets, the "root" will be 0.
+type bucket struct {
+	root     pgid   // page id of the bucket's root-level page
+	sequence uint64 // monotonically incrementing, used by NextSequence()
+}
+
+// newBucket returns a new bucket associated with a transaction.
+func newBucket(tx *Tx) Bucket {
+	var b = Bucket{tx: tx, FillPercent: DefaultFillPercent}
+	if tx.writable {
+		b.buckets = make(map[string]*Bucket)
+		b.nodes = make(map[pgid]*node)
+	}
+	return b
+}
+
+// Tx returns the tx of the bucket.
+func (b *Bucket) Tx() *Tx {
+	return b.tx
+}
+
+// Root returns the root of the bucket.
+func (b *Bucket) Root() pgid {
+	return b.root
+}
+
+// Writable returns whether the bucket is writable.
+func (b *Bucket) Writable() bool {
+	return b.tx.writable
+}
+
+// Cursor creates a cursor associated with the bucket.
+// The cursor is only valid as long as the transaction is open.
+// Do not use a cursor after the transaction is closed.
+func (b *Bucket) Cursor() *Cursor {
+	// Update transaction statistics.
+	b.tx.stats.CursorCount++
+
+	// Allocate and return a cursor.
+	return &Cursor{
+		bucket: b,
+		stack:  make([]elemRef, 0),
+	}
+}
+
+// Bucket retrieves a nested bucket by name.
+// Returns nil if the bucket does not exist.
+// The bucket instance is only valid for the lifetime of the transaction.
+func (b *Bucket) Bucket(name []byte) *Bucket {
+	if b.buckets != nil {
+		if child := b.buckets[string(name)]; child != nil {
+			return child
+		}
+	}
+
+	// Move cursor to key.
+	c := b.Cursor()
+	k, v, flags := c.seek(name)
+
+	// Return nil if the key doesn't exist or it is not a bucket.
+	if !bytes.Equal(name, k) || (flags&bucketLeafFlag) == 0 {
+		return nil
+	}
+
+	// Otherwise create a bucket and cache it.
+	var child = b.openBucket(v)
+	if b.buckets != nil {
+		b.buckets[string(name)] = child
+	}
+
+	return child
+}
+
+// Helper method that re-interprets a sub-bucket value
+// from a parent into a Bucket
+func (b *Bucket) openBucket(value []byte) *Bucket {
+	var child = newBucket(b.tx)
+
+	// If unaligned load/stores are broken on this arch and value is
+	// unaligned simply clone to an aligned byte array.
+	unaligned := brokenUnaligned && uintptr(unsafe.Pointer(&value[0]))&3 != 0
+
+	if unaligned {
+		value = cloneBytes(value)
+	}
+
+	// If this is a writable transaction then we need to copy the bucket entry.
+	// Read-only transactions can point directly at the mmap entry.
+	if b.tx.writable && !unaligned {
+		child.bucket = &bucket{}
+		*child.bucket = *(*bucket)(unsafe.Pointer(&value[0]))
+	} else {
+		child.bucket = (*bucket)(unsafe.Pointer(&value[0]))
+	}
+
+	// Save a reference to the inline page if the bucket is inline.
+	if child.root == 0 {
+		child.page = (*page)(unsafe.Pointer(&value[bucketHeaderSize]))
+	}
+
+	return &child
+}
+
+// CreateBucket creates a new bucket at the given key and returns the new bucket.
+// Returns an error if the key already exists, if the bucket name is blank, or if the bucket name is too long.
+// The bucket instance is only valid for the lifetime of the transaction.
+func (b *Bucket) CreateBucket(key []byte) (*Bucket, error) {
+	if b.tx.db == nil {
+		return nil, ErrTxClosed
+	} else if !b.tx.writable {
+		return nil, ErrTxNotWritable
+	} else if len(key) == 0 {
+		return nil, ErrBucketNameRequired
+	}
+
+	// Move cursor to correct position.
+	c := b.Cursor()
+	k, _, flags := c.seek(key)
+
+	// Return an error if there is an existing key.
+	if bytes.Equal(key, k) {
+		if (flags & bucketLeafFlag) != 0 {
+			return nil, ErrBucketExists
+		}
+		return nil, ErrIncompatibleValue
+	}
+
+	// Create empty, inline bucket.
+	var bucket = Bucket{
+		bucket:      &bucket{},
+		rootNode:    &node{isLeaf: true},
+		FillPercent: DefaultFillPercent,
+	}
+	var value = bucket.write()
+
+	// Insert into node.
+	key = cloneBytes(key)
+	c.node().put(key, key, value, 0, bucketLeafFlag)
+
+	// Since subbuckets are not allowed on inline buckets, we need to
+	// dereference the inline page, if it exists. This will cause the bucket
+	// to be treated as a regular, non-inline bucket for the rest of the tx.
+	b.page = nil
+
+	return b.Bucket(key), nil
+}
+
+// CreateBucketIfNotExists creates a new bucket if it doesn't already exist and returns a reference to it.
+// Returns an error if the bucket name is blank, or if the bucket name is too long.
+// The bucket instance is only valid for the lifetime of the transaction.
+func (b *Bucket) CreateBucketIfNotExists(key []byte) (*Bucket, error) {
+	child, err := b.CreateBucket(key)
+	if err == ErrBucketExists {
+		return b.Bucket(key), nil
+	} else if err != nil {
+		return nil, err
+	}
+	return child, nil
+}
+
+// DeleteBucket deletes a bucket at the given key.
+// Returns an error if the bucket does not exists, or if the key represents a non-bucket value.
+func (b *Bucket) DeleteBucket(key []byte) error {
+	if b.tx.db == nil {
+		return ErrTxClosed
+	} else if !b.Writable() {
+		return ErrTxNotWritable
+	}
+
+	// Move cursor to correct position.
+	c := b.Cursor()
+	k, _, flags := c.seek(key)
+
+	// Return an error if bucket doesn't exist or is not a bucket.
+	if !bytes.Equal(key, k) {
+		return ErrBucketNotFound
+	} else if (flags & bucketLeafFlag) == 0 {
+		return ErrIncompatibleValue
+	}
+
+	// Recursively delete all child buckets.
+	child := b.Bucket(key)
+	err := child.ForEach(func(k, v []byte) error {
+		if v == nil {
+			if err := child.DeleteBucket(k); err != nil {
+				return fmt.Errorf("delete bucket: %s", err)
+			}
+		}
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+
+	// Remove cached copy.
+	delete(b.buckets, string(key))
+
+	// Release all bucket pages to freelist.
+	child.nodes = nil
+	child.rootNode = nil
+	child.free()
+
+	// Delete the node if we have a matching key.
+	c.node().del(key)
+
+	return nil
+}
+
+// Get retrieves the value for a key in the bucket.
+// Returns a nil value if the key does not exist or if the key is a nested bucket.
+// The returned value is only valid for the life of the transaction.
+func (b *Bucket) Get(key []byte) []byte {
+	k, v, flags := b.Cursor().seek(key)
+
+	// Return nil if this is a bucket.
+	if (flags & bucketLeafFlag) != 0 {
+		return nil
+	}
+
+	// If our target node isn't the same key as what's passed in then return nil.
+	if !bytes.Equal(key, k) {
+		return nil
+	}
+	return v
+}
+
+// Put sets the value for a key in the bucket.
+// If the key exist then its previous value will be overwritten.
+// Supplied value must remain valid for the life of the transaction.
+// Returns an error if the bucket was created from a read-only transaction, if the key is blank, if the key is too large, or if the value is too large.
+func (b *Bucket) Put(key []byte, value []byte) error {
+	if b.tx.db == nil {
+		return ErrTxClosed
+	} else if !b.Writable() {
+		return ErrTxNotWritable
+	} else if len(key) == 0 {
+		return ErrKeyRequired
+	} else if len(key) > MaxKeySize {
+		return ErrKeyTooLarge
+	} else if int64(len(value)) > MaxValueSize {
+		return ErrValueTooLarge
+	}
+
+	// Move cursor to correct position.
+	c := b.Cursor()
+	k, _, flags := c.seek(key)
+
+	// Return an error if there is an existing key with a bucket value.
+	if bytes.Equal(key, k) && (flags&bucketLeafFlag) != 0 {
+		return ErrIncompatibleValue
+	}
+
+	// Insert into node.
+	key = cloneBytes(key)
+	c.node().put(key, key, value, 0, 0)
+
+	return nil
+}
+
+// Delete removes a key from the bucket.
+// If the key does not exist then nothing is done and a nil error is returned.
+// Returns an error if the bucket was created from a read-only transaction.
+func (b *Bucket) Delete(key []byte) error {
+	if b.tx.db == nil {
+		return ErrTxClosed
+	} else if !b.Writable() {
+		return ErrTxNotWritable
+	}
+
+	// Move cursor to correct position.
+	c := b.Cursor()
+	_, _, flags := c.seek(key)
+
+	// Return an error if there is already existing bucket value.
+	if (flags & bucketLeafFlag) != 0 {
+		return ErrIncompatibleValue
+	}
+
+	// Delete the node if we have a matching key.
+	c.node().del(key)
+
+	return nil
+}
+
+// Sequence returns the current integer for the bucket without incrementing it.
+func (b *Bucket) Sequence() uint64 { return b.bucket.sequence }
+
+// SetSequence updates the sequence number for the bucket.
+func (b *Bucket) SetSequence(v uint64) error {
+	if b.tx.db == nil {
+		return ErrTxClosed
+	} else if !b.Writable() {
+		return ErrTxNotWritable
+	}
+
+	// Materialize the root node if it hasn't been already so that the
+	// bucket will be saved during commit.
+	if b.rootNode == nil {
+		_ = b.node(b.root, nil)
+	}
+
+	// Increment and return the sequence.
+	b.bucket.sequence = v
+	return nil
+}
+
+// NextSequence returns an autoincrementing integer for the bucket.
+func (b *Bucket) NextSequence() (uint64, error) {
+	if b.tx.db == nil {
+		return 0, ErrTxClosed
+	} else if !b.Writable() {
+		return 0, ErrTxNotWritable
+	}
+
+	// Materialize the root node if it hasn't been already so that the
+	// bucket will be saved during commit.
+	if b.rootNode == nil {
+		_ = b.node(b.root, nil)
+	}
+
+	// Increment and return the sequence.
+	b.bucket.sequence++
+	return b.bucket.sequence, nil
+}
+
+// ForEach executes a function for each key/value pair in a bucket.
+// If the provided function returns an error then the iteration is stopped and
+// the error is returned to the caller. The provided function must not modify
+// the bucket; this will result in undefined behavior.
+func (b *Bucket) ForEach(fn func(k, v []byte) error) error {
+	if b.tx.db == nil {
+		return ErrTxClosed
+	}
+	c := b.Cursor()
+	for k, v := c.First(); k != nil; k, v = c.Next() {
+		if err := fn(k, v); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Stat returns stats on a bucket.
+func (b *Bucket) Stats() BucketStats {
+	var s, subStats BucketStats
+	pageSize := b.tx.db.pageSize
+	s.BucketN += 1
+	if b.root == 0 {
+		s.InlineBucketN += 1
+	}
+	b.forEachPage(func(p *page, depth int) {
+		if (p.flags & leafPageFlag) != 0 {
+			s.KeyN += int(p.count)
+
+			// used totals the used bytes for the page
+			used := pageHeaderSize
+
+			if p.count != 0 {
+				// If page has any elements, add all element headers.
+				used += leafPageElementSize * int(p.count-1)
+
+				// Add all element key, value sizes.
+				// The computation takes advantage of the fact that the position
+				// of the last element's key/value equals to the total of the sizes
+				// of all previous elements' keys and values.
+				// It also includes the last element's header.
+				lastElement := p.leafPageElement(p.count - 1)
+				used += int(lastElement.pos + lastElement.ksize + lastElement.vsize)
+			}
+
+			if b.root == 0 {
+				// For inlined bucket just update the inline stats
+				s.InlineBucketInuse += used
+			} else {
+				// For non-inlined bucket update all the leaf stats
+				s.LeafPageN++
+				s.LeafInuse += used
+				s.LeafOverflowN += int(p.overflow)
+
+				// Collect stats from sub-buckets.
+				// Do that by iterating over all element headers
+				// looking for the ones with the bucketLeafFlag.
+				for i := uint16(0); i < p.count; i++ {
+					e := p.leafPageElement(i)
+					if (e.flags & bucketLeafFlag) != 0 {
+						// For any bucket element, open the element value
+						// and recursively call Stats on the contained bucket.
+						subStats.Add(b.openBucket(e.value()).Stats())
+					}
+				}
+			}
+		} else if (p.flags & branchPageFlag) != 0 {
+			s.BranchPageN++
+			lastElement := p.branchPageElement(p.count - 1)
+
+			// used totals the used bytes for the page
+			// Add header and all element headers.
+			used := pageHeaderSize + (branchPageElementSize * int(p.count-1))
+
+			// Add size of all keys and values.
+			// Again, use the fact that last element's position equals to
+			// the total of key, value sizes of all previous elements.
+			used += int(lastElement.pos + lastElement.ksize)
+			s.BranchInuse += used
+			s.BranchOverflowN += int(p.overflow)
+		}
+
+		// Keep track of maximum page depth.
+		if depth+1 > s.Depth {
+			s.Depth = (depth + 1)
+		}
+	})
+
+	// Alloc stats can be computed from page counts and pageSize.
+	s.BranchAlloc = (s.BranchPageN + s.BranchOverflowN) * pageSize
+	s.LeafAlloc = (s.LeafPageN + s.LeafOverflowN) * pageSize
+
+	// Add the max depth of sub-buckets to get total nested depth.
+	s.Depth += subStats.Depth
+	// Add the stats for all sub-buckets
+	s.Add(subStats)
+	return s
+}
+
+// forEachPage iterates over every page in a bucket, including inline pages.
+func (b *Bucket) forEachPage(fn func(*page, int)) {
+	// If we have an inline page then just use that.
+	if b.page != nil {
+		fn(b.page, 0)
+		return
+	}
+
+	// Otherwise traverse the page hierarchy.
+	b.tx.forEachPage(b.root, 0, fn)
+}
+
+// forEachPageNode iterates over every page (or node) in a bucket.
+// This also includes inline pages.
+func (b *Bucket) forEachPageNode(fn func(*page, *node, int)) {
+	// If we have an inline page or root node then just use that.
+	if b.page != nil {
+		fn(b.page, nil, 0)
+		return
+	}
+	b._forEachPageNode(b.root, 0, fn)
+}
+
+func (b *Bucket) _forEachPageNode(pgid pgid, depth int, fn func(*page, *node, int)) {
+	var p, n = b.pageNode(pgid)
+
+	// Execute function.
+	fn(p, n, depth)
+
+	// Recursively loop over children.
+	if p != nil {
+		if (p.flags & branchPageFlag) != 0 {
+			for i := 0; i < int(p.count); i++ {
+				elem := p.branchPageElement(uint16(i))
+				b._forEachPageNode(elem.pgid, depth+1, fn)
+			}
+		}
+	} else {
+		if !n.isLeaf {
+			for _, inode := range n.inodes {
+				b._forEachPageNode(inode.pgid, depth+1, fn)
+			}
+		}
+	}
+}
+
+// spill writes all the nodes for this bucket to dirty pages.
+func (b *Bucket) spill() error {
+	// Spill all child buckets first.
+	for name, child := range b.buckets {
+		// If the child bucket is small enough and it has no child buckets then
+		// write it inline into the parent bucket's page. Otherwise spill it
+		// like a normal bucket and make the parent value a pointer to the page.
+		var value []byte
+		if child.inlineable() {
+			child.free()
+			value = child.write()
+		} else {
+			if err := child.spill(); err != nil {
+				return err
+			}
+
+			// Update the child bucket header in this bucket.
+			value = make([]byte, unsafe.Sizeof(bucket{}))
+			var bucket = (*bucket)(unsafe.Pointer(&value[0]))
+			*bucket = *child.bucket
+		}
+
+		// Skip writing the bucket if there are no materialized nodes.
+		if child.rootNode == nil {
+			continue
+		}
+
+		// Update parent node.
+		var c = b.Cursor()
+		k, _, flags := c.seek([]byte(name))
+		if !bytes.Equal([]byte(name), k) {
+			panic(fmt.Sprintf("misplaced bucket header: %x -> %x", []byte(name), k))
+		}
+		if flags&bucketLeafFlag == 0 {
+			panic(fmt.Sprintf("unexpected bucket header flag: %x", flags))
+		}
+		c.node().put([]byte(name), []byte(name), value, 0, bucketLeafFlag)
+	}
+
+	// Ignore if there's not a materialized root node.
+	if b.rootNode == nil {
+		return nil
+	}
+
+	// Spill nodes.
+	if err := b.rootNode.spill(); err != nil {
+		return err
+	}
+	b.rootNode = b.rootNode.root()
+
+	// Update the root node for this bucket.
+	if b.rootNode.pgid >= b.tx.meta.pgid {
+		panic(fmt.Sprintf("pgid (%d) above high water mark (%d)", b.rootNode.pgid, b.tx.meta.pgid))
+	}
+	b.root = b.rootNode.pgid
+
+	return nil
+}
+
+// inlineable returns true if a bucket is small enough to be written inline
+// and if it contains no subbuckets. Otherwise returns false.
+func (b *Bucket) inlineable() bool {
+	var n = b.rootNode
+
+	// Bucket must only contain a single leaf node.
+	if n == nil || !n.isLeaf {
+		return false
+	}
+
+	// Bucket is not inlineable if it contains subbuckets or if it goes beyond
+	// our threshold for inline bucket size.
+	var size = pageHeaderSize
+	for _, inode := range n.inodes {
+		size += leafPageElementSize + len(inode.key) + len(inode.value)
+
+		if inode.flags&bucketLeafFlag != 0 {
+			return false
+		} else if size > b.maxInlineBucketSize() {
+			return false
+		}
+	}
+
+	return true
+}
+
+// Returns the maximum total size of a bucket to make it a candidate for inlining.
+func (b *Bucket) maxInlineBucketSize() int {
+	return b.tx.db.pageSize / 4
+}
+
+// write allocates and writes a bucket to a byte slice.
+func (b *Bucket) write() []byte {
+	// Allocate the appropriate size.
+	var n = b.rootNode
+	var value = make([]byte, bucketHeaderSize+n.size())
+
+	// Write a bucket header.
+	var bucket = (*bucket)(unsafe.Pointer(&value[0]))
+	*bucket = *b.bucket
+
+	// Convert byte slice to a fake page and write the root node.
+	var p = (*page)(unsafe.Pointer(&value[bucketHeaderSize]))
+	n.write(p)
+
+	return value
+}
+
+// rebalance attempts to balance all nodes.
+func (b *Bucket) rebalance() {
+	for _, n := range b.nodes {
+		n.rebalance()
+	}
+	for _, child := range b.buckets {
+		child.rebalance()
+	}
+}
+
+// node creates a node from a page and associates it with a given parent.
+func (b *Bucket) node(pgid pgid, parent *node) *node {
+	_assert(b.nodes != nil, "nodes map expected")
+
+	// Retrieve node if it's already been created.
+	if n := b.nodes[pgid]; n != nil {
+		return n
+	}
+
+	// Otherwise create a node and cache it.
+	n := &node{bucket: b, parent: parent}
+	if parent == nil {
+		b.rootNode = n
+	} else {
+		parent.children = append(parent.children, n)
+	}
+
+	// Use the inline page if this is an inline bucket.
+	var p = b.page
+	if p == nil {
+		p = b.tx.page(pgid)
+	}
+
+	// Read the page into the node and cache it.
+	n.read(p)
+	b.nodes[pgid] = n
+
+	// Update statistics.
+	b.tx.stats.NodeCount++
+
+	return n
+}
+
+// free recursively frees all pages in the bucket.
+func (b *Bucket) free() {
+	if b.root == 0 {
+		return
+	}
+
+	var tx = b.tx
+	b.forEachPageNode(func(p *page, n *node, _ int) {
+		if p != nil {
+			tx.db.freelist.free(tx.meta.txid, p)
+		} else {
+			n.free()
+		}
+	})
+	b.root = 0
+}
+
+// dereference removes all references to the old mmap.
+func (b *Bucket) dereference() {
+	if b.rootNode != nil {
+		b.rootNode.root().dereference()
+	}
+
+	for _, child := range b.buckets {
+		child.dereference()
+	}
+}
+
+// pageNode returns the in-memory node, if it exists.
+// Otherwise returns the underlying page.
+func (b *Bucket) pageNode(id pgid) (*page, *node) {
+	// Inline buckets have a fake page embedded in their value so treat them
+	// differently. We'll return the rootNode (if available) or the fake page.
+	if b.root == 0 {
+		if id != 0 {
+			panic(fmt.Sprintf("inline bucket non-zero page access(2): %d != 0", id))
+		}
+		if b.rootNode != nil {
+			return nil, b.rootNode
+		}
+		return b.page, nil
+	}
+
+	// Check the node cache for non-inline buckets.
+	if b.nodes != nil {
+		if n := b.nodes[id]; n != nil {
+			return nil, n
+		}
+	}
+
+	// Finally lookup the page from the transaction if no node is materialized.
+	return b.tx.page(id), nil
+}
+
+// BucketStats records statistics about resources used by a bucket.
+type BucketStats struct {
+	// Page count statistics.
+	BranchPageN     int // number of logical branch pages
+	BranchOverflowN int // number of physical branch overflow pages
+	LeafPageN       int // number of logical leaf pages
+	LeafOverflowN   int // number of physical leaf overflow pages
+
+	// Tree statistics.
+	KeyN  int // number of keys/value pairs
+	Depth int // number of levels in B+tree
+
+	// Page size utilization.
+	BranchAlloc int // bytes allocated for physical branch pages
+	BranchInuse int // bytes actually used for branch data
+	LeafAlloc   int // bytes allocated for physical leaf pages
+	LeafInuse   int // bytes actually used for leaf data
+
+	// Bucket statistics
+	BucketN           int // total number of buckets including the top bucket
+	InlineBucketN     int // total number on inlined buckets
+	InlineBucketInuse int // bytes used for inlined buckets (also accounted for in LeafInuse)
+}
+
+func (s *BucketStats) Add(other BucketStats) {
+	s.BranchPageN += other.BranchPageN
+	s.BranchOverflowN += other.BranchOverflowN
+	s.LeafPageN += other.LeafPageN
+	s.LeafOverflowN += other.LeafOverflowN
+	s.KeyN += other.KeyN
+	if s.Depth < other.Depth {
+		s.Depth = other.Depth
+	}
+	s.BranchAlloc += other.BranchAlloc
+	s.BranchInuse += other.BranchInuse
+	s.LeafAlloc += other.LeafAlloc
+	s.LeafInuse += other.LeafInuse
+
+	s.BucketN += other.BucketN
+	s.InlineBucketN += other.InlineBucketN
+	s.InlineBucketInuse += other.InlineBucketInuse
+}
+
+// cloneBytes returns a copy of a given slice.
+func cloneBytes(v []byte) []byte {
+	var clone = make([]byte, len(v))
+	copy(clone, v)
+	return clone
+}

vendor/github.com/boltdb/bolt/cursor.go

@@ -0,0 +1,400 @@
+package bolt
+
+import (
+	"bytes"
+	"fmt"
+	"sort"
+)
+
+// Cursor represents an iterator that can traverse over all key/value pairs in a bucket in sorted order.
+// Cursors see nested buckets with value == nil.
+// Cursors can be obtained from a transaction and are valid as long as the transaction is open.
+//
+// Keys and values returned from the cursor are only valid for the life of the transaction.
+//
+// Changing data while traversing with a cursor may cause it to be invalidated
+// and return unexpected keys and/or values. You must reposition your cursor
+// after mutating data.
+type Cursor struct {
+	bucket *Bucket
+	stack  []elemRef
+}
+
+// Bucket returns the bucket that this cursor was created from.
+func (c *Cursor) Bucket() *Bucket {
+	return c.bucket
+}
+
+// First moves the cursor to the first item in the bucket and returns its key and value.
+// If the bucket is empty then a nil key and value are returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) First() (key []byte, value []byte) {
+	_assert(c.bucket.tx.db != nil, "tx closed")
+	c.stack = c.stack[:0]
+	p, n := c.bucket.pageNode(c.bucket.root)
+	c.stack = append(c.stack, elemRef{page: p, node: n, index: 0})
+	c.first()
+
+	// If we land on an empty page then move to the next value.
+	// https://github.com/boltdb/bolt/issues/450
+	if c.stack[len(c.stack)-1].count() == 0 {
+		c.next()
+	}
+
+	k, v, flags := c.keyValue()
+	if (flags & uint32(bucketLeafFlag)) != 0 {
+		return k, nil
+	}
+	return k, v
+
+}
+
+// Last moves the cursor to the last item in the bucket and returns its key and value.
+// If the bucket is empty then a nil key and value are returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) Last() (key []byte, value []byte) {
+	_assert(c.bucket.tx.db != nil, "tx closed")
+	c.stack = c.stack[:0]
+	p, n := c.bucket.pageNode(c.bucket.root)
+	ref := elemRef{page: p, node: n}
+	ref.index = ref.count() - 1
+	c.stack = append(c.stack, ref)
+	c.last()
+	k, v, flags := c.keyValue()
+	if (flags & uint32(bucketLeafFlag)) != 0 {
+		return k, nil
+	}
+	return k, v
+}
+
+// Next moves the cursor to the next item in the bucket and returns its key and value.
+// If the cursor is at the end of the bucket then a nil key and value are returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) Next() (key []byte, value []byte) {
+	_assert(c.bucket.tx.db != nil, "tx closed")
+	k, v, flags := c.next()
+	if (flags & uint32(bucketLeafFlag)) != 0 {
+		return k, nil
+	}
+	return k, v
+}
+
+// Prev moves the cursor to the previous item in the bucket and returns its key and value.
+// If the cursor is at the beginning of the bucket then a nil key and value are returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) Prev() (key []byte, value []byte) {
+	_assert(c.bucket.tx.db != nil, "tx closed")
+
+	// Attempt to move back one element until we're successful.
+	// Move up the stack as we hit the beginning of each page in our stack.
+	for i := len(c.stack) - 1; i >= 0; i-- {
+		elem := &c.stack[i]
+		if elem.index > 0 {
+			elem.index--
+			break
+		}
+		c.stack = c.stack[:i]
+	}
+
+	// If we've hit the end then return nil.
+	if len(c.stack) == 0 {
+		return nil, nil
+	}
+
+	// Move down the stack to find the last element of the last leaf under this branch.
+	c.last()
+	k, v, flags := c.keyValue()
+	if (flags & uint32(bucketLeafFlag)) != 0 {
+		return k, nil
+	}
+	return k, v
+}
+
+// Seek moves the cursor to a given key and returns it.
+// If the key does not exist then the next key is used. If no keys
+// follow, a nil key is returned.
+// The returned key and value are only valid for the life of the transaction.
+func (c *Cursor) Seek(seek []byte) (key []byte, value []byte) {
+	k, v, flags := c.seek(seek)
+
+	// If we ended up after the last element of a page then move to the next one.
+	if ref := &c.stack[len(c.stack)-1]; ref.index >= ref.count() {
+		k, v, flags = c.next()
+	}
+
+	if k == nil {
+		return nil, nil
+	} else if (flags & uint32(bucketLeafFlag)) != 0 {
+		return k, nil
+	}
+	return k, v
+}
+
+// Delete removes the current key/value under the cursor from the bucket.
+// Delete fails if current key/value is a bucket or if the transaction is not writable.
+func (c *Cursor) Delete() error {
+	if c.bucket.tx.db == nil {
+		return ErrTxClosed
+	} else if !c.bucket.Writable() {
+		return ErrTxNotWritable
+	}
+
+	key, _, flags := c.keyValue()
+	// Return an error if current value is a bucket.
+	if (flags & bucketLeafFlag) != 0 {
+		return ErrIncompatibleValue
+	}
+	c.node().del(key)
+
+	return nil
+}
+
+// seek moves the cursor to a given key and returns it.
+// If the key does not exist then the next key is used.
+func (c *Cursor) seek(seek []byte) (key []byte, value []byte, flags uint32) {
+	_assert(c.bucket.tx.db != nil, "tx closed")
+
+	// Start from root page/node and traverse to correct page.
+	c.stack = c.stack[:0]
+	c.search(seek, c.bucket.root)
+	ref := &c.stack[len(c.stack)-1]
+
+	// If the cursor is pointing to the end of page/node then return nil.
+	if ref.index >= ref.count() {
+		return nil, nil, 0
+	}
+
+	// If this is a bucket then return a nil value.
+	return c.keyValue()
+}
+
+// first moves the cursor to the first leaf element under the last page in the stack.
+func (c *Cursor) first() {
+	for {
+		// Exit when we hit a leaf page.
+		var ref = &c.stack[len(c.stack)-1]
+		if ref.isLeaf() {
+			break
+		}
+
+		// Keep adding pages pointing to the first element to the stack.
+		var pgid pgid
+		if ref.node != nil {
+			pgid = ref.node.inodes[ref.index].pgid
+		} else {
+			pgid = ref.page.branchPageElement(uint16(ref.index)).pgid
+		}
+		p, n := c.bucket.pageNode(pgid)
+		c.stack = append(c.stack, elemRef{page: p, node: n, index: 0})
+	}
+}
+
+// last moves the cursor to the last leaf element under the last page in the stack.
+func (c *Cursor) last() {
+	for {
+		// Exit when we hit a leaf page.
+		ref := &c.stack[len(c.stack)-1]
+		if ref.isLeaf() {
+			break
+		}
+
+		// Keep adding pages pointing to the last element in the stack.
+		var pgid pgid
+		if ref.node != nil {
+			pgid = ref.node.inodes[ref.index].pgid
+		} else {
+			pgid = ref.page.branchPageElement(uint16(ref.index)).pgid
+		}
+		p, n := c.bucket.pageNode(pgid)
+
+		var nextRef = elemRef{page: p, node: n}
+		nextRef.index = nextRef.count() - 1
+		c.stack = append(c.stack, nextRef)
+	}
+}
+
+// next moves to the next leaf element and returns the key and value.
+// If the cursor is at the last leaf element then it stays there and returns nil.
+func (c *Cursor) next() (key []byte, value []byte, flags uint32) {
+	for {
+		// Attempt to move over one element until we're successful.
+		// Move up the stack as we hit the end of each page in our stack.
+		var i int
+		for i = len(c.stack) - 1; i >= 0; i-- {
+			elem := &c.stack[i]
+			if elem.index < elem.count()-1 {
+				elem.index++
+				break
+			}
+		}
+
+		// If we've hit the root page then stop and return. This will leave the
+		// cursor on the last element of the last page.
+		if i == -1 {
+			return nil, nil, 0
+		}
+
+		// Otherwise start from where we left off in the stack and find the
+		// first element of the first leaf page.
+		c.stack = c.stack[:i+1]
+		c.first()
+
+		// If this is an empty page then restart and move back up the stack.
+		// https://github.com/boltdb/bolt/issues/450
+		if c.stack[len(c.stack)-1].count() == 0 {
+			continue
+		}
+
+		return c.keyValue()
+	}
+}
+
+// search recursively performs a binary search against a given page/node until it finds a given key.
+func (c *Cursor) search(key []byte, pgid pgid) {
+	p, n := c.bucket.pageNode(pgid)
+	if p != nil && (p.flags&(branchPageFlag|leafPageFlag)) == 0 {
+		panic(fmt.Sprintf("invalid page type: %d: %x", p.id, p.flags))
+	}
+	e := elemRef{page: p, node: n}
+	c.stack = append(c.stack, e)
+
+	// If we're on a leaf page/node then find the specific node.
+	if e.isLeaf() {
+		c.nsearch(key)
+		return
+	}
+
+	if n != nil {
+		c.searchNode(key, n)
+		return
+	}
+	c.searchPage(key, p)
+}
+
+func (c *Cursor) searchNode(key []byte, n *node) {
+	var exact bool
+	index := sort.Search(len(n.inodes), func(i int) bool {
+		// TODO(benbjohnson): Optimize this range search. It's a bit hacky right now.
+		// sort.Search() finds the lowest index where f() != -1 but we need the highest index.
+		ret := bytes.Compare(n.inodes[i].key, key)
+		if ret == 0 {
+			exact = true
+		}
+		return ret != -1
+	})
+	if !exact && index > 0 {
+		index--
+	}
+	c.stack[len(c.stack)-1].index = index
+
+	// Recursively search to the next page.
+	c.search(key, n.inodes[index].pgid)
+}
+
+func (c *Cursor) searchPage(key []byte, p *page) {
+	// Binary search for the correct range.
+	inodes := p.branchPageElements()
+
+	var exact bool
+	index := sort.Search(int(p.count), func(i int) bool {
+		// TODO(benbjohnson): Optimize this range search. It's a bit hacky right now.
+		// sort.Search() finds the lowest index where f() != -1 but we need the highest index.
+		ret := bytes.Compare(inodes[i].key(), key)
+		if ret == 0 {
+			exact = true
+		}
+		return ret != -1
+	})
+	if !exact && index > 0 {
+		index--
+	}
+	c.stack[len(c.stack)-1].index = index
+
+	// Recursively search to the next page.
+	c.search(key, inodes[index].pgid)
+}
+
+// nsearch searches the leaf node on the top of the stack for a key.
+func (c *Cursor) nsearch(key []byte) {
+	e := &c.stack[len(c.stack)-1]
+	p, n := e.page, e.node
+
+	// If we have a node then search its inodes.
+	if n != nil {
+		index := sort.Search(len(n.inodes), func(i int) bool {
+			return bytes.Compare(n.inodes[i].key, key) != -1
+		})
+		e.index = index
+		return
+	}
+
+	// If we have a page then search its leaf elements.
+	inodes := p.leafPageElements()
+	index := sort.Search(int(p.count), func(i int) bool {
+		return bytes.Compare(inodes[i].key(), key) != -1
+	})
+	e.index = index
+}
+
+// keyValue returns the key and value of the current leaf element.
+func (c *Cursor) keyValue() ([]byte, []byte, uint32) {
+	ref := &c.stack[len(c.stack)-1]
+	if ref.count() == 0 || ref.index >= ref.count() {
+		return nil, nil, 0
+	}
+
+	// Retrieve value from node.
+	if ref.node != nil {
+		inode := &ref.node.inodes[ref.index]
+		return inode.key, inode.value, inode.flags
+	}
+
+	// Or retrieve value from page.
+	elem := ref.page.leafPageElement(uint16(ref.index))
+	return elem.key(), elem.value(), elem.flags
+}
+
+// node returns the node that the cursor is currently positioned on.
+func (c *Cursor) node() *node {
+	_assert(len(c.stack) > 0, "accessing a node with a zero-length cursor stack")
+
+	// If the top of the stack is a leaf node then just return it.
+	if ref := &c.stack[len(c.stack)-1]; ref.node != nil && ref.isLeaf() {
+		return ref.node
+	}
+
+	// Start from root and traverse down the hierarchy.
+	var n = c.stack[0].node
+	if n == nil {
+		n = c.bucket.node(c.stack[0].page.id, nil)
+	}
+	for _, ref := range c.stack[:len(c.stack)-1] {
+		_assert(!n.isLeaf, "expected branch node")
+		n = n.childAt(int(ref.index))
+	}
+	_assert(n.isLeaf, "expected leaf node")
+	return n
+}
+
+// elemRef represents a reference to an element on a given page/node.
+type elemRef struct {
+	page  *page
+	node  *node
+	index int
+}
+
+// isLeaf returns whether the ref is pointing at a leaf page/node.
+func (r *elemRef) isLeaf() bool {
+	if r.node != nil {
+		return r.node.isLeaf
+	}
+	return (r.page.flags & leafPageFlag) != 0
+}
+
+// count returns the number of inodes or page elements.
+func (r *elemRef) count() int {
+	if r.node != nil {
+		return len(r.node.inodes)
+	}
+	return int(r.page.count)
+}

vendor/github.com/boltdb/bolt/doc.go

@@ -0,0 +1,44 @@
+/*
+Package bolt implements a low-level key/value store in pure Go. It supports
+fully serializable transactions, ACID semantics, and lock-free MVCC with
+multiple readers and a single writer. Bolt can be used for projects that
+want a simple data store without the need to add large dependencies such as
+Postgres or MySQL.
+
+Bolt is a single-level, zero-copy, B+tree data store. This means that Bolt is
+optimized for fast read access and does not require recovery in the event of a
+system crash. Transactions which have not finished committing will simply be
+rolled back in the event of a crash.
+
+The design of Bolt is based on Howard Chu's LMDB database project.
+
+Bolt currently works on Windows, Mac OS X, and Linux.
+
+
+Basics
+
+There are only a few types in Bolt: DB, Bucket, Tx, and Cursor. The DB is
+a collection of buckets and is represented by a single file on disk. A bucket is
+a collection of unique keys that are associated with values.
+
+Transactions provide either read-only or read-write access to the database.
+Read-only transactions can retrieve key/value pairs and can use Cursors to
+iterate over the dataset sequentially. Read-write transactions can create and
+delete buckets and can insert and remove keys. Only one read-write transaction
+is allowed at a time.
+
+
+Caveats
+
+The database uses a read-only, memory-mapped data file to ensure that
+applications cannot corrupt the database, however, this means that keys and
+values returned from Bolt cannot be changed. Writing to a read-only byte slice
+will cause Go to panic.
+
+Keys and values retrieved from the database are only valid for the life of
+the transaction. When used outside the transaction, these byte slices can
+point to different data or can point to invalid memory which will cause a panic.
+
+
+*/
+package bolt

vendor/github.com/boltdb/bolt/errors.go

@@ -0,0 +1,71 @@
+package bolt
+
+import "errors"
+
+// These errors can be returned when opening or calling methods on a DB.
+var (
+	// ErrDatabaseNotOpen is returned when a DB instance is accessed before it
+	// is opened or after it is closed.
+	ErrDatabaseNotOpen = errors.New("database not open")
+
+	// ErrDatabaseOpen is returned when opening a database that is
+	// already open.
+	ErrDatabaseOpen = errors.New("database already open")
+
+	// ErrInvalid is returned when both meta pages on a database are invalid.
+	// This typically occurs when a file is not a bolt database.
+	ErrInvalid = errors.New("invalid database")
+
+	// ErrVersionMismatch is returned when the data file was created with a
+	// different version of Bolt.
+	ErrVersionMismatch = errors.New("version mismatch")
+
+	// ErrChecksum is returned when either meta page checksum does not match.
+	ErrChecksum = errors.New("checksum error")
+
+	// ErrTimeout is returned when a database cannot obtain an exclusive lock
+	// on the data file after the timeout passed to Open().
+	ErrTimeout = errors.New("timeout")
+)
+
+// These errors can occur when beginning or committing a Tx.
+var (
+	// ErrTxNotWritable is returned when performing a write operation on a
+	// read-only transaction.
+	ErrTxNotWritable = errors.New("tx not writable")
+
+	// ErrTxClosed is returned when committing or rolling back a transaction
+	// that has already been committed or rolled back.
+	ErrTxClosed = errors.New("tx closed")
+
+	// ErrDatabaseReadOnly is returned when a mutating transaction is started on a
+	// read-only database.
+	ErrDatabaseReadOnly = errors.New("database is in read-only mode")
+)
+
+// These errors can occur when putting or deleting a value or a bucket.
+var (
+	// ErrBucketNotFound is returned when trying to access a bucket that has
+	// not been created yet.
+	ErrBucketNotFound = errors.New("bucket not found")
+
+	// ErrBucketExists is returned when creating a bucket that already exists.
+	ErrBucketExists = errors.New("bucket already exists")
+
+	// ErrBucketNameRequired is returned when creating a bucket with a blank name.
+	ErrBucketNameRequired = errors.New("bucket name required")
+
+	// ErrKeyRequired is returned when inserting a zero-length key.
+	ErrKeyRequired = errors.New("key required")
+
+	// ErrKeyTooLarge is returned when inserting a key that is larger than MaxKeySize.
+	ErrKeyTooLarge = errors.New("key too large")
+
+	// ErrValueTooLarge is returned when inserting a value that is larger than MaxValueSize.
+	ErrValueTooLarge = errors.New("value too large")
+
+	// ErrIncompatibleValue is returned when trying create or delete a bucket
+	// on an existing non-bucket key or when trying to create or delete a
+	// non-bucket key on an existing bucket key.
+	ErrIncompatibleValue = errors.New("incompatible value")
+)

vendor/github.com/boltdb/bolt/freelist.go

@@ -0,0 +1,252 @@
+package bolt
+
+import (
+	"fmt"
+	"sort"
+	"unsafe"
+)
+
+// freelist represents a list of all pages that are available for allocation.
+// It also tracks pages that have been freed but are still in use by open transactions.
+type freelist struct {
+	ids     []pgid          // all free and available free page ids.
+	pending map[txid][]pgid // mapping of soon-to-be free page ids by tx.
+	cache   map[pgid]bool   // fast lookup of all free and pending page ids.
+}
+
+// newFreelist returns an empty, initialized freelist.
+func newFreelist() *freelist {
+	return &freelist{
+		pending: make(map[txid][]pgid),
+		cache:   make(map[pgid]bool),
+	}
+}
+
+// size returns the size of the page after serialization.
+func (f *freelist) size() int {
+	n := f.count()
+	if n >= 0xFFFF {
+		// The first element will be used to store the count. See freelist.write.
+		n++
+	}
+	return pageHeaderSize + (int(unsafe.Sizeof(pgid(0))) * n)
+}
+
+// count returns count of pages on the freelist
+func (f *freelist) count() int {
+	return f.free_count() + f.pending_count()
+}
+
+// free_count returns count of free pages
+func (f *freelist) free_count() int {
+	return len(f.ids)
+}
+
+// pending_count returns count of pending pages
+func (f *freelist) pending_count() int {
+	var count int
+	for _, list := range f.pending {
+		count += len(list)
+	}
+	return count
+}
+
+// copyall copies into dst a list of all free ids and all pending ids in one sorted list.
+// f.count returns the minimum length required for dst.
+func (f *freelist) copyall(dst []pgid) {
+	m := make(pgids, 0, f.pending_count())
+	for _, list := range f.pending {
+		m = append(m, list...)
+	}
+	sort.Sort(m)
+	mergepgids(dst, f.ids, m)
+}
+
+// allocate returns the starting page id of a contiguous list of pages of a given size.
+// If a contiguous block cannot be found then 0 is returned.
+func (f *freelist) allocate(n int) pgid {
+	if len(f.ids) == 0 {
+		return 0
+	}
+
+	var initial, previd pgid
+	for i, id := range f.ids {
+		if id <= 1 {
+			panic(fmt.Sprintf("invalid page allocation: %d", id))
+		}
+
+		// Reset initial page if this is not contiguous.
+		if previd == 0 || id-previd != 1 {
+			initial = id
+		}
+
+		// If we found a contiguous block then remove it and return it.
+		if (id-initial)+1 == pgid(n) {
+			// If we're allocating off the beginning then take the fast path
+			// and just adjust the existing slice. This will use extra memory
+			// temporarily but the append() in free() will realloc the slice
+			// as is necessary.
+			if (i + 1) == n {
+				f.ids = f.ids[i+1:]
+			} else {
+				copy(f.ids[i-n+1:], f.ids[i+1:])
+				f.ids = f.ids[:len(f.ids)-n]
+			}
+
+			// Remove from the free cache.
+			for i := pgid(0); i < pgid(n); i++ {
+				delete(f.cache, initial+i)
+			}
+
+			return initial
+		}
+
+		previd = id
+	}
+	return 0
+}
+
+// free releases a page and its overflow for a given transaction id.
+// If the page is already free then a panic will occur.
+func (f *freelist) free(txid txid, p *page) {
+	if p.id <= 1 {
+		panic(fmt.Sprintf("cannot free page 0 or 1: %d", p.id))
+	}
+
+	// Free page and all its overflow pages.
+	var ids = f.pending[txid]
+	for id := p.id; id <= p.id+pgid(p.overflow); id++ {
+		// Verify that page is not already free.
+		if f.cache[id] {
+			panic(fmt.Sprintf("page %d already freed", id))
+		}
+
+		// Add to the freelist and cache.
+		ids = append(ids, id)
+		f.cache[id] = true
+	}
+	f.pending[txid] = ids
+}
+
+// release moves all page ids for a transaction id (or older) to the freelist.
+func (f *freelist) release(txid txid) {
+	m := make(pgids, 0)
+	for tid, ids := range f.pending {
+		if tid <= txid {
+			// Move transaction's pending pages to the available freelist.
+			// Don't remove from the cache since the page is still free.
+			m = append(m, ids...)
+			delete(f.pending, tid)
+		}
+	}
+	sort.Sort(m)
+	f.ids = pgids(f.ids).merge(m)
+}
+
+// rollback removes the pages from a given pending tx.
+func (f *freelist) rollback(txid txid) {
+	// Remove page ids from cache.
+	for _, id := range f.pending[txid] {
+		delete(f.cache, id)
+	}
+
+	// Remove pages from pending list.
+	delete(f.pending, txid)
+}
+
+// freed returns whether a given page is in the free list.
+func (f *freelist) freed(pgid pgid) bool {
+	return f.cache[pgid]
+}
+
+// read initializes the freelist from a freelist page.
+func (f *freelist) read(p *page) {
+	// If the page.count is at the max uint16 value (64k) then it's considered
+	// an overflow and the size of the freelist is stored as the first element.
+	idx, count := 0, int(p.count)
+	if count == 0xFFFF {
+		idx = 1
+		count = int(((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[0])
+	}
+
+	// Copy the list of page ids from the freelist.
+	if count == 0 {
+		f.ids = nil
+	} else {
+		ids := ((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[idx:count]
+		f.ids = make([]pgid, len(ids))
+		copy(f.ids, ids)
+
+		// Make sure they're sorted.
+		sort.Sort(pgids(f.ids))
+	}
+
+	// Rebuild the page cache.
+	f.reindex()
+}
+
+// write writes the page ids onto a freelist page. All free and pending ids are
+// saved to disk since in the event of a program crash, all pending ids will
+// become free.
+func (f *freelist) write(p *page) error {
+	// Combine the old free pgids and pgids waiting on an open transaction.
+
+	// Update the header flag.
+	p.flags |= freelistPageFlag
+
+	// The page.count can only hold up to 64k elements so if we overflow that
+	// number then we handle it by putting the size in the first element.
+	lenids := f.count()
+	if lenids == 0 {
+		p.count = uint16(lenids)
+	} else if lenids < 0xFFFF {
+		p.count = uint16(lenids)
+		f.copyall(((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[:])
+	} else {
+		p.count = 0xFFFF
+		((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[0] = pgid(lenids)
+		f.copyall(((*[maxAllocSize]pgid)(unsafe.Pointer(&p.ptr)))[1:])
+	}
+
+	return nil
+}
+
+// reload reads the freelist from a page and filters out pending items.
+func (f *freelist) reload(p *page) {
+	f.read(p)
+
+	// Build a cache of only pending pages.
+	pcache := make(map[pgid]bool)
+	for _, pendingIDs := range f.pending {
+		for _, pendingID := range pendingIDs {
+			pcache[pendingID] = true
+		}
+	}
+
+	// Check each page in the freelist and build a new available freelist
+	// with any pages not in the pending lists.
+	var a []pgid
+	for _, id := range f.ids {
+		if !pcache[id] {
+			a = append(a, id)
+		}
+	}
+	f.ids = a
+
+	// Once the available list is rebuilt then rebuild the free cache so that
+	// it includes the available and pending free pages.
+	f.reindex()
+}
+
+// reindex rebuilds the free cache based on available and pending free lists.
+func (f *freelist) reindex() {
+	f.cache = make(map[pgid]bool, len(f.ids))
+	for _, id := range f.ids {
+		f.cache[id] = true
+	}
+	for _, pendingIDs := range f.pending {
+		for _, pendingID := range pendingIDs {
+			f.cache[pendingID] = true
+		}
+	}
+}

vendor/github.com/boltdb/bolt/node.go

@@ -0,0 +1,604 @@
+package bolt
+
+import (
+	"bytes"
+	"fmt"
+	"sort"
+	"unsafe"
+)
+
+// node represents an in-memory, deserialized page.
+type node struct {
+	bucket     *Bucket
+	isLeaf     bool
+	unbalanced bool
+	spilled    bool
+	key        []byte
+	pgid       pgid
+	parent     *node
+	children   nodes
+	inodes     inodes
+}
+
+// root returns the top-level node this node is attached to.
+func (n *node) root() *node {
+	if n.parent == nil {
+		return n
+	}
+	return n.parent.root()
+}
+
+// minKeys returns the minimum number of inodes this node should have.
+func (n *node) minKeys() int {
+	if n.isLeaf {
+		return 1
+	}
+	return 2
+}
+
+// size returns the size of the node after serialization.
+func (n *node) size() int {
+	sz, elsz := pageHeaderSize, n.pageElementSize()
+	for i := 0; i < len(n.inodes); i++ {
+		item := &n.inodes[i]
+		sz += elsz + len(item.key) + len(item.value)
+	}
+	return sz
+}
+
+// sizeLessThan returns true if the node is less than a given size.
+// This is an optimization to avoid calculating a large node when we only need
+// to know if it fits inside a certain page size.
+func (n *node) sizeLessThan(v int) bool {
+	sz, elsz := pageHeaderSize, n.pageElementSize()
+	for i := 0; i < len(n.inodes); i++ {
+		item := &n.inodes[i]
+		sz += elsz + len(item.key) + len(item.value)
+		if sz >= v {
+			return false
+		}
+	}
+	return true
+}
+
+// pageElementSize returns the size of each page element based on the type of node.
+func (n *node) pageElementSize() int {
+	if n.isLeaf {
+		return leafPageElementSize
+	}
+	return branchPageElementSize
+}
+
+// childAt returns the child node at a given index.
+func (n *node) childAt(index int) *node {
+	if n.isLeaf {
+		panic(fmt.Sprintf("invalid childAt(%d) on a leaf node", index))
+	}
+	return n.bucket.node(n.inodes[index].pgid, n)
+}
+
+// childIndex returns the index of a given child node.
+func (n *node) childIndex(child *node) int {
+	index := sort.Search(len(n.inodes), func(i int) bool { return bytes.Compare(n.inodes[i].key, child.key) != -1 })
+	return index
+}
+
+// numChildren returns the number of children.
+func (n *node) numChildren() int {
+	return len(n.inodes)
+}
+
+// nextSibling returns the next node with the same parent.
+func (n *node) nextSibling() *node {
+	if n.parent == nil {
+		return nil
+	}
+	index := n.parent.childIndex(n)
+	if index >= n.parent.numChildren()-1 {
+		return nil
+	}
+	return n.parent.childAt(index + 1)
+}
+
+// prevSibling returns the previous node with the same parent.
+func (n *node) prevSibling() *node {
+	if n.parent == nil {
+		return nil
+	}
+	index := n.parent.childIndex(n)
+	if index == 0 {
+		return nil
+	}
+	return n.parent.childAt(index - 1)
+}
+
+// put inserts a key/value.
+func (n *node) put(oldKey, newKey, value []byte, pgid pgid, flags uint32) {
+	if pgid >= n.bucket.tx.meta.pgid {
+		panic(fmt.Sprintf("pgid (%d) above high water mark (%d)", pgid, n.bucket.tx.meta.pgid))
+	} else if len(oldKey) <= 0 {
+		panic("put: zero-length old key")
+	} else if len(newKey) <= 0 {
+		panic("put: zero-length new key")
+	}
+
+	// Find insertion index.
+	index := sort.Search(len(n.inodes), func(i int) bool { return bytes.Compare(n.inodes[i].key, oldKey) != -1 })
+
+	// Add capacity and shift nodes if we don't have an exact match and need to insert.
+	exact := (len(n.inodes) > 0 && index < len(n.inodes) && bytes.Equal(n.inodes[index].key, oldKey))
+	if !exact {
+		n.inodes = append(n.inodes, inode{})
+		copy(n.inodes[index+1:], n.inodes[index:])
+	}
+
+	inode := &n.inodes[index]
+	inode.flags = flags
+	inode.key = newKey
+	inode.value = value
+	inode.pgid = pgid
+	_assert(len(inode.key) > 0, "put: zero-length inode key")
+}
+
+// del removes a key from the node.
+func (n *node) del(key []byte) {
+	// Find index of key.
+	index := sort.Search(len(n.inodes), func(i int) bool { return bytes.Compare(n.inodes[i].key, key) != -1 })
+
+	// Exit if the key isn't found.
+	if index >= len(n.inodes) || !bytes.Equal(n.inodes[index].key, key) {
+		return
+	}
+
+	// Delete inode from the node.
+	n.inodes = append(n.inodes[:index], n.inodes[index+1:]...)
+
+	// Mark the node as needing rebalancing.
+	n.unbalanced = true
+}
+
+// read initializes the node from a page.
+func (n *node) read(p *page) {
+	n.pgid = p.id
+	n.isLeaf = ((p.flags & leafPageFlag) != 0)
+	n.inodes = make(inodes, int(p.count))
+
+	for i := 0; i < int(p.count); i++ {
+		inode := &n.inodes[i]
+		if n.isLeaf {
+			elem := p.leafPageElement(uint16(i))
+			inode.flags = elem.flags
+			inode.key = elem.key()
+			inode.value = elem.value()
+		} else {
+			elem := p.branchPageElement(uint16(i))
+			inode.pgid = elem.pgid
+			inode.key = elem.key()
+		}
+		_assert(len(inode.key) > 0, "read: zero-length inode key")
+	}
+
+	// Save first key so we can find the node in the parent when we spill.
+	if len(n.inodes) > 0 {
+		n.key = n.inodes[0].key
+		_assert(len(n.key) > 0, "read: zero-length node key")
+	} else {
+		n.key = nil
+	}
+}
+
+// write writes the items onto one or more pages.
+func (n *node) write(p *page) {
+	// Initialize page.
+	if n.isLeaf {
+		p.flags |= leafPageFlag
+	} else {
+		p.flags |= branchPageFlag
+	}
+
+	if len(n.inodes) >= 0xFFFF {
+		panic(fmt.Sprintf("inode overflow: %d (pgid=%d)", len(n.inodes), p.id))
+	}
+	p.count = uint16(len(n.inodes))
+
+	// Stop here if there are no items to write.
+	if p.count == 0 {
+		return
+	}
+
+	// Loop over each item and write it to the page.
+	b := (*[maxAllocSize]byte)(unsafe.Pointer(&p.ptr))[n.pageElementSize()*len(n.inodes):]
+	for i, item := range n.inodes {
+		_assert(len(item.key) > 0, "write: zero-length inode key")
+
+		// Write the page element.
+		if n.isLeaf {
+			elem := p.leafPageElement(uint16(i))
+			elem.pos = uint32(uintptr(unsafe.Pointer(&b[0])) - uintptr(unsafe.Pointer(elem)))
+			elem.flags = item.flags
+			elem.ksize = uint32(len(item.key))
+			elem.vsize = uint32(len(item.value))
+		} else {
+			elem := p.branchPageElement(uint16(i))
+			elem.pos = uint32(uintptr(unsafe.Pointer(&b[0])) - uintptr(unsafe.Pointer(elem)))
+			elem.ksize = uint32(len(item.key))
+			elem.pgid = item.pgid
+			_assert(elem.pgid != p.id, "write: circular dependency occurred")
+		}
+
+		// If the length of key+value is larger than the max allocation size
+		// then we need to reallocate the byte array pointer.
+		//
+		// See: https://github.com/boltdb/bolt/pull/335
+		klen, vlen := len(item.key), len(item.value)
+		if len(b) < klen+vlen {
+			b = (*[maxAllocSize]byte)(unsafe.Pointer(&b[0]))[:]
+		}
+
+		// Write data for the element to the end of the page.
+		copy(b[0:], item.key)
+		b = b[klen:]
+		copy(b[0:], item.value)
+		b = b[vlen:]
+	}
+
+	// DEBUG ONLY: n.dump()
+}
+
+// split breaks up a node into multiple smaller nodes, if appropriate.
+// This should only be called from the spill() function.
+func (n *node) split(pageSize int) []*node {
+	var nodes []*node
+
+	node := n
+	for {
+		// Split node into two.
+		a, b := node.splitTwo(pageSize)
+		nodes = append(nodes, a)
+
+		// If we can't split then exit the loop.
+		if b == nil {
+			break
+		}
+
+		// Set node to b so it gets split on the next iteration.
+		node = b
+	}
+
+	return nodes
+}
+
+// splitTwo breaks up a node into two smaller nodes, if appropriate.
+// This should only be called from the split() function.
+func (n *node) splitTwo(pageSize int) (*node, *node) {
+	// Ignore the split if the page doesn't have at least enough nodes for
+	// two pages or if the nodes can fit in a single page.
+	if len(n.inodes) <= (minKeysPerPage*2) || n.sizeLessThan(pageSize) {
+		return n, nil
+	}
+
+	// Determine the threshold before starting a new node.
+	var fillPercent = n.bucket.FillPercent
+	if fillPercent < minFillPercent {
+		fillPercent = minFillPercent
+	} else if fillPercent > maxFillPercent {
+		fillPercent = maxFillPercent
+	}
+	threshold := int(float64(pageSize) * fillPercent)
+
+	// Determine split position and sizes of the two pages.
+	splitIndex, _ := n.splitIndex(threshold)
+
+	// Split node into two separate nodes.
+	// If there's no parent then we'll need to create one.
+	if n.parent == nil {
+		n.parent = &node{bucket: n.bucket, children: []*node{n}}
+	}
+
+	// Create a new node and add it to the parent.
+	next := &node{bucket: n.bucket, isLeaf: n.isLeaf, parent: n.parent}
+	n.parent.children = append(n.parent.children, next)
+
+	// Split inodes across two nodes.
+	next.inodes = n.inodes[splitIndex:]
+	n.inodes = n.inodes[:splitIndex]
+
+	// Update the statistics.
+	n.bucket.tx.stats.Split++
+
+	return n, next
+}
+
+// splitIndex finds the position where a page will fill a given threshold.
+// It returns the index as well as the size of the first page.
+// This is only be called from split().
+func (n *node) splitIndex(threshold int) (index, sz int) {
+	sz = pageHeaderSize
+
+	// Loop until we only have the minimum number of keys required for the second page.
+	for i := 0; i < len(n.inodes)-minKeysPerPage; i++ {
+		index = i
+		inode := n.inodes[i]
+		elsize := n.pageElementSize() + len(inode.key) + len(inode.value)
+
+		// If we have at least the minimum number of keys and adding another
+		// node would put us over the threshold then exit and return.
+		if i >= minKeysPerPage && sz+elsize > threshold {
+			break
+		}
+
+		// Add the element size to the total size.
+		sz += elsize
+	}
+
+	return
+}
+
+// spill writes the nodes to dirty pages and splits nodes as it goes.
+// Returns an error if dirty pages cannot be allocated.
+func (n *node) spill() error {
+	var tx = n.bucket.tx
+	if n.spilled {
+		return nil
+	}
+
+	// Spill child nodes first. Child nodes can materialize sibling nodes in
+	// the case of split-merge so we cannot use a range loop. We have to check
+	// the children size on every loop iteration.
+	sort.Sort(n.children)
+	for i := 0; i < len(n.children); i++ {
+		if err := n.children[i].spill(); err != nil {
+			return err
+		}
+	}
+
+	// We no longer need the child list because it's only used for spill tracking.
+	n.children = nil
+
+	// Split nodes into appropriate sizes. The first node will always be n.
+	var nodes = n.split(tx.db.pageSize)
+	for _, node := range nodes {
+		// Add node's page to the freelist if it's not new.
+		if node.pgid > 0 {
+			tx.db.freelist.free(tx.meta.txid, tx.page(node.pgid))
+			node.pgid = 0
+		}
+
+		// Allocate contiguous space for the node.
+		p, err := tx.allocate((node.size() / tx.db.pageSize) + 1)
+		if err != nil {
+			return err
+		}
+
+		// Write the node.
+		if p.id >= tx.meta.pgid {
+			panic(fmt.Sprintf("pgid (%d) above high water mark (%d)", p.id, tx.meta.pgid))
+		}
+		node.pgid = p.id
+		node.write(p)
+		node.spilled = true
+
+		// Insert into parent inodes.
+		if node.parent != nil {
+			var key = node.key
+			if key == nil {
+				key = node.inodes[0].key
+			}
+
+			node.parent.put(key, node.inodes[0].key, nil, node.pgid, 0)
+			node.key = node.inodes[0].key
+			_assert(len(node.key) > 0, "spill: zero-length node key")
+		}
+
+		// Update the statistics.
+		tx.stats.Spill++
+	}
+
+	// If the root node split and created a new root then we need to spill that
+	// as well. We'll clear out the children to make sure it doesn't try to respill.
+	if n.parent != nil && n.parent.pgid == 0 {
+		n.children = nil
+		return n.parent.spill()
+	}
+
+	return nil
+}
+
+// rebalance attempts to combine the node with sibling nodes if the node fill
+// size is below a threshold or if there are not enough keys.
+func (n *node) rebalance() {
+	if !n.unbalanced {
+		return
+	}
+	n.unbalanced = false
+
+	// Update statistics.
+	n.bucket.tx.stats.Rebalance++
+
+	// Ignore if node is above threshold (25%) and has enough keys.
+	var threshold = n.bucket.tx.db.pageSize / 4
+	if n.size() > threshold && len(n.inodes) > n.minKeys() {
+		return
+	}
+
+	// Root node has special handling.
+	if n.parent == nil {
+		// If root node is a branch and only has one node then collapse it.
+		if !n.isLeaf && len(n.inodes) == 1 {
+			// Move root's child up.
+			child := n.bucket.node(n.inodes[0].pgid, n)
+			n.isLeaf = child.isLeaf
+			n.inodes = child.inodes[:]
+			n.children = child.children
+
+			// Reparent all child nodes being moved.
+			for _, inode := range n.inodes {
+				if child, ok := n.bucket.nodes[inode.pgid]; ok {
+					child.parent = n
+				}
+			}
+
+			// Remove old child.
+			child.parent = nil
+			delete(n.bucket.nodes, child.pgid)
+			child.free()
+		}
+
+		return
+	}
+
+	// If node has no keys then just remove it.
+	if n.numChildren() == 0 {
+		n.parent.del(n.key)
+		n.parent.removeChild(n)
+		delete(n.bucket.nodes, n.pgid)
+		n.free()
+		n.parent.rebalance()
+		return
+	}
+
+	_assert(n.parent.numChildren() > 1, "parent must have at least 2 children")
+
+	// Destination node is right sibling if idx == 0, otherwise left sibling.
+	var target *node
+	var useNextSibling = (n.parent.childIndex(n) == 0)
+	if useNextSibling {
+		target = n.nextSibling()
+	} else {
+		target = n.prevSibling()
+	}
+
+	// If both this node and the target node are too small then merge them.
+	if useNextSibling {
+		// Reparent all child nodes being moved.
+		for _, inode := range target.inodes {
+			if child, ok := n.bucket.nodes[inode.pgid]; ok {
+				child.parent.removeChild(child)
+				child.parent = n
+				child.parent.children = append(child.parent.children, child)
+			}
+		}
+
+		// Copy over inodes from target and remove target.
+		n.inodes = append(n.inodes, target.inodes...)
+		n.parent.del(target.key)
+		n.parent.removeChild(target)
+		delete(n.bucket.nodes, target.pgid)
+		target.free()
+	} else {
+		// Reparent all child nodes being moved.
+		for _, inode := range n.inodes {
+			if child, ok := n.bucket.nodes[inode.pgid]; ok {
+				child.parent.removeChild(child)
+				child.parent = target
+				child.parent.children = append(child.parent.children, child)
+			}
+		}
+
+		// Copy over inodes to target and remove node.
+		target.inodes = append(target.inodes, n.inodes...)
+		n.parent.del(n.key)
+		n.parent.removeChild(n)
+		delete(n.bucket.nodes, n.pgid)
+		n.free()
+	}
+
+	// Either this node or the target node was deleted from the parent so rebalance it.
+	n.parent.rebalance()
+}
+
+// removes a node from the list of in-memory children.
+// This does not affect the inodes.
+func (n *node) removeChild(target *node) {
+	for i, child := range n.children {
+		if child == target {
+			n.children = append(n.children[:i], n.children[i+1:]...)
+			return
+		}
+	}
+}
+
+// dereference causes the node to copy all its inode key/value references to heap memory.
+// This is required when the mmap is reallocated so inodes are not pointing to stale data.
+func (n *node) dereference() {
+	if n.key != nil {
+		key := make([]byte, len(n.key))
+		copy(key, n.key)
+		n.key = key
+		_assert(n.pgid == 0 || len(n.key) > 0, "dereference: zero-length node key on existing node")
+	}
+
+	for i := range n.inodes {
+		inode := &n.inodes[i]
+
+		key := make([]byte, len(inode.key))
+		copy(key, inode.key)
+		inode.key = key
+		_assert(len(inode.key) > 0, "dereference: zero-length inode key")
+
+		value := make([]byte, len(inode.value))
+		copy(value, inode.value)
+		inode.value = value
+	}
+
+	// Recursively dereference children.
+	for _, child := range n.children {
+		child.dereference()
+	}
+
+	// Update statistics.
+	n.bucket.tx.stats.NodeDeref++
+}
+
+// free adds the node's underlying page to the freelist.
+func (n *node) free() {
+	if n.pgid != 0 {
+		n.bucket.tx.db.freelist.free(n.bucket.tx.meta.txid, n.bucket.tx.page(n.pgid))
+		n.pgid = 0
+	}
+}
+
+// dump writes the contents of the node to STDERR for debugging purposes.
+/*
+func (n *node) dump() {
+	// Write node header.
+	var typ = "branch"
+	if n.isLeaf {
+		typ = "leaf"
+	}
+	warnf("[NODE %d {type=%s count=%d}]", n.pgid, typ, len(n.inodes))
+
+	// Write out abbreviated version of each item.
+	for _, item := range n.inodes {
+		if n.isLeaf {
+			if item.flags&bucketLeafFlag != 0 {
+				bucket := (*bucket)(unsafe.Pointer(&item.value[0]))
+				warnf("+L %08x -> (bucket root=%d)", trunc(item.key, 4), bucket.root)
+			} else {
+				warnf("+L %08x -> %08x", trunc(item.key, 4), trunc(item.value, 4))
+			}
+		} else {
+			warnf("+B %08x -> pgid=%d", trunc(item.key, 4), item.pgid)
+		}
+	}
+	warn("")
+}
+*/
+
+type nodes []*node
+
+func (s nodes) Len() int           { return len(s) }
+func (s nodes) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s nodes) Less(i, j int) bool { return bytes.Compare(s[i].inodes[0].key, s[j].inodes[0].key) == -1 }
+
+// inode represents an internal node inside of a node.
+// It can be used to point to elements in a page or point
+// to an element which hasn't been added to a page yet.
+type inode struct {
+	flags uint32
+	pgid  pgid
+	key   []byte
+	value []byte
+}
+
+type inodes []inode

vendor/github.com/boltdb/bolt/page.go

@@ -0,0 +1,197 @@
+package bolt
+
+import (
+	"fmt"
+	"os"
+	"sort"
+	"unsafe"
+)
+
+const pageHeaderSize = int(unsafe.Offsetof(((*page)(nil)).ptr))
+
+const minKeysPerPage = 2
+
+const branchPageElementSize = int(unsafe.Sizeof(branchPageElement{}))
+const leafPageElementSize = int(unsafe.Sizeof(leafPageElement{}))
+
+const (
+	branchPageFlag   = 0x01
+	leafPageFlag     = 0x02
+	metaPageFlag     = 0x04
+	freelistPageFlag = 0x10
+)
+
+const (
+	bucketLeafFlag = 0x01
+)
+
+type pgid uint64
+
+type page struct {
+	id       pgid
+	flags    uint16
+	count    uint16
+	overflow uint32
+	ptr      uintptr
+}
+
+// typ returns a human readable page type string used for debugging.
+func (p *page) typ() string {
+	if (p.flags & branchPageFlag) != 0 {
+		return "branch"
+	} else if (p.flags & leafPageFlag) != 0 {
+		return "leaf"
+	} else if (p.flags & metaPageFlag) != 0 {
+		return "meta"
+	} else if (p.flags & freelistPageFlag) != 0 {
+		return "freelist"
+	}
+	return fmt.Sprintf("unknown<%02x>", p.flags)
+}
+
+// meta returns a pointer to the metadata section of the page.
+func (p *page) meta() *meta {
+	return (*meta)(unsafe.Pointer(&p.ptr))
+}
+
+// leafPageElement retrieves the leaf node by index
+func (p *page) leafPageElement(index uint16) *leafPageElement {
+	n := &((*[0x7FFFFFF]leafPageElement)(unsafe.Pointer(&p.ptr)))[index]
+	return n
+}
+
+// leafPageElements retrieves a list of leaf nodes.
+func (p *page) leafPageElements() []leafPageElement {
+	if p.count == 0 {
+		return nil
+	}
+	return ((*[0x7FFFFFF]leafPageElement)(unsafe.Pointer(&p.ptr)))[:]
+}
+
+// branchPageElement retrieves the branch node by index
+func (p *page) branchPageElement(index uint16) *branchPageElement {
+	return &((*[0x7FFFFFF]branchPageElement)(unsafe.Pointer(&p.ptr)))[index]
+}
+
+// branchPageElements retrieves a list of branch nodes.
+func (p *page) branchPageElements() []branchPageElement {
+	if p.count == 0 {
+		return nil
+	}
+	return ((*[0x7FFFFFF]branchPageElement)(unsafe.Pointer(&p.ptr)))[:]
+}
+
+// dump writes n bytes of the page to STDERR as hex output.
+func (p *page) hexdump(n int) {
+	buf := (*[maxAllocSize]byte)(unsafe.Pointer(p))[:n]
+	fmt.Fprintf(os.Stderr, "%x\n", buf)
+}
+
+type pages []*page
+
+func (s pages) Len() int           { return len(s) }
+func (s pages) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s pages) Less(i, j int) bool { return s[i].id < s[j].id }
+
+// branchPageElement represents a node on a branch page.
+type branchPageElement struct {
+	pos   uint32
+	ksize uint32
+	pgid  pgid
+}
+
+// key returns a byte slice of the node key.
+func (n *branchPageElement) key() []byte {
+	buf := (*[maxAllocSize]byte)(unsafe.Pointer(n))
+	return (*[maxAllocSize]byte)(unsafe.Pointer(&buf[n.pos]))[:n.ksize]
+}
+
+// leafPageElement represents a node on a leaf page.
+type leafPageElement struct {
+	flags uint32
+	pos   uint32
+	ksize uint32
+	vsize uint32
+}
+
+// key returns a byte slice of the node key.
+func (n *leafPageElement) key() []byte {
+	buf := (*[maxAllocSize]byte)(unsafe.Pointer(n))
+	return (*[maxAllocSize]byte)(unsafe.Pointer(&buf[n.pos]))[:n.ksize:n.ksize]
+}
+
+// value returns a byte slice of the node value.
+func (n *leafPageElement) value() []byte {
+	buf := (*[maxAllocSize]byte)(unsafe.Pointer(n))
+	return (*[maxAllocSize]byte)(unsafe.Pointer(&buf[n.pos+n.ksize]))[:n.vsize:n.vsize]
+}
+
+// PageInfo represents human readable information about a page.
+type PageInfo struct {
+	ID            int
+	Type          string
+	Count         int
+	OverflowCount int
+}
+
+type pgids []pgid
+
+func (s pgids) Len() int           { return len(s) }
+func (s pgids) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+func (s pgids) Less(i, j int) bool { return s[i] < s[j] }
+
+// merge returns the sorted union of a and b.
+func (a pgids) merge(b pgids) pgids {
+	// Return the opposite slice if one is nil.
+	if len(a) == 0 {
+		return b
+	}
+	if len(b) == 0 {
+		return a
+	}
+	merged := make(pgids, len(a)+len(b))
+	mergepgids(merged, a, b)
+	return merged
+}
+
+// mergepgids copies the sorted union of a and b into dst.
+// If dst is too small, it panics.
+func mergepgids(dst, a, b pgids) {
+	if len(dst) < len(a)+len(b) {
+		panic(fmt.Errorf("mergepgids bad len %d < %d + %d", len(dst), len(a), len(b)))
+	}
+	// Copy in the opposite slice if one is nil.
+	if len(a) == 0 {
+		copy(dst, b)
+		return
+	}
+	if len(b) == 0 {
+		copy(dst, a)
+		return
+	}
+
+	// Merged will hold all elements from both lists.
+	merged := dst[:0]
+
+	// Assign lead to the slice with a lower starting value, follow to the higher value.
+	lead, follow := a, b
+	if b[0] < a[0] {
+		lead, follow = b, a
+	}
+
+	// Continue while there are elements in the lead.
+	for len(lead) > 0 {
+		// Merge largest prefix of lead that is ahead of follow[0].
+		n := sort.Search(len(lead), func(i int) bool { return lead[i] > follow[0] })
+		merged = append(merged, lead[:n]...)
+		if n >= len(lead) {
+			break
+		}
+
+		// Swap lead and follow.
+		lead, follow = follow, lead[n:]
+	}
+
+	// Append what's left in follow.
+	_ = append(merged, follow...)
+}

vendor/github.com/boltdb/bolt/tx.go

@@ -0,0 +1,684 @@
+package bolt
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"sort"
+	"strings"
+	"time"
+	"unsafe"
+)
+
+// txid represents the internal transaction identifier.
+type txid uint64
+
+// Tx represents a read-only or read/write transaction on the database.
+// Read-only transactions can be used for retrieving values for keys and creating cursors.
+// Read/write transactions can create and remove buckets and create and remove keys.
+//
+// IMPORTANT: You must commit or rollback transactions when you are done with
+// them. Pages can not be reclaimed by the writer until no more transactions
+// are using them. A long running read transaction can cause the database to
+// quickly grow.
+type Tx struct {
+	writable       bool
+	managed        bool
+	db             *DB
+	meta           *meta
+	root           Bucket
+	pages          map[pgid]*page
+	stats          TxStats
+	commitHandlers []func()
+
+	// WriteFlag specifies the flag for write-related methods like WriteTo().
+	// Tx opens the database file with the specified flag to copy the data.
+	//
+	// By default, the flag is unset, which works well for mostly in-memory
+	// workloads. For databases that are much larger than available RAM,
+	// set the flag to syscall.O_DIRECT to avoid trashing the page cache.
+	WriteFlag int
+}
+
+// init initializes the transaction.
+func (tx *Tx) init(db *DB) {
+	tx.db = db
+	tx.pages = nil
+
+	// Copy the meta page since it can be changed by the writer.
+	tx.meta = &meta{}
+	db.meta().copy(tx.meta)
+
+	// Copy over the root bucket.
+	tx.root = newBucket(tx)
+	tx.root.bucket = &bucket{}
+	*tx.root.bucket = tx.meta.root
+
+	// Increment the transaction id and add a page cache for writable transactions.
+	if tx.writable {
+		tx.pages = make(map[pgid]*page)
+		tx.meta.txid += txid(1)
+	}
+}
+
+// ID returns the transaction id.
+func (tx *Tx) ID() int {
+	return int(tx.meta.txid)
+}
+
+// DB returns a reference to the database that created the transaction.
+func (tx *Tx) DB() *DB {
+	return tx.db
+}
+
+// Size returns current database size in bytes as seen by this transaction.
+func (tx *Tx) Size() int64 {
+	return int64(tx.meta.pgid) * int64(tx.db.pageSize)
+}
+
+// Writable returns whether the transaction can perform write operations.
+func (tx *Tx) Writable() bool {
+	return tx.writable
+}
+
+// Cursor creates a cursor associated with the root bucket.
+// All items in the cursor will return a nil value because all root bucket keys point to buckets.
+// The cursor is only valid as long as the transaction is open.
+// Do not use a cursor after the transaction is closed.
+func (tx *Tx) Cursor() *Cursor {
+	return tx.root.Cursor()
+}
+
+// Stats retrieves a copy of the current transaction statistics.
+func (tx *Tx) Stats() TxStats {
+	return tx.stats
+}
+
+// Bucket retrieves a bucket by name.
+// Returns nil if the bucket does not exist.
+// The bucket instance is only valid for the lifetime of the transaction.
+func (tx *Tx) Bucket(name []byte) *Bucket {
+	return tx.root.Bucket(name)
+}
+
+// CreateBucket creates a new bucket.
+// Returns an error if the bucket already exists, if the bucket name is blank, or if the bucket name is too long.
+// The bucket instance is only valid for the lifetime of the transaction.
+func (tx *Tx) CreateBucket(name []byte) (*Bucket, error) {
+	return tx.root.CreateBucket(name)
+}
+
+// CreateBucketIfNotExists creates a new bucket if it doesn't already exist.
+// Returns an error if the bucket name is blank, or if the bucket name is too long.
+// The bucket instance is only valid for the lifetime of the transaction.
+func (tx *Tx) CreateBucketIfNotExists(name []byte) (*Bucket, error) {
+	return tx.root.CreateBucketIfNotExists(name)
+}
+
+// DeleteBucket deletes a bucket.
+// Returns an error if the bucket cannot be found or if the key represents a non-bucket value.
+func (tx *Tx) DeleteBucket(name []byte) error {
+	return tx.root.DeleteBucket(name)
+}
+
+// ForEach executes a function for each bucket in the root.
+// If the provided function returns an error then the iteration is stopped and
+// the error is returned to the caller.
+func (tx *Tx) ForEach(fn func(name []byte, b *Bucket) error) error {
+	return tx.root.ForEach(func(k, v []byte) error {
+		if err := fn(k, tx.root.Bucket(k)); err != nil {
+			return err
+		}
+		return nil
+	})
+}
+
+// OnCommit adds a handler function to be executed after the transaction successfully commits.
+func (tx *Tx) OnCommit(fn func()) {
+	tx.commitHandlers = append(tx.commitHandlers, fn)
+}
+
+// Commit writes all changes to disk and updates the meta page.
+// Returns an error if a disk write error occurs, or if Commit is
+// called on a read-only transaction.
+func (tx *Tx) Commit() error {
+	_assert(!tx.managed, "managed tx commit not allowed")
+	if tx.db == nil {
+		return ErrTxClosed
+	} else if !tx.writable {
+		return ErrTxNotWritable
+	}
+
+	// TODO(benbjohnson): Use vectorized I/O to write out dirty pages.
+
+	// Rebalance nodes which have had deletions.
+	var startTime = time.Now()
+	tx.root.rebalance()
+	if tx.stats.Rebalance > 0 {
+		tx.stats.RebalanceTime += time.Since(startTime)
+	}
+
+	// spill data onto dirty pages.
+	startTime = time.Now()
+	if err := tx.root.spill(); err != nil {
+		tx.rollback()
+		return err
+	}
+	tx.stats.SpillTime += time.Since(startTime)
+
+	// Free the old root bucket.
+	tx.meta.root.root = tx.root.root
+
+	opgid := tx.meta.pgid
+
+	// Free the freelist and allocate new pages for it. This will overestimate
+	// the size of the freelist but not underestimate the size (which would be bad).
+	tx.db.freelist.free(tx.meta.txid, tx.db.page(tx.meta.freelist))
+	p, err := tx.allocate((tx.db.freelist.size() / tx.db.pageSize) + 1)
+	if err != nil {
+		tx.rollback()
+		return err
+	}
+	if err := tx.db.freelist.write(p); err != nil {
+		tx.rollback()
+		return err
+	}
+	tx.meta.freelist = p.id
+
+	// If the high water mark has moved up then attempt to grow the database.
+	if tx.meta.pgid > opgid {
+		if err := tx.db.grow(int(tx.meta.pgid+1) * tx.db.pageSize); err != nil {
+			tx.rollback()
+			return err
+		}
+	}
+
+	// Write dirty pages to disk.
+	startTime = time.Now()
+	if err := tx.write(); err != nil {
+		tx.rollback()
+		return err
+	}
+
+	// If strict mode is enabled then perform a consistency check.
+	// Only the first consistency error is reported in the panic.
+	if tx.db.StrictMode {
+		ch := tx.Check()
+		var errs []string
+		for {
+			err, ok := <-ch
+			if !ok {
+				break
+			}
+			errs = append(errs, err.Error())
+		}
+		if len(errs) > 0 {
+			panic("check fail: " + strings.Join(errs, "\n"))
+		}
+	}
+
+	// Write meta to disk.
+	if err := tx.writeMeta(); err != nil {
+		tx.rollback()
+		return err
+	}
+	tx.stats.WriteTime += time.Since(startTime)
+
+	// Finalize the transaction.
+	tx.close()
+
+	// Execute commit handlers now that the locks have been removed.
+	for _, fn := range tx.commitHandlers {
+		fn()
+	}
+
+	return nil
+}
+
+// Rollback closes the transaction and ignores all previous updates. Read-only
+// transactions must be rolled back and not committed.
+func (tx *Tx) Rollback() error {
+	_assert(!tx.managed, "managed tx rollback not allowed")
+	if tx.db == nil {
+		return ErrTxClosed
+	}
+	tx.rollback()
+	return nil
+}
+
+func (tx *Tx) rollback() {
+	if tx.db == nil {
+		return
+	}
+	if tx.writable {
+		tx.db.freelist.rollback(tx.meta.txid)
+		tx.db.freelist.reload(tx.db.page(tx.db.meta().freelist))
+	}
+	tx.close()
+}
+
+func (tx *Tx) close() {
+	if tx.db == nil {
+		return
+	}
+	if tx.writable {
+		// Grab freelist stats.
+		var freelistFreeN = tx.db.freelist.free_count()
+		var freelistPendingN = tx.db.freelist.pending_count()
+		var freelistAlloc = tx.db.freelist.size()
+
+		// Remove transaction ref & writer lock.
+		tx.db.rwtx = nil
+		tx.db.rwlock.Unlock()
+
+		// Merge statistics.
+		tx.db.statlock.Lock()
+		tx.db.stats.FreePageN = freelistFreeN
+		tx.db.stats.PendingPageN = freelistPendingN
+		tx.db.stats.FreeAlloc = (freelistFreeN + freelistPendingN) * tx.db.pageSize
+		tx.db.stats.FreelistInuse = freelistAlloc
+		tx.db.stats.TxStats.add(&tx.stats)
+		tx.db.statlock.Unlock()
+	} else {
+		tx.db.removeTx(tx)
+	}
+
+	// Clear all references.
+	tx.db = nil
+	tx.meta = nil
+	tx.root = Bucket{tx: tx}
+	tx.pages = nil
+}
+
+// Copy writes the entire database to a writer.
+// This function exists for backwards compatibility. Use WriteTo() instead.
+func (tx *Tx) Copy(w io.Writer) error {
+	_, err := tx.WriteTo(w)
+	return err
+}
+
+// WriteTo writes the entire database to a writer.
+// If err == nil then exactly tx.Size() bytes will be written into the writer.
+func (tx *Tx) WriteTo(w io.Writer) (n int64, err error) {
+	// Attempt to open reader with WriteFlag
+	f, err := os.OpenFile(tx.db.path, os.O_RDONLY|tx.WriteFlag, 0)
+	if err != nil {
+		return 0, err
+	}
+	defer func() { _ = f.Close() }()
+
+	// Generate a meta page. We use the same page data for both meta pages.
+	buf := make([]byte, tx.db.pageSize)
+	page := (*page)(unsafe.Pointer(&buf[0]))
+	page.flags = metaPageFlag
+	*page.meta() = *tx.meta
+
+	// Write meta 0.
+	page.id = 0
+	page.meta().checksum = page.meta().sum64()
+	nn, err := w.Write(buf)
+	n += int64(nn)
+	if err != nil {
+		return n, fmt.Errorf("meta 0 copy: %s", err)
+	}
+
+	// Write meta 1 with a lower transaction id.
+	page.id = 1
+	page.meta().txid -= 1
+	page.meta().checksum = page.meta().sum64()
+	nn, err = w.Write(buf)
+	n += int64(nn)
+	if err != nil {
+		return n, fmt.Errorf("meta 1 copy: %s", err)
+	}
+
+	// Move past the meta pages in the file.
+	if _, err := f.Seek(int64(tx.db.pageSize*2), os.SEEK_SET); err != nil {
+		return n, fmt.Errorf("seek: %s", err)
+	}
+
+	// Copy data pages.
+	wn, err := io.CopyN(w, f, tx.Size()-int64(tx.db.pageSize*2))
+	n += wn
+	if err != nil {
+		return n, err
+	}
+
+	return n, f.Close()
+}
+
+// CopyFile copies the entire database to file at the given path.
+// A reader transaction is maintained during the copy so it is safe to continue
+// using the database while a copy is in progress.
+func (tx *Tx) CopyFile(path string, mode os.FileMode) error {
+	f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, mode)
+	if err != nil {
+		return err
+	}
+
+	err = tx.Copy(f)
+	if err != nil {
+		_ = f.Close()
+		return err
+	}
+	return f.Close()
+}
+
+// Check performs several consistency checks on the database for this transaction.
+// An error is returned if any inconsistency is found.
+//
+// It can be safely run concurrently on a writable transaction. However, this
+// incurs a high cost for large databases and databases with a lot of subbuckets
+// because of caching. This overhead can be removed if running on a read-only
+// transaction, however, it is not safe to execute other writer transactions at
+// the same time.
+func (tx *Tx) Check() <-chan error {
+	ch := make(chan error)
+	go tx.check(ch)
+	return ch
+}
+
+func (tx *Tx) check(ch chan error) {
+	// Check if any pages are double freed.
+	freed := make(map[pgid]bool)
+	all := make([]pgid, tx.db.freelist.count())
+	tx.db.freelist.copyall(all)
+	for _, id := range all {
+		if freed[id] {
+			ch <- fmt.Errorf("page %d: already freed", id)
+		}
+		freed[id] = true
+	}
+
+	// Track every reachable page.
+	reachable := make(map[pgid]*page)
+	reachable[0] = tx.page(0) // meta0
+	reachable[1] = tx.page(1) // meta1
+	for i := uint32(0); i <= tx.page(tx.meta.freelist).overflow; i++ {
+		reachable[tx.meta.freelist+pgid(i)] = tx.page(tx.meta.freelist)
+	}
+
+	// Recursively check buckets.
+	tx.checkBucket(&tx.root, reachable, freed, ch)
+
+	// Ensure all pages below high water mark are either reachable or freed.
+	for i := pgid(0); i < tx.meta.pgid; i++ {
+		_, isReachable := reachable[i]
+		if !isReachable && !freed[i] {
+			ch <- fmt.Errorf("page %d: unreachable unfreed", int(i))
+		}
+	}
+
+	// Close the channel to signal completion.
+	close(ch)
+}
+
+func (tx *Tx) checkBucket(b *Bucket, reachable map[pgid]*page, freed map[pgid]bool, ch chan error) {
+	// Ignore inline buckets.
+	if b.root == 0 {
+		return
+	}
+
+	// Check every page used by this bucket.
+	b.tx.forEachPage(b.root, 0, func(p *page, _ int) {
+		if p.id > tx.meta.pgid {
+			ch <- fmt.Errorf("page %d: out of bounds: %d", int(p.id), int(b.tx.meta.pgid))
+		}
+
+		// Ensure each page is only referenced once.
+		for i := pgid(0); i <= pgid(p.overflow); i++ {
+			var id = p.id + i
+			if _, ok := reachable[id]; ok {
+				ch <- fmt.Errorf("page %d: multiple references", int(id))
+			}
+			reachable[id] = p
+		}
+
+		// We should only encounter un-freed leaf and branch pages.
+		if freed[p.id] {
+			ch <- fmt.Errorf("page %d: reachable freed", int(p.id))
+		} else if (p.flags&branchPageFlag) == 0 && (p.flags&leafPageFlag) == 0 {
+			ch <- fmt.Errorf("page %d: invalid type: %s", int(p.id), p.typ())
+		}
+	})
+
+	// Check each bucket within this bucket.
+	_ = b.ForEach(func(k, v []byte) error {
+		if child := b.Bucket(k); child != nil {
+			tx.checkBucket(child, reachable, freed, ch)
+		}
+		return nil
+	})
+}
+
+// allocate returns a contiguous block of memory starting at a given page.
+func (tx *Tx) allocate(count int) (*page, error) {
+	p, err := tx.db.allocate(count)
+	if err != nil {
+		return nil, err
+	}
+
+	// Save to our page cache.
+	tx.pages[p.id] = p
+
+	// Update statistics.
+	tx.stats.PageCount++
+	tx.stats.PageAlloc += count * tx.db.pageSize
+
+	return p, nil
+}
+
+// write writes any dirty pages to disk.
+func (tx *Tx) write() error {
+	// Sort pages by id.
+	pages := make(pages, 0, len(tx.pages))
+	for _, p := range tx.pages {
+		pages = append(pages, p)
+	}
+	// Clear out page cache early.
+	tx.pages = make(map[pgid]*page)
+	sort.Sort(pages)
+
+	// Write pages to disk in order.
+	for _, p := range pages {
+		size := (int(p.overflow) + 1) * tx.db.pageSize
+		offset := int64(p.id) * int64(tx.db.pageSize)
+
+		// Write out page in "max allocation" sized chunks.
+		ptr := (*[maxAllocSize]byte)(unsafe.Pointer(p))
+		for {
+			// Limit our write to our max allocation size.
+			sz := size
+			if sz > maxAllocSize-1 {
+				sz = maxAllocSize - 1
+			}
+
+			// Write chunk to disk.
+			buf := ptr[:sz]
+			if _, err := tx.db.ops.writeAt(buf, offset); err != nil {
+				return err
+			}
+
+			// Update statistics.
+			tx.stats.Write++
+
+			// Exit inner for loop if we've written all the chunks.
+			size -= sz
+			if size == 0 {
+				break
+			}
+
+			// Otherwise move offset forward and move pointer to next chunk.
+			offset += int64(sz)
+			ptr = (*[maxAllocSize]byte)(unsafe.Pointer(&ptr[sz]))
+		}
+	}
+
+	// Ignore file sync if flag is set on DB.
+	if !tx.db.NoSync || IgnoreNoSync {
+		if err := fdatasync(tx.db); err != nil {
+			return err
+		}
+	}
+
+	// Put small pages back to page pool.
+	for _, p := range pages {
+		// Ignore page sizes over 1 page.
+		// These are allocated using make() instead of the page pool.
+		if int(p.overflow) != 0 {
+			continue
+		}
+
+		buf := (*[maxAllocSize]byte)(unsafe.Pointer(p))[:tx.db.pageSize]
+
+		// See https://go.googlesource.com/go/+/f03c9202c43e0abb130669852082117ca50aa9b1
+		for i := range buf {
+			buf[i] = 0
+		}
+		tx.db.pagePool.Put(buf)
+	}
+
+	return nil
+}
+
+// writeMeta writes the meta to the disk.
+func (tx *Tx) writeMeta() error {
+	// Create a temporary buffer for the meta page.
+	buf := make([]byte, tx.db.pageSize)
+	p := tx.db.pageInBuffer(buf, 0)
+	tx.meta.write(p)
+
+	// Write the meta page to file.
+	if _, err := tx.db.ops.writeAt(buf, int64(p.id)*int64(tx.db.pageSize)); err != nil {
+		return err
+	}
+	if !tx.db.NoSync || IgnoreNoSync {
+		if err := fdatasync(tx.db); err != nil {
+			return err
+		}
+	}
+
+	// Update statistics.
+	tx.stats.Write++
+
+	return nil
+}
+
+// page returns a reference to the page with a given id.
+// If page has been written to then a temporary buffered page is returned.
+func (tx *Tx) page(id pgid) *page {
+	// Check the dirty pages first.
+	if tx.pages != nil {
+		if p, ok := tx.pages[id]; ok {
+			return p
+		}
+	}
+
+	// Otherwise return directly from the mmap.
+	return tx.db.page(id)
+}
+
+// forEachPage iterates over every page within a given page and executes a function.
+func (tx *Tx) forEachPage(pgid pgid, depth int, fn func(*page, int)) {
+	p := tx.page(pgid)
+
+	// Execute function.
+	fn(p, depth)
+
+	// Recursively loop over children.
+	if (p.flags & branchPageFlag) != 0 {
+		for i := 0; i < int(p.count); i++ {
+			elem := p.branchPageElement(uint16(i))
+			tx.forEachPage(elem.pgid, depth+1, fn)
+		}
+	}
+}
+
+// Page returns page information for a given page number.
+// This is only safe for concurrent use when used by a writable transaction.
+func (tx *Tx) Page(id int) (*PageInfo, error) {
+	if tx.db == nil {
+		return nil, ErrTxClosed
+	} else if pgid(id) >= tx.meta.pgid {
+		return nil, nil
+	}
+
+	// Build the page info.
+	p := tx.db.page(pgid(id))
+	info := &PageInfo{
+		ID:            id,
+		Count:         int(p.count),
+		OverflowCount: int(p.overflow),
+	}
+
+	// Determine the type (or if it's free).
+	if tx.db.freelist.freed(pgid(id)) {
+		info.Type = "free"
+	} else {
+		info.Type = p.typ()
+	}
+
+	return info, nil
+}
+
+// TxStats represents statistics about the actions performed by the transaction.
+type TxStats struct {
+	// Page statistics.
+	PageCount int // number of page allocations
+	PageAlloc int // total bytes allocated
+
+	// Cursor statistics.
+	CursorCount int // number of cursors created
+
+	// Node statistics
+	NodeCount int // number of node allocations
+	NodeDeref int // number of node dereferences
+
+	// Rebalance statistics.
+	Rebalance     int           // number of node rebalances
+	RebalanceTime time.Duration // total time spent rebalancing
+
+	// Split/Spill statistics.
+	Split     int           // number of nodes split
+	Spill     int           // number of nodes spilled
+	SpillTime time.Duration // total time spent spilling
+
+	// Write statistics.
+	Write     int           // number of writes performed
+	WriteTime time.Duration // total time spent writing to disk
+}
+
+func (s *TxStats) add(other *TxStats) {
+	s.PageCount += other.PageCount
+	s.PageAlloc += other.PageAlloc
+	s.CursorCount += other.CursorCount
+	s.NodeCount += other.NodeCount
+	s.NodeDeref += other.NodeDeref
+	s.Rebalance += other.Rebalance
+	s.RebalanceTime += other.RebalanceTime
+	s.Split += other.Split
+	s.Spill += other.Spill
+	s.SpillTime += other.SpillTime
+	s.Write += other.Write
+	s.WriteTime += other.WriteTime
+}
+
+// Sub calculates and returns the difference between two sets of transaction stats.
+// This is useful when obtaining stats at two different points and time and
+// you need the performance counters that occurred within that time span.
+func (s *TxStats) Sub(other *TxStats) TxStats {
+	var diff TxStats
+	diff.PageCount = s.PageCount - other.PageCount
+	diff.PageAlloc = s.PageAlloc - other.PageAlloc
+	diff.CursorCount = s.CursorCount - other.CursorCount
+	diff.NodeCount = s.NodeCount - other.NodeCount
+	diff.NodeDeref = s.NodeDeref - other.NodeDeref
+	diff.Rebalance = s.Rebalance - other.Rebalance
+	diff.RebalanceTime = s.RebalanceTime - other.RebalanceTime
+	diff.Split = s.Split - other.Split
+	diff.Spill = s.Spill - other.Spill
+	diff.SpillTime = s.SpillTime - other.SpillTime
+	diff.Write = s.Write - other.Write
+	diff.WriteTime = s.WriteTime - other.WriteTime
+	return diff
+}

vendor/github.com/didip/tollbooth/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 Didip Kerabat
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/didip/tollbooth/README.md

@@ -0,0 +1,65 @@
+[![GoDoc](https://godoc.org/github.com/didip/tollbooth?status.svg)](http://godoc.org/github.com/didip/tollbooth)
+[![license](http://img.shields.io/badge/license-MIT-red.svg?style=flat)](https://raw.githubusercontent.com/didip/tollbooth/master/LICENSE)
+
+## Tollbooth
+
+This is a generic middleware to rate-limit HTTP requests.
+
+**NOTE:** This library is considered finished, any new activities are probably centered around `thirdparty` modules.
+
+
+## Five Minutes Tutorial
+```
+package main
+
+import (
+    "github.com/didip/tollbooth"
+    "net/http"
+    "time"
+)
+
+func HelloHandler(w http.ResponseWriter, req *http.Request) {
+    w.Write([]byte("Hello, World!"))
+}
+
+func main() {
+    // Create a request limiter per handler.
+    http.Handle("/", tollbooth.LimitFuncHandler(tollbooth.NewLimiter(1, time.Second), HelloHandler))
+    http.ListenAndServe(":12345", nil)
+}
+```
+
+## Features
+
+1. Rate-limit by request's remote IP, path, methods, custom headers, & basic auth usernames.
+    ```
+    limiter := tollbooth.NewLimiter(1, time.Second)
+
+    // Configure list of places to look for IP address.
+    // By default it's: "RemoteAddr", "X-Forwarded-For", "X-Real-IP"
+    // If your application is behind a proxy, set "X-Forwarded-For" first.
+    limiter.IPLookups = []string{"RemoteAddr", "X-Forwarded-For", "X-Real-IP"}
+
+    // Limit only GET and POST requests.
+    limiter.Methods = []string{"GET", "POST"}
+
+    // Limit request headers containing certain values.
+    // Typically, you prefetched these values from the database.
+    limiter.Headers = make(map[string][]string)
+    limiter.Headers["X-Access-Token"] = []string{"abc123", "xyz098"}
+
+    // Limit based on basic auth usernames.
+    // Typically, you prefetched these values from the database.
+    limiter.BasicAuthUsers = []string{"bob", "joe", "didip"}
+    ```
+
+2. Each request handler can be rate-limited individually.
+
+3. Compose your own middleware by using `LimitByKeys()`.
+
+4. Tollbooth does not require external storage since it uses an algorithm called [Token Bucket](http://en.wikipedia.org/wiki/Token_bucket) [(Go library: ratelimit)](https://github.com/juju/ratelimit).
+
+
+# Other Web Frameworks
+
+Support for other web frameworks are defined under `/thirdparty` directory.

vendor/github.com/didip/tollbooth/config/config.go

@@ -0,0 +1,77 @@
+// Package config provides data structure to configure rate-limiter.
+package config
+
+import (
+	"sync"
+	"time"
+
+	"github.com/juju/ratelimit"
+)
+
+// NewLimiter is a constructor for Limiter.
+func NewLimiter(max int64, ttl time.Duration) *Limiter {
+	limiter := &Limiter{Max: max, TTL: ttl}
+	limiter.MessageContentType = "text/plain; charset=utf-8"
+	limiter.Message = "You have reached maximum request limit."
+	limiter.StatusCode = 429
+	limiter.tokenBuckets = make(map[string]*ratelimit.Bucket)
+	limiter.IPLookups = []string{"RemoteAddr", "X-Forwarded-For", "X-Real-IP"}
+
+	return limiter
+}
+
+// Limiter is a config struct to limit a particular request handler.
+type Limiter struct {
+	// HTTP message when limit is reached.
+	Message string
+
+	// Content-Type for Message
+	MessageContentType string
+
+	// HTTP status code when limit is reached.
+	StatusCode int
+
+	// Maximum number of requests to limit per duration.
+	Max int64
+
+	// Duration of rate-limiter.
+	TTL time.Duration
+
+	// List of places to look up IP address.
+	// Default is "RemoteAddr", "X-Forwarded-For", "X-Real-IP".
+	// You can rearrange the order as you like.
+	IPLookups []string
+
+	// List of HTTP Methods to limit (GET, POST, PUT, etc.).
+	// Empty means limit all methods.
+	Methods []string
+
+	// List of HTTP headers to limit.
+	// Empty means skip headers checking.
+	Headers map[string][]string
+
+	// List of basic auth usernames to limit.
+	BasicAuthUsers []string
+
+	// Throttler struct
+	tokenBuckets map[string]*ratelimit.Bucket
+
+	sync.RWMutex
+}
+
+// LimitReached returns a bool indicating if the Bucket identified by key ran out of tokens.
+func (l *Limiter) LimitReached(key string) bool {
+	l.Lock()
+	if _, found := l.tokenBuckets[key]; !found {
+		l.tokenBuckets[key] = ratelimit.NewBucket(l.TTL, l.Max)
+	}
+
+	_, isSoonerThanMaxWait := l.tokenBuckets[key].TakeMaxDuration(1, 0)
+	l.Unlock()
+
+	if isSoonerThanMaxWait {
+		return false
+	}
+
+	return true
+}

vendor/github.com/didip/tollbooth/errors/errors.go

@@ -0,0 +1,15 @@
+// Package errors provide data structure for errors.
+package errors
+
+import "fmt"
+
+// HTTPError is an error struct that returns both message and status code.
+type HTTPError struct {
+	Message    string
+	StatusCode int
+}
+
+// Error returns error message.
+func (httperror *HTTPError) Error() string {
+	return fmt.Sprintf("%v: %v", httperror.StatusCode, httperror.Message)
+}

vendor/github.com/didip/tollbooth/libstring/libstring.go

@@ -0,0 +1,50 @@
+// Package libstring provides various string related functions.
+package libstring
+
+import (
+	"net/http"
+	"strings"
+)
+
+// StringInSlice finds needle in a slice of strings.
+func StringInSlice(sliceString []string, needle string) bool {
+	for _, b := range sliceString {
+		if b == needle {
+			return true
+		}
+	}
+	return false
+}
+
+func ipAddrFromRemoteAddr(s string) string {
+	idx := strings.LastIndex(s, ":")
+	if idx == -1 {
+		return s
+	}
+	return s[:idx]
+}
+
+// RemoteIP finds IP Address given http.Request struct.
+func RemoteIP(ipLookups []string, r *http.Request) string {
+	realIP := r.Header.Get("X-Real-IP")
+	forwardedFor := r.Header.Get("X-Forwarded-For")
+
+	for _, lookup := range ipLookups {
+		if lookup == "RemoteAddr" {
+			return ipAddrFromRemoteAddr(r.RemoteAddr)
+		}
+		if lookup == "X-Forwarded-For" && forwardedFor != "" {
+			// X-Forwarded-For is potentially a list of addresses separated with ","
+			parts := strings.Split(forwardedFor, ",")
+			for i, p := range parts {
+				parts[i] = strings.TrimSpace(p)
+			}
+			return parts[0]
+		}
+		if lookup == "X-Real-IP" && realIP != "" {
+			return realIP
+		}
+	}
+
+	return ""
+}

vendor/github.com/didip/tollbooth/tollbooth.go

@@ -0,0 +1,161 @@
+// Package tollbooth provides rate-limiting logic to HTTP request handler.
+package tollbooth
+
+import (
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/didip/tollbooth/config"
+	"github.com/didip/tollbooth/errors"
+	"github.com/didip/tollbooth/libstring"
+)
+
+// NewLimiter is a convenience function to config.NewLimiter.
+func NewLimiter(max int64, ttl time.Duration) *config.Limiter {
+	return config.NewLimiter(max, ttl)
+}
+
+// LimitByKeys keeps track number of request made by keys separated by pipe.
+// It returns HTTPError when limit is exceeded.
+func LimitByKeys(limiter *config.Limiter, keys []string) *errors.HTTPError {
+	if limiter.LimitReached(strings.Join(keys, "|")) {
+		return &errors.HTTPError{Message: limiter.Message, StatusCode: limiter.StatusCode}
+	}
+
+	return nil
+}
+
+// LimitByRequest builds keys based on http.Request struct,
+// loops through all the keys, and check if any one of them returns HTTPError.
+func LimitByRequest(limiter *config.Limiter, r *http.Request) *errors.HTTPError {
+	sliceKeys := BuildKeys(limiter, r)
+
+	// Loop sliceKeys and check if one of them has error.
+	for _, keys := range sliceKeys {
+		httpError := LimitByKeys(limiter, keys)
+		if httpError != nil {
+			return httpError
+		}
+	}
+
+	return nil
+}
+
+// BuildKeys generates a slice of keys to rate-limit by given config and request structs.
+func BuildKeys(limiter *config.Limiter, r *http.Request) [][]string {
+	remoteIP := libstring.RemoteIP(limiter.IPLookups, r)
+	path := r.URL.Path
+	sliceKeys := make([][]string, 0)
+
+	// Don't BuildKeys if remoteIP is blank.
+	if remoteIP == "" {
+		return sliceKeys
+	}
+
+	if limiter.Methods != nil && limiter.Headers != nil && limiter.BasicAuthUsers != nil {
+		// Limit by HTTP methods and HTTP headers+values and Basic Auth credentials.
+		if libstring.StringInSlice(limiter.Methods, r.Method) {
+			for headerKey, headerValues := range limiter.Headers {
+				if (headerValues == nil || len(headerValues) <= 0) && r.Header.Get(headerKey) != "" {
+					// If header values are empty, rate-limit all request with headerKey.
+					username, _, ok := r.BasicAuth()
+					if ok && libstring.StringInSlice(limiter.BasicAuthUsers, username) {
+						sliceKeys = append(sliceKeys, []string{remoteIP, path, r.Method, headerKey, username})
+					}
+
+				} else if len(headerValues) > 0 && r.Header.Get(headerKey) != "" {
+					// If header values are not empty, rate-limit all request with headerKey and headerValues.
+					for _, headerValue := range headerValues {
+						username, _, ok := r.BasicAuth()
+						if ok && libstring.StringInSlice(limiter.BasicAuthUsers, username) {
+							sliceKeys = append(sliceKeys, []string{remoteIP, path, r.Method, headerKey, headerValue, username})
+						}
+					}
+				}
+			}
+		}
+
+	} else if limiter.Methods != nil && limiter.Headers != nil {
+		// Limit by HTTP methods and HTTP headers+values.
+		if libstring.StringInSlice(limiter.Methods, r.Method) {
+			for headerKey, headerValues := range limiter.Headers {
+				if (headerValues == nil || len(headerValues) <= 0) && r.Header.Get(headerKey) != "" {
+					// If header values are empty, rate-limit all request with headerKey.
+					sliceKeys = append(sliceKeys, []string{remoteIP, path, r.Method, headerKey})
+
+				} else if len(headerValues) > 0 && r.Header.Get(headerKey) != "" {
+					// If header values are not empty, rate-limit all request with headerKey and headerValues.
+					for _, headerValue := range headerValues {
+						sliceKeys = append(sliceKeys, []string{remoteIP, path, r.Method, headerKey, headerValue})
+					}
+				}
+			}
+		}
+
+	} else if limiter.Methods != nil && limiter.BasicAuthUsers != nil {
+		// Limit by HTTP methods and Basic Auth credentials.
+		if libstring.StringInSlice(limiter.Methods, r.Method) {
+			username, _, ok := r.BasicAuth()
+			if ok && libstring.StringInSlice(limiter.BasicAuthUsers, username) {
+				sliceKeys = append(sliceKeys, []string{remoteIP, path, r.Method, username})
+			}
+		}
+
+	} else if limiter.Methods != nil {
+		// Limit by HTTP methods.
+		if libstring.StringInSlice(limiter.Methods, r.Method) {
+			sliceKeys = append(sliceKeys, []string{remoteIP, path, r.Method})
+		}
+
+	} else if limiter.Headers != nil {
+		// Limit by HTTP headers+values.
+		for headerKey, headerValues := range limiter.Headers {
+			if (headerValues == nil || len(headerValues) <= 0) && r.Header.Get(headerKey) != "" {
+				// If header values are empty, rate-limit all request with headerKey.
+				sliceKeys = append(sliceKeys, []string{remoteIP, path, headerKey})
+
+			} else if len(headerValues) > 0 && r.Header.Get(headerKey) != "" {
+				// If header values are not empty, rate-limit all request with headerKey and headerValues.
+				for _, headerValue := range headerValues {
+					sliceKeys = append(sliceKeys, []string{remoteIP, path, headerKey, headerValue})
+				}
+			}
+		}
+
+	} else if limiter.BasicAuthUsers != nil {
+		// Limit by Basic Auth credentials.
+		username, _, ok := r.BasicAuth()
+		if ok && libstring.StringInSlice(limiter.BasicAuthUsers, username) {
+			sliceKeys = append(sliceKeys, []string{remoteIP, path, username})
+		}
+	} else {
+		// Default: Limit by remoteIP and path.
+		sliceKeys = append(sliceKeys, []string{remoteIP, path})
+	}
+
+	return sliceKeys
+}
+
+// LimitHandler is a middleware that performs rate-limiting given http.Handler struct.
+func LimitHandler(limiter *config.Limiter, next http.Handler) http.Handler {
+	middle := func(w http.ResponseWriter, r *http.Request) {
+		httpError := LimitByRequest(limiter, r)
+		if httpError != nil {
+			w.Header().Add("Content-Type", limiter.MessageContentType)
+			w.WriteHeader(httpError.StatusCode)
+			w.Write([]byte(httpError.Message))
+			return
+		}
+
+		// There's no rate-limit error, serve the next handler.
+		next.ServeHTTP(w, r)
+	}
+
+	return http.HandlerFunc(middle)
+}
+
+// LimitFuncHandler is a middleware that performs rate-limiting given request handler function.
+func LimitFuncHandler(limiter *config.Limiter, nextFunc func(http.ResponseWriter, *http.Request)) http.Handler {
+	return LimitHandler(limiter, http.HandlerFunc(nextFunc))
+}

vendor/github.com/go-chi/chi/CHANGELOG.md

@@ -0,0 +1,86 @@
+# Changelog
+
+## v3.1.5
+
+- Setup golint and go vet for the project
+- As per golint, we've redefined `func ServerBaseContext(h http.Handler, baseCtx context.Context) http.Handler`
+  to `func ServerBaseContext(baseCtx context.Context, h http.Handler) http.Handler`
+
+
+## v3.1.0 (2017-07-10)
+
+- Fix a few minor issues after v3 release
+- Move `docgen` sub-pkg to https://github.com/go-chi/docgen
+- Move `render` sub-pkg to https://github.com/go-chi/render
+- Add new `URLFormat` handler to chi/middleware sub-pkg to make working with url mime 
+  suffixes easier, ie. parsing `/articles/1.json` and `/articles/1.xml`. See comments in
+  https://github.com/go-chi/chi/blob/master/middleware/url_format.go for example usage.
+
+
+## v3.0.0 (2017-06-21)
+
+- Major update to chi library with many exciting updates, but also some *breaking changes*
+- URL parameter syntax changed from `/:id` to `/{id}` for even more flexible routing, such as
+  `/articles/{month}-{day}-{year}-{slug}`, `/articles/{id}`, and `/articles/{id}.{ext}` on the
+  same router
+- Support for regexp for routing patterns, in the form of `/{paramKey:regExp}` for example:
+  `r.Get("/articles/{name:[a-z]+}", h)` and `chi.URLParam(r, "name")`
+- Add `Method` and `MethodFunc` to `chi.Router` to allow routing definitions such as
+  `r.Method("GET", "/", h)` which provides a cleaner interface for custom handlers like
+  in `_examples/custom-handler`
+- Deprecating `mux#FileServer` helper function. Instead, we encourage users to create their
+  own using file handler with the stdlib, see `_examples/fileserver` for an example
+- Add support for LINK/UNLINK http methods via `r.Method()` and `r.MethodFunc()`
+- Moved the chi project to its own organization, to allow chi-related community packages to
+  be easily discovered and supported, at: https://github.com/go-chi
+- *NOTE:* please update your import paths to `"github.com/go-chi/chi"`
+- *NOTE:* chi v2 is still available at https://github.com/go-chi/chi/tree/v2
+
+
+## v2.1.0 (2017-03-30)
+
+- Minor improvements and update to the chi core library
+- Introduced a brand new `chi/render` sub-package to complete the story of building
+  APIs to offer a pattern for managing well-defined request / response payloads. Please
+  check out the updated `_examples/rest` example for how it works.
+- Added `MethodNotAllowed(h http.HandlerFunc)` to chi.Router interface
+
+
+## v2.0.0 (2017-01-06)
+
+- After many months of v2 being in an RC state with many companies and users running it in
+  production, the inclusion of some improvements to the middlewares, we are very pleased to
+  announce v2.0.0 of chi.
+
+
+## v2.0.0-rc1 (2016-07-26)
+
+- Huge update! chi v2 is a large refactor targetting Go 1.7+. As of Go 1.7, the popular
+  community `"net/context"` package has been included in the standard library as `"context"` and
+  utilized by `"net/http"` and `http.Request` to managing deadlines, cancelation signals and other
+  request-scoped values. We're very excited about the new context addition and are proud to
+  introduce chi v2, a minimal and powerful routing package for building large HTTP services,
+  with zero external dependencies. Chi focuses on idiomatic design and encourages the use of 
+  stdlib HTTP handlers and middlwares.
+- chi v2 deprecates its `chi.Handler` interface and requires `http.Handler` or `http.HandlerFunc`
+- chi v2 stores URL routing parameters and patterns in the standard request context: `r.Context()`
+- chi v2 lower-level routing context is accessible by `chi.RouteContext(r.Context()) *chi.Context`,
+  which provides direct access to URL routing parameters, the routing path and the matching
+  routing patterns.
+- Users upgrading from chi v1 to v2, need to:
+  1. Update the old chi.Handler signature, `func(ctx context.Context, w http.ResponseWriter, r *http.Request)` to
+     the standard http.Handler: `func(w http.ResponseWriter, r *http.Request)`
+  2. Use `chi.URLParam(r *http.Request, paramKey string) string`
+     or `URLParamFromCtx(ctx context.Context, paramKey string) string` to access a url parameter value
+
+
+## v1.0.0 (2016-07-01)
+
+- Released chi v1 stable https://github.com/go-chi/chi/tree/v1.0.0 for Go 1.6 and older.
+
+
+## v0.9.0 (2016-03-31)
+
+- Reuse context objects via sync.Pool for zero-allocation routing [#33](https://github.com/go-chi/chi/pull/33)
+- BREAKING NOTE: due to subtle API changes, previously `chi.URLParams(ctx)["id"]` used to access url parameters
+  has changed to: `chi.URLParam(ctx, "id")`

vendor/github.com/go-chi/chi/CONTRIBUTING.md

@@ -0,0 +1,31 @@
+# Contributing
+
+## Prerequisites
+
+1. [Install Go][go-install].
+2. Download the sources and switch the working directory:
+
+    ```bash
+    go get -u -d github.com/go-chi/chi
+    cd $GOPATH/src/github.com/go-chi/chi
+    ```
+
+## Submitting a Pull Request
+
+A typical workflow is:
+
+1. [Fork the repository.][fork] [This tip maybe also helpful.][go-fork-tip]
+2. [Create a topic branch.][branch]
+3. Add tests for your change.
+4. Run `go test`. If your tests pass, return to the step 3.
+5. Implement the change and ensure the steps from the previous step pass.
+6. Run `goimports -w .`, to ensure the new code conforms to Go formatting guideline.
+7. [Add, commit and push your changes.][git-help]
+8. [Submit a pull request.][pull-req]
+
+[go-install]: https://golang.org/doc/install
+[go-fork-tip]: http://blog.campoy.cat/2014/03/github-and-go-forking-pull-requests-and.html
+[fork]: https://help.github.com/articles/fork-a-repo
+[branch]: http://learn.github.com/p/branching.html
+[git-help]: https://guides.github.com
+[pull-req]: https://help.github.com/articles/using-pull-requests

vendor/github.com/go-chi/chi/LICENSE

@@ -0,0 +1,20 @@
+Copyright (c) 2015-present Peter Kieltyka (https://github.com/pkieltyka)
+
+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/go-chi/chi/README.md

@@ -0,0 +1,422 @@
+# <img alt="chi" src="https://cdn.rawgit.com/go-chi/chi/master/_examples/chi.svg" width="220" />
+
+
+[![GoDoc Widget]][GoDoc] [![Travis Widget]][Travis]
+
+`chi` is a lightweight, idiomatic and composable router for building Go 1.7+ HTTP services. It's
+especially good at helping you write large REST API services that are kept maintainable as your
+project grows and changes. `chi` is built on the new `context` package introduced in Go 1.7 to
+handle signaling, cancelation and request-scoped values across a handler chain.
+
+The focus of the project has been to seek out an elegant and comfortable design for writing
+REST API servers, written during the development of the Pressly API service that powers our
+public API service, which in turn powers all of our client-side applications.
+
+The key considerations of chi's design are: project structure, maintainability, standard http
+handlers (stdlib-only), developer productivity, and deconstructing a large system into many small
+parts. The core router `github.com/go-chi/chi` is quite small (less than 1000 LOC), but we've also
+included some useful/optional subpackages: [middleware](/middleware), [render](https://github.com/go-chi/render) and [docgen](https://github.com/go-chi/docgen). We hope you enjoy it too!
+
+## Install
+
+`go get -u github.com/go-chi/chi`
+
+
+## Features
+
+* **Lightweight** - cloc'd in <1000 LOC for the chi router
+* **Fast** - yes, see [benchmarks](#benchmarks)
+* **100% compatible with net/http** - use any http or middleware pkg in the ecosystem that is also compatible with `net/http`
+* **Designed for modular/composable APIs** - middlewares, inline middlewares, route groups and subrouter mounting
+* **Context control** - built on new `context` package, providing value chaining, cancelations and timeouts
+* **Robust** - in production at Pressly, CloudFlare, Heroku, 99Designs, and many others (see [discussion](https://github.com/go-chi/chi/issues/91))
+* **Doc generation** - `docgen` auto-generates routing documentation from your source to JSON or Markdown
+* **No external dependencies** - plain ol' Go 1.7+ stdlib + net/http
+
+
+## Examples
+
+* [rest](https://github.com/go-chi/chi/blob/master/_examples/rest/main.go) - REST APIs made easy, productive and maintainable
+* [logging](https://github.com/go-chi/chi/blob/master/_examples/logging/main.go) - Easy structured logging for any backend
+* [limits](https://github.com/go-chi/chi/blob/master/_examples/limits/main.go) - Timeouts and Throttling
+* [todos-resource](https://github.com/go-chi/chi/blob/master/_examples/todos-resource/main.go) - Struct routers/handlers, an example of another code layout style
+* [versions](https://github.com/go-chi/chi/blob/master/_examples/versions/main.go) - Demo of `chi/render` subpkg
+* [fileserver](https://github.com/go-chi/chi/blob/master/_examples/fileserver/main.go) - Easily serve static files
+* [graceful](https://github.com/go-chi/chi/blob/master/_examples/graceful/main.go) - Graceful context signaling and server shutdown
+
+
+**As easy as:**
+
+```go
+package main
+
+import (
+	"net/http"
+	"github.com/go-chi/chi"
+)
+
+func main() {
+	r := chi.NewRouter()
+	r.Get("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte("welcome"))
+	})
+	http.ListenAndServe(":3000", r)
+}
+```
+
+**REST Preview:**
+
+Here is a little preview of how routing looks like with chi. Also take a look at the generated routing docs
+in JSON ([routes.json](https://github.com/go-chi/chi/blob/master/_examples/rest/routes.json)) and in
+Markdown ([routes.md](https://github.com/go-chi/chi/blob/master/_examples/rest/routes.md)).
+
+I highly recommend reading the source of the [examples](#examples) listed above, they will show you all the features
+of chi and serve as a good form of documentation.
+
+```go
+import (
+  //...
+  "context"
+  "github.com/go-chi/chi"
+  "github.com/go-chi/chi/middleware"
+)
+
+func main() {
+  r := chi.NewRouter()
+
+  // A good base middleware stack
+  r.Use(middleware.RequestID)
+  r.Use(middleware.RealIP)
+  r.Use(middleware.Logger)
+  r.Use(middleware.Recoverer)
+
+  // Set a timeout value on the request context (ctx), that will signal
+  // through ctx.Done() that the request has timed out and further
+  // processing should be stopped.
+  r.Use(middleware.Timeout(60 * time.Second))
+
+  r.Get("/", func(w http.ResponseWriter, r *http.Request) {
+    w.Write([]byte("hi"))
+  })
+
+  // RESTy routes for "articles" resource
+  r.Route("/articles", func(r chi.Router) {
+    r.With(paginate).Get("/", listArticles)                           // GET /articles
+    r.With(paginate).Get("/{month}-{day}-{year}", listArticlesByDate) // GET /articles/01-16-2017
+
+    r.Post("/", createArticle)                                        // POST /articles
+    r.Get("/search", searchArticles)                                  // GET /articles/search
+
+    // Regexp url parameters:
+    r.Get("/{articleSlug:[a-z-]+}", getArticleBySlug)                // GET /articles/home-is-toronto
+    
+    // Subrouters:
+    r.Route("/{articleID}", func(r chi.Router) {
+      r.Use(ArticleCtx)
+      r.Get("/", getArticle)                                          // GET /articles/123
+      r.Put("/", updateArticle)                                       // PUT /articles/123
+      r.Delete("/", deleteArticle)                                    // DELETE /articles/123
+    })
+  })
+
+  // Mount the admin sub-router
+  r.Mount("/admin", adminRouter())
+
+  http.ListenAndServe(":3333", r)
+}
+
+func ArticleCtx(next http.Handler) http.Handler {
+  return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+    articleID := chi.URLParam(r, "articleID")
+    article, err := dbGetArticle(articleID)
+    if err != nil {
+      http.Error(w, http.StatusText(404), 404)
+      return
+    }
+    ctx := context.WithValue(r.Context(), "article", article)
+    next.ServeHTTP(w, r.WithContext(ctx))
+  })
+}
+
+func getArticle(w http.ResponseWriter, r *http.Request) {
+  ctx := r.Context()
+  article, ok := ctx.Value("article").(*Article)
+  if !ok {
+    http.Error(w, http.StatusText(422), 422)
+    return
+  }
+  w.Write([]byte(fmt.Sprintf("title:%s", article.Title)))
+}
+
+// A completely separate router for administrator routes
+func adminRouter() http.Handler {
+  r := chi.NewRouter()
+  r.Use(AdminOnly)
+  r.Get("/", adminIndex)
+  r.Get("/accounts", adminListAccounts)
+  return r
+}
+
+func AdminOnly(next http.Handler) http.Handler {
+  return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+    ctx := r.Context()
+    perm, ok := ctx.Value("acl.permission").(YourPermissionType)
+    if !ok || !perm.IsAdmin() {
+      http.Error(w, http.StatusText(403), 403)
+      return
+    }
+    next.ServeHTTP(w, r)
+  })
+}
+```
+
+
+## Router design
+
+chi's router is based on a kind of [Patricia Radix trie](https://en.wikipedia.org/wiki/Radix_tree).
+The router is fully compatible with `net/http`.
+
+Built on top of the tree is the `Router` interface:
+
+```go
+// Router consisting of the core routing methods used by chi's Mux,
+// using only the standard net/http.
+type Router interface {
+	http.Handler
+	Routes
+
+	// Use appends one of more middlewares onto the Router stack.
+	Use(middlewares ...func(http.Handler) http.Handler)
+
+	// With adds inline middlewares for an endpoint handler.
+	With(middlewares ...func(http.Handler) http.Handler) Router
+
+	// Group adds a new inline-Router along the current routing
+	// path, with a fresh middleware stack for the inline-Router.
+	Group(fn func(r Router)) Router
+
+	// Route mounts a sub-Router along a `pattern`` string.
+	Route(pattern string, fn func(r Router)) Router
+
+	// Mount attaches another http.Handler along ./pattern/*
+	Mount(pattern string, h http.Handler)
+
+	// Handle and HandleFunc adds routes for `pattern` that matches
+	// all HTTP methods.
+	Handle(pattern string, h http.Handler)
+	HandleFunc(pattern string, h http.HandlerFunc)
+
+	// Method and MethodFunc adds routes for `pattern` that matches
+	// the `method` HTTP method.
+	Method(method, pattern string, h http.Handler)
+	MethodFunc(method, pattern string, h http.HandlerFunc)
+
+	// HTTP-method routing along `pattern`
+	Connect(pattern string, h http.HandlerFunc)
+	Delete(pattern string, h http.HandlerFunc)
+	Get(pattern string, h http.HandlerFunc)
+	Head(pattern string, h http.HandlerFunc)
+	Options(pattern string, h http.HandlerFunc)
+	Patch(pattern string, h http.HandlerFunc)
+	Post(pattern string, h http.HandlerFunc)
+	Put(pattern string, h http.HandlerFunc)
+	Trace(pattern string, h http.HandlerFunc)
+
+	// NotFound defines a handler to respond whenever a route could
+	// not be found.
+	NotFound(h http.HandlerFunc)
+
+	// MethodNotAllowed defines a handler to respond whenever a method is
+	// not allowed.
+	MethodNotAllowed(h http.HandlerFunc)
+}
+
+// Routes interface adds two methods for router traversal, which is also
+// used by the `docgen` subpackage to generation documentation for Routers.
+type Routes interface {
+	// Routes returns the routing tree in an easily traversable structure.
+	Routes() []Route
+
+	// Middlewares returns the list of middlewares in use by the router.
+	Middlewares() Middlewares
+}
+```
+
+Each routing method accepts a URL `pattern` and chain of `handlers`. The URL pattern
+supports named params (ie. `/users/{userID}`) and wildcards (ie. `/admin/*`). URL parameters
+can be fetched at runtime by calling `chi.URLParam(r, "userID")` for named parameters
+and `chi.URLParam(r, "*")` for a wildcard parameter.
+
+
+### Middleware handlers
+
+chi's middlewares are just stdlib net/http middleware handlers. There is nothing special
+about them, which means the router and all the tooling is designed to be compatible and
+friendly with any middleware in the community. This offers much better extensibility and reuse
+of packages and is at the heart of chi's purpose.
+
+Here is an example of a standard net/http middleware handler using the new request context
+available in Go 1.7+. This middleware sets a hypothetical user identifier on the request
+context and calls the next handler in the chain.
+
+```go
+// HTTP middleware setting a value on the request context
+func MyMiddleware(next http.Handler) http.Handler {
+  return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+    ctx := context.WithValue(r.Context(), "user", "123")
+    next.ServeHTTP(w, r.WithContext(ctx))
+  })
+}
+```
+
+
+### Request handlers
+
+chi uses standard net/http request handlers. This little snippet is an example of a http.Handler
+func that reads a user identifier from the request context - hypothetically, identifying
+the user sending an authenticated request, validated+set by a previous middleware handler.
+
+```go
+// HTTP handler accessing data from the request context.
+func MyRequestHandler(w http.ResponseWriter, r *http.Request) {
+  user := r.Context().Value("user").(string)
+  w.Write([]byte(fmt.Sprintf("hi %s", user)))
+}
+```
+
+
+### URL parameters
+
+chi's router parses and stores URL parameters right onto the request context. Here is
+an example of how to access URL params in your net/http handlers. And of course, middlewares
+are able to access the same information.
+
+```go
+// HTTP handler accessing the url routing parameters.
+func MyRequestHandler(w http.ResponseWriter, r *http.Request) {
+  userID := chi.URLParam(r, "userID") // from a route like /users/{userID}
+
+  ctx := r.Context()
+  key := ctx.Value("key").(string)
+
+  w.Write([]byte(fmt.Sprintf("hi %v, %v", userID, key)))
+}
+```
+
+
+## Middlewares
+
+chi comes equipped with an optional `middleware` package, providing a suite of standard
+`net/http` middlewares. Please note, any middleware in the ecosystem that is also compatible
+with `net/http` can be used with chi's mux.
+
+----------------------------------------------------------------------------------------------------------
+| Middleware           | Description                                                                     |
+|:---------------------|:---------------------------------------------------------------------------------
+| RequestID            | Injects a request ID into the context of each request.                          |
+| RealIP               | Sets a http.Request's RemoteAddr to either X-Forwarded-For or X-Real-IP.        |
+| Logger               | Logs the start and end of each request with the elapsed processing time.        |
+| Recoverer            | Gracefully absorb panics and prints the stack trace.                            |
+| NoCache              | Sets response headers to prevent clients from caching.                          |
+| Timeout              | Signals to the request context when the timeout deadline is reached.            |
+| Throttle             | Puts a ceiling on the number of concurrent requests.                            |
+| Compress             | Gzip compression for clients that accept compressed responses.                  |
+| Profiler             | Easily attach net/http/pprof to your routers.                                   |
+| StripSlashes         | Strip slashes on routing paths.                                                 |
+| RedirectSlashes      | Redirect slashes on routing paths.                                              |
+| WithValue            | Short-hand middleware to set a key/value on the request context.                |
+| Heartbeat            | Monitoring endpoint to check the servers pulse.                                 |
+----------------------------------------------------------------------------------------------------------
+
+Other cool community net/http middlewares:
+
+* [jwtauth](https://github.com/goware/jwtauth) - JWT authenticator
+* [cors](https://github.com/goware/cors) - CORS middleware
+* [httpcoala](https://github.com/goware/httpcoala) - Request coalescer
+* [chi-authz](https://github.com/casbin/chi-authz) - Authorization middleware built on https://github.com/hsluoyz/casbin
+
+please [submit a PR](./CONTRIBUTING.md) if you'd like to include a link to a chi middleware
+
+
+## context?
+
+`context` is a tiny pkg that provides simple interface to signal context across call stacks
+and goroutines. It was originally written by [Sameer Ajmani](https://github.com/Sajmani)
+and is available in stdlib since go1.7.
+
+Learn more at https://blog.golang.org/context
+
+and..
+* Docs: https://golang.org/pkg/context
+* Source: https://github.com/golang/go/tree/master/src/context
+
+
+## Benchmarks
+
+The benchmark suite: https://github.com/pkieltyka/go-http-routing-benchmark
+
+Comparison with other routers (as of June 21, 2017): https://gist.github.com/pkieltyka/c089f309abeb179cfc4deaa519956d8c
+
+```shell
+BenchmarkChi_Param        	 3000000	       427 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_Param5       	 2000000	       631 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_Param20      	 1000000	      1343 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_ParamWrite   	 3000000	       477 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_GithubStatic 	 3000000	       452 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_GithubParam  	 2000000	       616 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_GithubAll    	   10000	    130637 ns/op	   61716 B/op	     406 allocs/op
+BenchmarkChi_GPlusStatic  	 3000000	       415 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_GPlusParam   	 3000000	       465 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_GPlus2Params 	 3000000	       548 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_GPlusAll     	  200000	      6895 ns/op	    3952 B/op	      26 allocs/op
+BenchmarkChi_ParseStatic  	 3000000	       407 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_ParseParam   	 3000000	       451 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_Parse2Params 	 3000000	       504 ns/op	     304 B/op	       2 allocs/op
+BenchmarkChi_ParseAll     	  100000	     13221 ns/op	    7904 B/op	      52 allocs/op
+BenchmarkChi_StaticAll    	   20000	     84327 ns/op	   47731 B/op	     314 allocs/op
+```
+
+NOTE: the allocs in the benchmark above are from the calls to http.Request's
+`WithContext(context.Context)` method that clones the http.Request, sets the `Context()`
+on the duplicated (alloc'd) request and returns it the new request object. This is just
+how setting context on a request in Go 1.7+ works.
+
+
+## Credits
+
+* Carl Jackson for https://github.com/zenazn/goji
+  * Parts of chi's thinking comes from goji, and chi's middleware package
+    sources from goji.
+* Armon Dadgar for https://github.com/armon/go-radix
+* Contributions: [@VojtechVitek](https://github.com/VojtechVitek)
+
+We'll be more than happy to see [your contributions](./CONTRIBUTING.md)!
+
+
+## Beyond REST
+
+chi is just a http router that lets you decompose request handling into many smaller layers.
+Many companies including Pressly.com (of course) use chi to write REST services for their public
+APIs. But, REST is just a convention for managing state via HTTP, and there's a lot of other pieces
+required to write a complete client-server system or network of microservices.
+
+Looking ahead beyond REST, I also recommend some newer works in the field coming from
+[gRPC](https://github.com/grpc/grpc-go), [NATS](https://nats.io), [go-kit](https://github.com/go-kit/kit)
+and even [graphql](https://github.com/graphql-go/graphql). They're all pretty cool with their
+own unique approaches and benefits. Specifically, I'd look at gRPC since it makes client-server
+communication feel like a single program on a single computer, no need to hand-write a client library
+and the request/response payloads are typed contracts. NATS is pretty amazing too as a super
+fast and lightweight pub-sub transport that can speak protobufs, with nice service discovery -
+an excellent combination with gRPC.
+
+
+## License
+
+Copyright (c) 2015-present [Peter Kieltyka](https://github.com/pkieltyka)
+
+Licensed under [MIT License](./LICENSE)
+
+[GoDoc]: https://godoc.org/github.com/go-chi/chi
+[GoDoc Widget]: https://godoc.org/github.com/go-chi/chi?status.svg
+[Travis]: https://travis-ci.org/go-chi/chi
+[Travis Widget]: https://travis-ci.org/go-chi/chi.svg?branch=master

vendor/github.com/go-chi/chi/chain.go

@@ -0,0 +1,49 @@
+package chi
+
+import "net/http"
+
+// Chain returns a Middlewares type from a slice of middleware handlers.
+func Chain(middlewares ...func(http.Handler) http.Handler) Middlewares {
+	return Middlewares(middlewares)
+}
+
+// Handler builds and returns a http.Handler from the chain of middlewares,
+// with `h http.Handler` as the final handler.
+func (mws Middlewares) Handler(h http.Handler) http.Handler {
+	return &ChainHandler{mws, h, chain(mws, h)}
+}
+
+// HandlerFunc builds and returns a http.Handler from the chain of middlewares,
+// with `h http.Handler` as the final handler.
+func (mws Middlewares) HandlerFunc(h http.HandlerFunc) http.Handler {
+	return &ChainHandler{mws, h, chain(mws, h)}
+}
+
+// ChainHandler is a http.Handler with support for handler composition and
+// execution.
+type ChainHandler struct {
+	Middlewares Middlewares
+	Endpoint    http.Handler
+	chain       http.Handler
+}
+
+func (c *ChainHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	c.chain.ServeHTTP(w, r)
+}
+
+// chain builds a http.Handler composed of an inline middleware stack and endpoint
+// handler in the order they are passed.
+func chain(middlewares []func(http.Handler) http.Handler, endpoint http.Handler) http.Handler {
+	// Return ahead of time if there aren't any middlewares for the chain
+	if len(middlewares) == 0 {
+		return endpoint
+	}
+
+	// Wrap the end handler with the middleware chain
+	h := middlewares[len(middlewares)-1](endpoint)
+	for i := len(middlewares) - 2; i >= 0; i-- {
+		h = middlewares[i](h)
+	}
+
+	return h
+}

vendor/github.com/go-chi/chi/chi.go

@@ -0,0 +1,103 @@
+//
+// Package chi is a small, idiomatic and composable router for building HTTP services.
+//
+// chi requires Go 1.7 or newer.
+//
+// Example:
+//  package main
+//
+//  import (
+//  	"net/http"
+//
+//  	"github.com/go-chi/chi"
+//  	"github.com/go-chi/chi/middleware"
+//  )
+//
+//  func main() {
+//  	r := chi.NewRouter()
+//  	r.Use(middleware.Logger)
+//  	r.Use(middleware.Recoverer)
+//
+//  	r.Get("/", func(w http.ResponseWriter, r *http.Request) {
+//  		w.Write([]byte("root."))
+//  	})
+//
+//  	http.ListenAndServe(":3333", r)
+//  }
+//
+// See github.com/go-chi/chi/_examples/ for more in-depth examples.
+//
+package chi
+
+import "net/http"
+
+// NewRouter returns a new Mux object that implements the Router interface.
+func NewRouter() *Mux {
+	return NewMux()
+}
+
+// Router consisting of the core routing methods used by chi's Mux,
+// using only the standard net/http.
+type Router interface {
+	http.Handler
+	Routes
+
+	// Use appends one of more middlewares onto the Router stack.
+	Use(middlewares ...func(http.Handler) http.Handler)
+
+	// With adds inline middlewares for an endpoint handler.
+	With(middlewares ...func(http.Handler) http.Handler) Router
+
+	// Group adds a new inline-Router along the current routing
+	// path, with a fresh middleware stack for the inline-Router.
+	Group(fn func(r Router)) Router
+
+	// Route mounts a sub-Router along a `pattern`` string.
+	Route(pattern string, fn func(r Router)) Router
+
+	// Mount attaches another http.Handler along ./pattern/*
+	Mount(pattern string, h http.Handler)
+
+	// Handle and HandleFunc adds routes for `pattern` that matches
+	// all HTTP methods.
+	Handle(pattern string, h http.Handler)
+	HandleFunc(pattern string, h http.HandlerFunc)
+
+	// Method and MethodFunc adds routes for `pattern` that matches
+	// the `method` HTTP method.
+	Method(method, pattern string, h http.Handler)
+	MethodFunc(method, pattern string, h http.HandlerFunc)
+
+	// HTTP-method routing along `pattern`
+	Connect(pattern string, h http.HandlerFunc)
+	Delete(pattern string, h http.HandlerFunc)
+	Get(pattern string, h http.HandlerFunc)
+	Head(pattern string, h http.HandlerFunc)
+	Options(pattern string, h http.HandlerFunc)
+	Patch(pattern string, h http.HandlerFunc)
+	Post(pattern string, h http.HandlerFunc)
+	Put(pattern string, h http.HandlerFunc)
+	Trace(pattern string, h http.HandlerFunc)
+
+	// NotFound defines a handler to respond whenever a route could
+	// not be found.
+	NotFound(h http.HandlerFunc)
+
+	// MethodNotAllowed defines a handler to respond whenever a method is
+	// not allowed.
+	MethodNotAllowed(h http.HandlerFunc)
+}
+
+// Routes interface adds two methods for router traversal, which is also
+// used by the `docgen` subpackage to generation documentation for Routers.
+type Routes interface {
+	// Routes returns the routing tree in an easily traversable structure.
+	Routes() []Route
+
+	// Middlewares returns the list of middlewares in use by the router.
+	Middlewares() Middlewares
+}
+
+// Middlewares type is a slice of standard middleware handlers with methods
+// to compose middleware chains and http.Handler's.
+type Middlewares []func(http.Handler) http.Handler

vendor/github.com/go-chi/chi/context.go

@@ -0,0 +1,156 @@
+package chi
+
+import (
+	"context"
+	"net"
+	"net/http"
+	"strings"
+)
+
+var (
+	// RouteCtxKey is the context.Context key to store the request context.
+	RouteCtxKey = &contextKey{"RouteContext"}
+)
+
+// Context is the default routing context set on the root node of a
+// request context to track route patterns, URL parameters and
+// an optional routing path.
+type Context struct {
+	// Routing path override used during the route search.
+	// See Mux#routeHTTP method.
+	RoutePath string
+
+	// Routing pattern stack throughout the lifecycle of the request,
+	// across all connected routers. It is a record of all matching
+	// patterns across a stack of sub-routers.
+	RoutePatterns []string
+
+	// URLParams are the stack of routeParams captured during the
+	// routing lifecycle across a stack of sub-routers.
+	URLParams RouteParams
+
+	// The endpoint routing pattern that matched the request URI path
+	// or `RoutePath` of the current sub-router. This value will update
+	// during the lifecycle of a request passing through a stack of
+	// sub-routers.
+	routePattern string
+
+	// Route parameters matched for the current sub-router. It is
+	// intentionally unexported so it cant be tampered.
+	routeParams RouteParams
+
+	// methodNotAllowed hint
+	methodNotAllowed bool
+}
+
+// NewRouteContext returns a new routing Context object.
+func NewRouteContext() *Context {
+	return &Context{}
+}
+
+// reset a routing context to its initial state.
+func (x *Context) reset() {
+	x.RoutePath = ""
+	x.RoutePatterns = x.RoutePatterns[:0]
+	x.URLParams.Keys = x.URLParams.Keys[:0]
+	x.URLParams.Values = x.URLParams.Values[:0]
+
+	x.routePattern = ""
+	x.routeParams.Keys = x.routeParams.Keys[:0]
+	x.routeParams.Values = x.routeParams.Values[:0]
+	x.methodNotAllowed = false
+}
+
+// URLParam returns the corresponding URL parameter value from the request
+// routing context.
+func (x *Context) URLParam(key string) string {
+	for k := len(x.URLParams.Keys) - 1; k >= 0; k-- {
+		if x.URLParams.Keys[k] == key {
+			return x.URLParams.Values[k]
+		}
+	}
+	return ""
+}
+
+// RoutePattern builds the routing pattern string for the particular
+// request, at the particular point during routing. This means, the value
+// will change throughout the execution of a request in a router. That is
+// why its advised to only use this value after calling the next handler.
+//
+// For example,
+//
+// func Instrument(next http.Handler) http.Handler {
+//   return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+//     next.ServeHTTP(w, r)
+//     routePattern := chi.RouteContext(r.Context()).RoutePattern()
+//     measure(w, r, routePattern)
+// 	 })
+// }
+func (x *Context) RoutePattern() string {
+	routePattern := strings.Join(x.RoutePatterns, "")
+	return strings.Replace(routePattern, "/*/", "/", -1)
+}
+
+// RouteContext returns chi's routing Context object from a
+// http.Request Context.
+func RouteContext(ctx context.Context) *Context {
+	return ctx.Value(RouteCtxKey).(*Context)
+}
+
+// URLParam returns the url parameter from a http.Request object.
+func URLParam(r *http.Request, key string) string {
+	if rctx := RouteContext(r.Context()); rctx != nil {
+		return rctx.URLParam(key)
+	}
+	return ""
+}
+
+// URLParamFromCtx returns the url parameter from a http.Request Context.
+func URLParamFromCtx(ctx context.Context, key string) string {
+	if rctx := RouteContext(ctx); rctx != nil {
+		return rctx.URLParam(key)
+	}
+	return ""
+}
+
+// RouteParams is a structure to track URL routing parameters efficiently.
+type RouteParams struct {
+	Keys, Values []string
+}
+
+// Add will append a URL parameter to the end of the route param
+func (s *RouteParams) Add(key, value string) {
+	(*s).Keys = append((*s).Keys, key)
+	(*s).Values = append((*s).Values, value)
+}
+
+// ServerBaseContext wraps an http.Handler to set the request context to the
+// `baseCtx`.
+func ServerBaseContext(baseCtx context.Context, h http.Handler) http.Handler {
+	fn := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ctx := r.Context()
+		baseCtx := baseCtx
+
+		// Copy over default net/http server context keys
+		if v, ok := ctx.Value(http.ServerContextKey).(*http.Server); ok {
+			baseCtx = context.WithValue(baseCtx, http.ServerContextKey, v)
+		}
+		if v, ok := ctx.Value(http.LocalAddrContextKey).(net.Addr); ok {
+			baseCtx = context.WithValue(baseCtx, http.LocalAddrContextKey, v)
+		}
+
+		h.ServeHTTP(w, r.WithContext(baseCtx))
+	})
+	return fn
+}
+
+// contextKey is a value for use with context.WithValue. It's used as
+// a pointer so it fits in an interface{} without allocation. This technique
+// for defining context keys was copied from Go 1.7's new use of context in net/http.
+type contextKey struct {
+	name string
+}
+
+func (k *contextKey) String() string {
+	return "chi context value " + k.name
+}

vendor/github.com/go-chi/chi/middleware/closenotify17.go

@@ -0,0 +1,42 @@
+// +build go1.7,!go1.8
+
+package middleware
+
+import (
+	"context"
+	"net/http"
+)
+
+// CloseNotify is a middleware that cancels ctx when the underlying
+// connection has gone away. It can be used to cancel long operations
+// on the server when the client disconnects before the response is ready.
+//
+// Note: this behaviour is standard in Go 1.8+, so the middleware does nothing
+// on 1.8+ and exists just for backwards compatibility.
+func CloseNotify(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		cn, ok := w.(http.CloseNotifier)
+		if !ok {
+			panic("chi/middleware: CloseNotify expects http.ResponseWriter to implement http.CloseNotifier interface")
+		}
+		closeNotifyCh := cn.CloseNotify()
+
+		ctx, cancel := context.WithCancel(r.Context())
+		defer cancel()
+
+		go func() {
+			select {
+			case <-ctx.Done():
+				return
+			case <-closeNotifyCh:
+				cancel()
+				return
+			}
+		}()
+
+		r = r.WithContext(ctx)
+		next.ServeHTTP(w, r)
+	}
+
+	return http.HandlerFunc(fn)
+}

vendor/github.com/go-chi/chi/middleware/closenotify18.go

@@ -0,0 +1,17 @@
+// +build go1.8
+
+package middleware
+
+import (
+	"net/http"
+)
+
+// CloseNotify is a middleware that cancels ctx when the underlying
+// connection has gone away. It can be used to cancel long operations
+// on the server when the client disconnects before the response is ready.
+//
+// Note: this behaviour is standard in Go 1.8+, so the middleware does nothing
+// on 1.8+ and exists just for backwards compatibility.
+func CloseNotify(next http.Handler) http.Handler {
+	return next
+}

vendor/github.com/go-chi/chi/middleware/compress.go

@@ -0,0 +1,212 @@
+package middleware
+
+import (
+	"bufio"
+	"compress/flate"
+	"compress/gzip"
+	"errors"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+)
+
+type encoding int
+
+const (
+	encodingNone encoding = iota
+	encodingGzip
+	encodingDeflate
+)
+
+var defaultContentTypes = map[string]struct{}{
+	"text/html":                struct{}{},
+	"text/css":                 struct{}{},
+	"text/plain":               struct{}{},
+	"text/javascript":          struct{}{},
+	"application/javascript":   struct{}{},
+	"application/x-javascript": struct{}{},
+	"application/json":         struct{}{},
+	"application/atom+xml":     struct{}{},
+	"application/rss+xml":      struct{}{},
+}
+
+// DefaultCompress is a middleware that compresses response
+// body of predefined content types to a data format based
+// on Accept-Encoding request header. It uses a default
+// compression level.
+func DefaultCompress(next http.Handler) http.Handler {
+	return Compress(flate.DefaultCompression)(next)
+}
+
+// Compress is a middleware that compresses response
+// body of a given content types to a data format based
+// on Accept-Encoding request header. It uses a given
+// compression level.
+func Compress(level int, types ...string) func(next http.Handler) http.Handler {
+	contentTypes := defaultContentTypes
+	if len(types) > 0 {
+		contentTypes = make(map[string]struct{}, len(types))
+		for _, t := range types {
+			contentTypes[t] = struct{}{}
+		}
+	}
+
+	return func(next http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			mcw := &maybeCompressResponseWriter{
+				ResponseWriter: w,
+				w:              w,
+				contentTypes:   contentTypes,
+				encoding:       selectEncoding(r.Header),
+				level:          level,
+			}
+			defer mcw.Close()
+
+			next.ServeHTTP(mcw, r)
+		}
+
+		return http.HandlerFunc(fn)
+	}
+}
+
+func selectEncoding(h http.Header) encoding {
+	enc := h.Get("Accept-Encoding")
+
+	switch {
+	// TODO:
+	// case "br":    // Brotli, experimental. Firefox 2016, to-be-in Chromium.
+	// case "lzma":  // Opera.
+	// case "sdch":  // Chrome, Android. Gzip output + dictionary header.
+
+	case strings.Contains(enc, "gzip"):
+		// TODO: Exception for old MSIE browsers that can't handle non-HTML?
+		// https://zoompf.com/blog/2012/02/lose-the-wait-http-compression
+		return encodingGzip
+
+	case strings.Contains(enc, "deflate"):
+		// HTTP 1.1 "deflate" (RFC 2616) stands for DEFLATE data (RFC 1951)
+		// wrapped with zlib (RFC 1950). The zlib wrapper uses Adler-32
+		// checksum compared to CRC-32 used in "gzip" and thus is faster.
+		//
+		// But.. some old browsers (MSIE, Safari 5.1) incorrectly expect
+		// raw DEFLATE data only, without the mentioned zlib wrapper.
+		// Because of this major confusion, most modern browsers try it
+		// both ways, first looking for zlib headers.
+		// Quote by Mark Adler: http://stackoverflow.com/a/9186091/385548
+		//
+		// The list of browsers having problems is quite big, see:
+		// http://zoompf.com/blog/2012/02/lose-the-wait-http-compression
+		// https://web.archive.org/web/20120321182910/http://www.vervestudios.co/projects/compression-tests/results
+		//
+		// That's why we prefer gzip over deflate. It's just more reliable
+		// and not significantly slower than gzip.
+		return encodingDeflate
+
+		// NOTE: Not implemented, intentionally:
+		// case "compress": // LZW. Deprecated.
+		// case "bzip2":    // Too slow on-the-fly.
+		// case "zopfli":   // Too slow on-the-fly.
+		// case "xz":       // Too slow on-the-fly.
+	}
+
+	return encodingNone
+}
+
+type maybeCompressResponseWriter struct {
+	http.ResponseWriter
+	w            io.Writer
+	encoding     encoding
+	contentTypes map[string]struct{}
+	level        int
+	wroteHeader  bool
+}
+
+func (w *maybeCompressResponseWriter) WriteHeader(code int) {
+	if w.wroteHeader {
+		return
+	}
+	w.wroteHeader = true
+	defer w.ResponseWriter.WriteHeader(code)
+
+	// Already compressed data?
+	if w.ResponseWriter.Header().Get("Content-Encoding") != "" {
+		return
+	}
+	// The content-length after compression is unknown
+	w.ResponseWriter.Header().Del("Content-Length")
+
+	// Parse the first part of the Content-Type response header.
+	contentType := ""
+	parts := strings.Split(w.ResponseWriter.Header().Get("Content-Type"), ";")
+	if len(parts) > 0 {
+		contentType = parts[0]
+	}
+
+	// Is the content type compressable?
+	if _, ok := w.contentTypes[contentType]; !ok {
+		return
+	}
+
+	// Select the compress writer.
+	switch w.encoding {
+	case encodingGzip:
+		gw, err := gzip.NewWriterLevel(w.ResponseWriter, w.level)
+		if err != nil {
+			w.w = w.ResponseWriter
+			return
+		}
+		w.w = gw
+		w.ResponseWriter.Header().Set("Content-Encoding", "gzip")
+
+	case encodingDeflate:
+		dw, err := flate.NewWriter(w.ResponseWriter, w.level)
+		if err != nil {
+			w.w = w.ResponseWriter
+			return
+		}
+		w.w = dw
+		w.ResponseWriter.Header().Set("Content-Encoding", "deflate")
+	}
+}
+
+func (w *maybeCompressResponseWriter) Write(p []byte) (int, error) {
+	if !w.wroteHeader {
+		w.WriteHeader(http.StatusOK)
+	}
+
+	return w.w.Write(p)
+}
+
+func (w *maybeCompressResponseWriter) Flush() {
+	if f, ok := w.w.(http.Flusher); ok {
+		f.Flush()
+	}
+}
+
+func (w *maybeCompressResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	if hj, ok := w.w.(http.Hijacker); ok {
+		return hj.Hijack()
+	}
+	return nil, nil, errors.New("chi/middleware: http.Hijacker is unavailable on the writer")
+}
+
+func (w *maybeCompressResponseWriter) CloseNotify() <-chan bool {
+	if cn, ok := w.w.(http.CloseNotifier); ok {
+		return cn.CloseNotify()
+	}
+
+	// If the underlying writer does not implement http.CloseNotifier, return
+	// a channel that never receives a value. The semantics here is that the
+	// client never disconnnects before the request is processed by the
+	// http.Handler, which is close enough to the default behavior (when
+	// CloseNotify() is not even called).
+	return make(chan bool, 1)
+}
+
+func (w *maybeCompressResponseWriter) Close() error {
+	if c, ok := w.w.(io.WriteCloser); ok {
+		return c.Close()
+	}
+	return errors.New("chi/middleware: io.WriteCloser is unavailable on the writer")
+}

vendor/github.com/go-chi/chi/middleware/compress18.go

@@ -0,0 +1,15 @@
+// +build go1.8
+
+package middleware
+
+import (
+	"errors"
+	"net/http"
+)
+
+func (w *maybeCompressResponseWriter) Push(target string, opts *http.PushOptions) error {
+	if ps, ok := w.w.(http.Pusher); ok {
+		return ps.Push(target, opts)
+	}
+	return errors.New("chi/middleware: http.Pusher is unavailable on the writer")
+}

vendor/github.com/go-chi/chi/middleware/heartbeat.go

@@ -0,0 +1,26 @@
+package middleware
+
+import (
+	"net/http"
+	"strings"
+)
+
+// Heartbeat endpoint middleware useful to setting up a path like
+// `/ping` that load balancers or uptime testing external services
+// can make a request before hitting any routes. It's also convenient
+// to place this above ACL middlewares as well.
+func Heartbeat(endpoint string) func(http.Handler) http.Handler {
+	f := func(h http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			if r.Method == "GET" && strings.EqualFold(r.URL.Path, endpoint) {
+				w.Header().Set("Content-Type", "text/plain")
+				w.WriteHeader(http.StatusOK)
+				w.Write([]byte("."))
+				return
+			}
+			h.ServeHTTP(w, r)
+		}
+		return http.HandlerFunc(fn)
+	}
+	return f
+}

vendor/github.com/go-chi/chi/middleware/logger.go

@@ -0,0 +1,149 @@
+package middleware
+
+import (
+	"bytes"
+	"context"
+	"log"
+	"net/http"
+	"os"
+	"time"
+)
+
+var (
+	// LogEntryCtxKey is the context.Context key to store the request log entry.
+	LogEntryCtxKey = &contextKey{"LogEntry"}
+
+	// DefaultLogger is called by the Logger middleware handler to log each request.
+	// Its made a package-level variable so that it can be reconfigured for custom
+	// logging configurations.
+	DefaultLogger = RequestLogger(&DefaultLogFormatter{Logger: log.New(os.Stdout, "", log.LstdFlags)})
+)
+
+// Logger is a middleware that logs the start and end of each request, along
+// with some useful data about what was requested, what the response status was,
+// and how long it took to return. When standard output is a TTY, Logger will
+// print in color, otherwise it will print in black and white. Logger prints a
+// request ID if one is provided.
+//
+// Alternatively, look at https://github.com/pressly/lg and the `lg.RequestLogger`
+// middleware pkg.
+func Logger(next http.Handler) http.Handler {
+	return DefaultLogger(next)
+}
+
+// RequestLogger returns a logger handler using a custom LogFormatter.
+func RequestLogger(f LogFormatter) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			entry := f.NewLogEntry(r)
+			ww := NewWrapResponseWriter(w, r.ProtoMajor)
+
+			t1 := time.Now()
+			defer func() {
+				entry.Write(ww.Status(), ww.BytesWritten(), time.Since(t1))
+			}()
+
+			next.ServeHTTP(ww, WithLogEntry(r, entry))
+		}
+		return http.HandlerFunc(fn)
+	}
+}
+
+// LogFormatter initiates the beginning of a new LogEntry per request.
+// See DefaultLogFormatter for an example implementation.
+type LogFormatter interface {
+	NewLogEntry(r *http.Request) LogEntry
+}
+
+// LogEntry records the final log when a request completes.
+// See defaultLogEntry for an example implementation.
+type LogEntry interface {
+	Write(status, bytes int, elapsed time.Duration)
+	Panic(v interface{}, stack []byte)
+}
+
+// GetLogEntry returns the in-context LogEntry for a request.
+func GetLogEntry(r *http.Request) LogEntry {
+	entry, _ := r.Context().Value(LogEntryCtxKey).(LogEntry)
+	return entry
+}
+
+// WithLogEntry sets the in-context LogEntry for a request.
+func WithLogEntry(r *http.Request, entry LogEntry) *http.Request {
+	r = r.WithContext(context.WithValue(r.Context(), LogEntryCtxKey, entry))
+	return r
+}
+
+// DefaultLogFormatter is a simple logger that implements a LogFormatter.
+type DefaultLogFormatter struct {
+	Logger *log.Logger
+}
+
+// NewLogEntry creates a new LogEntry for the request.
+func (l *DefaultLogFormatter) NewLogEntry(r *http.Request) LogEntry {
+	entry := &defaultLogEntry{
+		DefaultLogFormatter: l,
+		request:             r,
+		buf:                 &bytes.Buffer{},
+	}
+
+	reqID := GetReqID(r.Context())
+	if reqID != "" {
+		cW(entry.buf, nYellow, "[%s] ", reqID)
+	}
+	cW(entry.buf, nCyan, "\"")
+	cW(entry.buf, bMagenta, "%s ", r.Method)
+
+	scheme := "http"
+	if r.TLS != nil {
+		scheme = "https"
+	}
+	cW(entry.buf, nCyan, "%s://%s%s %s\" ", scheme, r.Host, r.RequestURI, r.Proto)
+
+	entry.buf.WriteString("from ")
+	entry.buf.WriteString(r.RemoteAddr)
+	entry.buf.WriteString(" - ")
+
+	return entry
+}
+
+type defaultLogEntry struct {
+	*DefaultLogFormatter
+	request *http.Request
+	buf     *bytes.Buffer
+}
+
+func (l *defaultLogEntry) Write(status, bytes int, elapsed time.Duration) {
+	switch {
+	case status < 200:
+		cW(l.buf, bBlue, "%03d", status)
+	case status < 300:
+		cW(l.buf, bGreen, "%03d", status)
+	case status < 400:
+		cW(l.buf, bCyan, "%03d", status)
+	case status < 500:
+		cW(l.buf, bYellow, "%03d", status)
+	default:
+		cW(l.buf, bRed, "%03d", status)
+	}
+
+	cW(l.buf, bBlue, " %dB", bytes)
+
+	l.buf.WriteString(" in ")
+	if elapsed < 500*time.Millisecond {
+		cW(l.buf, nGreen, "%s", elapsed)
+	} else if elapsed < 5*time.Second {
+		cW(l.buf, nYellow, "%s", elapsed)
+	} else {
+		cW(l.buf, nRed, "%s", elapsed)
+	}
+
+	l.Logger.Print(l.buf.String())
+}
+
+func (l *defaultLogEntry) Panic(v interface{}, stack []byte) {
+	panicEntry := l.NewLogEntry(l.request).(*defaultLogEntry)
+	cW(panicEntry.buf, bRed, "panic: %+v", v)
+	l.Logger.Print(panicEntry.buf.String())
+	l.Logger.Print(string(stack))
+}

vendor/github.com/go-chi/chi/middleware/middleware.go

@@ -0,0 +1,12 @@
+package middleware
+
+// contextKey is a value for use with context.WithValue. It's used as
+// a pointer so it fits in an interface{} without allocation. This technique
+// for defining context keys was copied from Go 1.7's new use of context in net/http.
+type contextKey struct {
+	name string
+}
+
+func (k *contextKey) String() string {
+	return "chi/middleware context value " + k.name
+}

vendor/github.com/go-chi/chi/middleware/nocache.go

@@ -0,0 +1,58 @@
+package middleware
+
+// Ported from Goji's middleware, source:
+// https://github.com/zenazn/goji/tree/master/web/middleware
+
+import (
+	"net/http"
+	"time"
+)
+
+// Unix epoch time
+var epoch = time.Unix(0, 0).Format(time.RFC1123)
+
+// Taken from https://github.com/mytrile/nocache
+var noCacheHeaders = map[string]string{
+	"Expires":         epoch,
+	"Cache-Control":   "no-cache, no-store, must-revalidate, private, max-age=0",
+	"Pragma":          "no-cache",
+	"X-Accel-Expires": "0",
+}
+
+var etagHeaders = []string{
+	"ETag",
+	"If-Modified-Since",
+	"If-Match",
+	"If-None-Match",
+	"If-Range",
+	"If-Unmodified-Since",
+}
+
+// NoCache is a simple piece of middleware that sets a number of HTTP headers to prevent
+// a router (or subrouter) from being cached by an upstream proxy and/or client.
+//
+// As per http://wiki.nginx.org/HttpProxyModule - NoCache sets:
+//      Expires: Thu, 01 Jan 1970 00:00:00 UTC
+//      Cache-Control: no-cache, private, max-age=0
+//      X-Accel-Expires: 0
+//      Pragma: no-cache (for HTTP/1.0 proxies/clients)
+func NoCache(h http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+
+		// Delete any ETag headers that may have been set
+		for _, v := range etagHeaders {
+			if r.Header.Get(v) != "" {
+				r.Header.Del(v)
+			}
+		}
+
+		// Set our NoCache headers
+		for k, v := range noCacheHeaders {
+			w.Header().Set(k, v)
+		}
+
+		h.ServeHTTP(w, r)
+	}
+
+	return http.HandlerFunc(fn)
+}

vendor/github.com/go-chi/chi/middleware/profiler.go

@@ -0,0 +1,59 @@
+package middleware
+
+import (
+	"expvar"
+	"fmt"
+	"net/http"
+	"net/http/pprof"
+
+	"github.com/go-chi/chi"
+)
+
+// Profiler is a convenient subrouter used for mounting net/http/pprof. ie.
+//
+//  func MyService() http.Handler {
+//    r := chi.NewRouter()
+//    // ..middlewares
+//    r.Mount("/debug", middleware.Profiler())
+//    // ..routes
+//    return r
+//  }
+func Profiler() http.Handler {
+	r := chi.NewRouter()
+	r.Use(NoCache)
+
+	r.Get("/", func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, r.RequestURI+"/pprof/", 301)
+	})
+	r.HandleFunc("/pprof", func(w http.ResponseWriter, r *http.Request) {
+		http.Redirect(w, r, r.RequestURI+"/", 301)
+	})
+
+	r.HandleFunc("/pprof/", pprof.Index)
+	r.HandleFunc("/pprof/cmdline", pprof.Cmdline)
+	r.HandleFunc("/pprof/profile", pprof.Profile)
+	r.HandleFunc("/pprof/symbol", pprof.Symbol)
+	r.HandleFunc("/pprof/trace", pprof.Trace)
+	r.Handle("/pprof/block", pprof.Handler("block"))
+	r.Handle("/pprof/heap", pprof.Handler("heap"))
+	r.Handle("/pprof/goroutine", pprof.Handler("goroutine"))
+	r.Handle("/pprof/threadcreate", pprof.Handler("threadcreate"))
+	r.HandleFunc("/vars", expVars)
+
+	return r
+}
+
+// Replicated from expvar.go as not public.
+func expVars(w http.ResponseWriter, r *http.Request) {
+	first := true
+	w.Header().Set("Content-Type", "application/json")
+	fmt.Fprintf(w, "{\n")
+	expvar.Do(func(kv expvar.KeyValue) {
+		if !first {
+			fmt.Fprintf(w, ",\n")
+		}
+		first = false
+		fmt.Fprintf(w, "%q: %s", kv.Key, kv.Value)
+	})
+	fmt.Fprintf(w, "\n}\n")
+}

vendor/github.com/go-chi/chi/middleware/realip.go

@@ -0,0 +1,54 @@
+package middleware
+
+// Ported from Goji's middleware, source:
+// https://github.com/zenazn/goji/tree/master/web/middleware
+
+import (
+	"net/http"
+	"strings"
+)
+
+var xForwardedFor = http.CanonicalHeaderKey("X-Forwarded-For")
+var xRealIP = http.CanonicalHeaderKey("X-Real-IP")
+
+// RealIP is a middleware that sets a http.Request's RemoteAddr to the results
+// of parsing either the X-Forwarded-For header or the X-Real-IP header (in that
+// order).
+//
+// This middleware should be inserted fairly early in the middleware stack to
+// ensure that subsequent layers (e.g., request loggers) which examine the
+// RemoteAddr will see the intended value.
+//
+// You should only use this middleware if you can trust the headers passed to
+// you (in particular, the two headers this middleware uses), for example
+// because you have placed a reverse proxy like HAProxy or nginx in front of
+// Goji. If your reverse proxies are configured to pass along arbitrary header
+// values from the client, or if you use this middleware without a reverse
+// proxy, malicious clients will be able to make you very sad (or, depending on
+// how you're using RemoteAddr, vulnerable to an attack of some sort).
+func RealIP(h http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		if rip := realIP(r); rip != "" {
+			r.RemoteAddr = rip
+		}
+		h.ServeHTTP(w, r)
+	}
+
+	return http.HandlerFunc(fn)
+}
+
+func realIP(r *http.Request) string {
+	var ip string
+
+	if xff := r.Header.Get(xForwardedFor); xff != "" {
+		i := strings.Index(xff, ", ")
+		if i == -1 {
+			i = len(xff)
+		}
+		ip = xff[:i]
+	} else if xrip := r.Header.Get(xRealIP); xrip != "" {
+		ip = xrip
+	}
+
+	return ip
+}

vendor/github.com/go-chi/chi/middleware/recoverer.go

@@ -0,0 +1,39 @@
+package middleware
+
+// The original work was derived from Goji's middleware, source:
+// https://github.com/zenazn/goji/tree/master/web/middleware
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"runtime/debug"
+)
+
+// Recoverer is a middleware that recovers from panics, logs the panic (and a
+// backtrace), and returns a HTTP 500 (Internal Server Error) status if
+// possible. Recoverer prints a request ID if one is provided.
+//
+// Alternatively, look at https://github.com/pressly/lg middleware pkgs.
+func Recoverer(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		defer func() {
+			if rvr := recover(); rvr != nil {
+
+				logEntry := GetLogEntry(r)
+				if logEntry != nil {
+					logEntry.Panic(rvr, debug.Stack())
+				} else {
+					fmt.Fprintf(os.Stderr, "Panic: %+v\n", rvr)
+					debug.PrintStack()
+				}
+
+				http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
+			}
+		}()
+
+		next.ServeHTTP(w, r)
+	}
+
+	return http.HandlerFunc(fn)
+}

vendor/github.com/go-chi/chi/middleware/request_id.go

@@ -0,0 +1,88 @@
+package middleware
+
+// Ported from Goji's middleware, source:
+// https://github.com/zenazn/goji/tree/master/web/middleware
+
+import (
+	"context"
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+	"net/http"
+	"os"
+	"strings"
+	"sync/atomic"
+)
+
+// Key to use when setting the request ID.
+type ctxKeyRequestID int
+
+// RequestIDKey is the key that holds th unique request ID in a request context.
+const RequestIDKey ctxKeyRequestID = 0
+
+var prefix string
+var reqid uint64
+
+// A quick note on the statistics here: we're trying to calculate the chance that
+// two randomly generated base62 prefixes will collide. We use the formula from
+// http://en.wikipedia.org/wiki/Birthday_problem
+//
+// P[m, n] \approx 1 - e^{-m^2/2n}
+//
+// We ballpark an upper bound for $m$ by imagining (for whatever reason) a server
+// that restarts every second over 10 years, for $m = 86400 * 365 * 10 = 315360000$
+//
+// For a $k$ character base-62 identifier, we have $n(k) = 62^k$
+//
+// Plugging this in, we find $P[m, n(10)] \approx 5.75%$, which is good enough for
+// our purposes, and is surely more than anyone would ever need in practice -- a
+// process that is rebooted a handful of times a day for a hundred years has less
+// than a millionth of a percent chance of generating two colliding IDs.
+
+func init() {
+	hostname, err := os.Hostname()
+	if hostname == "" || err != nil {
+		hostname = "localhost"
+	}
+	var buf [12]byte
+	var b64 string
+	for len(b64) < 10 {
+		rand.Read(buf[:])
+		b64 = base64.StdEncoding.EncodeToString(buf[:])
+		b64 = strings.NewReplacer("+", "", "/", "").Replace(b64)
+	}
+
+	prefix = fmt.Sprintf("%s/%s", hostname, b64[0:10])
+}
+
+// RequestID is a middleware that injects a request ID into the context of each
+// request. A request ID is a string of the form "host.example.com/random-0001",
+// where "random" is a base62 random string that uniquely identifies this go
+// process, and where the last number is an atomically incremented request
+// counter.
+func RequestID(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		myid := atomic.AddUint64(&reqid, 1)
+		ctx := r.Context()
+		ctx = context.WithValue(ctx, RequestIDKey, fmt.Sprintf("%s-%06d", prefix, myid))
+		next.ServeHTTP(w, r.WithContext(ctx))
+	}
+	return http.HandlerFunc(fn)
+}
+
+// GetReqID returns a request ID from the given context if one is present.
+// Returns the empty string if a request ID cannot be found.
+func GetReqID(ctx context.Context) string {
+	if ctx == nil {
+		return ""
+	}
+	if reqID, ok := ctx.Value(RequestIDKey).(string); ok {
+		return reqID
+	}
+	return ""
+}
+
+// NextRequestID generates the next request ID in the sequence.
+func NextRequestID() uint64 {
+	return atomic.AddUint64(&reqid, 1)
+}

vendor/github.com/go-chi/chi/middleware/strip.go

@@ -0,0 +1,48 @@
+package middleware
+
+import (
+	"net/http"
+
+	"github.com/go-chi/chi"
+)
+
+// StripSlashes is a middleware that will match request paths with a trailing
+// slash, strip it from the path and continue routing through the mux, if a route
+// matches, then it will serve the handler.
+func StripSlashes(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		var path string
+		rctx := chi.RouteContext(r.Context())
+		if rctx.RoutePath != "" {
+			path = rctx.RoutePath
+		} else {
+			path = r.URL.Path
+		}
+		if len(path) > 1 && path[len(path)-1] == '/' {
+			rctx.RoutePath = path[:len(path)-1]
+		}
+		next.ServeHTTP(w, r)
+	}
+	return http.HandlerFunc(fn)
+}
+
+// RedirectSlashes is a middleware that will match request paths with a trailing
+// slash and redirect to the same path, less the trailing slash.
+func RedirectSlashes(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		var path string
+		rctx := chi.RouteContext(r.Context())
+		if rctx.RoutePath != "" {
+			path = rctx.RoutePath
+		} else {
+			path = r.URL.Path
+		}
+		if len(path) > 1 && path[len(path)-1] == '/' {
+			path = path[:len(path)-1]
+			http.Redirect(w, r, path, 301)
+			return
+		}
+		next.ServeHTTP(w, r)
+	}
+	return http.HandlerFunc(fn)
+}

vendor/github.com/go-chi/chi/middleware/terminal.go

@@ -0,0 +1,63 @@
+package middleware
+
+// Ported from Goji's middleware, source:
+// https://github.com/zenazn/goji/tree/master/web/middleware
+
+import (
+	"fmt"
+	"io"
+	"os"
+)
+
+var (
+	// Normal colors
+	nBlack   = []byte{'\033', '[', '3', '0', 'm'}
+	nRed     = []byte{'\033', '[', '3', '1', 'm'}
+	nGreen   = []byte{'\033', '[', '3', '2', 'm'}
+	nYellow  = []byte{'\033', '[', '3', '3', 'm'}
+	nBlue    = []byte{'\033', '[', '3', '4', 'm'}
+	nMagenta = []byte{'\033', '[', '3', '5', 'm'}
+	nCyan    = []byte{'\033', '[', '3', '6', 'm'}
+	nWhite   = []byte{'\033', '[', '3', '7', 'm'}
+	// Bright colors
+	bBlack   = []byte{'\033', '[', '3', '0', ';', '1', 'm'}
+	bRed     = []byte{'\033', '[', '3', '1', ';', '1', 'm'}
+	bGreen   = []byte{'\033', '[', '3', '2', ';', '1', 'm'}
+	bYellow  = []byte{'\033', '[', '3', '3', ';', '1', 'm'}
+	bBlue    = []byte{'\033', '[', '3', '4', ';', '1', 'm'}
+	bMagenta = []byte{'\033', '[', '3', '5', ';', '1', 'm'}
+	bCyan    = []byte{'\033', '[', '3', '6', ';', '1', 'm'}
+	bWhite   = []byte{'\033', '[', '3', '7', ';', '1', 'm'}
+
+	reset = []byte{'\033', '[', '0', 'm'}
+)
+
+var isTTY bool
+
+func init() {
+	// This is sort of cheating: if stdout is a character device, we assume
+	// that means it's a TTY. Unfortunately, there are many non-TTY
+	// character devices, but fortunately stdout is rarely set to any of
+	// them.
+	//
+	// We could solve this properly by pulling in a dependency on
+	// code.google.com/p/go.crypto/ssh/terminal, for instance, but as a
+	// heuristic for whether to print in color or in black-and-white, I'd
+	// really rather not.
+	fi, err := os.Stdout.Stat()
+	if err == nil {
+		m := os.ModeDevice | os.ModeCharDevice
+		isTTY = fi.Mode()&m == m
+	}
+}
+
+// colorWrite
+func cW(w io.Writer, color []byte, s string, args ...interface{}) {
+	if isTTY {
+		w.Write(color)
+	}
+	fmt.Fprintf(w, s, args...)
+	if isTTY {
+		w.Write(reset)
+	}
+}

vendor/github.com/go-chi/chi/middleware/throttler.go

@@ -0,0 +1,101 @@
+package middleware
+
+import (
+	"net/http"
+	"time"
+)
+
+const (
+	errCapacityExceeded = "Server capacity exceeded."
+	errTimedOut         = "Timed out while waiting for a pending request to complete."
+	errContextCanceled  = "Context was canceled."
+)
+
+var (
+	defaultBacklogTimeout = time.Second * 60
+)
+
+// Throttle is a middleware that limits number of currently processed requests
+// at a time.
+func Throttle(limit int) func(http.Handler) http.Handler {
+	return ThrottleBacklog(limit, 0, defaultBacklogTimeout)
+}
+
+// ThrottleBacklog is a middleware that limits number of currently processed
+// requests at a time and provides a backlog for holding a finite number of
+// pending requests.
+func ThrottleBacklog(limit int, backlogLimit int, backlogTimeout time.Duration) func(http.Handler) http.Handler {
+	if limit < 1 {
+		panic("chi/middleware: Throttle expects limit > 0")
+	}
+
+	if backlogLimit < 0 {
+		panic("chi/middleware: Throttle expects backlogLimit to be positive")
+	}
+
+	t := throttler{
+		tokens:         make(chan token, limit),
+		backlogTokens:  make(chan token, limit+backlogLimit),
+		backlogTimeout: backlogTimeout,
+	}
+
+	// Filling tokens.
+	for i := 0; i < limit+backlogLimit; i++ {
+		if i < limit {
+			t.tokens <- token{}
+		}
+		t.backlogTokens <- token{}
+	}
+
+	fn := func(h http.Handler) http.Handler {
+		t.h = h
+		return &t
+	}
+
+	return fn
+}
+
+// token represents a request that is being processed.
+type token struct{}
+
+// throttler limits number of currently processed requests at a time.
+type throttler struct {
+	h              http.Handler
+	tokens         chan token
+	backlogTokens  chan token
+	backlogTimeout time.Duration
+}
+
+// ServeHTTP is the primary throttler request handler
+func (t *throttler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	select {
+	case <-ctx.Done():
+		http.Error(w, errContextCanceled, http.StatusServiceUnavailable)
+		return
+	case btok := <-t.backlogTokens:
+		timer := time.NewTimer(t.backlogTimeout)
+
+		defer func() {
+			t.backlogTokens <- btok
+		}()
+
+		select {
+		case <-timer.C:
+			http.Error(w, errTimedOut, http.StatusServiceUnavailable)
+			return
+		case <-ctx.Done():
+			http.Error(w, errContextCanceled, http.StatusServiceUnavailable)
+			return
+		case tok := <-t.tokens:
+			defer func() {
+				t.tokens <- tok
+			}()
+			t.h.ServeHTTP(w, r)
+		}
+		return
+	default:
+		http.Error(w, errCapacityExceeded, http.StatusServiceUnavailable)
+		return
+	}
+}

vendor/github.com/go-chi/chi/middleware/timeout.go

@@ -0,0 +1,48 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+	"time"
+)
+
+// Timeout is a middleware that cancels ctx after a given timeout and return
+// a 504 Gateway Timeout error to the client.
+//
+// It's required that you select the ctx.Done() channel to check for the signal
+// if the context has reached its deadline and return, otherwise the timeout
+// signal will be just ignored.
+//
+// ie. a route/handler may look like:
+//
+//  r.Get("/long", func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+// 	 processTime := time.Duration(rand.Intn(4)+1) * time.Second
+//
+// 	 select {
+// 	 case <-ctx.Done():
+// 	 	return
+//
+// 	 case <-time.After(processTime):
+// 	 	 // The above channel simulates some hard work.
+// 	 }
+//
+// 	 w.Write([]byte("done"))
+//  })
+//
+func Timeout(timeout time.Duration) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			ctx, cancel := context.WithTimeout(r.Context(), timeout)
+			defer func() {
+				cancel()
+				if ctx.Err() == context.DeadlineExceeded {
+					w.WriteHeader(http.StatusGatewayTimeout)
+				}
+			}()
+
+			r = r.WithContext(ctx)
+			next.ServeHTTP(w, r)
+		}
+		return http.HandlerFunc(fn)
+	}
+}

vendor/github.com/go-chi/chi/middleware/url_format.go

@@ -0,0 +1,72 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+	"strings"
+
+	"github.com/go-chi/chi"
+)
+
+var (
+	// URLFormatCtxKey is the context.Context key to store the URL format data
+	// for a request.
+	URLFormatCtxKey = &contextKey{"URLFormat"}
+)
+
+// URLFormat is a middleware that parses the url extension from a request path and stores it
+// on the context as a string under the key `middleware.URLFormatCtxKey`. The middleware will
+// trim the suffix from the routing path and continue routing.
+//
+// Routers should not include a url parameter for the suffix when using this middleware.
+//
+// Sample usage.. for url paths: `/articles/1`, `/articles/1.json` and `/articles/1.xml`
+//
+//  func routes() http.Handler {
+//    r := chi.NewRouter()
+//    r.Use(middleware.URLFormat)
+//
+//    r.Get("/articles/{id}", ListArticles)
+//
+//    return r
+//  }
+//
+//  func ListArticles(w http.ResponseWriter, r *http.Request) {
+// 	  urlFormat, _ := r.Context().Value(middleware.URLFormatCtxKey).(string)
+//
+// 	  switch urlFormat {
+// 	  case "json":
+// 	  	render.JSON(w, r, articles)
+// 	  case "xml:"
+// 	  	render.XML(w, r, articles)
+// 	  default:
+// 	  	render.JSON(w, r, articles)
+// 	  }
+// }
+//
+func URLFormat(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		ctx := r.Context()
+
+		var format string
+		path := r.URL.Path
+
+		if strings.Index(path, ".") > 0 {
+			base := strings.LastIndex(path, "/")
+			idx := strings.Index(path[base:], ".")
+
+			if idx > 0 {
+				idx += base
+				format = path[idx+1:]
+
+				rctx := chi.RouteContext(r.Context())
+				rctx.RoutePath = path[:idx]
+			}
+		}
+
+		r = r.WithContext(context.WithValue(ctx, URLFormatCtxKey, format))
+
+		next.ServeHTTP(w, r)
+	}
+	return http.HandlerFunc(fn)
+}

vendor/github.com/go-chi/chi/middleware/value.go

@@ -0,0 +1,17 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+)
+
+// WithValue is a middleware that sets a given key/value in a context chain.
+func WithValue(key interface{}, val interface{}) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			r = r.WithContext(context.WithValue(r.Context(), key, val))
+			next.ServeHTTP(w, r)
+		}
+		return http.HandlerFunc(fn)
+	}
+}

vendor/github.com/go-chi/chi/middleware/wrap_writer.go

@@ -0,0 +1,148 @@
+package middleware
+
+// The original work was derived from Goji's middleware, source:
+// https://github.com/zenazn/goji/tree/master/web/middleware
+
+import (
+	"bufio"
+	"io"
+	"net"
+	"net/http"
+)
+
+// WrapResponseWriter is a proxy around an http.ResponseWriter that allows you to hook
+// into various parts of the response process.
+type WrapResponseWriter interface {
+	http.ResponseWriter
+	// Status returns the HTTP status of the request, or 0 if one has not
+	// yet been sent.
+	Status() int
+	// BytesWritten returns the total number of bytes sent to the client.
+	BytesWritten() int
+	// Tee causes the response body to be written to the given io.Writer in
+	// addition to proxying the writes through. Only one io.Writer can be
+	// tee'd to at once: setting a second one will overwrite the first.
+	// Writes will be sent to the proxy before being written to this
+	// io.Writer. It is illegal for the tee'd writer to be modified
+	// concurrently with writes.
+	Tee(io.Writer)
+	// Unwrap returns the original proxied target.
+	Unwrap() http.ResponseWriter
+}
+
+// basicWriter wraps a http.ResponseWriter that implements the minimal
+// http.ResponseWriter interface.
+type basicWriter struct {
+	http.ResponseWriter
+	wroteHeader bool
+	code        int
+	bytes       int
+	tee         io.Writer
+}
+
+func (b *basicWriter) WriteHeader(code int) {
+	if !b.wroteHeader {
+		b.code = code
+		b.wroteHeader = true
+		b.ResponseWriter.WriteHeader(code)
+	}
+}
+func (b *basicWriter) Write(buf []byte) (int, error) {
+	b.WriteHeader(http.StatusOK)
+	n, err := b.ResponseWriter.Write(buf)
+	if b.tee != nil {
+		_, err2 := b.tee.Write(buf[:n])
+		// Prefer errors generated by the proxied writer.
+		if err == nil {
+			err = err2
+		}
+	}
+	b.bytes += n
+	return n, err
+}
+func (b *basicWriter) maybeWriteHeader() {
+	if !b.wroteHeader {
+		b.WriteHeader(http.StatusOK)
+	}
+}
+func (b *basicWriter) Status() int {
+	return b.code
+}
+func (b *basicWriter) BytesWritten() int {
+	return b.bytes
+}
+func (b *basicWriter) Tee(w io.Writer) {
+	b.tee = w
+}
+func (b *basicWriter) Unwrap() http.ResponseWriter {
+	return b.ResponseWriter
+}
+
+type flushWriter struct {
+	basicWriter
+}
+
+func (f *flushWriter) Flush() {
+	fl := f.basicWriter.ResponseWriter.(http.Flusher)
+	fl.Flush()
+}
+
+var _ http.Flusher = &flushWriter{}
+
+// httpFancyWriter is a HTTP writer that additionally satisfies http.CloseNotifier,
+// http.Flusher, http.Hijacker, and io.ReaderFrom. It exists for the common case
+// of wrapping the http.ResponseWriter that package http gives you, in order to
+// make the proxied object support the full method set of the proxied object.
+type httpFancyWriter struct {
+	basicWriter
+}
+
+func (f *httpFancyWriter) CloseNotify() <-chan bool {
+	cn := f.basicWriter.ResponseWriter.(http.CloseNotifier)
+	return cn.CloseNotify()
+}
+func (f *httpFancyWriter) Flush() {
+	fl := f.basicWriter.ResponseWriter.(http.Flusher)
+	fl.Flush()
+}
+func (f *httpFancyWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	hj := f.basicWriter.ResponseWriter.(http.Hijacker)
+	return hj.Hijack()
+}
+func (f *httpFancyWriter) ReadFrom(r io.Reader) (int64, error) {
+	if f.basicWriter.tee != nil {
+		n, err := io.Copy(&f.basicWriter, r)
+		f.basicWriter.bytes += int(n)
+		return n, err
+	}
+	rf := f.basicWriter.ResponseWriter.(io.ReaderFrom)
+	f.basicWriter.maybeWriteHeader()
+	n, err := rf.ReadFrom(r)
+	f.basicWriter.bytes += int(n)
+	return n, err
+}
+
+var _ http.CloseNotifier = &httpFancyWriter{}
+var _ http.Flusher = &httpFancyWriter{}
+var _ http.Hijacker = &httpFancyWriter{}
+var _ io.ReaderFrom = &httpFancyWriter{}
+
+// http2FancyWriter is a HTTP2 writer that additionally satisfies http.CloseNotifier,
+// http.Flusher, and io.ReaderFrom. It exists for the common case
+// of wrapping the http.ResponseWriter that package http gives you, in order to
+// make the proxied object support the full method set of the proxied object.
+type http2FancyWriter struct {
+	basicWriter
+}
+
+func (f *http2FancyWriter) CloseNotify() <-chan bool {
+	cn := f.basicWriter.ResponseWriter.(http.CloseNotifier)
+	return cn.CloseNotify()
+}
+func (f *http2FancyWriter) Flush() {
+	fl := f.basicWriter.ResponseWriter.(http.Flusher)
+	fl.Flush()
+}
+
+var _ http.CloseNotifier = &http2FancyWriter{}
+var _ http.Flusher = &http2FancyWriter{}

vendor/github.com/go-chi/chi/middleware/wrap_writer17.go

@@ -0,0 +1,34 @@
+// +build go1.7,!go1.8
+
+package middleware
+
+import (
+	"io"
+	"net/http"
+)
+
+// NewWrapResponseWriter wraps an http.ResponseWriter, returning a proxy that allows you to
+// hook into various parts of the response process.
+func NewWrapResponseWriter(w http.ResponseWriter, protoMajor int) WrapResponseWriter {
+	_, cn := w.(http.CloseNotifier)
+	_, fl := w.(http.Flusher)
+
+	bw := basicWriter{ResponseWriter: w}
+
+	if protoMajor == 2 {
+		if cn && fl {
+			return &http2FancyWriter{bw}
+		}
+	} else {
+		_, hj := w.(http.Hijacker)
+		_, rf := w.(io.ReaderFrom)
+		if cn && fl && hj && rf {
+			return &httpFancyWriter{bw}
+		}
+	}
+	if fl {
+		return &flushWriter{bw}
+	}
+
+	return &bw
+}

vendor/github.com/go-chi/chi/middleware/wrap_writer18.go

@@ -0,0 +1,41 @@
+// +build go1.8
+
+package middleware
+
+import (
+	"io"
+	"net/http"
+)
+
+// NewWrapResponseWriter wraps an http.ResponseWriter, returning a proxy that allows you to
+// hook into various parts of the response process.
+func NewWrapResponseWriter(w http.ResponseWriter, protoMajor int) WrapResponseWriter {
+	_, cn := w.(http.CloseNotifier)
+	_, fl := w.(http.Flusher)
+
+	bw := basicWriter{ResponseWriter: w}
+
+	if protoMajor == 2 {
+		_, ps := w.(http.Pusher)
+		if cn && fl && ps {
+			return &http2FancyWriter{bw}
+		}
+	} else {
+		_, hj := w.(http.Hijacker)
+		_, rf := w.(io.ReaderFrom)
+		if cn && fl && hj && rf {
+			return &httpFancyWriter{bw}
+		}
+	}
+	if fl {
+		return &flushWriter{bw}
+	}
+
+	return &bw
+}
+
+func (f *http2FancyWriter) Push(target string, opts *http.PushOptions) error {
+	return f.basicWriter.ResponseWriter.(http.Pusher).Push(target, opts)
+}
+
+var _ http.Pusher = &http2FancyWriter{}

vendor/github.com/go-chi/chi/mux.go

@@ -0,0 +1,437 @@
+package chi
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"strings"
+	"sync"
+)
+
+var _ Router = &Mux{}
+
+// Mux is a simple HTTP route multiplexer that parses a request path,
+// records any URL params, and executes an end handler. It implements
+// the http.Handler interface and is friendly with the standard library.
+//
+// Mux is designed to be fast, minimal and offer a powerful API for building
+// modular and composable HTTP services with a large set of handlers. It's
+// particularly useful for writing large REST API services that break a handler
+// into many smaller parts composed of middlewares and end handlers.
+type Mux struct {
+	// The radix trie router
+	tree *node
+
+	// The middleware stack
+	middlewares []func(http.Handler) http.Handler
+
+	// Controls the behaviour of middleware chain generation when a mux
+	// is registered as an inline group inside another mux.
+	inline bool
+	parent *Mux
+
+	// The computed mux handler made of the chained middleware stack and
+	// the tree router
+	handler http.Handler
+
+	// Routing context pool
+	pool sync.Pool
+
+	// Custom route not found handler
+	notFoundHandler http.HandlerFunc
+
+	// Custom method not allowed handler
+	methodNotAllowedHandler http.HandlerFunc
+}
+
+// NewMux returns a newly initialized Mux object that implements the Router
+// interface.
+func NewMux() *Mux {
+	mux := &Mux{tree: &node{}}
+	mux.pool.New = func() interface{} {
+		return NewRouteContext()
+	}
+	return mux
+}
+
+// ServeHTTP is the single method of the http.Handler interface that makes
+// Mux interoperable with the standard library. It uses a sync.Pool to get and
+// reuse routing contexts for each request.
+func (mx *Mux) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// Ensure the mux has some routes defined on the mux
+	if mx.handler == nil {
+		panic("chi: attempting to route to a mux with no handlers.")
+	}
+
+	// Check if a routing context already exists from a parent router.
+	rctx, _ := r.Context().Value(RouteCtxKey).(*Context)
+	if rctx != nil {
+		mx.handler.ServeHTTP(w, r)
+		return
+	}
+
+	// Fetch a RouteContext object from the sync pool, and call the computed
+	// mx.handler that is comprised of mx.middlewares + mx.routeHTTP.
+	// Once the request is finished, reset the routing context and put it back
+	// into the pool for reuse from another request.
+	rctx = mx.pool.Get().(*Context)
+	rctx.reset()
+	r = r.WithContext(context.WithValue(r.Context(), RouteCtxKey, rctx))
+	mx.handler.ServeHTTP(w, r)
+	mx.pool.Put(rctx)
+}
+
+// Use appends a middleware handler to the Mux middleware stack.
+//
+// The middleware stack for any Mux will execute before searching for a matching
+// route to a specific handler, which provides opportunity to respond early,
+// change the course of the request execution, or set request-scoped values for
+// the next http.Handler.
+func (mx *Mux) Use(middlewares ...func(http.Handler) http.Handler) {
+	if mx.handler != nil {
+		panic("chi: all middlewares must be defined before routes on a mux")
+	}
+	mx.middlewares = append(mx.middlewares, middlewares...)
+}
+
+// Handle adds the route `pattern` that matches any http method to
+// execute the `handler` http.Handler.
+func (mx *Mux) Handle(pattern string, handler http.Handler) {
+	mx.handle(mALL, pattern, handler)
+}
+
+// HandleFunc adds the route `pattern` that matches any http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) HandleFunc(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mALL, pattern, handlerFn)
+}
+
+// Method adds the route `pattern` that matches `method` http method to
+// execute the `handler` http.Handler.
+func (mx *Mux) Method(method, pattern string, handler http.Handler) {
+	m, ok := methodMap[strings.ToUpper(method)]
+	if !ok {
+		panic(fmt.Sprintf("chi: '%s' http method is not supported.", method))
+	}
+	mx.handle(m, pattern, handler)
+}
+
+// MethodFunc adds the route `pattern` that matches `method` http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) MethodFunc(method, pattern string, handlerFn http.HandlerFunc) {
+	mx.Method(method, pattern, handlerFn)
+}
+
+// Connect adds the route `pattern` that matches a CONNECT http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) Connect(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mCONNECT, pattern, handlerFn)
+}
+
+// Delete adds the route `pattern` that matches a DELETE http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) Delete(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mDELETE, pattern, handlerFn)
+}
+
+// Get adds the route `pattern` that matches a GET http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) Get(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mGET, pattern, handlerFn)
+}
+
+// Head adds the route `pattern` that matches a HEAD http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) Head(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mHEAD, pattern, handlerFn)
+}
+
+// Options adds the route `pattern` that matches a OPTIONS http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) Options(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mOPTIONS, pattern, handlerFn)
+}
+
+// Patch adds the route `pattern` that matches a PATCH http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) Patch(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mPATCH, pattern, handlerFn)
+}
+
+// Post adds the route `pattern` that matches a POST http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) Post(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mPOST, pattern, handlerFn)
+}
+
+// Put adds the route `pattern` that matches a PUT http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) Put(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mPUT, pattern, handlerFn)
+}
+
+// Trace adds the route `pattern` that matches a TRACE http method to
+// execute the `handlerFn` http.HandlerFunc.
+func (mx *Mux) Trace(pattern string, handlerFn http.HandlerFunc) {
+	mx.handle(mTRACE, pattern, handlerFn)
+}
+
+// NotFound sets a custom http.HandlerFunc for routing paths that could
+// not be found. The default 404 handler is `http.NotFound`.
+func (mx *Mux) NotFound(handlerFn http.HandlerFunc) {
+	// Build NotFound handler chain
+	m := mx
+	hFn := handlerFn
+	if mx.inline && mx.parent != nil {
+		m = mx.parent
+		hFn = Chain(mx.middlewares...).HandlerFunc(hFn).ServeHTTP
+	}
+
+	// Update the notFoundHandler from this point forward
+	m.notFoundHandler = hFn
+	m.updateSubRoutes(func(subMux *Mux) {
+		if subMux.notFoundHandler == nil {
+			subMux.NotFound(hFn)
+		}
+	})
+}
+
+// MethodNotAllowed sets a custom http.HandlerFunc for routing paths where the
+// method is unresolved. The default handler returns a 405 with an empty body.
+func (mx *Mux) MethodNotAllowed(handlerFn http.HandlerFunc) {
+	// Build MethodNotAllowed handler chain
+	m := mx
+	hFn := handlerFn
+	if mx.inline && mx.parent != nil {
+		m = mx.parent
+		hFn = Chain(mx.middlewares...).HandlerFunc(hFn).ServeHTTP
+	}
+
+	// Update the methodNotAllowedHandler from this point forward
+	m.methodNotAllowedHandler = hFn
+	m.updateSubRoutes(func(subMux *Mux) {
+		if subMux.methodNotAllowedHandler == nil {
+			subMux.MethodNotAllowed(hFn)
+		}
+	})
+}
+
+// With adds inline middlewares for an endpoint handler.
+func (mx *Mux) With(middlewares ...func(http.Handler) http.Handler) Router {
+	// Similarly as in handle(), we must build the mux handler once further
+	// middleware registration isn't allowed for this stack, like now.
+	if !mx.inline && mx.handler == nil {
+		mx.buildRouteHandler()
+	}
+
+	// Copy middlewares from parent inline muxs
+	var mws Middlewares
+	if mx.inline {
+		mws = make(Middlewares, len(mx.middlewares))
+		copy(mws, mx.middlewares)
+	}
+	mws = append(mws, middlewares...)
+
+	im := &Mux{inline: true, parent: mx, tree: mx.tree, middlewares: mws}
+	return im
+}
+
+// Group creates a new inline-Mux with a fresh middleware stack. It's useful
+// for a group of handlers along the same routing path that use an additional
+// set of middlewares. See _examples/.
+func (mx *Mux) Group(fn func(r Router)) Router {
+	im := mx.With().(*Mux)
+	if fn != nil {
+		fn(im)
+	}
+	return im
+}
+
+// Route creates a new Mux with a fresh middleware stack and mounts it
+// along the `pattern` as a subrouter. Effectively, this is a short-hand
+// call to Mount. See _examples/.
+func (mx *Mux) Route(pattern string, fn func(r Router)) Router {
+	subRouter := NewRouter()
+	if fn != nil {
+		fn(subRouter)
+	}
+	mx.Mount(pattern, subRouter)
+	return subRouter
+}
+
+// Mount attaches another http.Handler or chi Router as a subrouter along a routing
+// path. It's very useful to split up a large API as many independent routers and
+// compose them as a single service using Mount. See _examples/.
+//
+// Note that Mount() simply sets a wildcard along the `pattern` that will continue
+// routing at the `handler`, which in most cases is another chi.Router. As a result,
+// if you define two Mount() routes on the exact same pattern the mount will panic.
+func (mx *Mux) Mount(pattern string, handler http.Handler) {
+	// Provide runtime safety for ensuring a pattern isn't mounted on an existing
+	// routing pattern.
+	if mx.tree.matchPattern(pattern+"*") || mx.tree.matchPattern(pattern+"/*") {
+		panic(fmt.Sprintf("chi: attempting to Mount() a handler on an existing path, '%s'", pattern))
+	}
+
+	// Assign sub-Router's with the parent not found & method not allowed handler if not specified.
+	subr, ok := handler.(*Mux)
+	if ok && subr.notFoundHandler == nil && mx.notFoundHandler != nil {
+		subr.NotFound(mx.notFoundHandler)
+	}
+	if ok && subr.methodNotAllowedHandler == nil && mx.methodNotAllowedHandler != nil {
+		subr.MethodNotAllowed(mx.methodNotAllowedHandler)
+	}
+
+	// Wrap the sub-router in a handlerFunc to scope the request path for routing.
+	mountHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		rctx := RouteContext(r.Context())
+		rctx.RoutePath = "/"
+
+		nx := len(rctx.routeParams.Keys) - 1 // index of last param in list
+		if nx >= 0 && rctx.routeParams.Keys[nx] == "*" && len(rctx.routeParams.Values) > nx {
+			rctx.RoutePath += rctx.routeParams.Values[nx]
+		}
+
+		handler.ServeHTTP(w, r)
+	})
+
+	if pattern == "" || pattern[len(pattern)-1] != '/' {
+		notFoundHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			mx.NotFoundHandler().ServeHTTP(w, r)
+		})
+
+		mx.handle(mALL|mSTUB, pattern, mountHandler)
+		mx.handle(mALL|mSTUB, pattern+"/", notFoundHandler)
+		pattern += "/"
+	}
+
+	method := mALL
+	subroutes, _ := handler.(Routes)
+	if subroutes != nil {
+		method |= mSTUB
+	}
+	n := mx.handle(method, pattern+"*", mountHandler)
+
+	if subroutes != nil {
+		n.subroutes = subroutes
+	}
+}
+
+// Middlewares returns a slice of middleware handler functions.
+func (mx *Mux) Middlewares() Middlewares {
+	return mx.middlewares
+}
+
+// Routes returns a slice of routing information from the tree,
+// useful for traversing available routes of a router.
+func (mx *Mux) Routes() []Route {
+	return mx.tree.routes()
+}
+
+// NotFoundHandler returns the default Mux 404 responder whenever a route
+// cannot be found.
+func (mx *Mux) NotFoundHandler() http.HandlerFunc {
+	if mx.notFoundHandler != nil {
+		return mx.notFoundHandler
+	}
+	return http.NotFound
+}
+
+// MethodNotAllowedHandler returns the default Mux 405 responder whenever
+// a method cannot be resolved for a route.
+func (mx *Mux) MethodNotAllowedHandler() http.HandlerFunc {
+	if mx.methodNotAllowedHandler != nil {
+		return mx.methodNotAllowedHandler
+	}
+	return methodNotAllowedHandler
+}
+
+// buildRouteHandler builds the single mux handler that is a chain of the middleware
+// stack, as defined by calls to Use(), and the tree router (Mux) itself. After this
+// point, no other middlewares can be registered on this Mux's stack. But you can still
+// compose additional middlewares via Group()'s or using a chained middleware handler.
+func (mx *Mux) buildRouteHandler() {
+	mx.handler = chain(mx.middlewares, http.HandlerFunc(mx.routeHTTP))
+}
+
+// handle registers a http.Handler in the routing tree for a particular http method
+// and routing pattern.
+func (mx *Mux) handle(method methodTyp, pattern string, handler http.Handler) *node {
+	if len(pattern) == 0 || pattern[0] != '/' {
+		panic(fmt.Sprintf("chi: routing pattern must begin with '/' in '%s'", pattern))
+	}
+
+	// Build the final routing handler for this Mux.
+	if !mx.inline && mx.handler == nil {
+		mx.buildRouteHandler()
+	}
+
+	// Build endpoint handler with inline middlewares for the route
+	var h http.Handler
+	if mx.inline {
+		mx.handler = http.HandlerFunc(mx.routeHTTP)
+		h = Chain(mx.middlewares...).Handler(handler)
+	} else {
+		h = handler
+	}
+
+	// Add the endpoint to the tree and return the node
+	return mx.tree.InsertRoute(method, pattern, h)
+}
+
+// routeHTTP routes a http.Request through the Mux routing tree to serve
+// the matching handler for a particular http method.
+func (mx *Mux) routeHTTP(w http.ResponseWriter, r *http.Request) {
+	// Grab the route context object
+	rctx := r.Context().Value(RouteCtxKey).(*Context)
+
+	// The request routing path
+	routePath := rctx.RoutePath
+	if routePath == "" {
+		if r.URL.RawPath != "" {
+			routePath = r.URL.RawPath
+		} else {
+			routePath = r.URL.Path
+		}
+	}
+
+	// Check if method is supported by chi
+	method, ok := methodMap[r.Method]
+	if !ok {
+		mx.MethodNotAllowedHandler().ServeHTTP(w, r)
+		return
+	}
+
+	// Find the route
+	hs := mx.tree.FindRoute(rctx, method, routePath)
+	if hs == nil {
+		if rctx.methodNotAllowed {
+			mx.MethodNotAllowedHandler().ServeHTTP(w, r)
+		} else {
+			mx.NotFoundHandler().ServeHTTP(w, r)
+		}
+		return
+	}
+	h, _ := hs[method]
+
+	// Serve it up
+	h.handler.ServeHTTP(w, r)
+}
+
+// Recursively update data on child routers.
+func (mx *Mux) updateSubRoutes(fn func(subMux *Mux)) {
+	for _, r := range mx.tree.routes() {
+		subMux, ok := r.SubRoutes.(*Mux)
+		if !ok {
+			continue
+		}
+		fn(subMux)
+	}
+}
+
+// methodNotAllowedHandler is a helper function to respond with a 405,
+// method not allowed.
+func methodNotAllowedHandler(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(405)
+	w.Write(nil)
+}

vendor/github.com/go-chi/chi/tree.go

@@ -0,0 +1,804 @@
+package chi
+
+// Radix tree implementation below is a based on the original work by
+// Armon Dadgar in https://github.com/armon/go-radix/blob/master/radix.go
+// (MIT licensed). It's been heavily modified for use as a HTTP routing tree.
+
+import (
+	"fmt"
+	"net/http"
+	"regexp"
+	"sort"
+	"strings"
+)
+
+type methodTyp int
+
+const (
+	mCONNECT methodTyp = 1 << iota
+	mDELETE
+	mGET
+	mHEAD
+	mLINK
+	mOPTIONS
+	mPATCH
+	mPOST
+	mPUT
+	mTRACE
+	mUNLINK
+	mSTUB
+
+	mALL methodTyp = mCONNECT | mDELETE | mGET | mHEAD | mLINK |
+		mOPTIONS | mPATCH | mPOST | mPUT | mTRACE | mUNLINK
+)
+
+var methodMap = map[string]methodTyp{
+	"CONNECT": mCONNECT,
+	"DELETE":  mDELETE,
+	"GET":     mGET,
+	"HEAD":    mHEAD,
+	"LINK":    mLINK,
+	"OPTIONS": mOPTIONS,
+	"PATCH":   mPATCH,
+	"POST":    mPOST,
+	"PUT":     mPUT,
+	"TRACE":   mTRACE,
+	"UNLINK":  mUNLINK,
+}
+
+type nodeTyp uint8
+
+const (
+	ntStatic   nodeTyp = iota // /home
+	ntRegexp                  // /{id:[0-9]+}
+	ntParam                   // /{user}
+	ntCatchAll                // /api/v1/*
+)
+
+type node struct {
+	// node type: static, regexp, param, catchAll
+	typ nodeTyp
+
+	// first byte of the prefix
+	label byte
+
+	// first byte of the child prefix
+	tail byte
+
+	// prefix is the common prefix we ignore
+	prefix string
+
+	// regexp matcher for regexp nodes
+	rex *regexp.Regexp
+
+	// HTTP handler endpoints on the leaf node
+	endpoints endpoints
+
+	// subroutes on the leaf node
+	subroutes Routes
+
+	// child nodes should be stored in-order for iteration,
+	// in groups of the node type.
+	children [ntCatchAll + 1]nodes
+}
+
+// endpoints is a mapping of http method constants to handlers
+// for a given route.
+type endpoints map[methodTyp]*endpoint
+
+type endpoint struct {
+	// endpoint handler
+	handler http.Handler
+
+	// pattern is the routing pattern for handler nodes
+	pattern string
+
+	// parameter keys recorded on handler nodes
+	paramKeys []string
+}
+
+func (s endpoints) Value(method methodTyp) *endpoint {
+	mh, ok := s[method]
+	if !ok {
+		mh = &endpoint{}
+		s[method] = mh
+	}
+	return mh
+}
+
+func (n *node) InsertRoute(method methodTyp, pattern string, handler http.Handler) *node {
+	var parent *node
+	search := pattern
+
+	for {
+		// Handle key exhaustion
+		if len(search) == 0 {
+			// Insert or update the node's leaf handler
+			n.setEndpoint(method, handler, pattern)
+			return n
+		}
+
+		// We're going to be searching for a wild node next,
+		// in this case, we need to get the tail
+		var label = search[0]
+		var segTail byte
+		var segEndIdx int
+		var segTyp nodeTyp
+		var segRexpat string
+		if label == '{' || label == '*' {
+			segTyp, _, segRexpat, segTail, _, segEndIdx = patNextSegment(search)
+		}
+
+		var prefix string
+		if segTyp == ntRegexp {
+			prefix = segRexpat
+		}
+
+		// Look for the edge to attach to
+		parent = n
+		n = n.getEdge(segTyp, label, segTail, prefix)
+
+		// No edge, create one
+		if n == nil {
+			child := &node{label: label, tail: segTail, prefix: search}
+			hn := parent.addChild(child, search)
+			hn.setEndpoint(method, handler, pattern)
+
+			return hn
+		}
+
+		// Found an edge to match the pattern
+
+		if n.typ > ntStatic {
+			// We found a param node, trim the param from the search path and continue.
+			// This param/wild pattern segment would already be on the tree from a previous
+			// call to addChild when creating a new node.
+			search = search[segEndIdx:]
+			continue
+		}
+
+		// Static nodes fall below here.
+		// Determine longest prefix of the search key on match.
+		commonPrefix := longestPrefix(search, n.prefix)
+		if commonPrefix == len(n.prefix) {
+			// the common prefix is as long as the current node's prefix we're attempting to insert.
+			// keep the search going.
+			search = search[commonPrefix:]
+			continue
+		}
+
+		// Split the node
+		child := &node{
+			typ:    ntStatic,
+			prefix: search[:commonPrefix],
+		}
+		parent.replaceChild(search[0], segTail, child)
+
+		// Restore the existing node
+		n.label = n.prefix[commonPrefix]
+		n.prefix = n.prefix[commonPrefix:]
+		child.addChild(n, n.prefix)
+
+		// If the new key is a subset, set the method/handler on this node and finish.
+		search = search[commonPrefix:]
+		if len(search) == 0 {
+			child.setEndpoint(method, handler, pattern)
+			return child
+		}
+
+		// Create a new edge for the node
+		subchild := &node{
+			typ:    ntStatic,
+			label:  search[0],
+			prefix: search,
+		}
+		hn := child.addChild(subchild, search)
+		hn.setEndpoint(method, handler, pattern)
+		return hn
+	}
+}
+
+// addChild appends the new `child` node to the tree using the `pattern` as the trie key.
+// For a URL router like chi's, we split the static, param, regexp and wildcard segments
+// into different nodes. In addition, addChild will recursively call itself until every
+// pattern segment is added to the url pattern tree as individual nodes, depending on type.
+func (n *node) addChild(child *node, prefix string) *node {
+	search := prefix
+
+	// handler leaf node added to the tree is the child.
+	// this may be overridden later down the flow
+	hn := child
+
+	// Parse next segment
+	segTyp, _, segRexpat, segTail, segStartIdx, segEndIdx := patNextSegment(search)
+
+	// Add child depending on next up segment
+	switch segTyp {
+
+	case ntStatic:
+		// Search prefix is all static (that is, has no params in path)
+		// noop
+
+	default:
+		// Search prefix contains a param, regexp or wildcard
+
+		if segTyp == ntRegexp {
+			rex, err := regexp.Compile(segRexpat)
+			if err != nil {
+				panic(fmt.Sprintf("chi: invalid regexp pattern '%s' in route param", segRexpat))
+			}
+			child.prefix = segRexpat
+			child.rex = rex
+		}
+
+		if segStartIdx == 0 {
+			// Route starts with a param
+			child.typ = segTyp
+
+			if segTyp == ntCatchAll {
+				segStartIdx = -1
+			} else {
+				segStartIdx = segEndIdx
+			}
+			if segStartIdx < 0 {
+				segStartIdx = len(search)
+			}
+			child.tail = segTail // for params, we set the tail
+
+			if segStartIdx != len(search) {
+				// add static edge for the remaining part, split the end.
+				// its not possible to have adjacent param nodes, so its certainly
+				// going to be a static node next.
+
+				search = search[segStartIdx:] // advance search position
+
+				nn := &node{
+					typ:    ntStatic,
+					label:  search[0],
+					prefix: search,
+				}
+				hn = child.addChild(nn, search)
+			}
+
+		} else if segStartIdx > 0 {
+			// Route has some param
+
+			// starts with a static segment
+			child.typ = ntStatic
+			child.prefix = search[:segStartIdx]
+			child.rex = nil
+
+			// add the param edge node
+			search = search[segStartIdx:]
+
+			nn := &node{
+				typ:   segTyp,
+				label: search[0],
+				tail:  segTail,
+			}
+			hn = child.addChild(nn, search)
+
+		}
+	}
+
+	n.children[child.typ] = append(n.children[child.typ], child)
+	n.children[child.typ].Sort()
+	return hn
+}
+
+func (n *node) replaceChild(label, tail byte, child *node) {
+	for i := 0; i < len(n.children[child.typ]); i++ {
+		if n.children[child.typ][i].label == label && n.children[child.typ][i].tail == tail {
+			n.children[child.typ][i] = child
+			n.children[child.typ][i].label = label
+			n.children[child.typ][i].tail = tail
+			return
+		}
+	}
+	panic("chi: replacing missing child")
+}
+
+func (n *node) getEdge(ntyp nodeTyp, label, tail byte, prefix string) *node {
+	nds := n.children[ntyp]
+	for i := 0; i < len(nds); i++ {
+		if nds[i].label == label && nds[i].tail == tail {
+			if ntyp == ntRegexp && nds[i].prefix != prefix {
+				continue
+			}
+			return nds[i]
+		}
+	}
+	return nil
+}
+
+func (n *node) setEndpoint(method methodTyp, handler http.Handler, pattern string) {
+	// Set the handler for the method type on the node
+	if n.endpoints == nil {
+		n.endpoints = make(endpoints, 0)
+	}
+
+	paramKeys := patParamKeys(pattern)
+
+	if method&mSTUB == mSTUB {
+		n.endpoints.Value(mSTUB).handler = handler
+	}
+	if method&mALL == mALL {
+		h := n.endpoints.Value(mALL)
+		h.handler = handler
+		h.pattern = pattern
+		h.paramKeys = paramKeys
+		for _, m := range methodMap {
+			h := n.endpoints.Value(m)
+			h.handler = handler
+			h.pattern = pattern
+			h.paramKeys = paramKeys
+		}
+	} else {
+		h := n.endpoints.Value(method)
+		h.handler = handler
+		h.pattern = pattern
+		h.paramKeys = paramKeys
+	}
+}
+
+func (n *node) FindRoute(rctx *Context, method methodTyp, path string) endpoints {
+	// Reset the context routing pattern and params
+	rctx.routePattern = ""
+	rctx.routeParams.Keys = rctx.routeParams.Keys[:0]
+	rctx.routeParams.Values = rctx.routeParams.Values[:0]
+
+	// Find the routing handlers for the path
+	rn := n.findRoute(rctx, method, path)
+	if rn == nil {
+		return nil
+	}
+
+	// Record the routing params in the request lifecycle
+	rctx.URLParams.Keys = append(rctx.URLParams.Keys, rctx.routeParams.Keys...)
+	rctx.URLParams.Values = append(rctx.URLParams.Values, rctx.routeParams.Values...)
+
+	// Record the routing pattern in the request lifecycle
+	if rn.endpoints[method].pattern != "" {
+		rctx.routePattern = rn.endpoints[method].pattern
+		rctx.RoutePatterns = append(rctx.RoutePatterns, rctx.routePattern)
+	}
+
+	return rn.endpoints
+}
+
+// Recursive edge traversal by checking all nodeTyp groups along the way.
+// It's like searching through a multi-dimensional radix trie.
+func (n *node) findRoute(rctx *Context, method methodTyp, path string) *node {
+	nn := n
+	search := path
+
+	for t, nds := range nn.children {
+		ntyp := nodeTyp(t)
+		if len(nds) == 0 {
+			continue
+		}
+
+		var xn *node
+		xsearch := search
+
+		var label byte
+		if search != "" {
+			label = search[0]
+		}
+
+		switch ntyp {
+		case ntStatic:
+			xn = nds.findEdge(label)
+			if xn == nil || !strings.HasPrefix(xsearch, xn.prefix) {
+				continue
+			}
+			xsearch = xsearch[len(xn.prefix):]
+
+		case ntParam, ntRegexp:
+			// short-circuit and return no matching route for empty param values
+			if xsearch == "" {
+				continue
+			}
+
+			// serially loop through each node grouped by the tail delimiter
+			for idx := 0; idx < len(nds); idx++ {
+				xn = nds[idx]
+
+				// label for param nodes is the delimiter byte
+				p := strings.IndexByte(xsearch, xn.tail)
+
+				if p <= 0 {
+					if xn.tail == '/' {
+						p = len(xsearch)
+					} else {
+						continue
+					}
+				}
+
+				if ntyp == ntRegexp && xn.rex != nil {
+					if xn.rex.Match([]byte(xsearch[:p])) == false {
+						continue
+					}
+				} else if strings.IndexByte(xsearch[:p], '/') != -1 {
+					// avoid a match across path segments
+					continue
+				}
+
+				rctx.routeParams.Values = append(rctx.routeParams.Values, xsearch[:p])
+				xsearch = xsearch[p:]
+				break
+			}
+
+		default:
+			// catch-all nodes
+			rctx.routeParams.Values = append(rctx.routeParams.Values, search)
+			xn = nds[0]
+			xsearch = ""
+		}
+
+		if xn == nil {
+			continue
+		}
+
+		// did we find it yet?
+		if len(xsearch) == 0 {
+			if xn.isLeaf() {
+				h, _ := xn.endpoints[method]
+				if h != nil && h.handler != nil {
+					rctx.routeParams.Keys = append(rctx.routeParams.Keys, h.paramKeys...)
+					return xn
+				}
+
+				// flag that the routing context found a route, but not a corresponding
+				// supported method
+				rctx.methodNotAllowed = true
+			}
+		}
+
+		// recursively find the next node..
+		fin := xn.findRoute(rctx, method, xsearch)
+		if fin != nil {
+			return fin
+		}
+
+		// Did not find final handler, let's remove the param here if it was set
+		if xn.typ > ntStatic {
+			if len(rctx.routeParams.Values) > 0 {
+				rctx.routeParams.Values = rctx.routeParams.Values[:len(rctx.routeParams.Values)-1]
+			}
+		}
+
+	}
+
+	return nil
+}
+
+func (n *node) findEdge(ntyp nodeTyp, label byte) *node {
+	nds := n.children[ntyp]
+	num := len(nds)
+	idx := 0
+
+	switch ntyp {
+	case ntStatic, ntParam, ntRegexp:
+		i, j := 0, num-1
+		for i <= j {
+			idx = i + (j-i)/2
+			if label > nds[idx].label {
+				i = idx + 1
+			} else if label < nds[idx].label {
+				j = idx - 1
+			} else {
+				i = num // breaks cond
+			}
+		}
+		if nds[idx].label != label {
+			return nil
+		}
+		return nds[idx]
+
+	default: // catch all
+		return nds[idx]
+	}
+}
+
+func (n *node) isEmpty() bool {
+	for _, nds := range n.children {
+		if len(nds) > 0 {
+			return false
+		}
+	}
+	return true
+}
+
+func (n *node) isLeaf() bool {
+	return n.endpoints != nil
+}
+
+func (n *node) matchPattern(pattern string) bool {
+	nn := n
+	for _, nds := range nn.children {
+		if len(nds) == 0 {
+			continue
+		}
+
+		n = nn.findEdge(nds[0].typ, pattern[0])
+		if n == nil {
+			continue
+		}
+
+		var idx int
+		var xpattern string
+
+		switch n.typ {
+		case ntStatic:
+			idx = longestPrefix(pattern, n.prefix)
+			if idx < len(n.prefix) {
+				continue
+			}
+
+		case ntParam, ntRegexp:
+			idx = strings.IndexByte(pattern, '}') + 1
+
+		case ntCatchAll:
+			idx = longestPrefix(pattern, "*")
+
+		default:
+			panic("chi: unknown node type")
+		}
+
+		xpattern = pattern[idx:]
+		if len(xpattern) == 0 {
+			return true
+		}
+
+		return n.matchPattern(xpattern)
+	}
+	return false
+}
+
+func (n *node) routes() []Route {
+	rts := []Route{}
+
+	n.walk(func(eps endpoints, subroutes Routes) bool {
+		if eps[mSTUB] != nil && eps[mSTUB].handler != nil && subroutes == nil {
+			return false
+		}
+
+		// Group methodHandlers by unique patterns
+		pats := make(map[string]endpoints, 0)
+
+		for mt, h := range eps {
+			if h.pattern == "" {
+				continue
+			}
+			p, ok := pats[h.pattern]
+			if !ok {
+				p = endpoints{}
+				pats[h.pattern] = p
+			}
+			p[mt] = h
+		}
+
+		for p, mh := range pats {
+			hs := make(map[string]http.Handler, 0)
+			if mh[mALL] != nil && mh[mALL].handler != nil {
+				hs["*"] = mh[mALL].handler
+			}
+
+			for mt, h := range mh {
+				if h.handler == nil {
+					continue
+				}
+				m := methodTypString(mt)
+				if m == "" {
+					continue
+				}
+				hs[m] = h.handler
+			}
+
+			rt := Route{p, hs, subroutes}
+			rts = append(rts, rt)
+		}
+
+		return false
+	})
+
+	return rts
+}
+
+func (n *node) walk(fn func(eps endpoints, subroutes Routes) bool) bool {
+	// Visit the leaf values if any
+	if (n.endpoints != nil || n.subroutes != nil) && fn(n.endpoints, n.subroutes) {
+		return true
+	}
+
+	// Recurse on the children
+	for _, ns := range n.children {
+		for _, cn := range ns {
+			if cn.walk(fn) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// patNextSegment returns the next segment details from a pattern:
+// node type, param key, regexp string, param tail byte, param starting index, param ending index
+func patNextSegment(pattern string) (nodeTyp, string, string, byte, int, int) {
+	ps := strings.Index(pattern, "{")
+	ws := strings.Index(pattern, "*")
+
+	if ps < 0 && ws < 0 {
+		return ntStatic, "", "", 0, 0, len(pattern) // we return the entire thing
+	}
+
+	// Sanity check
+	if ps >= 0 && ws >= 0 && ws < ps {
+		panic("chi: wildcard '*' must be the last pattern in a route, otherwise use a '{param}'")
+	}
+
+	var tail byte = '/' // Default endpoint tail to / byte
+
+	if ps >= 0 {
+		// Param/Regexp pattern is next
+		nt := ntParam
+		pe := strings.Index(pattern, "}")
+		if pe < 0 {
+			panic("chi: route param closing delimiter '}' is missing")
+		}
+
+		key := pattern[ps+1 : pe]
+		pe++ // set end to next position
+
+		if pe < len(pattern) {
+			tail = pattern[pe]
+		}
+
+		var rexpat string
+		if idx := strings.Index(key, ":"); idx >= 0 {
+			nt = ntRegexp
+			rexpat = key[idx+1:]
+			key = key[:idx]
+		}
+
+		return nt, key, rexpat, tail, ps, pe
+	}
+
+	// Wildcard pattern as finale
+	// TODO: should we panic if there is stuff after the * ???
+	return ntCatchAll, "*", "", 0, ws, len(pattern)
+}
+
+func patParamKeys(pattern string) []string {
+	pat := pattern
+	paramKeys := []string{}
+	for {
+		ptyp, paramKey, _, _, _, e := patNextSegment(pat)
+		if ptyp == ntStatic {
+			return paramKeys
+		}
+		for i := 0; i < len(paramKeys); i++ {
+			if paramKeys[i] == paramKey {
+				panic(fmt.Sprintf("chi: routing pattern '%s' contains duplicate param key, '%s'", pattern, paramKey))
+			}
+		}
+		paramKeys = append(paramKeys, paramKey)
+		pat = pat[e:]
+	}
+}
+
+// longestPrefix finds the length of the shared prefix
+// of two strings
+func longestPrefix(k1, k2 string) int {
+	max := len(k1)
+	if l := len(k2); l < max {
+		max = l
+	}
+	var i int
+	for i = 0; i < max; i++ {
+		if k1[i] != k2[i] {
+			break
+		}
+	}
+	return i
+}
+
+func methodTypString(method methodTyp) string {
+	for s, t := range methodMap {
+		if method == t {
+			return s
+		}
+	}
+	return ""
+}
+
+type nodes []*node
+
+// Sort the list of nodes by label
+func (ns nodes) Sort()              { sort.Sort(ns); ns.tailSort() }
+func (ns nodes) Len() int           { return len(ns) }
+func (ns nodes) Swap(i, j int)      { ns[i], ns[j] = ns[j], ns[i] }
+func (ns nodes) Less(i, j int) bool { return ns[i].label < ns[j].label }
+
+// tailSort pushes nodes with '/' as the tail to the end of the list for param nodes.
+// The list order determines the traversal order.
+func (ns nodes) tailSort() {
+	for i := len(ns) - 1; i >= 0; i-- {
+		if ns[i].typ > ntStatic && ns[i].tail == '/' {
+			ns.Swap(i, len(ns)-1)
+			return
+		}
+	}
+}
+
+func (ns nodes) findEdge(label byte) *node {
+	num := len(ns)
+	idx := 0
+	i, j := 0, num-1
+	for i <= j {
+		idx = i + (j-i)/2
+		if label > ns[idx].label {
+			i = idx + 1
+		} else if label < ns[idx].label {
+			j = idx - 1
+		} else {
+			i = num // breaks cond
+		}
+	}
+	if ns[idx].label != label {
+		return nil
+	}
+	return ns[idx]
+}
+
+// Route describes the details of a routing handler.
+type Route struct {
+	Pattern   string
+	Handlers  map[string]http.Handler
+	SubRoutes Routes
+}
+
+// WalkFunc is the type of the function called for each method and route visited by Walk.
+type WalkFunc func(method string, route string, handler http.Handler, middlewares ...func(http.Handler) http.Handler) error
+
+// Walk walks any router tree that implements Routes interface.
+func Walk(r Routes, walkFn WalkFunc) error {
+	return walk(r, walkFn, "")
+}
+
+func walk(r Routes, walkFn WalkFunc, parentRoute string, parentMw ...func(http.Handler) http.Handler) error {
+	for _, route := range r.Routes() {
+		mws := make([]func(http.Handler) http.Handler, len(parentMw))
+		copy(mws, parentMw)
+		mws = append(mws, r.Middlewares()...)
+
+		if route.SubRoutes != nil {
+			if err := walk(route.SubRoutes, walkFn, parentRoute+route.Pattern, mws...); err != nil {
+				return err
+			}
+			continue
+		}
+
+		for method, handler := range route.Handlers {
+			if method == "*" {
+				// Ignore a "catchAll" method, since we pass down all the specific methods for each route.
+				continue
+			}
+
+			fullRoute := parentRoute + route.Pattern
+
+			if chain, ok := handler.(*ChainHandler); ok {
+				if err := walkFn(method, fullRoute, chain.Endpoint, append(mws, chain.Middlewares...)...); err != nil {
+					return err
+				}
+			} else {
+				if err := walkFn(method, fullRoute, handler, mws...); err != nil {
+					return err
+				}
+			}
+		}
+	}
+
+	return nil
+}

vendor/github.com/go-chi/render/LICENSE

@@ -0,0 +1,20 @@
+Copyright (c) 2016-Present https://github.com/go-chi authors
+
+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/go-chi/render/README.md

@@ -0,0 +1,24 @@
+# render
+
+The `render` package helps manage HTTP request / response payloads.
+
+Every well-designed, robust and maintainable Web Service / REST API also needs
+well-*defined* request and response payloads. Together with the endpoint handlers,
+the request and response payloads make up the contract between your server and the
+clients calling on it.
+
+Typically in a REST API application, you will have your data models (objects/structs)
+that hold lower-level runtime application state, and at times you need to assemble,
+decorate, hide or transform the representation before responding to a client. That
+server output (response payload) structure, is also likely the input structure to
+another handler on the server.
+
+This is where `render` comes in - offering a few simple helpers and interfaces to
+provide a simple pattern for managing payload encoding and decoding.
+
+We've also combined it with some helpers for responding to content types and parsing
+request bodies. Please have a look at the [rest](https://github.com/go-chi/chi/blob/master/_examples/rest/main.go)
+example which uses the latest chi/render sub-pkg.
+
+All feedback is welcome, thank you!
+

vendor/github.com/go-chi/render/content_type.go

@@ -0,0 +1,84 @@
+package render
+
+import (
+	"context"
+	"net/http"
+	"strings"
+)
+
+var (
+	ContentTypeCtxKey = &contextKey{"ContentType"}
+)
+
+// ContentType is an enumeration of common HTTP content types.
+type ContentType int
+
+// ContentTypes handled by this package.
+const (
+	ContentTypeUnknown = iota
+	ContentTypePlainText
+	ContentTypeHTML
+	ContentTypeJSON
+	ContentTypeXML
+	ContentTypeForm
+	ContentTypeEventStream
+)
+
+func GetContentType(s string) ContentType {
+	s = strings.TrimSpace(strings.Split(s, ";")[0])
+	switch s {
+	case "text/plain":
+		return ContentTypePlainText
+	case "text/html", "application/xhtml+xml":
+		return ContentTypeHTML
+	case "application/json", "text/javascript":
+		return ContentTypeJSON
+	case "text/xml", "application/xml":
+		return ContentTypeXML
+	case "application/x-www-form-urlencoded":
+		return ContentTypeForm
+	case "text/event-stream":
+		return ContentTypeEventStream
+	default:
+		return ContentTypeUnknown
+	}
+}
+
+// SetContentType is a middleware that forces response Content-Type.
+func SetContentType(contentType ContentType) func(next http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		fn := func(w http.ResponseWriter, r *http.Request) {
+			r = r.WithContext(context.WithValue(r.Context(), ContentTypeCtxKey, contentType))
+			next.ServeHTTP(w, r)
+		}
+		return http.HandlerFunc(fn)
+	}
+}
+
+// GetRequestContentType is a helper function that returns ContentType based on
+// context or request headers.
+func GetRequestContentType(r *http.Request) ContentType {
+	if contentType, ok := r.Context().Value(ContentTypeCtxKey).(ContentType); ok {
+		return contentType
+	}
+	return GetContentType(r.Header.Get("Content-Type"))
+}
+
+func GetAcceptedContentType(r *http.Request) ContentType {
+	if contentType, ok := r.Context().Value(ContentTypeCtxKey).(ContentType); ok {
+		return contentType
+	}
+
+	var contentType ContentType
+
+	// Parse request Accept header.
+	fields := strings.Split(r.Header.Get("Accept"), ",")
+	if len(fields) > 0 {
+		contentType = GetContentType(strings.TrimSpace(fields[0]))
+	}
+
+	if contentType == ContentTypeUnknown {
+		contentType = ContentTypePlainText
+	}
+	return contentType
+}

vendor/github.com/go-chi/render/decoder.go

@@ -0,0 +1,44 @@
+package render
+
+import (
+	"encoding/json"
+	"encoding/xml"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+)
+
+// Decode is a package-level variable set to our default Decoder. We do this
+// because it allows you to set render.Decode to another function with the
+// same function signature, while also utilizing the render.Decoder() function
+// itself. Effectively, allowing you to easily add your own logic to the package
+// defaults. For example, maybe you want to impose a limit on the number of
+// bytes allowed to be read from the request body.
+var Decode = DefaultDecoder
+
+func DefaultDecoder(r *http.Request, v interface{}) error {
+	var err error
+
+	switch GetRequestContentType(r) {
+	case ContentTypeJSON:
+		err = DecodeJSON(r.Body, v)
+	case ContentTypeXML:
+		err = DecodeXML(r.Body, v)
+	// case ContentTypeForm: // TODO
+	default:
+		err = errors.New("render: unable to automatically decode the request content type")
+	}
+
+	return err
+}
+
+func DecodeJSON(r io.Reader, v interface{}) error {
+	defer io.Copy(ioutil.Discard, r)
+	return json.NewDecoder(r).Decode(v)
+}
+
+func DecodeXML(r io.Reader, v interface{}) error {
+	defer io.Copy(ioutil.Discard, r)
+	return xml.NewDecoder(r).Decode(v)
+}

vendor/github.com/go-chi/render/render.go

@@ -0,0 +1,134 @@
+package render
+
+import (
+	"net/http"
+	"reflect"
+)
+
+// Renderer interface for managing response payloads.
+type Renderer interface {
+	Render(w http.ResponseWriter, r *http.Request) error
+}
+
+// Binder interface for managing request payloads.
+type Binder interface {
+	Bind(r *http.Request) error
+}
+
+// Bind decodes a request body and executes the Binder method of the
+// payload structure.
+func Bind(r *http.Request, v Binder) error {
+	if err := Decode(r, v); err != nil {
+		return err
+	}
+	return binder(r, v)
+}
+
+// Render renders a single payload and respond to the client request.
+func Render(w http.ResponseWriter, r *http.Request, v Renderer) error {
+	if err := renderer(w, r, v); err != nil {
+		return err
+	}
+	Respond(w, r, v)
+	return nil
+}
+
+// RenderList renders a slice of payloads and responds to the client request.
+func RenderList(w http.ResponseWriter, r *http.Request, l []Renderer) error {
+	for _, v := range l {
+		if err := renderer(w, r, v); err != nil {
+			return err
+		}
+	}
+	Respond(w, r, l)
+	return nil
+}
+
+// Executed top-down
+func renderer(w http.ResponseWriter, r *http.Request, v Renderer) error {
+	rv := reflect.ValueOf(v)
+	if rv.Kind() == reflect.Ptr {
+		rv = rv.Elem()
+	}
+
+	// We call it top-down.
+	if err := v.Render(w, r); err != nil {
+		return err
+	}
+
+	// We're done if the Renderer isn't a struct object
+	if rv.Kind() != reflect.Struct {
+		return nil
+	}
+
+	// For structs, we call Render on each field that implements Renderer
+	for i := 0; i < rv.NumField(); i++ {
+		f := rv.Field(i)
+		if f.Type().Implements(rendererType) {
+
+			if f.IsNil() {
+				continue
+			}
+
+			fv := f.Interface().(Renderer)
+			if err := renderer(w, r, fv); err != nil {
+				return err
+			}
+
+		}
+	}
+
+	return nil
+}
+
+// Executed bottom-up
+func binder(r *http.Request, v Binder) error {
+	rv := reflect.ValueOf(v)
+	if rv.Kind() == reflect.Ptr {
+		rv = rv.Elem()
+	}
+
+	// Call Binder on non-struct types right away
+	if rv.Kind() != reflect.Struct {
+		return v.Bind(r)
+	}
+
+	// For structs, we call Bind on each field that implements Binder
+	for i := 0; i < rv.NumField(); i++ {
+		f := rv.Field(i)
+		if f.Type().Implements(binderType) {
+
+			if f.IsNil() {
+				continue
+			}
+
+			fv := f.Interface().(Binder)
+			if err := binder(r, fv); err != nil {
+				return err
+			}
+		}
+	}
+
+	// We call it bottom-up
+	if err := v.Bind(r); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+var (
+	rendererType = reflect.TypeOf(new(Renderer)).Elem()
+	binderType   = reflect.TypeOf(new(Binder)).Elem()
+)
+
+// contextKey is a value for use with context.WithValue. It's used as
+// a pointer so it fits in an interface{} without allocation. This technique
+// for defining context keys was copied from Go 1.7's new use of context in net/http.
+type contextKey struct {
+	name string
+}
+
+func (k *contextKey) String() string {
+	return "chi render context value " + k.name
+}

vendor/github.com/go-chi/render/responder.go

@@ -0,0 +1,228 @@
+package render
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"encoding/xml"
+	"fmt"
+	"net/http"
+	"reflect"
+)
+
+// M is a convenience alias for quickly building a map structure that is going
+// out to a responder. Just a short-hand.
+type M map[string]interface{}
+
+// Respond is a package-level variable set to our default Responder. We do this
+// because it allows you to set render.Respond to another function with the
+// same function signature, while also utilizing the render.Responder() function
+// itself. Effectively, allowing you to easily add your own logic to the package
+// defaults. For example, maybe you want to test if v is an error and respond
+// differently, or log something before you respond.
+var Respond = DefaultResponder
+
+// StatusCtxKey is a context key to record a future HTTP response status code.
+var StatusCtxKey = &contextKey{"Status"}
+
+// Status sets a HTTP response status code hint into request context at any point
+// during the request life-cycle. Before the Responder sends its response header
+// it will check the StatusCtxKey
+func Status(r *http.Request, status int) {
+	*r = *r.WithContext(context.WithValue(r.Context(), StatusCtxKey, status))
+}
+
+// Respond handles streaming JSON and XML responses, automatically setting the
+// Content-Type based on request headers. It will default to a JSON response.
+func DefaultResponder(w http.ResponseWriter, r *http.Request, v interface{}) {
+	if v != nil {
+		switch reflect.TypeOf(v).Kind() {
+		case reflect.Chan:
+			switch GetAcceptedContentType(r) {
+			case ContentTypeEventStream:
+				channelEventStream(w, r, v)
+				return
+			default:
+				v = channelIntoSlice(w, r, v)
+			}
+		}
+	}
+
+	// Format response based on request Accept header.
+	switch GetAcceptedContentType(r) {
+	case ContentTypeJSON:
+		JSON(w, r, v)
+	case ContentTypeXML:
+		XML(w, r, v)
+	default:
+		JSON(w, r, v)
+	}
+}
+
+// PlainText writes a string to the response, setting the Content-Type as
+// text/plain.
+func PlainText(w http.ResponseWriter, r *http.Request, v string) {
+	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
+	if status, ok := r.Context().Value(StatusCtxKey).(int); ok {
+		w.WriteHeader(status)
+	}
+	w.Write([]byte(v))
+}
+
+// Data writes raw bytes to the response, setting the Content-Type as
+// application/octet-stream.
+func Data(w http.ResponseWriter, r *http.Request, v []byte) {
+	w.Header().Set("Content-Type", "application/octet-stream")
+	if status, ok := r.Context().Value(StatusCtxKey).(int); ok {
+		w.WriteHeader(status)
+	}
+	w.Write(v)
+}
+
+// HTML writes a string to the response, setting the Content-Type as text/html.
+func HTML(w http.ResponseWriter, r *http.Request, v string) {
+	w.Header().Set("Content-Type", "text/html; charset=utf-8")
+	if status, ok := r.Context().Value(StatusCtxKey).(int); ok {
+		w.WriteHeader(status)
+	}
+	w.Write([]byte(v))
+}
+
+// JSON marshals 'v' to JSON, automatically escaping HTML and setting the
+// Content-Type as application/json.
+func JSON(w http.ResponseWriter, r *http.Request, v interface{}) {
+	buf := &bytes.Buffer{}
+	enc := json.NewEncoder(buf)
+	enc.SetEscapeHTML(true)
+	if err := enc.Encode(v); err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if status, ok := r.Context().Value(StatusCtxKey).(int); ok {
+		w.WriteHeader(status)
+	}
+	w.Write(buf.Bytes())
+}
+
+// XML marshals 'v' to JSON, setting the Content-Type as application/xml. It
+// will automatically prepend a generic XML header (see encoding/xml.Header) if
+// one is not found in the first 100 bytes of 'v'.
+func XML(w http.ResponseWriter, r *http.Request, v interface{}) {
+	b, err := xml.Marshal(v)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	w.Header().Set("Content-Type", "application/xml; charset=utf-8")
+	if status, ok := r.Context().Value(StatusCtxKey).(int); ok {
+		w.WriteHeader(status)
+	}
+
+	// Try to find <?xml header in first 100 bytes (just in case there're some XML comments).
+	findHeaderUntil := len(b)
+	if findHeaderUntil > 100 {
+		findHeaderUntil = 100
+	}
+	if !bytes.Contains(b[:findHeaderUntil], []byte("<?xml")) {
+		// No header found. Print it out first.
+		w.Write([]byte(xml.Header))
+	}
+
+	w.Write(b)
+}
+
+// NoContent returns a HTTP 204 "No Content" response.
+func NoContent(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(204)
+}
+
+func channelEventStream(w http.ResponseWriter, r *http.Request, v interface{}) {
+	if reflect.TypeOf(v).Kind() != reflect.Chan {
+		panic(fmt.Sprintf("render: event stream expects a channel, not %v", reflect.TypeOf(v).Kind()))
+	}
+
+	w.Header().Set("Content-Type", "text/event-stream; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-cache")
+	w.Header().Set("Connection", "keep-alive")
+	w.WriteHeader(200)
+
+	ctx := r.Context()
+	for {
+		switch chosen, recv, ok := reflect.Select([]reflect.SelectCase{
+			{Dir: reflect.SelectRecv, Chan: reflect.ValueOf(ctx.Done())},
+			{Dir: reflect.SelectRecv, Chan: reflect.ValueOf(v)},
+		}); chosen {
+		case 0: // equivalent to: case <-ctx.Done()
+			w.Write([]byte("event: error\ndata: {\"error\":\"Server Timeout\"}\n\n"))
+			return
+
+		default: // equivalent to: case v, ok := <-stream
+			if !ok {
+				w.Write([]byte("event: EOF\n\n"))
+				return
+			}
+			v := recv.Interface()
+
+			// Build each channel item.
+			if rv, ok := v.(Renderer); ok {
+				err := renderer(w, r, rv)
+				if err != nil {
+					v = err
+				} else {
+					v = rv
+				}
+			}
+
+			bytes, err := json.Marshal(v)
+			if err != nil {
+				w.Write([]byte(fmt.Sprintf("event: error\ndata: {\"error\":\"%v\"}\n\n", err)))
+				if f, ok := w.(http.Flusher); ok {
+					f.Flush()
+				}
+				continue
+			}
+			w.Write([]byte(fmt.Sprintf("event: data\ndata: %s\n\n", bytes)))
+			if f, ok := w.(http.Flusher); ok {
+				f.Flush()
+			}
+		}
+	}
+}
+
+// channelIntoSlice buffers channel data into a slice.
+func channelIntoSlice(w http.ResponseWriter, r *http.Request, from interface{}) interface{} {
+	ctx := r.Context()
+
+	var to []interface{}
+	for {
+		switch chosen, recv, ok := reflect.Select([]reflect.SelectCase{
+			{Dir: reflect.SelectRecv, Chan: reflect.ValueOf(ctx.Done())},
+			{Dir: reflect.SelectRecv, Chan: reflect.ValueOf(from)},
+		}); chosen {
+		case 0: // equivalent to: case <-ctx.Done()
+			http.Error(w, "Server Timeout", 504)
+			return nil
+
+		default: // equivalent to: case v, ok := <-stream
+			if !ok {
+				return to
+			}
+			v := recv.Interface()
+
+			// Render each channel item.
+			if rv, ok := v.(Renderer); ok {
+				err := renderer(w, r, rv)
+				if err != nil {
+					v = err
+				} else {
+					v = rv
+				}
+			}
+
+			to = append(to, v)
+		}
+	}
+}

vendor/github.com/hashicorp/logutils/LICENSE

@@ -0,0 +1,354 @@
+Mozilla Public License, version 2.0
+
+1. Definitions
+
+1.1. “Contributor”
+
+     means each individual or legal entity that creates, contributes to the
+     creation of, or owns Covered Software.
+
+1.2. “Contributor Version”
+
+     means the combination of the Contributions of others (if any) used by a
+     Contributor and that particular Contributor’s Contribution.
+
+1.3. “Contribution”
+
+     means Covered Software of a particular Contributor.
+
+1.4. “Covered Software”
+
+     means Source Code Form to which the initial Contributor has attached the
+     notice in Exhibit A, the Executable Form of such Source Code Form, and
+     Modifications of such Source Code Form, in each case including portions
+     thereof.
+
+1.5. “Incompatible With Secondary Licenses”
+     means
+
+     a. that the initial Contributor has attached the notice described in
+        Exhibit B to the Covered Software; or
+
+     b. that the Covered Software was made available under the terms of version
+        1.1 or earlier of the License, but not also under the terms of a
+        Secondary License.
+
+1.6. “Executable Form”
+
+     means any form of the work other than Source Code Form.
+
+1.7. “Larger Work”
+
+     means a work that combines Covered Software with other material, in a separate
+     file or files, that is not Covered Software.
+
+1.8. “License”
+
+     means this document.
+
+1.9. “Licensable”
+
+     means having the right to grant, to the maximum extent possible, whether at the
+     time of the initial grant or subsequently, any and all of the rights conveyed by
+     this License.
+
+1.10. “Modifications”
+
+     means any of the following:
+
+     a. any file in Source Code Form that results from an addition to, deletion
+        from, or modification of the contents of Covered Software; or
+
+     b. any new file in Source Code Form that contains any Covered Software.
+
+1.11. “Patent Claims” of a Contributor
+
+      means any patent claim(s), including without limitation, method, process,
+      and apparatus claims, in any patent Licensable by such Contributor that
+      would be infringed, but for the grant of the License, by the making,
+      using, selling, offering for sale, having made, import, or transfer of
+      either its Contributions or its Contributor Version.
+
+1.12. “Secondary License”
+
+      means either the GNU General Public License, Version 2.0, the GNU Lesser
+      General Public License, Version 2.1, the GNU Affero General Public
+      License, Version 3.0, or any later versions of those licenses.
+
+1.13. “Source Code Form”
+
+      means the form of the work preferred for making modifications.
+
+1.14. “You” (or “Your”)
+
+      means an individual or a legal entity exercising rights under this
+      License. For legal entities, “You” includes any entity that controls, is
+      controlled by, or is under common control with You. For purposes of this
+      definition, “control” means (a) the power, direct or indirect, to cause
+      the direction or management of such entity, whether by contract or
+      otherwise, or (b) ownership of more than fifty percent (50%) of the
+      outstanding shares or beneficial ownership of such entity.
+
+
+2. License Grants and Conditions
+
+2.1. Grants
+
+     Each Contributor hereby grants You a world-wide, royalty-free,
+     non-exclusive license:
+
+     a. under intellectual property rights (other than patent or trademark)
+        Licensable by such Contributor to use, reproduce, make available,
+        modify, display, perform, distribute, and otherwise exploit its
+        Contributions, either on an unmodified basis, with Modifications, or as
+        part of a Larger Work; and
+
+     b. under Patent Claims of such Contributor to make, use, sell, offer for
+        sale, have made, import, and otherwise transfer either its Contributions
+        or its Contributor Version.
+
+2.2. Effective Date
+
+     The licenses granted in Section 2.1 with respect to any Contribution become
+     effective for each Contribution on the date the Contributor first distributes
+     such Contribution.
+
+2.3. Limitations on Grant Scope
+
+     The licenses granted in this Section 2 are the only rights granted under this
+     License. No additional rights or licenses will be implied from the distribution
+     or licensing of Covered Software under this License. Notwithstanding Section
+     2.1(b) above, no patent license is granted by a Contributor:
+
+     a. for any code that a Contributor has removed from Covered Software; or
+
+     b. for infringements caused by: (i) Your and any other third party’s
+        modifications of Covered Software, or (ii) the combination of its
+        Contributions with other software (except as part of its Contributor
+        Version); or
+
+     c. under Patent Claims infringed by Covered Software in the absence of its
+        Contributions.
+
+     This License does not grant any rights in the trademarks, service marks, or
+     logos of any Contributor (except as may be necessary to comply with the
+     notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+     No Contributor makes additional grants as a result of Your choice to
+     distribute the Covered Software under a subsequent version of this License
+     (see Section 10.2) or under the terms of a Secondary License (if permitted
+     under the terms of Section 3.3).
+
+2.5. Representation
+
+     Each Contributor represents that the Contributor believes its Contributions
+     are its original creation(s) or it has sufficient rights to grant the
+     rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+     This License is not intended to limit any rights You have under applicable
+     copyright doctrines of fair use, fair dealing, or other equivalents.
+
+2.7. Conditions
+
+     Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+     Section 2.1.
+
+
+3. Responsibilities
+
+3.1. Distribution of Source Form
+
+     All distribution of Covered Software in Source Code Form, including any
+     Modifications that You create or to which You contribute, must be under the
+     terms of this License. You must inform recipients that the Source Code Form
+     of the Covered Software is governed by the terms of this License, and how
+     they can obtain a copy of this License. You may not attempt to alter or
+     restrict the recipients’ rights in the Source Code Form.
+
+3.2. Distribution of Executable Form
+
+     If You distribute Covered Software in Executable Form then:
+
+     a. such Covered Software must also be made available in Source Code Form,
+        as described in Section 3.1, and You must inform recipients of the
+        Executable Form how they can obtain a copy of such Source Code Form by
+        reasonable means in a timely manner, at a charge no more than the cost
+        of distribution to the recipient; and
+
+     b. You may distribute such Executable Form under the terms of this License,
+        or sublicense it under different terms, provided that the license for
+        the Executable Form does not attempt to limit or alter the recipients’
+        rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+     You may create and distribute a Larger Work under terms of Your choice,
+     provided that You also comply with the requirements of this License for the
+     Covered Software. If the Larger Work is a combination of Covered Software
+     with a work governed by one or more Secondary Licenses, and the Covered
+     Software is not Incompatible With Secondary Licenses, this License permits
+     You to additionally distribute such Covered Software under the terms of
+     such Secondary License(s), so that the recipient of the Larger Work may, at
+     their option, further distribute the Covered Software under the terms of
+     either this License or such Secondary License(s).
+
+3.4. Notices
+
+     You may not remove or alter the substance of any license notices (including
+     copyright notices, patent notices, disclaimers of warranty, or limitations
+     of liability) contained within the Source Code Form of the Covered
+     Software, except that You may alter any license notices to the extent
+     required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+     You may choose to offer, and to charge a fee for, warranty, support,
+     indemnity or liability obligations to one or more recipients of Covered
+     Software. However, You may do so only on Your own behalf, and not on behalf
+     of any Contributor. You must make it absolutely clear that any such
+     warranty, support, indemnity, or liability obligation is offered by You
+     alone, and You hereby agree to indemnify every Contributor for any
+     liability incurred by such Contributor as a result of warranty, support,
+     indemnity or liability terms You offer. You may include additional
+     disclaimers of warranty and limitations of liability specific to any
+     jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+
+   If it is impossible for You to comply with any of the terms of this License
+   with respect to some or all of the Covered Software due to statute, judicial
+   order, or regulation then You must: (a) comply with the terms of this License
+   to the maximum extent possible; and (b) describe the limitations and the code
+   they affect. Such description must be placed in a text file included with all
+   distributions of the Covered Software under this License. Except to the
+   extent prohibited by statute or regulation, such description must be
+   sufficiently detailed for a recipient of ordinary skill to be able to
+   understand it.
+
+5. Termination
+
+5.1. The rights granted under this License will terminate automatically if You
+     fail to comply with any of its terms. However, if You become compliant,
+     then the rights granted under this License from a particular Contributor
+     are reinstated (a) provisionally, unless and until such Contributor
+     explicitly and finally terminates Your grants, and (b) on an ongoing basis,
+     if such Contributor fails to notify You of the non-compliance by some
+     reasonable means prior to 60 days after You have come back into compliance.
+     Moreover, Your grants from a particular Contributor are reinstated on an
+     ongoing basis if such Contributor notifies You of the non-compliance by
+     some reasonable means, this is the first time You have received notice of
+     non-compliance with this License from such Contributor, and You become
+     compliant prior to 30 days after Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+     infringement claim (excluding declaratory judgment actions, counter-claims,
+     and cross-claims) alleging that a Contributor Version directly or
+     indirectly infringes any patent, then the rights granted to You by any and
+     all Contributors for the Covered Software under Section 2.1 of this License
+     shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
+     license agreements (excluding distributors and resellers) which have been
+     validly granted by You or Your distributors under this License prior to
+     termination shall survive termination.
+
+6. Disclaimer of Warranty
+
+   Covered Software is provided under this License on an “as is” basis, without
+   warranty of any kind, either expressed, implied, or statutory, including,
+   without limitation, warranties that the Covered Software is free of defects,
+   merchantable, fit for a particular purpose or non-infringing. The entire
+   risk as to the quality and performance of the Covered Software is with You.
+   Should any Covered Software prove defective in any respect, You (not any
+   Contributor) assume the cost of any necessary servicing, repair, or
+   correction. This disclaimer of warranty constitutes an essential part of this
+   License. No use of  any Covered Software is authorized under this License
+   except under this disclaimer.
+
+7. Limitation of Liability
+
+   Under no circumstances and under no legal theory, whether tort (including
+   negligence), contract, or otherwise, shall any Contributor, or anyone who
+   distributes Covered Software as permitted above, be liable to You for any
+   direct, indirect, special, incidental, or consequential damages of any
+   character including, without limitation, damages for lost profits, loss of
+   goodwill, work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses, even if such party shall have been
+   informed of the possibility of such damages. This limitation of liability
+   shall not apply to liability for death or personal injury resulting from such
+   party’s negligence to the extent applicable law prohibits such limitation.
+   Some jurisdictions do not allow the exclusion or limitation of incidental or
+   consequential damages, so this exclusion and limitation may not apply to You.
+
+8. Litigation
+
+   Any litigation relating to this License may be brought only in the courts of
+   a jurisdiction where the defendant maintains its principal place of business
+   and such litigation shall be governed by laws of that jurisdiction, without
+   reference to its conflict-of-law provisions. Nothing in this Section shall
+   prevent a party’s ability to bring cross-claims or counter-claims.
+
+9. Miscellaneous
+
+   This License represents the complete agreement concerning the subject matter
+   hereof. If any provision of this License is held to be unenforceable, such
+   provision shall be reformed only to the extent necessary to make it
+   enforceable. Any law or regulation which provides that the language of a
+   contract shall be construed against the drafter shall not be used to construe
+   this License against a Contributor.
+
+
+10. Versions of the License
+
+10.1. New Versions
+
+      Mozilla Foundation is the license steward. Except as provided in Section
+      10.3, no one other than the license steward has the right to modify or
+      publish new versions of this License. Each version will be given a
+      distinguishing version number.
+
+10.2. Effect of New Versions
+
+      You may distribute the Covered Software under the terms of the version of
+      the License under which You originally received the Covered Software, or
+      under the terms of any subsequent version published by the license
+      steward.
+
+10.3. Modified Versions
+
+      If you create software not governed by this License, and you want to
+      create a new license for such software, you may create and use a modified
+      version of this License if you rename the license and remove any
+      references to the name of the license steward (except to note that such
+      modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary Licenses
+      If You choose to distribute Source Code Form that is Incompatible With
+      Secondary Licenses under the terms of this version of the License, the
+      notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+
+      This Source Code Form is subject to the
+      terms of the Mozilla Public License, v.
+      2.0. If a copy of the MPL was not
+      distributed with this file, You can
+      obtain one at
+      http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular file, then
+You may include the notice in a location (such as a LICENSE file in a relevant
+directory) where a recipient would be likely to look for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - “Incompatible With Secondary Licenses” Notice
+
+      This Source Code Form is “Incompatible
+      With Secondary Licenses”, as defined by
+      the Mozilla Public License, v. 2.0.
+

vendor/github.com/hashicorp/logutils/README.md

@@ -0,0 +1,36 @@
+# logutils
+
+logutils is a Go package that augments the standard library "log" package
+to make logging a bit more modern, without fragmenting the Go ecosystem
+with new logging packages.
+
+## The simplest thing that could possibly work
+
+Presumably your application already uses the default `log` package. To switch, you'll want your code to look like the following:
+
+```go
+package main
+
+import (
+	"log"
+	"os"
+
+	"github.com/hashicorp/logutils"
+)
+
+func main() {
+	filter := &logutils.LevelFilter{
+		Levels: []logutils.LogLevel{"DEBUG", "WARN", "ERROR"},
+		MinLevel: logutils.LogLevel("WARN"),
+		Writer: os.Stderr,
+	}
+	log.SetOutput(filter)
+
+	log.Print("[DEBUG] Debugging") // this will not print
+	log.Print("[WARN] Warning") // this will
+	log.Print("[ERROR] Erring") // and so will this
+	log.Print("Message I haven't updated") // and so will this
+}
+```
+
+This logs to standard error exactly like go's standard logger. Any log messages you haven't converted to have a level will continue to print as before.

vendor/github.com/hashicorp/logutils/level.go

@@ -0,0 +1,81 @@
+// Package logutils augments the standard log package with levels.
+package logutils
+
+import (
+	"bytes"
+	"io"
+	"sync"
+)
+
+type LogLevel string
+
+// LevelFilter is an io.Writer that can be used with a logger that
+// will filter out log messages that aren't at least a certain level.
+//
+// Once the filter is in use somewhere, it is not safe to modify
+// the structure.
+type LevelFilter struct {
+	// Levels is the list of log levels, in increasing order of
+	// severity. Example might be: {"DEBUG", "WARN", "ERROR"}.
+	Levels []LogLevel
+
+	// MinLevel is the minimum level allowed through
+	MinLevel LogLevel
+
+	// The underlying io.Writer where log messages that pass the filter
+	// will be set.
+	Writer io.Writer
+
+	badLevels map[LogLevel]struct{}
+	once      sync.Once
+}
+
+// Check will check a given line if it would be included in the level
+// filter.
+func (f *LevelFilter) Check(line []byte) bool {
+	f.once.Do(f.init)
+
+	// Check for a log level
+	var level LogLevel
+	x := bytes.IndexByte(line, '[')
+	if x >= 0 {
+		y := bytes.IndexByte(line[x:], ']')
+		if y >= 0 {
+			level = LogLevel(line[x+1 : x+y])
+		}
+	}
+
+	_, ok := f.badLevels[level]
+	return !ok
+}
+
+func (f *LevelFilter) Write(p []byte) (n int, err error) {
+	// Note in general that io.Writer can receive any byte sequence
+	// to write, but the "log" package always guarantees that we only
+	// get a single line. We use that as a slight optimization within
+	// this method, assuming we're dealing with a single, complete line
+	// of log data.
+
+	if !f.Check(p) {
+		return len(p), nil
+	}
+
+	return f.Writer.Write(p)
+}
+
+// SetMinLevel is used to update the minimum log level
+func (f *LevelFilter) SetMinLevel(min LogLevel) {
+	f.MinLevel = min
+	f.init()
+}
+
+func (f *LevelFilter) init() {
+	badLevels := make(map[LogLevel]struct{})
+	for _, level := range f.Levels {
+		if level == f.MinLevel {
+			break
+		}
+		badLevels[level] = struct{}{}
+	}
+	f.badLevels = badLevels
+}

vendor/github.com/jessevdk/go-flags/LICENSE

@@ -0,0 +1,26 @@
+Copyright (c) 2012 Jesse van den Kieboom. All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+     notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+     copyright notice, this list of conditions and the following disclaimer
+     in the documentation and/or other materials provided with the
+     distribution.
+   * Neither the name of Google Inc. nor the names of its
+     contributors may be used to endorse or promote products derived from
+     this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/jessevdk/go-flags/README.md

@@ -0,0 +1,135 @@
+go-flags: a go library for parsing command line arguments
+=========================================================
+
+[![GoDoc](https://godoc.org/github.com/jessevdk/go-flags?status.png)](https://godoc.org/github.com/jessevdk/go-flags) [![Build Status](https://travis-ci.org/jessevdk/go-flags.svg?branch=master)](https://travis-ci.org/jessevdk/go-flags) [![Coverage Status](https://img.shields.io/coveralls/jessevdk/go-flags.svg)](https://coveralls.io/r/jessevdk/go-flags?branch=master)
+
+This library provides similar functionality to the builtin flag library of
+go, but provides much more functionality and nicer formatting. From the
+documentation:
+
+Package flags provides an extensive command line option parser.
+The flags package is similar in functionality to the go builtin flag package
+but provides more options and uses reflection to provide a convenient and
+succinct way of specifying command line options.
+
+Supported features:
+* Options with short names (-v)
+* Options with long names (--verbose)
+* Options with and without arguments (bool v.s. other type)
+* Options with optional arguments and default values
+* Multiple option groups each containing a set of options
+* Generate and print well-formatted help message
+* Passing remaining command line arguments after -- (optional)
+* Ignoring unknown command line options (optional)
+* Supports -I/usr/include -I=/usr/include -I /usr/include option argument specification
+* Supports multiple short options -aux
+* Supports all primitive go types (string, int{8..64}, uint{8..64}, float)
+* Supports same option multiple times (can store in slice or last option counts)
+* Supports maps
+* Supports function callbacks
+* Supports namespaces for (nested) option groups
+
+The flags package uses structs, reflection and struct field tags
+to allow users to specify command line options. This results in very simple
+and concise specification of your application options. For example:
+
+```go
+type Options struct {
+	Verbose []bool `short:"v" long:"verbose" description:"Show verbose debug information"`
+}
+```
+
+This specifies one option with a short name -v and a long name --verbose.
+When either -v or --verbose is found on the command line, a 'true' value
+will be appended to the Verbose field. e.g. when specifying -vvv, the
+resulting value of Verbose will be {[true, true, true]}.
+
+Example:
+--------
+```go
+var opts struct {
+	// Slice of bool will append 'true' each time the option
+	// is encountered (can be set multiple times, like -vvv)
+	Verbose []bool `short:"v" long:"verbose" description:"Show verbose debug information"`
+
+	// Example of automatic marshalling to desired type (uint)
+	Offset uint `long:"offset" description:"Offset"`
+
+	// Example of a callback, called each time the option is found.
+	Call func(string) `short:"c" description:"Call phone number"`
+
+	// Example of a required flag
+	Name string `short:"n" long:"name" description:"A name" required:"true"`
+
+	// Example of a value name
+	File string `short:"f" long:"file" description:"A file" value-name:"FILE"`
+
+	// Example of a pointer
+	Ptr *int `short:"p" description:"A pointer to an integer"`
+
+	// Example of a slice of strings
+	StringSlice []string `short:"s" description:"A slice of strings"`
+
+	// Example of a slice of pointers
+	PtrSlice []*string `long:"ptrslice" description:"A slice of pointers to string"`
+
+	// Example of a map
+	IntMap map[string]int `long:"intmap" description:"A map from string to int"`
+}
+
+// Callback which will invoke callto:<argument> to call a number.
+// Note that this works just on OS X (and probably only with
+// Skype) but it shows the idea.
+opts.Call = func(num string) {
+	cmd := exec.Command("open", "callto:"+num)
+	cmd.Start()
+	cmd.Process.Release()
+}
+
+// Make some fake arguments to parse.
+args := []string{
+	"-vv",
+	"--offset=5",
+	"-n", "Me",
+	"-p", "3",
+	"-s", "hello",
+	"-s", "world",
+	"--ptrslice", "hello",
+	"--ptrslice", "world",
+	"--intmap", "a:1",
+	"--intmap", "b:5",
+	"arg1",
+	"arg2",
+	"arg3",
+}
+
+// Parse flags from `args'. Note that here we use flags.ParseArgs for
+// the sake of making a working example. Normally, you would simply use
+// flags.Parse(&opts) which uses os.Args
+args, err := flags.ParseArgs(&opts, args)
+
+if err != nil {
+	panic(err)
+	os.Exit(1)
+}
+
+fmt.Printf("Verbosity: %v\n", opts.Verbose)
+fmt.Printf("Offset: %d\n", opts.Offset)
+fmt.Printf("Name: %s\n", opts.Name)
+fmt.Printf("Ptr: %d\n", *opts.Ptr)
+fmt.Printf("StringSlice: %v\n", opts.StringSlice)
+fmt.Printf("PtrSlice: [%v %v]\n", *opts.PtrSlice[0], *opts.PtrSlice[1])
+fmt.Printf("IntMap: [a:%v b:%v]\n", opts.IntMap["a"], opts.IntMap["b"])
+fmt.Printf("Remaining args: %s\n", strings.Join(args, " "))
+
+// Output: Verbosity: [true true]
+// Offset: 5
+// Name: Me
+// Ptr: 3
+// StringSlice: [hello world]
+// PtrSlice: [hello world]
+// IntMap: [a:1 b:5]
+// Remaining args: arg1 arg2 arg3
+```
+
+More information can be found in the godocs: <http://godoc.org/github.com/jessevdk/go-flags>

vendor/github.com/jessevdk/go-flags/arg.go

@@ -0,0 +1,24 @@
+package flags
+
+import (
+	"reflect"
+)
+
+// Arg represents a positional argument on the command line.
+type Arg struct {
+	// The name of the positional argument (used in the help)
+	Name string
+
+	// A description of the positional argument (used in the help)
+	Description string
+
+	// Whether a positional argument is required
+	Required int
+
+	value reflect.Value
+	tag   multiTag
+}
+
+func (a *Arg) isRemaining() bool {
+	return a.value.Type().Kind() == reflect.Slice
+}

vendor/github.com/jessevdk/go-flags/check_crosscompile.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+set -e
+
+echo '# linux arm7'
+GOARM=7 GOARCH=arm GOOS=linux go build
+echo '# linux arm5'
+GOARM=5 GOARCH=arm GOOS=linux go build
+echo '# windows 386'
+GOARCH=386 GOOS=windows go build
+echo '# windows amd64'
+GOARCH=amd64 GOOS=windows go build
+echo '# darwin'
+GOARCH=amd64 GOOS=darwin go build
+echo '# freebsd'
+GOARCH=amd64 GOOS=freebsd go build

vendor/github.com/jessevdk/go-flags/closest.go

@@ -0,0 +1,59 @@
+package flags
+
+func levenshtein(s string, t string) int {
+	if len(s) == 0 {
+		return len(t)
+	}
+
+	if len(t) == 0 {
+		return len(s)
+	}
+
+	dists := make([][]int, len(s)+1)
+	for i := range dists {
+		dists[i] = make([]int, len(t)+1)
+		dists[i][0] = i
+	}
+
+	for j := range t {
+		dists[0][j] = j
+	}
+
+	for i, sc := range s {
+		for j, tc := range t {
+			if sc == tc {
+				dists[i+1][j+1] = dists[i][j]
+			} else {
+				dists[i+1][j+1] = dists[i][j] + 1
+				if dists[i+1][j] < dists[i+1][j+1] {
+					dists[i+1][j+1] = dists[i+1][j] + 1
+				}
+				if dists[i][j+1] < dists[i+1][j+1] {
+					dists[i+1][j+1] = dists[i][j+1] + 1
+				}
+			}
+		}
+	}
+
+	return dists[len(s)][len(t)]
+}
+
+func closestChoice(cmd string, choices []string) (string, int) {
+	if len(choices) == 0 {
+		return "", 0
+	}
+
+	mincmd := -1
+	mindist := -1
+
+	for i, c := range choices {
+		l := levenshtein(cmd, c)
+
+		if mincmd < 0 || l < mindist {
+			mindist = l
+			mincmd = i
+		}
+	}
+
+	return choices[mincmd], mindist
+}

vendor/github.com/jessevdk/go-flags/command.go

@@ -0,0 +1,441 @@
+package flags
+
+import (
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+	"unsafe"
+)
+
+// Command represents an application command. Commands can be added to the
+// parser (which itself is a command) and are selected/executed when its name
+// is specified on the command line. The Command type embeds a Group and
+// therefore also carries a set of command specific options.
+type Command struct {
+	// Embedded, see Group for more information
+	*Group
+
+	// The name by which the command can be invoked
+	Name string
+
+	// The active sub command (set by parsing) or nil
+	Active *Command
+
+	// Whether subcommands are optional
+	SubcommandsOptional bool
+
+	// Aliases for the command
+	Aliases []string
+
+	// Whether positional arguments are required
+	ArgsRequired bool
+
+	commands            []*Command
+	hasBuiltinHelpGroup bool
+	args                []*Arg
+}
+
+// Commander is an interface which can be implemented by any command added in
+// the options. When implemented, the Execute method will be called for the last
+// specified (sub)command providing the remaining command line arguments.
+type Commander interface {
+	// Execute will be called for the last active (sub)command. The
+	// args argument contains the remaining command line arguments. The
+	// error that Execute returns will be eventually passed out of the
+	// Parse method of the Parser.
+	Execute(args []string) error
+}
+
+// Usage is an interface which can be implemented to show a custom usage string
+// in the help message shown for a command.
+type Usage interface {
+	// Usage is called for commands to allow customized printing of command
+	// usage in the generated help message.
+	Usage() string
+}
+
+type lookup struct {
+	shortNames map[string]*Option
+	longNames  map[string]*Option
+
+	commands map[string]*Command
+}
+
+// AddCommand adds a new command to the parser with the given name and data. The
+// data needs to be a pointer to a struct from which the fields indicate which
+// options are in the command. The provided data can implement the Command and
+// Usage interfaces.
+func (c *Command) AddCommand(command string, shortDescription string, longDescription string, data interface{}) (*Command, error) {
+	cmd := newCommand(command, shortDescription, longDescription, data)
+
+	cmd.parent = c
+
+	if err := cmd.scan(); err != nil {
+		return nil, err
+	}
+
+	c.commands = append(c.commands, cmd)
+	return cmd, nil
+}
+
+// AddGroup adds a new group to the command with the given name and data. The
+// data needs to be a pointer to a struct from which the fields indicate which
+// options are in the group.
+func (c *Command) AddGroup(shortDescription string, longDescription string, data interface{}) (*Group, error) {
+	group := newGroup(shortDescription, longDescription, data)
+
+	group.parent = c
+
+	if err := group.scanType(c.scanSubcommandHandler(group)); err != nil {
+		return nil, err
+	}
+
+	c.groups = append(c.groups, group)
+	return group, nil
+}
+
+// Commands returns a list of subcommands of this command.
+func (c *Command) Commands() []*Command {
+	return c.commands
+}
+
+// Find locates the subcommand with the given name and returns it. If no such
+// command can be found Find will return nil.
+func (c *Command) Find(name string) *Command {
+	for _, cc := range c.commands {
+		if cc.match(name) {
+			return cc
+		}
+	}
+
+	return nil
+}
+
+// FindOptionByLongName finds an option that is part of the command, or any of
+// its parent commands, by matching its long name (including the option
+// namespace).
+func (c *Command) FindOptionByLongName(longName string) (option *Option) {
+	for option == nil && c != nil {
+		option = c.Group.FindOptionByLongName(longName)
+
+		c, _ = c.parent.(*Command)
+	}
+
+	return option
+}
+
+// FindOptionByShortName finds an option that is part of the command, or any of
+// its parent commands, by matching its long name (including the option
+// namespace).
+func (c *Command) FindOptionByShortName(shortName rune) (option *Option) {
+	for option == nil && c != nil {
+		option = c.Group.FindOptionByShortName(shortName)
+
+		c, _ = c.parent.(*Command)
+	}
+
+	return option
+}
+
+// Args returns a list of positional arguments associated with this command.
+func (c *Command) Args() []*Arg {
+	ret := make([]*Arg, len(c.args))
+	copy(ret, c.args)
+
+	return ret
+}
+
+func newCommand(name string, shortDescription string, longDescription string, data interface{}) *Command {
+	return &Command{
+		Group: newGroup(shortDescription, longDescription, data),
+		Name:  name,
+	}
+}
+
+func (c *Command) scanSubcommandHandler(parentg *Group) scanHandler {
+	f := func(realval reflect.Value, sfield *reflect.StructField) (bool, error) {
+		mtag := newMultiTag(string(sfield.Tag))
+
+		if err := mtag.Parse(); err != nil {
+			return true, err
+		}
+
+		positional := mtag.Get("positional-args")
+
+		if len(positional) != 0 {
+			stype := realval.Type()
+
+			for i := 0; i < stype.NumField(); i++ {
+				field := stype.Field(i)
+
+				m := newMultiTag((string(field.Tag)))
+
+				if err := m.Parse(); err != nil {
+					return true, err
+				}
+
+				name := m.Get("positional-arg-name")
+
+				if len(name) == 0 {
+					name = field.Name
+				}
+
+				var required int
+
+				sreq := m.Get("required")
+
+				if sreq != "" {
+					required = 1
+
+					if preq, err := strconv.ParseInt(sreq, 10, 32); err == nil {
+						required = int(preq)
+					}
+				}
+
+				arg := &Arg{
+					Name:        name,
+					Description: m.Get("description"),
+					Required:    required,
+
+					value: realval.Field(i),
+					tag:   m,
+				}
+
+				c.args = append(c.args, arg)
+
+				if len(mtag.Get("required")) != 0 {
+					c.ArgsRequired = true
+				}
+			}
+
+			return true, nil
+		}
+
+		subcommand := mtag.Get("command")
+
+		if len(subcommand) != 0 {
+			ptrval := reflect.NewAt(realval.Type(), unsafe.Pointer(realval.UnsafeAddr()))
+
+			shortDescription := mtag.Get("description")
+			longDescription := mtag.Get("long-description")
+			subcommandsOptional := mtag.Get("subcommands-optional")
+			aliases := mtag.GetMany("alias")
+
+			subc, err := c.AddCommand(subcommand, shortDescription, longDescription, ptrval.Interface())
+			if err != nil {
+				return true, err
+			}
+
+			subc.Hidden = mtag.Get("hidden") != ""
+
+			if len(subcommandsOptional) > 0 {
+				subc.SubcommandsOptional = true
+			}
+
+			if len(aliases) > 0 {
+				subc.Aliases = aliases
+			}
+
+			return true, nil
+		}
+
+		return parentg.scanSubGroupHandler(realval, sfield)
+	}
+
+	return f
+}
+
+func (c *Command) scan() error {
+	return c.scanType(c.scanSubcommandHandler(c.Group))
+}
+
+func (c *Command) eachOption(f func(*Command, *Group, *Option)) {
+	c.eachCommand(func(c *Command) {
+		c.eachGroup(func(g *Group) {
+			for _, option := range g.options {
+				f(c, g, option)
+			}
+		})
+	}, true)
+}
+
+func (c *Command) eachCommand(f func(*Command), recurse bool) {
+	f(c)
+
+	for _, cc := range c.commands {
+		if recurse {
+			cc.eachCommand(f, true)
+		} else {
+			f(cc)
+		}
+	}
+}
+
+func (c *Command) eachActiveGroup(f func(cc *Command, g *Group)) {
+	c.eachGroup(func(g *Group) {
+		f(c, g)
+	})
+
+	if c.Active != nil {
+		c.Active.eachActiveGroup(f)
+	}
+}
+
+func (c *Command) addHelpGroups(showHelp func() error) {
+	if !c.hasBuiltinHelpGroup {
+		c.addHelpGroup(showHelp)
+		c.hasBuiltinHelpGroup = true
+	}
+
+	for _, cc := range c.commands {
+		cc.addHelpGroups(showHelp)
+	}
+}
+
+func (c *Command) makeLookup() lookup {
+	ret := lookup{
+		shortNames: make(map[string]*Option),
+		longNames:  make(map[string]*Option),
+		commands:   make(map[string]*Command),
+	}
+
+	parent := c.parent
+
+	var parents []*Command
+
+	for parent != nil {
+		if cmd, ok := parent.(*Command); ok {
+			parents = append(parents, cmd)
+			parent = cmd.parent
+		} else {
+			parent = nil
+		}
+	}
+
+	for i := len(parents) - 1; i >= 0; i-- {
+		parents[i].fillLookup(&ret, true)
+	}
+
+	c.fillLookup(&ret, false)
+	return ret
+}
+
+func (c *Command) fillLookup(ret *lookup, onlyOptions bool) {
+	c.eachGroup(func(g *Group) {
+		for _, option := range g.options {
+			if option.ShortName != 0 {
+				ret.shortNames[string(option.ShortName)] = option
+			}
+
+			if len(option.LongName) > 0 {
+				ret.longNames[option.LongNameWithNamespace()] = option
+			}
+		}
+	})
+
+	if onlyOptions {
+		return
+	}
+
+	for _, subcommand := range c.commands {
+		ret.commands[subcommand.Name] = subcommand
+
+		for _, a := range subcommand.Aliases {
+			ret.commands[a] = subcommand
+		}
+	}
+}
+
+func (c *Command) groupByName(name string) *Group {
+	if grp := c.Group.groupByName(name); grp != nil {
+		return grp
+	}
+
+	for _, subc := range c.commands {
+		prefix := subc.Name + "."
+
+		if strings.HasPrefix(name, prefix) {
+			if grp := subc.groupByName(name[len(prefix):]); grp != nil {
+				return grp
+			}
+		} else if name == subc.Name {
+			return subc.Group
+		}
+	}
+
+	return nil
+}
+
+type commandList []*Command
+
+func (c commandList) Less(i, j int) bool {
+	return c[i].Name < c[j].Name
+}
+
+func (c commandList) Len() int {
+	return len(c)
+}
+
+func (c commandList) Swap(i, j int) {
+	c[i], c[j] = c[j], c[i]
+}
+
+func (c *Command) sortedVisibleCommands() []*Command {
+	ret := commandList(c.visibleCommands())
+	sort.Sort(ret)
+
+	return []*Command(ret)
+}
+
+func (c *Command) visibleCommands() []*Command {
+	ret := make([]*Command, 0, len(c.commands))
+
+	for _, cmd := range c.commands {
+		if !cmd.Hidden {
+			ret = append(ret, cmd)
+		}
+	}
+
+	return ret
+}
+
+func (c *Command) match(name string) bool {
+	if c.Name == name {
+		return true
+	}
+
+	for _, v := range c.Aliases {
+		if v == name {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (c *Command) hasCliOptions() bool {
+	ret := false
+
+	c.eachGroup(func(g *Group) {
+		if g.isBuiltinHelp {
+			return
+		}
+
+		for _, opt := range g.options {
+			if opt.canCli() {
+				ret = true
+			}
+		}
+	})
+
+	return ret
+}
+
+func (c *Command) fillParseState(s *parseState) {
+	s.positional = make([]*Arg, len(c.args))
+	copy(s.positional, c.args)
+
+	s.lookup = c.makeLookup()
+	s.command = c
+}

vendor/github.com/jessevdk/go-flags/completion.go

@@ -0,0 +1,300 @@
+package flags
+
+import (
+	"fmt"
+	"path/filepath"
+	"reflect"
+	"sort"
+	"strings"
+	"unicode/utf8"
+)
+
+// Completion is a type containing information of a completion.
+type Completion struct {
+	// The completed item
+	Item string
+
+	// A description of the completed item (optional)
+	Description string
+}
+
+type completions []Completion
+
+func (c completions) Len() int {
+	return len(c)
+}
+
+func (c completions) Less(i, j int) bool {
+	return c[i].Item < c[j].Item
+}
+
+func (c completions) Swap(i, j int) {
+	c[i], c[j] = c[j], c[i]
+}
+
+// Completer is an interface which can be implemented by types
+// to provide custom command line argument completion.
+type Completer interface {
+	// Complete receives a prefix representing a (partial) value
+	// for its type and should provide a list of possible valid
+	// completions.
+	Complete(match string) []Completion
+}
+
+type completion struct {
+	parser *Parser
+}
+
+// Filename is a string alias which provides filename completion.
+type Filename string
+
+func completionsWithoutDescriptions(items []string) []Completion {
+	ret := make([]Completion, len(items))
+
+	for i, v := range items {
+		ret[i].Item = v
+	}
+
+	return ret
+}
+
+// Complete returns a list of existing files with the given
+// prefix.
+func (f *Filename) Complete(match string) []Completion {
+	ret, _ := filepath.Glob(match + "*")
+	return completionsWithoutDescriptions(ret)
+}
+
+func (c *completion) skipPositional(s *parseState, n int) {
+	if n >= len(s.positional) {
+		s.positional = nil
+	} else {
+		s.positional = s.positional[n:]
+	}
+}
+
+func (c *completion) completeOptionNames(names map[string]*Option, prefix string, match string) []Completion {
+	n := make([]Completion, 0, len(names))
+
+	for k, opt := range names {
+		if strings.HasPrefix(k, match) && !opt.Hidden {
+			n = append(n, Completion{
+				Item:        prefix + k,
+				Description: opt.Description,
+			})
+		}
+	}
+
+	return n
+}
+
+func (c *completion) completeLongNames(s *parseState, prefix string, match string) []Completion {
+	return c.completeOptionNames(s.lookup.longNames, prefix, match)
+}
+
+func (c *completion) completeShortNames(s *parseState, prefix string, match string) []Completion {
+	if len(match) != 0 {
+		return []Completion{
+			Completion{
+				Item: prefix + match,
+			},
+		}
+	}
+
+	return c.completeOptionNames(s.lookup.shortNames, prefix, match)
+}
+
+func (c *completion) completeCommands(s *parseState, match string) []Completion {
+	n := make([]Completion, 0, len(s.command.commands))
+
+	for _, cmd := range s.command.commands {
+		if cmd.data != c && strings.HasPrefix(cmd.Name, match) {
+			n = append(n, Completion{
+				Item:        cmd.Name,
+				Description: cmd.ShortDescription,
+			})
+		}
+	}
+
+	return n
+}
+
+func (c *completion) completeValue(value reflect.Value, prefix string, match string) []Completion {
+	i := value.Interface()
+
+	var ret []Completion
+
+	if cmp, ok := i.(Completer); ok {
+		ret = cmp.Complete(match)
+	} else if value.CanAddr() {
+		if cmp, ok = value.Addr().Interface().(Completer); ok {
+			ret = cmp.Complete(match)
+		}
+	}
+
+	for i, v := range ret {
+		ret[i].Item = prefix + v.Item
+	}
+
+	return ret
+}
+
+func (c *completion) completeArg(arg *Arg, prefix string, match string) []Completion {
+	if arg.isRemaining() {
+		// For remaining positional args (that are parsed into a slice), complete
+		// based on the element type.
+		return c.completeValue(reflect.New(arg.value.Type().Elem()), prefix, match)
+	}
+
+	return c.completeValue(arg.value, prefix, match)
+}
+
+func (c *completion) complete(args []string) []Completion {
+	if len(args) == 0 {
+		args = []string{""}
+	}
+
+	s := &parseState{
+		args: args,
+	}
+
+	c.parser.fillParseState(s)
+
+	var opt *Option
+
+	for len(s.args) > 1 {
+		arg := s.pop()
+
+		if (c.parser.Options&PassDoubleDash) != None && arg == "--" {
+			opt = nil
+			c.skipPositional(s, len(s.args)-1)
+
+			break
+		}
+
+		if argumentIsOption(arg) {
+			prefix, optname, islong := stripOptionPrefix(arg)
+			optname, _, argument := splitOption(prefix, optname, islong)
+
+			if argument == nil {
+				var o *Option
+				canarg := true
+
+				if islong {
+					o = s.lookup.longNames[optname]
+				} else {
+					for i, r := range optname {
+						sname := string(r)
+						o = s.lookup.shortNames[sname]
+
+						if o == nil {
+							break
+						}
+
+						if i == 0 && o.canArgument() && len(optname) != len(sname) {
+							canarg = false
+							break
+						}
+					}
+				}
+
+				if o == nil && (c.parser.Options&PassAfterNonOption) != None {
+					opt = nil
+					c.skipPositional(s, len(s.args)-1)
+
+					break
+				} else if o != nil && o.canArgument() && !o.OptionalArgument && canarg {
+					if len(s.args) > 1 {
+						s.pop()
+					} else {
+						opt = o
+					}
+				}
+			}
+		} else {
+			if len(s.positional) > 0 {
+				if !s.positional[0].isRemaining() {
+					// Don't advance beyond a remaining positional arg (because
+					// it consumes all subsequent args).
+					s.positional = s.positional[1:]
+				}
+			} else if cmd, ok := s.lookup.commands[arg]; ok {
+				cmd.fillParseState(s)
+			}
+
+			opt = nil
+		}
+	}
+
+	lastarg := s.args[len(s.args)-1]
+	var ret []Completion
+
+	if opt != nil {
+		// Completion for the argument of 'opt'
+		ret = c.completeValue(opt.value, "", lastarg)
+	} else if argumentStartsOption(lastarg) {
+		// Complete the option
+		prefix, optname, islong := stripOptionPrefix(lastarg)
+		optname, split, argument := splitOption(prefix, optname, islong)
+
+		if argument == nil && !islong {
+			rname, n := utf8.DecodeRuneInString(optname)
+			sname := string(rname)
+
+			if opt := s.lookup.shortNames[sname]; opt != nil && opt.canArgument() {
+				ret = c.completeValue(opt.value, prefix+sname, optname[n:])
+			} else {
+				ret = c.completeShortNames(s, prefix, optname)
+			}
+		} else if argument != nil {
+			if islong {
+				opt = s.lookup.longNames[optname]
+			} else {
+				opt = s.lookup.shortNames[optname]
+			}
+
+			if opt != nil {
+				ret = c.completeValue(opt.value, prefix+optname+split, *argument)
+			}
+		} else if islong {
+			ret = c.completeLongNames(s, prefix, optname)
+		} else {
+			ret = c.completeShortNames(s, prefix, optname)
+		}
+	} else if len(s.positional) > 0 {
+		// Complete for positional argument
+		ret = c.completeArg(s.positional[0], "", lastarg)
+	} else if len(s.command.commands) > 0 {
+		// Complete for command
+		ret = c.completeCommands(s, lastarg)
+	}
+
+	sort.Sort(completions(ret))
+	return ret
+}
+
+func (c *completion) print(items []Completion, showDescriptions bool) {
+	if showDescriptions && len(items) > 1 {
+		maxl := 0
+
+		for _, v := range items {
+			if len(v.Item) > maxl {
+				maxl = len(v.Item)
+			}
+		}
+
+		for _, v := range items {
+			fmt.Printf("%s", v.Item)
+
+			if len(v.Description) > 0 {
+				fmt.Printf("%s  # %s", strings.Repeat(" ", maxl-len(v.Item)), v.Description)
+			}
+
+			fmt.Printf("\n")
+		}
+	} else {
+		for _, v := range items {
+			fmt.Println(v.Item)
+		}
+	}
+}

vendor/github.com/jessevdk/go-flags/convert.go

@@ -0,0 +1,341 @@
+// Copyright 2012 Jesse van den Kieboom. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package flags
+
+import (
+	"fmt"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// Marshaler is the interface implemented by types that can marshal themselves
+// to a string representation of the flag.
+type Marshaler interface {
+	// MarshalFlag marshals a flag value to its string representation.
+	MarshalFlag() (string, error)
+}
+
+// Unmarshaler is the interface implemented by types that can unmarshal a flag
+// argument to themselves. The provided value is directly passed from the
+// command line.
+type Unmarshaler interface {
+	// UnmarshalFlag unmarshals a string value representation to the flag
+	// value (which therefore needs to be a pointer receiver).
+	UnmarshalFlag(value string) error
+}
+
+func getBase(options multiTag, base int) (int, error) {
+	sbase := options.Get("base")
+
+	var err error
+	var ivbase int64
+
+	if sbase != "" {
+		ivbase, err = strconv.ParseInt(sbase, 10, 32)
+		base = int(ivbase)
+	}
+
+	return base, err
+}
+
+func convertMarshal(val reflect.Value) (bool, string, error) {
+	// Check first for the Marshaler interface
+	if val.Type().NumMethod() > 0 && val.CanInterface() {
+		if marshaler, ok := val.Interface().(Marshaler); ok {
+			ret, err := marshaler.MarshalFlag()
+			return true, ret, err
+		}
+	}
+
+	return false, "", nil
+}
+
+func convertToString(val reflect.Value, options multiTag) (string, error) {
+	if ok, ret, err := convertMarshal(val); ok {
+		return ret, err
+	}
+
+	tp := val.Type()
+
+	// Support for time.Duration
+	if tp == reflect.TypeOf((*time.Duration)(nil)).Elem() {
+		stringer := val.Interface().(fmt.Stringer)
+		return stringer.String(), nil
+	}
+
+	switch tp.Kind() {
+	case reflect.String:
+		return val.String(), nil
+	case reflect.Bool:
+		if val.Bool() {
+			return "true", nil
+		}
+
+		return "false", nil
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		base, err := getBase(options, 10)
+
+		if err != nil {
+			return "", err
+		}
+
+		return strconv.FormatInt(val.Int(), base), nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		base, err := getBase(options, 10)
+
+		if err != nil {
+			return "", err
+		}
+
+		return strconv.FormatUint(val.Uint(), base), nil
+	case reflect.Float32, reflect.Float64:
+		return strconv.FormatFloat(val.Float(), 'g', -1, tp.Bits()), nil
+	case reflect.Slice:
+		if val.Len() == 0 {
+			return "", nil
+		}
+
+		ret := "["
+
+		for i := 0; i < val.Len(); i++ {
+			if i != 0 {
+				ret += ", "
+			}
+
+			item, err := convertToString(val.Index(i), options)
+
+			if err != nil {
+				return "", err
+			}
+
+			ret += item
+		}
+
+		return ret + "]", nil
+	case reflect.Map:
+		ret := "{"
+
+		for i, key := range val.MapKeys() {
+			if i != 0 {
+				ret += ", "
+			}
+
+			keyitem, err := convertToString(key, options)
+
+			if err != nil {
+				return "", err
+			}
+
+			item, err := convertToString(val.MapIndex(key), options)
+
+			if err != nil {
+				return "", err
+			}
+
+			ret += keyitem + ":" + item
+		}
+
+		return ret + "}", nil
+	case reflect.Ptr:
+		return convertToString(reflect.Indirect(val), options)
+	case reflect.Interface:
+		if !val.IsNil() {
+			return convertToString(val.Elem(), options)
+		}
+	}
+
+	return "", nil
+}
+
+func convertUnmarshal(val string, retval reflect.Value) (bool, error) {
+	if retval.Type().NumMethod() > 0 && retval.CanInterface() {
+		if unmarshaler, ok := retval.Interface().(Unmarshaler); ok {
+			return true, unmarshaler.UnmarshalFlag(val)
+		}
+	}
+
+	if retval.Type().Kind() != reflect.Ptr && retval.CanAddr() {
+		return convertUnmarshal(val, retval.Addr())
+	}
+
+	if retval.Type().Kind() == reflect.Interface && !retval.IsNil() {
+		return convertUnmarshal(val, retval.Elem())
+	}
+
+	return false, nil
+}
+
+func convert(val string, retval reflect.Value, options multiTag) error {
+	if ok, err := convertUnmarshal(val, retval); ok {
+		return err
+	}
+
+	tp := retval.Type()
+
+	// Support for time.Duration
+	if tp == reflect.TypeOf((*time.Duration)(nil)).Elem() {
+		parsed, err := time.ParseDuration(val)
+
+		if err != nil {
+			return err
+		}
+
+		retval.SetInt(int64(parsed))
+		return nil
+	}
+
+	switch tp.Kind() {
+	case reflect.String:
+		retval.SetString(val)
+	case reflect.Bool:
+		if val == "" {
+			retval.SetBool(true)
+		} else {
+			b, err := strconv.ParseBool(val)
+
+			if err != nil {
+				return err
+			}
+
+			retval.SetBool(b)
+		}
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		base, err := getBase(options, 10)
+
+		if err != nil {
+			return err
+		}
+
+		parsed, err := strconv.ParseInt(val, base, tp.Bits())
+
+		if err != nil {
+			return err
+		}
+
+		retval.SetInt(parsed)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		base, err := getBase(options, 10)
+
+		if err != nil {
+			return err
+		}
+
+		parsed, err := strconv.ParseUint(val, base, tp.Bits())
+
+		if err != nil {
+			return err
+		}
+
+		retval.SetUint(parsed)
+	case reflect.Float32, reflect.Float64:
+		parsed, err := strconv.ParseFloat(val, tp.Bits())
+
+		if err != nil {
+			return err
+		}
+
+		retval.SetFloat(parsed)
+	case reflect.Slice:
+		elemtp := tp.Elem()
+
+		elemvalptr := reflect.New(elemtp)
+		elemval := reflect.Indirect(elemvalptr)
+
+		if err := convert(val, elemval, options); err != nil {
+			return err
+		}
+
+		retval.Set(reflect.Append(retval, elemval))
+	case reflect.Map:
+		parts := strings.SplitN(val, ":", 2)
+
+		key := parts[0]
+		var value string
+
+		if len(parts) == 2 {
+			value = parts[1]
+		}
+
+		keytp := tp.Key()
+		keyval := reflect.New(keytp)
+
+		if err := convert(key, keyval, options); err != nil {
+			return err
+		}
+
+		valuetp := tp.Elem()
+		valueval := reflect.New(valuetp)
+
+		if err := convert(value, valueval, options); err != nil {
+			return err
+		}
+
+		if retval.IsNil() {
+			retval.Set(reflect.MakeMap(tp))
+		}
+
+		retval.SetMapIndex(reflect.Indirect(keyval), reflect.Indirect(valueval))
+	case reflect.Ptr:
+		if retval.IsNil() {
+			retval.Set(reflect.New(retval.Type().Elem()))
+		}
+
+		return convert(val, reflect.Indirect(retval), options)
+	case reflect.Interface:
+		if !retval.IsNil() {
+			return convert(val, retval.Elem(), options)
+		}
+	}
+
+	return nil
+}
+
+func isPrint(s string) bool {
+	for _, c := range s {
+		if !strconv.IsPrint(c) {
+			return false
+		}
+	}
+
+	return true
+}
+
+func quoteIfNeeded(s string) string {
+	if !isPrint(s) {
+		return strconv.Quote(s)
+	}
+
+	return s
+}
+
+func quoteIfNeededV(s []string) []string {
+	ret := make([]string, len(s))
+
+	for i, v := range s {
+		ret[i] = quoteIfNeeded(v)
+	}
+
+	return ret
+}
+
+func quoteV(s []string) []string {
+	ret := make([]string, len(s))
+
+	for i, v := range s {
+		ret[i] = strconv.Quote(v)
+	}
+
+	return ret
+}
+
+func unquoteIfPossible(s string) (string, error) {
+	if len(s) == 0 || s[0] != '"' {
+		return s, nil
+	}
+
+	return strconv.Unquote(s)
+}

vendor/github.com/jessevdk/go-flags/error.go

@@ -0,0 +1,134 @@
+package flags
+
+import (
+	"fmt"
+)
+
+// ErrorType represents the type of error.
+type ErrorType uint
+
+const (
+	// ErrUnknown indicates a generic error.
+	ErrUnknown ErrorType = iota
+
+	// ErrExpectedArgument indicates that an argument was expected.
+	ErrExpectedArgument
+
+	// ErrUnknownFlag indicates an unknown flag.
+	ErrUnknownFlag
+
+	// ErrUnknownGroup indicates an unknown group.
+	ErrUnknownGroup
+
+	// ErrMarshal indicates a marshalling error while converting values.
+	ErrMarshal
+
+	// ErrHelp indicates that the built-in help was shown (the error
+	// contains the help message).
+	ErrHelp
+
+	// ErrNoArgumentForBool indicates that an argument was given for a
+	// boolean flag (which don't not take any arguments).
+	ErrNoArgumentForBool
+
+	// ErrRequired indicates that a required flag was not provided.
+	ErrRequired
+
+	// ErrShortNameTooLong indicates that a short flag name was specified,
+	// longer than one character.
+	ErrShortNameTooLong
+
+	// ErrDuplicatedFlag indicates that a short or long flag has been
+	// defined more than once
+	ErrDuplicatedFlag
+
+	// ErrTag indicates an error while parsing flag tags.
+	ErrTag
+
+	// ErrCommandRequired indicates that a command was required but not
+	// specified
+	ErrCommandRequired
+
+	// ErrUnknownCommand indicates that an unknown command was specified.
+	ErrUnknownCommand
+
+	// ErrInvalidChoice indicates an invalid option value which only allows
+	// a certain number of choices.
+	ErrInvalidChoice
+
+	// ErrInvalidTag indicates an invalid tag or invalid use of an existing tag
+	ErrInvalidTag
+)
+
+func (e ErrorType) String() string {
+	switch e {
+	case ErrUnknown:
+		return "unknown"
+	case ErrExpectedArgument:
+		return "expected argument"
+	case ErrUnknownFlag:
+		return "unknown flag"
+	case ErrUnknownGroup:
+		return "unknown group"
+	case ErrMarshal:
+		return "marshal"
+	case ErrHelp:
+		return "help"
+	case ErrNoArgumentForBool:
+		return "no argument for bool"
+	case ErrRequired:
+		return "required"
+	case ErrShortNameTooLong:
+		return "short name too long"
+	case ErrDuplicatedFlag:
+		return "duplicated flag"
+	case ErrTag:
+		return "tag"
+	case ErrCommandRequired:
+		return "command required"
+	case ErrUnknownCommand:
+		return "unknown command"
+	case ErrInvalidChoice:
+		return "invalid choice"
+	case ErrInvalidTag:
+		return "invalid tag"
+	}
+
+	return "unrecognized error type"
+}
+
+// Error represents a parser error. The error returned from Parse is of this
+// type. The error contains both a Type and Message.
+type Error struct {
+	// The type of error
+	Type ErrorType
+
+	// The error message
+	Message string
+}
+
+// Error returns the error's message
+func (e *Error) Error() string {
+	return e.Message
+}
+
+func newError(tp ErrorType, message string) *Error {
+	return &Error{
+		Type:    tp,
+		Message: message,
+	}
+}
+
+func newErrorf(tp ErrorType, format string, args ...interface{}) *Error {
+	return newError(tp, fmt.Sprintf(format, args...))
+}
+
+func wrapError(err error) *Error {
+	ret, ok := err.(*Error)
+
+	if !ok {
+		return newError(ErrUnknown, err.Error())
+	}
+
+	return ret
+}

vendor/github.com/jessevdk/go-flags/flags.go

@@ -0,0 +1,256 @@
+// Copyright 2012 Jesse van den Kieboom. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package flags provides an extensive command line option parser.
+The flags package is similar in functionality to the go built-in flag package
+but provides more options and uses reflection to provide a convenient and
+succinct way of specifying command line options.
+
+
+Supported features
+
+The following features are supported in go-flags:
+
+    Options with short names (-v)
+    Options with long names (--verbose)
+    Options with and without arguments (bool v.s. other type)
+    Options with optional arguments and default values
+    Option default values from ENVIRONMENT_VARIABLES, including slice and map values
+    Multiple option groups each containing a set of options
+    Generate and print well-formatted help message
+    Passing remaining command line arguments after -- (optional)
+    Ignoring unknown command line options (optional)
+    Supports -I/usr/include -I=/usr/include -I /usr/include option argument specification
+    Supports multiple short options -aux
+    Supports all primitive go types (string, int{8..64}, uint{8..64}, float)
+    Supports same option multiple times (can store in slice or last option counts)
+    Supports maps
+    Supports function callbacks
+    Supports namespaces for (nested) option groups
+
+Additional features specific to Windows:
+    Options with short names (/v)
+    Options with long names (/verbose)
+    Windows-style options with arguments use a colon as the delimiter
+    Modify generated help message with Windows-style / options
+
+
+Basic usage
+
+The flags package uses structs, reflection and struct field tags
+to allow users to specify command line options. This results in very simple
+and concise specification of your application options. For example:
+
+    type Options struct {
+        Verbose []bool `short:"v" long:"verbose" description:"Show verbose debug information"`
+    }
+
+This specifies one option with a short name -v and a long name --verbose.
+When either -v or --verbose is found on the command line, a 'true' value
+will be appended to the Verbose field. e.g. when specifying -vvv, the
+resulting value of Verbose will be {[true, true, true]}.
+
+Slice options work exactly the same as primitive type options, except that
+whenever the option is encountered, a value is appended to the slice.
+
+Map options from string to primitive type are also supported. On the command
+line, you specify the value for such an option as key:value. For example
+
+    type Options struct {
+        AuthorInfo string[string] `short:"a"`
+    }
+
+Then, the AuthorInfo map can be filled with something like
+-a name:Jesse -a "surname:van den Kieboom".
+
+Finally, for full control over the conversion between command line argument
+values and options, user defined types can choose to implement the Marshaler
+and Unmarshaler interfaces.
+
+
+Available field tags
+
+The following is a list of tags for struct fields supported by go-flags:
+
+    short:            the short name of the option (single character)
+    long:             the long name of the option
+    required:         whether an option is required to appear on the command
+                      line. If a required option is not present, the parser will
+                      return ErrRequired (optional)
+    description:      the description of the option (optional)
+    long-description: the long description of the option. Currently only
+                      displayed in generated man pages (optional)
+    no-flag:          if non-empty this field is ignored as an option (optional)
+
+    optional:       whether an argument of the option is optional. When an
+                    argument is optional it can only be specified using
+                    --option=argument (optional)
+    optional-value: the value of an optional option when the option occurs
+                    without an argument. This tag can be specified multiple
+                    times in the case of maps or slices (optional)
+    default:        the default value of an option. This tag can be specified
+                    multiple times in the case of slices or maps (optional)
+    default-mask:   when specified, this value will be displayed in the help
+                    instead of the actual default value. This is useful
+                    mostly for hiding otherwise sensitive information from
+                    showing up in the help. If default-mask takes the special
+                    value "-", then no default value will be shown at all
+                    (optional)
+    env:            the default value of the option is overridden from the
+                    specified environment variable, if one has been defined.
+                    (optional)
+    env-delim:      the 'env' default value from environment is split into
+                    multiple values with the given delimiter string, use with
+                    slices and maps (optional)
+    value-name:     the name of the argument value (to be shown in the help)
+                    (optional)
+    choice:         limits the values for an option to a set of values.
+                    This tag can be specified mltiple times (optional)
+    hidden:         the option is not visible in the help or man page.
+
+    base: a base (radix) used to convert strings to integer values, the
+          default base is 10 (i.e. decimal) (optional)
+
+    ini-name:       the explicit ini option name (optional)
+    no-ini:         if non-empty this field is ignored as an ini option
+                    (optional)
+
+    group:                when specified on a struct field, makes the struct
+                          field a separate group with the given name (optional)
+    namespace:            when specified on a group struct field, the namespace
+                          gets prepended to every option's long name and
+                          subgroup's namespace of this group, separated by
+                          the parser's namespace delimiter (optional)
+    command:              when specified on a struct field, makes the struct
+                          field a (sub)command with the given name (optional)
+    subcommands-optional: when specified on a command struct field, makes
+                          any subcommands of that command optional (optional)
+    alias:                when specified on a command struct field, adds the
+                          specified name as an alias for the command. Can be
+                          be specified multiple times to add more than one
+                          alias (optional)
+    positional-args:      when specified on a field with a struct type,
+                          uses the fields of that struct to parse remaining
+                          positional command line arguments into (in order
+                          of the fields). If a field has a slice type,
+                          then all remaining arguments will be added to it.
+                          Positional arguments are optional by default,
+                          unless the "required" tag is specified together
+                          with the "positional-args" tag. The "required" tag
+                          can also be set on the individual rest argument
+                          fields, to require only the first N positional
+                          arguments. If the "required" tag is set on the
+                          rest arguments slice, then its value determines
+                          the minimum amount of rest arguments that needs to
+                          be provided (e.g. `required:"2"`) (optional)
+    positional-arg-name:  used on a field in a positional argument struct; name
+                          of the positional argument placeholder to be shown in
+                          the help (optional)
+
+Either the `short:` tag or the `long:` must be specified to make the field eligible as an
+option.
+
+
+Option groups
+
+Option groups are a simple way to semantically separate your options. All
+options in a particular group are shown together in the help under the name
+of the group. Namespaces can be used to specify option long names more
+precisely and emphasize the options affiliation to their group.
+
+There are currently three ways to specify option groups.
+
+    1. Use NewNamedParser specifying the various option groups.
+    2. Use AddGroup to add a group to an existing parser.
+    3. Add a struct field to the top-level options annotated with the
+       group:"group-name" tag.
+
+
+
+Commands
+
+The flags package also has basic support for commands. Commands are often
+used in monolithic applications that support various commands or actions.
+Take git for example, all of the add, commit, checkout, etc. are called
+commands. Using commands you can easily separate multiple functions of your
+application.
+
+There are currently two ways to specify a command.
+
+    1. Use AddCommand on an existing parser.
+    2. Add a struct field to your options struct annotated with the
+       command:"command-name" tag.
+
+The most common, idiomatic way to implement commands is to define a global
+parser instance and implement each command in a separate file. These
+command files should define a go init function which calls AddCommand on
+the global parser.
+
+When parsing ends and there is an active command and that command implements
+the Commander interface, then its Execute method will be run with the
+remaining command line arguments.
+
+Command structs can have options which become valid to parse after the
+command has been specified on the command line, in addition to the options
+of all the parent commands. I.e. considering a -v flag on the parser and an
+add command, the following are equivalent:
+
+    ./app -v add
+    ./app add -v
+
+However, if the -v flag is defined on the add command, then the first of
+the two examples above would fail since the -v flag is not defined before
+the add command.
+
+
+Completion
+
+go-flags has builtin support to provide bash completion of flags, commands
+and argument values. To use completion, the binary which uses go-flags
+can be invoked in a special environment to list completion of the current
+command line argument. It should be noted that this `executes` your application,
+and it is up to the user to make sure there are no negative side effects (for
+example from init functions).
+
+Setting the environment variable `GO_FLAGS_COMPLETION=1` enables completion
+by replacing the argument parsing routine with the completion routine which
+outputs completions for the passed arguments. The basic invocation to
+complete a set of arguments is therefore:
+
+    GO_FLAGS_COMPLETION=1 ./completion-example arg1 arg2 arg3
+
+where `completion-example` is the binary, `arg1` and `arg2` are
+the current arguments, and `arg3` (the last argument) is the argument
+to be completed. If the GO_FLAGS_COMPLETION is set to "verbose", then
+descriptions of possible completion items will also be shown, if there
+are more than 1 completion items.
+
+To use this with bash completion, a simple file can be written which
+calls the binary which supports go-flags completion:
+
+    _completion_example() {
+        # All arguments except the first one
+        args=("${COMP_WORDS[@]:1:$COMP_CWORD}")
+
+        # Only split on newlines
+        local IFS=$'\n'
+
+        # Call completion (note that the first element of COMP_WORDS is
+        # the executable itself)
+        COMPREPLY=($(GO_FLAGS_COMPLETION=1 ${COMP_WORDS[0]} "${args[@]}"))
+        return 0
+    }
+
+    complete -F _completion_example completion-example
+
+Completion requires the parser option PassDoubleDash and is therefore enforced if the environment variable GO_FLAGS_COMPLETION is set.
+
+Customized completion for argument values is supported by implementing
+the flags.Completer interface for the argument value type. An example
+of a type which does so is the flags.Filename type, an alias of string
+allowing simple filename completion. A slice or array argument value
+whose element type implements flags.Completer will also be completed.
+*/
+package flags

vendor/github.com/jessevdk/go-flags/group.go

@@ -0,0 +1,385 @@
+// Copyright 2012 Jesse van den Kieboom. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package flags
+
+import (
+	"errors"
+	"reflect"
+	"strings"
+	"unicode/utf8"
+	"unsafe"
+)
+
+// ErrNotPointerToStruct indicates that a provided data container is not
+// a pointer to a struct. Only pointers to structs are valid data containers
+// for options.
+var ErrNotPointerToStruct = errors.New("provided data is not a pointer to struct")
+
+// Group represents an option group. Option groups can be used to logically
+// group options together under a description. Groups are only used to provide
+// more structure to options both for the user (as displayed in the help message)
+// and for you, since groups can be nested.
+type Group struct {
+	// A short description of the group. The
+	// short description is primarily used in the built-in generated help
+	// message
+	ShortDescription string
+
+	// A long description of the group. The long
+	// description is primarily used to present information on commands
+	// (Command embeds Group) in the built-in generated help and man pages.
+	LongDescription string
+
+	// The namespace of the group
+	Namespace string
+
+	// If true, the group is not displayed in the help or man page
+	Hidden bool
+
+	// The parent of the group or nil if it has no parent
+	parent interface{}
+
+	// All the options in the group
+	options []*Option
+
+	// All the subgroups
+	groups []*Group
+
+	// Whether the group represents the built-in help group
+	isBuiltinHelp bool
+
+	data interface{}
+}
+
+type scanHandler func(reflect.Value, *reflect.StructField) (bool, error)
+
+// AddGroup adds a new group to the command with the given name and data. The
+// data needs to be a pointer to a struct from which the fields indicate which
+// options are in the group.
+func (g *Group) AddGroup(shortDescription string, longDescription string, data interface{}) (*Group, error) {
+	group := newGroup(shortDescription, longDescription, data)
+
+	group.parent = g
+
+	if err := group.scan(); err != nil {
+		return nil, err
+	}
+
+	g.groups = append(g.groups, group)
+	return group, nil
+}
+
+// Groups returns the list of groups embedded in this group.
+func (g *Group) Groups() []*Group {
+	return g.groups
+}
+
+// Options returns the list of options in this group.
+func (g *Group) Options() []*Option {
+	return g.options
+}
+
+// Find locates the subgroup with the given short description and returns it.
+// If no such group can be found Find will return nil. Note that the description
+// is matched case insensitively.
+func (g *Group) Find(shortDescription string) *Group {
+	lshortDescription := strings.ToLower(shortDescription)
+
+	var ret *Group
+
+	g.eachGroup(func(gg *Group) {
+		if gg != g && strings.ToLower(gg.ShortDescription) == lshortDescription {
+			ret = gg
+		}
+	})
+
+	return ret
+}
+
+func (g *Group) findOption(matcher func(*Option) bool) (option *Option) {
+	g.eachGroup(func(g *Group) {
+		for _, opt := range g.options {
+			if option == nil && matcher(opt) {
+				option = opt
+			}
+		}
+	})
+
+	return option
+}
+
+// FindOptionByLongName finds an option that is part of the group, or any of its
+// subgroups, by matching its long name (including the option namespace).
+func (g *Group) FindOptionByLongName(longName string) *Option {
+	return g.findOption(func(option *Option) bool {
+		return option.LongNameWithNamespace() == longName
+	})
+}
+
+// FindOptionByShortName finds an option that is part of the group, or any of
+// its subgroups, by matching its short name.
+func (g *Group) FindOptionByShortName(shortName rune) *Option {
+	return g.findOption(func(option *Option) bool {
+		return option.ShortName == shortName
+	})
+}
+
+func newGroup(shortDescription string, longDescription string, data interface{}) *Group {
+	return &Group{
+		ShortDescription: shortDescription,
+		LongDescription:  longDescription,
+
+		data: data,
+	}
+}
+
+func (g *Group) optionByName(name string, namematch func(*Option, string) bool) *Option {
+	prio := 0
+	var retopt *Option
+
+	g.eachGroup(func(g *Group) {
+		for _, opt := range g.options {
+			if namematch != nil && namematch(opt, name) && prio < 4 {
+				retopt = opt
+				prio = 4
+			}
+
+			if name == opt.field.Name && prio < 3 {
+				retopt = opt
+				prio = 3
+			}
+
+			if name == opt.LongNameWithNamespace() && prio < 2 {
+				retopt = opt
+				prio = 2
+			}
+
+			if opt.ShortName != 0 && name == string(opt.ShortName) && prio < 1 {
+				retopt = opt
+				prio = 1
+			}
+		}
+	})
+
+	return retopt
+}
+
+func (g *Group) eachGroup(f func(*Group)) {
+	f(g)
+
+	for _, gg := range g.groups {
+		gg.eachGroup(f)
+	}
+}
+
+func (g *Group) scanStruct(realval reflect.Value, sfield *reflect.StructField, handler scanHandler) error {
+	stype := realval.Type()
+
+	if sfield != nil {
+		if ok, err := handler(realval, sfield); err != nil {
+			return err
+		} else if ok {
+			return nil
+		}
+	}
+
+	for i := 0; i < stype.NumField(); i++ {
+		field := stype.Field(i)
+
+		// PkgName is set only for non-exported fields, which we ignore
+		if field.PkgPath != "" && !field.Anonymous {
+			continue
+		}
+
+		mtag := newMultiTag(string(field.Tag))
+
+		if err := mtag.Parse(); err != nil {
+			return err
+		}
+
+		// Skip fields with the no-flag tag
+		if mtag.Get("no-flag") != "" {
+			continue
+		}
+
+		// Dive deep into structs or pointers to structs
+		kind := field.Type.Kind()
+		fld := realval.Field(i)
+
+		if kind == reflect.Struct {
+			if err := g.scanStruct(fld, &field, handler); err != nil {
+				return err
+			}
+		} else if kind == reflect.Ptr && field.Type.Elem().Kind() == reflect.Struct {
+			if fld.IsNil() {
+				fld.Set(reflect.New(fld.Type().Elem()))
+			}
+
+			if err := g.scanStruct(reflect.Indirect(fld), &field, handler); err != nil {
+				return err
+			}
+		}
+
+		longname := mtag.Get("long")
+		shortname := mtag.Get("short")
+
+		// Need at least either a short or long name
+		if longname == "" && shortname == "" && mtag.Get("ini-name") == "" {
+			continue
+		}
+
+		short := rune(0)
+		rc := utf8.RuneCountInString(shortname)
+
+		if rc > 1 {
+			return newErrorf(ErrShortNameTooLong,
+				"short names can only be 1 character long, not `%s'",
+				shortname)
+
+		} else if rc == 1 {
+			short, _ = utf8.DecodeRuneInString(shortname)
+		}
+
+		description := mtag.Get("description")
+		def := mtag.GetMany("default")
+
+		optionalValue := mtag.GetMany("optional-value")
+		valueName := mtag.Get("value-name")
+		defaultMask := mtag.Get("default-mask")
+
+		optional := (mtag.Get("optional") != "")
+		required := (mtag.Get("required") != "")
+		choices := mtag.GetMany("choice")
+		hidden := (mtag.Get("hidden") != "")
+
+		option := &Option{
+			Description:      description,
+			ShortName:        short,
+			LongName:         longname,
+			Default:          def,
+			EnvDefaultKey:    mtag.Get("env"),
+			EnvDefaultDelim:  mtag.Get("env-delim"),
+			OptionalArgument: optional,
+			OptionalValue:    optionalValue,
+			Required:         required,
+			ValueName:        valueName,
+			DefaultMask:      defaultMask,
+			Choices:          choices,
+			Hidden:           hidden,
+
+			group: g,
+
+			field: field,
+			value: realval.Field(i),
+			tag:   mtag,
+		}
+
+		if option.isBool() && option.Default != nil {
+			return newErrorf(ErrInvalidTag,
+				"boolean flag `%s' may not have default values, they always default to `false' and can only be turned on",
+				option.shortAndLongName())
+		}
+
+		g.options = append(g.options, option)
+	}
+
+	return nil
+}
+
+func (g *Group) checkForDuplicateFlags() *Error {
+	shortNames := make(map[rune]*Option)
+	longNames := make(map[string]*Option)
+
+	var duplicateError *Error
+
+	g.eachGroup(func(g *Group) {
+		for _, option := range g.options {
+			if option.LongName != "" {
+				longName := option.LongNameWithNamespace()
+
+				if otherOption, ok := longNames[longName]; ok {
+					duplicateError = newErrorf(ErrDuplicatedFlag, "option `%s' uses the same long name as option `%s'", option, otherOption)
+					return
+				}
+				longNames[longName] = option
+			}
+			if option.ShortName != 0 {
+				if otherOption, ok := shortNames[option.ShortName]; ok {
+					duplicateError = newErrorf(ErrDuplicatedFlag, "option `%s' uses the same short name as option `%s'", option, otherOption)
+					return
+				}
+				shortNames[option.ShortName] = option
+			}
+		}
+	})
+
+	return duplicateError
+}
+
+func (g *Group) scanSubGroupHandler(realval reflect.Value, sfield *reflect.StructField) (bool, error) {
+	mtag := newMultiTag(string(sfield.Tag))
+
+	if err := mtag.Parse(); err != nil {
+		return true, err
+	}
+
+	subgroup := mtag.Get("group")
+
+	if len(subgroup) != 0 {
+		ptrval := reflect.NewAt(realval.Type(), unsafe.Pointer(realval.UnsafeAddr()))
+		description := mtag.Get("description")
+
+		group, err := g.AddGroup(subgroup, description, ptrval.Interface())
+		if err != nil {
+			return true, err
+		}
+
+		group.Namespace = mtag.Get("namespace")
+		group.Hidden = mtag.Get("hidden") != ""
+
+		return true, nil
+	}
+
+	return false, nil
+}
+
+func (g *Group) scanType(handler scanHandler) error {
+	// Get all the public fields in the data struct
+	ptrval := reflect.ValueOf(g.data)
+
+	if ptrval.Type().Kind() != reflect.Ptr {
+		panic(ErrNotPointerToStruct)
+	}
+
+	stype := ptrval.Type().Elem()
+
+	if stype.Kind() != reflect.Struct {
+		panic(ErrNotPointerToStruct)
+	}
+
+	realval := reflect.Indirect(ptrval)
+
+	if err := g.scanStruct(realval, nil, handler); err != nil {
+		return err
+	}
+
+	if err := g.checkForDuplicateFlags(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (g *Group) scan() error {
+	return g.scanType(g.scanSubGroupHandler)
+}
+
+func (g *Group) groupByName(name string) *Group {
+	if len(name) == 0 {
+		return g
+	}
+
+	return g.Find(name)
+}

vendor/github.com/jessevdk/go-flags/help.go

@@ -0,0 +1,485 @@
+// Copyright 2012 Jesse van den Kieboom. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package flags
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"runtime"
+	"strings"
+	"unicode/utf8"
+)
+
+type alignmentInfo struct {
+	maxLongLen      int
+	hasShort        bool
+	hasValueName    bool
+	terminalColumns int
+	indent          bool
+}
+
+const (
+	paddingBeforeOption                 = 2
+	distanceBetweenOptionAndDescription = 2
+)
+
+func (a *alignmentInfo) descriptionStart() int {
+	ret := a.maxLongLen + distanceBetweenOptionAndDescription
+
+	if a.hasShort {
+		ret += 2
+	}
+
+	if a.maxLongLen > 0 {
+		ret += 4
+	}
+
+	if a.hasValueName {
+		ret += 3
+	}
+
+	return ret
+}
+
+func (a *alignmentInfo) updateLen(name string, indent bool) {
+	l := utf8.RuneCountInString(name)
+
+	if indent {
+		l = l + 4
+	}
+
+	if l > a.maxLongLen {
+		a.maxLongLen = l
+	}
+}
+
+func (p *Parser) getAlignmentInfo() alignmentInfo {
+	ret := alignmentInfo{
+		maxLongLen:      0,
+		hasShort:        false,
+		hasValueName:    false,
+		terminalColumns: getTerminalColumns(),
+	}
+
+	if ret.terminalColumns <= 0 {
+		ret.terminalColumns = 80
+	}
+
+	var prevcmd *Command
+
+	p.eachActiveGroup(func(c *Command, grp *Group) {
+		if c != prevcmd {
+			for _, arg := range c.args {
+				ret.updateLen(arg.Name, c != p.Command)
+			}
+		}
+
+		for _, info := range grp.options {
+			if !info.canCli() {
+				continue
+			}
+
+			if info.ShortName != 0 {
+				ret.hasShort = true
+			}
+
+			if len(info.ValueName) > 0 {
+				ret.hasValueName = true
+			}
+
+			l := info.LongNameWithNamespace() + info.ValueName
+
+			if len(info.Choices) != 0 {
+				l += "[" + strings.Join(info.Choices, "|") + "]"
+			}
+
+			ret.updateLen(l, c != p.Command)
+		}
+	})
+
+	return ret
+}
+
+func wrapText(s string, l int, prefix string) string {
+	var ret string
+
+	// Basic text wrapping of s at spaces to fit in l
+	lines := strings.Split(s, "\n")
+
+	for _, line := range lines {
+		var retline string
+
+		line = strings.TrimSpace(line)
+
+		for len(line) > l {
+			// Try to split on space
+			suffix := ""
+
+			pos := strings.LastIndex(line[:l], " ")
+
+			if pos < 0 {
+				pos = l - 1
+				suffix = "-\n"
+			}
+
+			if len(retline) != 0 {
+				retline += "\n" + prefix
+			}
+
+			retline += strings.TrimSpace(line[:pos]) + suffix
+			line = strings.TrimSpace(line[pos:])
+		}
+
+		if len(line) > 0 {
+			if len(retline) != 0 {
+				retline += "\n" + prefix
+			}
+
+			retline += line
+		}
+
+		if len(ret) > 0 {
+			ret += "\n"
+
+			if len(retline) > 0 {
+				ret += prefix
+			}
+		}
+
+		ret += retline
+	}
+
+	return ret
+}
+
+func (p *Parser) writeHelpOption(writer *bufio.Writer, option *Option, info alignmentInfo) {
+	line := &bytes.Buffer{}
+
+	prefix := paddingBeforeOption
+
+	if info.indent {
+		prefix += 4
+	}
+
+	if option.Hidden {
+		return
+	}
+
+	line.WriteString(strings.Repeat(" ", prefix))
+
+	if option.ShortName != 0 {
+		line.WriteRune(defaultShortOptDelimiter)
+		line.WriteRune(option.ShortName)
+	} else if info.hasShort {
+		line.WriteString("  ")
+	}
+
+	descstart := info.descriptionStart() + paddingBeforeOption
+
+	if len(option.LongName) > 0 {
+		if option.ShortName != 0 {
+			line.WriteString(", ")
+		} else if info.hasShort {
+			line.WriteString("  ")
+		}
+
+		line.WriteString(defaultLongOptDelimiter)
+		line.WriteString(option.LongNameWithNamespace())
+	}
+
+	if option.canArgument() {
+		line.WriteRune(defaultNameArgDelimiter)
+
+		if len(option.ValueName) > 0 {
+			line.WriteString(option.ValueName)
+		}
+
+		if len(option.Choices) > 0 {
+			line.WriteString("[" + strings.Join(option.Choices, "|") + "]")
+		}
+	}
+
+	written := line.Len()
+	line.WriteTo(writer)
+
+	if option.Description != "" {
+		dw := descstart - written
+		writer.WriteString(strings.Repeat(" ", dw))
+
+		var def string
+
+		if len(option.DefaultMask) != 0 && option.DefaultMask != "-" {
+			def = option.DefaultMask
+		} else {
+			def = option.defaultLiteral
+		}
+
+		var envDef string
+		if option.EnvDefaultKey != "" {
+			var envPrintable string
+			if runtime.GOOS == "windows" {
+				envPrintable = "%" + option.EnvDefaultKey + "%"
+			} else {
+				envPrintable = "$" + option.EnvDefaultKey
+			}
+			envDef = fmt.Sprintf(" [%s]", envPrintable)
+		}
+
+		var desc string
+
+		if def != "" {
+			desc = fmt.Sprintf("%s (default: %v)%s", option.Description, def, envDef)
+		} else {
+			desc = option.Description + envDef
+		}
+
+		writer.WriteString(wrapText(desc,
+			info.terminalColumns-descstart,
+			strings.Repeat(" ", descstart)))
+	}
+
+	writer.WriteString("\n")
+}
+
+func maxCommandLength(s []*Command) int {
+	if len(s) == 0 {
+		return 0
+	}
+
+	ret := len(s[0].Name)
+
+	for _, v := range s[1:] {
+		l := len(v.Name)
+
+		if l > ret {
+			ret = l
+		}
+	}
+
+	return ret
+}
+
+// WriteHelp writes a help message containing all the possible options and
+// their descriptions to the provided writer. Note that the HelpFlag parser
+// option provides a convenient way to add a -h/--help option group to the
+// command line parser which will automatically show the help messages using
+// this method.
+func (p *Parser) WriteHelp(writer io.Writer) {
+	if writer == nil {
+		return
+	}
+
+	wr := bufio.NewWriter(writer)
+	aligninfo := p.getAlignmentInfo()
+
+	cmd := p.Command
+
+	for cmd.Active != nil {
+		cmd = cmd.Active
+	}
+
+	if p.Name != "" {
+		wr.WriteString("Usage:\n")
+		wr.WriteString(" ")
+
+		allcmd := p.Command
+
+		for allcmd != nil {
+			var usage string
+
+			if allcmd == p.Command {
+				if len(p.Usage) != 0 {
+					usage = p.Usage
+				} else if p.Options&HelpFlag != 0 {
+					usage = "[OPTIONS]"
+				}
+			} else if us, ok := allcmd.data.(Usage); ok {
+				usage = us.Usage()
+			} else if allcmd.hasCliOptions() {
+				usage = fmt.Sprintf("[%s-OPTIONS]", allcmd.Name)
+			}
+
+			if len(usage) != 0 {
+				fmt.Fprintf(wr, " %s %s", allcmd.Name, usage)
+			} else {
+				fmt.Fprintf(wr, " %s", allcmd.Name)
+			}
+
+			if len(allcmd.args) > 0 {
+				fmt.Fprintf(wr, " ")
+			}
+
+			for i, arg := range allcmd.args {
+				if i != 0 {
+					fmt.Fprintf(wr, " ")
+				}
+
+				name := arg.Name
+
+				if arg.isRemaining() {
+					name = name + "..."
+				}
+
+				if !allcmd.ArgsRequired {
+					fmt.Fprintf(wr, "[%s]", name)
+				} else {
+					fmt.Fprintf(wr, "%s", name)
+				}
+			}
+
+			if allcmd.Active == nil && len(allcmd.commands) > 0 {
+				var co, cc string
+
+				if allcmd.SubcommandsOptional {
+					co, cc = "[", "]"
+				} else {
+					co, cc = "<", ">"
+				}
+
+				visibleCommands := allcmd.visibleCommands()
+
+				if len(visibleCommands) > 3 {
+					fmt.Fprintf(wr, " %scommand%s", co, cc)
+				} else {
+					subcommands := allcmd.sortedVisibleCommands()
+					names := make([]string, len(subcommands))
+
+					for i, subc := range subcommands {
+						names[i] = subc.Name
+					}
+
+					fmt.Fprintf(wr, " %s%s%s", co, strings.Join(names, " | "), cc)
+				}
+			}
+
+			allcmd = allcmd.Active
+		}
+
+		fmt.Fprintln(wr)
+
+		if len(cmd.LongDescription) != 0 {
+			fmt.Fprintln(wr)
+
+			t := wrapText(cmd.LongDescription,
+				aligninfo.terminalColumns,
+				"")
+
+			fmt.Fprintln(wr, t)
+		}
+	}
+
+	c := p.Command
+
+	for c != nil {
+		printcmd := c != p.Command
+
+		c.eachGroup(func(grp *Group) {
+			first := true
+
+			// Skip built-in help group for all commands except the top-level
+			// parser
+			if grp.Hidden || (grp.isBuiltinHelp && c != p.Command) {
+				return
+			}
+
+			for _, info := range grp.options {
+				if !info.canCli() || info.Hidden {
+					continue
+				}
+
+				if printcmd {
+					fmt.Fprintf(wr, "\n[%s command options]\n", c.Name)
+					aligninfo.indent = true
+					printcmd = false
+				}
+
+				if first && cmd.Group != grp {
+					fmt.Fprintln(wr)
+
+					if aligninfo.indent {
+						wr.WriteString("    ")
+					}
+
+					fmt.Fprintf(wr, "%s:\n", grp.ShortDescription)
+					first = false
+				}
+
+				p.writeHelpOption(wr, info, aligninfo)
+			}
+		})
+
+		var args []*Arg
+		for _, arg := range c.args {
+			if arg.Description != "" {
+				args = append(args, arg)
+			}
+		}
+
+		if len(args) > 0 {
+			if c == p.Command {
+				fmt.Fprintf(wr, "\nArguments:\n")
+			} else {
+				fmt.Fprintf(wr, "\n[%s command arguments]\n", c.Name)
+			}
+
+			descStart := aligninfo.descriptionStart() + paddingBeforeOption
+
+			for _, arg := range args {
+				argPrefix := strings.Repeat(" ", paddingBeforeOption)
+				argPrefix += arg.Name
+
+				if len(arg.Description) > 0 {
+					argPrefix += ":"
+					wr.WriteString(argPrefix)
+
+					// Space between "arg:" and the description start
+					descPadding := strings.Repeat(" ", descStart-len(argPrefix))
+					// How much space the description gets before wrapping
+					descWidth := aligninfo.terminalColumns - 1 - descStart
+					// Whitespace to which we can indent new description lines
+					descPrefix := strings.Repeat(" ", descStart)
+
+					wr.WriteString(descPadding)
+					wr.WriteString(wrapText(arg.Description, descWidth, descPrefix))
+				} else {
+					wr.WriteString(argPrefix)
+				}
+
+				fmt.Fprintln(wr)
+			}
+		}
+
+		c = c.Active
+	}
+
+	scommands := cmd.sortedVisibleCommands()
+
+	if len(scommands) > 0 {
+		maxnamelen := maxCommandLength(scommands)
+
+		fmt.Fprintln(wr)
+		fmt.Fprintln(wr, "Available commands:")
+
+		for _, c := range scommands {
+			fmt.Fprintf(wr, "  %s", c.Name)
+
+			if len(c.ShortDescription) > 0 {
+				pad := strings.Repeat(" ", maxnamelen-len(c.Name))
+				fmt.Fprintf(wr, "%s  %s", pad, c.ShortDescription)
+
+				if len(c.Aliases) > 0 {
+					fmt.Fprintf(wr, " (aliases: %s)", strings.Join(c.Aliases, ", "))
+				}
+
+			}
+
+			fmt.Fprintln(wr)
+		}
+	}
+
+	wr.Flush()
+}

vendor/github.com/jessevdk/go-flags/ini.go

@@ -0,0 +1,593 @@
+package flags
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+// IniError contains location information on where an error occured.
+type IniError struct {
+	// The error message.
+	Message string
+
+	// The filename of the file in which the error occurred.
+	File string
+
+	// The line number at which the error occurred.
+	LineNumber uint
+}
+
+// Error provides a "file:line: message" formatted message of the ini error.
+func (x *IniError) Error() string {
+	return fmt.Sprintf(
+		"%s:%d: %s",
+		x.File,
+		x.LineNumber,
+		x.Message,
+	)
+}
+
+// IniOptions for writing
+type IniOptions uint
+
+const (
+	// IniNone indicates no options.
+	IniNone IniOptions = 0
+
+	// IniIncludeDefaults indicates that default values should be written.
+	IniIncludeDefaults = 1 << iota
+
+	// IniCommentDefaults indicates that if IniIncludeDefaults is used
+	// options with default values are written but commented out.
+	IniCommentDefaults
+
+	// IniIncludeComments indicates that comments containing the description
+	// of an option should be written.
+	IniIncludeComments
+
+	// IniDefault provides a default set of options.
+	IniDefault = IniIncludeComments
+)
+
+// IniParser is a utility to read and write flags options from and to ini
+// formatted strings.
+type IniParser struct {
+	parser *Parser
+}
+
+type iniValue struct {
+	Name       string
+	Value      string
+	Quoted     bool
+	LineNumber uint
+}
+
+type iniSection []iniValue
+
+type ini struct {
+	File     string
+	Sections map[string]iniSection
+}
+
+// NewIniParser creates a new ini parser for a given Parser.
+func NewIniParser(p *Parser) *IniParser {
+	return &IniParser{
+		parser: p,
+	}
+}
+
+// IniParse is a convenience function to parse command line options with default
+// settings from an ini formatted file. The provided data is a pointer to a struct
+// representing the default option group (named "Application Options"). For
+// more control, use flags.NewParser.
+func IniParse(filename string, data interface{}) error {
+	p := NewParser(data, Default)
+
+	return NewIniParser(p).ParseFile(filename)
+}
+
+// ParseFile parses flags from an ini formatted file. See Parse for more
+// information on the ini file format. The returned errors can be of the type
+// flags.Error or flags.IniError.
+func (i *IniParser) ParseFile(filename string) error {
+	i.parser.clearIsSet()
+
+	ini, err := readIniFromFile(filename)
+
+	if err != nil {
+		return err
+	}
+
+	return i.parse(ini)
+}
+
+// Parse parses flags from an ini format. You can use ParseFile as a
+// convenience function to parse from a filename instead of a general
+// io.Reader.
+//
+// The format of the ini file is as follows:
+//
+//     [Option group name]
+//     option = value
+//
+// Each section in the ini file represents an option group or command in the
+// flags parser. The default flags parser option group (i.e. when using
+// flags.Parse) is named 'Application Options'. The ini option name is matched
+// in the following order:
+//
+//     1. Compared to the ini-name tag on the option struct field (if present)
+//     2. Compared to the struct field name
+//     3. Compared to the option long name (if present)
+//     4. Compared to the option short name (if present)
+//
+// Sections for nested groups and commands can be addressed using a dot `.'
+// namespacing notation (i.e [subcommand.Options]). Group section names are
+// matched case insensitive.
+//
+// The returned errors can be of the type flags.Error or flags.IniError.
+func (i *IniParser) Parse(reader io.Reader) error {
+	i.parser.clearIsSet()
+
+	ini, err := readIni(reader, "")
+
+	if err != nil {
+		return err
+	}
+
+	return i.parse(ini)
+}
+
+// WriteFile writes the flags as ini format into a file. See WriteIni
+// for more information. The returned error occurs when the specified file
+// could not be opened for writing.
+func (i *IniParser) WriteFile(filename string, options IniOptions) error {
+	return writeIniToFile(i, filename, options)
+}
+
+// Write writes the current values of all the flags to an ini format.
+// See Parse for more information on the ini file format. You typically
+// call this only after settings have been parsed since the default values of each
+// option are stored just before parsing the flags (this is only relevant when
+// IniIncludeDefaults is _not_ set in options).
+func (i *IniParser) Write(writer io.Writer, options IniOptions) {
+	writeIni(i, writer, options)
+}
+
+func readFullLine(reader *bufio.Reader) (string, error) {
+	var line []byte
+
+	for {
+		l, more, err := reader.ReadLine()
+
+		if err != nil {
+			return "", err
+		}
+
+		if line == nil && !more {
+			return string(l), nil
+		}
+
+		line = append(line, l...)
+
+		if !more {
+			break
+		}
+	}
+
+	return string(line), nil
+}
+
+func optionIniName(option *Option) string {
+	name := option.tag.Get("_read-ini-name")
+
+	if len(name) != 0 {
+		return name
+	}
+
+	name = option.tag.Get("ini-name")
+
+	if len(name) != 0 {
+		return name
+	}
+
+	return option.field.Name
+}
+
+func writeGroupIni(cmd *Command, group *Group, namespace string, writer io.Writer, options IniOptions) {
+	var sname string
+
+	if len(namespace) != 0 {
+		sname = namespace
+	}
+
+	if cmd.Group != group && len(group.ShortDescription) != 0 {
+		if len(sname) != 0 {
+			sname += "."
+		}
+
+		sname += group.ShortDescription
+	}
+
+	sectionwritten := false
+	comments := (options & IniIncludeComments) != IniNone
+
+	for _, option := range group.options {
+		if option.isFunc() || option.Hidden {
+			continue
+		}
+
+		if len(option.tag.Get("no-ini")) != 0 {
+			continue
+		}
+
+		val := option.value
+
+		if (options&IniIncludeDefaults) == IniNone && option.valueIsDefault() {
+			continue
+		}
+
+		if !sectionwritten {
+			fmt.Fprintf(writer, "[%s]\n", sname)
+			sectionwritten = true
+		}
+
+		if comments && len(option.Description) != 0 {
+			fmt.Fprintf(writer, "; %s\n", option.Description)
+		}
+
+		oname := optionIniName(option)
+
+		commentOption := (options&(IniIncludeDefaults|IniCommentDefaults)) == IniIncludeDefaults|IniCommentDefaults && option.valueIsDefault()
+
+		kind := val.Type().Kind()
+		switch kind {
+		case reflect.Slice:
+			kind = val.Type().Elem().Kind()
+
+			if val.Len() == 0 {
+				writeOption(writer, oname, kind, "", "", true, option.iniQuote)
+			} else {
+				for idx := 0; idx < val.Len(); idx++ {
+					v, _ := convertToString(val.Index(idx), option.tag)
+
+					writeOption(writer, oname, kind, "", v, commentOption, option.iniQuote)
+				}
+			}
+		case reflect.Map:
+			kind = val.Type().Elem().Kind()
+
+			if val.Len() == 0 {
+				writeOption(writer, oname, kind, "", "", true, option.iniQuote)
+			} else {
+				mkeys := val.MapKeys()
+				keys := make([]string, len(val.MapKeys()))
+				kkmap := make(map[string]reflect.Value)
+
+				for i, k := range mkeys {
+					keys[i], _ = convertToString(k, option.tag)
+					kkmap[keys[i]] = k
+				}
+
+				sort.Strings(keys)
+
+				for _, k := range keys {
+					v, _ := convertToString(val.MapIndex(kkmap[k]), option.tag)
+
+					writeOption(writer, oname, kind, k, v, commentOption, option.iniQuote)
+				}
+			}
+		default:
+			v, _ := convertToString(val, option.tag)
+
+			writeOption(writer, oname, kind, "", v, commentOption, option.iniQuote)
+		}
+
+		if comments {
+			fmt.Fprintln(writer)
+		}
+	}
+
+	if sectionwritten && !comments {
+		fmt.Fprintln(writer)
+	}
+}
+
+func writeOption(writer io.Writer, optionName string, optionType reflect.Kind, optionKey string, optionValue string, commentOption bool, forceQuote bool) {
+	if forceQuote || (optionType == reflect.String && !isPrint(optionValue)) {
+		optionValue = strconv.Quote(optionValue)
+	}
+
+	comment := ""
+	if commentOption {
+		comment = "; "
+	}
+
+	fmt.Fprintf(writer, "%s%s =", comment, optionName)
+
+	if optionKey != "" {
+		fmt.Fprintf(writer, " %s:%s", optionKey, optionValue)
+	} else if optionValue != "" {
+		fmt.Fprintf(writer, " %s", optionValue)
+	}
+
+	fmt.Fprintln(writer)
+}
+
+func writeCommandIni(command *Command, namespace string, writer io.Writer, options IniOptions) {
+	command.eachGroup(func(group *Group) {
+		if !group.Hidden {
+			writeGroupIni(command, group, namespace, writer, options)
+		}
+	})
+
+	for _, c := range command.commands {
+		var nns string
+
+		if c.Hidden {
+			continue
+		}
+
+		if len(namespace) != 0 {
+			nns = c.Name + "." + nns
+		} else {
+			nns = c.Name
+		}
+
+		writeCommandIni(c, nns, writer, options)
+	}
+}
+
+func writeIni(parser *IniParser, writer io.Writer, options IniOptions) {
+	writeCommandIni(parser.parser.Command, "", writer, options)
+}
+
+func writeIniToFile(parser *IniParser, filename string, options IniOptions) error {
+	file, err := os.Create(filename)
+
+	if err != nil {
+		return err
+	}
+
+	defer file.Close()
+
+	writeIni(parser, file, options)
+
+	return nil
+}
+
+func readIniFromFile(filename string) (*ini, error) {
+	file, err := os.Open(filename)
+
+	if err != nil {
+		return nil, err
+	}
+
+	defer file.Close()
+
+	return readIni(file, filename)
+}
+
+func readIni(contents io.Reader, filename string) (*ini, error) {
+	ret := &ini{
+		File:     filename,
+		Sections: make(map[string]iniSection),
+	}
+
+	reader := bufio.NewReader(contents)
+
+	// Empty global section
+	section := make(iniSection, 0, 10)
+	sectionname := ""
+
+	ret.Sections[sectionname] = section
+
+	var lineno uint
+
+	for {
+		line, err := readFullLine(reader)
+
+		if err == io.EOF {
+			break
+		} else if err != nil {
+			return nil, err
+		}
+
+		lineno++
+		line = strings.TrimSpace(line)
+
+		// Skip empty lines and lines starting with ; (comments)
+		if len(line) == 0 || line[0] == ';' || line[0] == '#' {
+			continue
+		}
+
+		if line[0] == '[' {
+			if line[0] != '[' || line[len(line)-1] != ']' {
+				return nil, &IniError{
+					Message:    "malformed section header",
+					File:       filename,
+					LineNumber: lineno,
+				}
+			}
+
+			name := strings.TrimSpace(line[1 : len(line)-1])
+
+			if len(name) == 0 {
+				return nil, &IniError{
+					Message:    "empty section name",
+					File:       filename,
+					LineNumber: lineno,
+				}
+			}
+
+			sectionname = name
+			section = ret.Sections[name]
+
+			if section == nil {
+				section = make(iniSection, 0, 10)
+				ret.Sections[name] = section
+			}
+
+			continue
+		}
+
+		// Parse option here
+		keyval := strings.SplitN(line, "=", 2)
+
+		if len(keyval) != 2 {
+			return nil, &IniError{
+				Message:    fmt.Sprintf("malformed key=value (%s)", line),
+				File:       filename,
+				LineNumber: lineno,
+			}
+		}
+
+		name := strings.TrimSpace(keyval[0])
+		value := strings.TrimSpace(keyval[1])
+		quoted := false
+
+		if len(value) != 0 && value[0] == '"' {
+			if v, err := strconv.Unquote(value); err == nil {
+				value = v
+
+				quoted = true
+			} else {
+				return nil, &IniError{
+					Message:    err.Error(),
+					File:       filename,
+					LineNumber: lineno,
+				}
+			}
+		}
+
+		section = append(section, iniValue{
+			Name:       name,
+			Value:      value,
+			Quoted:     quoted,
+			LineNumber: lineno,
+		})
+
+		ret.Sections[sectionname] = section
+	}
+
+	return ret, nil
+}
+
+func (i *IniParser) matchingGroups(name string) []*Group {
+	if len(name) == 0 {
+		var ret []*Group
+
+		i.parser.eachGroup(func(g *Group) {
+			ret = append(ret, g)
+		})
+
+		return ret
+	}
+
+	g := i.parser.groupByName(name)
+
+	if g != nil {
+		return []*Group{g}
+	}
+
+	return nil
+}
+
+func (i *IniParser) parse(ini *ini) error {
+	p := i.parser
+
+	var quotesLookup = make(map[*Option]bool)
+
+	for name, section := range ini.Sections {
+		groups := i.matchingGroups(name)
+
+		if len(groups) == 0 {
+			return newErrorf(ErrUnknownGroup, "could not find option group `%s'", name)
+		}
+
+		for _, inival := range section {
+			var opt *Option
+
+			for _, group := range groups {
+				opt = group.optionByName(inival.Name, func(o *Option, n string) bool {
+					return strings.ToLower(o.tag.Get("ini-name")) == strings.ToLower(n)
+				})
+
+				if opt != nil && len(opt.tag.Get("no-ini")) != 0 {
+					opt = nil
+				}
+
+				if opt != nil {
+					break
+				}
+			}
+
+			if opt == nil {
+				if (p.Options & IgnoreUnknown) == None {
+					return &IniError{
+						Message:    fmt.Sprintf("unknown option: %s", inival.Name),
+						File:       ini.File,
+						LineNumber: inival.LineNumber,
+					}
+				}
+
+				continue
+			}
+
+			pval := &inival.Value
+
+			if !opt.canArgument() && len(inival.Value) == 0 {
+				pval = nil
+			} else {
+				if opt.value.Type().Kind() == reflect.Map {
+					parts := strings.SplitN(inival.Value, ":", 2)
+
+					// only handle unquoting
+					if len(parts) == 2 && parts[1][0] == '"' {
+						if v, err := strconv.Unquote(parts[1]); err == nil {
+							parts[1] = v
+
+							inival.Quoted = true
+						} else {
+							return &IniError{
+								Message:    err.Error(),
+								File:       ini.File,
+								LineNumber: inival.LineNumber,
+							}
+						}
+
+						s := parts[0] + ":" + parts[1]
+
+						pval = &s
+					}
+				}
+			}
+
+			if err := opt.set(pval); err != nil {
+				return &IniError{
+					Message:    err.Error(),
+					File:       ini.File,
+					LineNumber: inival.LineNumber,
+				}
+			}
+
+			// either all INI values are quoted or only values who need quoting
+			if _, ok := quotesLookup[opt]; !inival.Quoted || !ok {
+				quotesLookup[opt] = inival.Quoted
+			}
+
+			opt.tag.Set("_read-ini-name", inival.Name)
+		}
+	}
+
+	for opt, quoted := range quotesLookup {
+		opt.iniQuote = quoted
+	}
+
+	return nil
+}

vendor/github.com/jessevdk/go-flags/man.go

@@ -0,0 +1,205 @@
+package flags
+
+import (
+	"fmt"
+	"io"
+	"runtime"
+	"strings"
+	"time"
+)
+
+func manQuote(s string) string {
+	return strings.Replace(s, "\\", "\\\\", -1)
+}
+
+func formatForMan(wr io.Writer, s string) {
+	for {
+		idx := strings.IndexRune(s, '`')
+
+		if idx < 0 {
+			fmt.Fprintf(wr, "%s", manQuote(s))
+			break
+		}
+
+		fmt.Fprintf(wr, "%s", manQuote(s[:idx]))
+
+		s = s[idx+1:]
+		idx = strings.IndexRune(s, '\'')
+
+		if idx < 0 {
+			fmt.Fprintf(wr, "%s", manQuote(s))
+			break
+		}
+
+		fmt.Fprintf(wr, "\\fB%s\\fP", manQuote(s[:idx]))
+		s = s[idx+1:]
+	}
+}
+
+func writeManPageOptions(wr io.Writer, grp *Group) {
+	grp.eachGroup(func(group *Group) {
+		if group.Hidden || len(group.options) == 0 {
+			return
+		}
+
+		// If the parent (grp) has any subgroups, display their descriptions as
+		// subsection headers similar to the output of --help.
+		if group.ShortDescription != "" && len(grp.groups) > 0 {
+			fmt.Fprintf(wr, ".SS %s\n", group.ShortDescription)
+
+			if group.LongDescription != "" {
+				formatForMan(wr, group.LongDescription)
+				fmt.Fprintln(wr, "")
+			}
+		}
+
+		for _, opt := range group.options {
+			if !opt.canCli() || opt.Hidden {
+				continue
+			}
+
+			fmt.Fprintln(wr, ".TP")
+			fmt.Fprintf(wr, "\\fB")
+
+			if opt.ShortName != 0 {
+				fmt.Fprintf(wr, "\\fB\\-%c\\fR", opt.ShortName)
+			}
+
+			if len(opt.LongName) != 0 {
+				if opt.ShortName != 0 {
+					fmt.Fprintf(wr, ", ")
+				}
+
+				fmt.Fprintf(wr, "\\fB\\-\\-%s\\fR", manQuote(opt.LongNameWithNamespace()))
+			}
+
+			if len(opt.ValueName) != 0 || opt.OptionalArgument {
+				if opt.OptionalArgument {
+					fmt.Fprintf(wr, " [\\fI%s=%s\\fR]", manQuote(opt.ValueName), manQuote(strings.Join(quoteV(opt.OptionalValue), ", ")))
+				} else {
+					fmt.Fprintf(wr, " \\fI%s\\fR", manQuote(opt.ValueName))
+				}
+			}
+
+			if len(opt.Default) != 0 {
+				fmt.Fprintf(wr, " <default: \\fI%s\\fR>", manQuote(strings.Join(quoteV(opt.Default), ", ")))
+			} else if len(opt.EnvDefaultKey) != 0 {
+				if runtime.GOOS == "windows" {
+					fmt.Fprintf(wr, " <default: \\fI%%%s%%\\fR>", manQuote(opt.EnvDefaultKey))
+				} else {
+					fmt.Fprintf(wr, " <default: \\fI$%s\\fR>", manQuote(opt.EnvDefaultKey))
+				}
+			}
+
+			if opt.Required {
+				fmt.Fprintf(wr, " (\\fIrequired\\fR)")
+			}
+
+			fmt.Fprintln(wr, "\\fP")
+
+			if len(opt.Description) != 0 {
+				formatForMan(wr, opt.Description)
+				fmt.Fprintln(wr, "")
+			}
+		}
+	})
+}
+
+func writeManPageSubcommands(wr io.Writer, name string, root *Command) {
+	commands := root.sortedVisibleCommands()
+
+	for _, c := range commands {
+		var nn string
+
+		if c.Hidden {
+			continue
+		}
+
+		if len(name) != 0 {
+			nn = name + " " + c.Name
+		} else {
+			nn = c.Name
+		}
+
+		writeManPageCommand(wr, nn, root, c)
+	}
+}
+
+func writeManPageCommand(wr io.Writer, name string, root *Command, command *Command) {
+	fmt.Fprintf(wr, ".SS %s\n", name)
+	fmt.Fprintln(wr, command.ShortDescription)
+
+	if len(command.LongDescription) > 0 {
+		fmt.Fprintln(wr, "")
+
+		cmdstart := fmt.Sprintf("The %s command", manQuote(command.Name))
+
+		if strings.HasPrefix(command.LongDescription, cmdstart) {
+			fmt.Fprintf(wr, "The \\fI%s\\fP command", manQuote(command.Name))
+
+			formatForMan(wr, command.LongDescription[len(cmdstart):])
+			fmt.Fprintln(wr, "")
+		} else {
+			formatForMan(wr, command.LongDescription)
+			fmt.Fprintln(wr, "")
+		}
+	}
+
+	var usage string
+	if us, ok := command.data.(Usage); ok {
+		usage = us.Usage()
+	} else if command.hasCliOptions() {
+		usage = fmt.Sprintf("[%s-OPTIONS]", command.Name)
+	}
+
+	var pre string
+	if root.hasCliOptions() {
+		pre = fmt.Sprintf("%s [OPTIONS] %s", root.Name, command.Name)
+	} else {
+		pre = fmt.Sprintf("%s %s", root.Name, command.Name)
+	}
+
+	if len(usage) > 0 {
+		fmt.Fprintf(wr, "\n\\fBUsage\\fP: %s %s\n.TP\n", manQuote(pre), manQuote(usage))
+	}
+
+	if len(command.Aliases) > 0 {
+		fmt.Fprintf(wr, "\n\\fBAliases\\fP: %s\n\n", manQuote(strings.Join(command.Aliases, ", ")))
+	}
+
+	writeManPageOptions(wr, command.Group)
+	writeManPageSubcommands(wr, name, command)
+}
+
+// WriteManPage writes a basic man page in groff format to the specified
+// writer.
+func (p *Parser) WriteManPage(wr io.Writer) {
+	t := time.Now()
+
+	fmt.Fprintf(wr, ".TH %s 1 \"%s\"\n", manQuote(p.Name), t.Format("2 January 2006"))
+	fmt.Fprintln(wr, ".SH NAME")
+	fmt.Fprintf(wr, "%s \\- %s\n", manQuote(p.Name), manQuote(p.ShortDescription))
+	fmt.Fprintln(wr, ".SH SYNOPSIS")
+
+	usage := p.Usage
+
+	if len(usage) == 0 {
+		usage = "[OPTIONS]"
+	}
+
+	fmt.Fprintf(wr, "\\fB%s\\fP %s\n", manQuote(p.Name), manQuote(usage))
+	fmt.Fprintln(wr, ".SH DESCRIPTION")
+
+	formatForMan(wr, p.LongDescription)
+	fmt.Fprintln(wr, "")
+
+	fmt.Fprintln(wr, ".SH OPTIONS")
+
+	writeManPageOptions(wr, p.Command.Group)
+
+	if len(p.visibleCommands()) > 0 {
+		fmt.Fprintln(wr, ".SH COMMANDS")
+
+		writeManPageSubcommands(wr, "", p.Command)
+	}
+}

vendor/github.com/jessevdk/go-flags/multitag.go

@@ -0,0 +1,140 @@
+package flags
+
+import (
+	"strconv"
+)
+
+type multiTag struct {
+	value string
+	cache map[string][]string
+}
+
+func newMultiTag(v string) multiTag {
+	return multiTag{
+		value: v,
+	}
+}
+
+func (x *multiTag) scan() (map[string][]string, error) {
+	v := x.value
+
+	ret := make(map[string][]string)
+
+	// This is mostly copied from reflect.StructTag.Get
+	for v != "" {
+		i := 0
+
+		// Skip whitespace
+		for i < len(v) && v[i] == ' ' {
+			i++
+		}
+
+		v = v[i:]
+
+		if v == "" {
+			break
+		}
+
+		// Scan to colon to find key
+		i = 0
+
+		for i < len(v) && v[i] != ' ' && v[i] != ':' && v[i] != '"' {
+			i++
+		}
+
+		if i >= len(v) {
+			return nil, newErrorf(ErrTag, "expected `:' after key name, but got end of tag (in `%v`)", x.value)
+		}
+
+		if v[i] != ':' {
+			return nil, newErrorf(ErrTag, "expected `:' after key name, but got `%v' (in `%v`)", v[i], x.value)
+		}
+
+		if i+1 >= len(v) {
+			return nil, newErrorf(ErrTag, "expected `\"' to start tag value at end of tag (in `%v`)", x.value)
+		}
+
+		if v[i+1] != '"' {
+			return nil, newErrorf(ErrTag, "expected `\"' to start tag value, but got `%v' (in `%v`)", v[i+1], x.value)
+		}
+
+		name := v[:i]
+		v = v[i+1:]
+
+		// Scan quoted string to find value
+		i = 1
+
+		for i < len(v) && v[i] != '"' {
+			if v[i] == '\n' {
+				return nil, newErrorf(ErrTag, "unexpected newline in tag value `%v' (in `%v`)", name, x.value)
+			}
+
+			if v[i] == '\\' {
+				i++
+			}
+			i++
+		}
+
+		if i >= len(v) {
+			return nil, newErrorf(ErrTag, "expected end of tag value `\"' at end of tag (in `%v`)", x.value)
+		}
+
+		val, err := strconv.Unquote(v[:i+1])
+
+		if err != nil {
+			return nil, newErrorf(ErrTag, "Malformed value of tag `%v:%v` => %v (in `%v`)", name, v[:i+1], err, x.value)
+		}
+
+		v = v[i+1:]
+
+		ret[name] = append(ret[name], val)
+	}
+
+	return ret, nil
+}
+
+func (x *multiTag) Parse() error {
+	vals, err := x.scan()
+	x.cache = vals
+
+	return err
+}
+
+func (x *multiTag) cached() map[string][]string {
+	if x.cache == nil {
+		cache, _ := x.scan()
+
+		if cache == nil {
+			cache = make(map[string][]string)
+		}
+
+		x.cache = cache
+	}
+
+	return x.cache
+}
+
+func (x *multiTag) Get(key string) string {
+	c := x.cached()
+
+	if v, ok := c[key]; ok {
+		return v[len(v)-1]
+	}
+
+	return ""
+}
+
+func (x *multiTag) GetMany(key string) []string {
+	c := x.cached()
+	return c[key]
+}
+
+func (x *multiTag) Set(key string, value string) {
+	c := x.cached()
+	c[key] = []string{value}
+}
+
+func (x *multiTag) SetMany(key string, value []string) {
+	c := x.cached()
+	c[key] = value
+}

vendor/github.com/jessevdk/go-flags/option.go

@@ -0,0 +1,434 @@
+package flags
+
+import (
+	"bytes"
+	"fmt"
+	"reflect"
+	"strings"
+	"syscall"
+	"unicode/utf8"
+)
+
+// Option flag information. Contains a description of the option, short and
+// long name as well as a default value and whether an argument for this
+// flag is optional.
+type Option struct {
+	// The description of the option flag. This description is shown
+	// automatically in the built-in help.
+	Description string
+
+	// The short name of the option (a single character). If not 0, the
+	// option flag can be 'activated' using -<ShortName>. Either ShortName
+	// or LongName needs to be non-empty.
+	ShortName rune
+
+	// The long name of the option. If not "", the option flag can be
+	// activated using --<LongName>. Either ShortName or LongName needs
+	// to be non-empty.
+	LongName string
+
+	// The default value of the option.
+	Default []string
+
+	// The optional environment default value key name.
+	EnvDefaultKey string
+
+	// The optional delimiter string for EnvDefaultKey values.
+	EnvDefaultDelim string
+
+	// If true, specifies that the argument to an option flag is optional.
+	// When no argument to the flag is specified on the command line, the
+	// value of OptionalValue will be set in the field this option represents.
+	// This is only valid for non-boolean options.
+	OptionalArgument bool
+
+	// The optional value of the option. The optional value is used when
+	// the option flag is marked as having an OptionalArgument. This means
+	// that when the flag is specified, but no option argument is given,
+	// the value of the field this option represents will be set to
+	// OptionalValue. This is only valid for non-boolean options.
+	OptionalValue []string
+
+	// If true, the option _must_ be specified on the command line. If the
+	// option is not specified, the parser will generate an ErrRequired type
+	// error.
+	Required bool
+
+	// A name for the value of an option shown in the Help as --flag [ValueName]
+	ValueName string
+
+	// A mask value to show in the help instead of the default value. This
+	// is useful for hiding sensitive information in the help, such as
+	// passwords.
+	DefaultMask string
+
+	// If non empty, only a certain set of values is allowed for an option.
+	Choices []string
+
+	// If true, the option is not displayed in the help or man page
+	Hidden bool
+
+	// The group which the option belongs to
+	group *Group
+
+	// The struct field which the option represents.
+	field reflect.StructField
+
+	// The struct field value which the option represents.
+	value reflect.Value
+
+	// Determines if the option will be always quoted in the INI output
+	iniQuote bool
+
+	tag            multiTag
+	isSet          bool
+	preventDefault bool
+
+	defaultLiteral string
+}
+
+// LongNameWithNamespace returns the option's long name with the group namespaces
+// prepended by walking up the option's group tree. Namespaces and the long name
+// itself are separated by the parser's namespace delimiter. If the long name is
+// empty an empty string is returned.
+func (option *Option) LongNameWithNamespace() string {
+	if len(option.LongName) == 0 {
+		return ""
+	}
+
+	// fetch the namespace delimiter from the parser which is always at the
+	// end of the group hierarchy
+	namespaceDelimiter := ""
+	g := option.group
+
+	for {
+		if p, ok := g.parent.(*Parser); ok {
+			namespaceDelimiter = p.NamespaceDelimiter
+
+			break
+		}
+
+		switch i := g.parent.(type) {
+		case *Command:
+			g = i.Group
+		case *Group:
+			g = i
+		}
+	}
+
+	// concatenate long name with namespace
+	longName := option.LongName
+	g = option.group
+
+	for g != nil {
+		if g.Namespace != "" {
+			longName = g.Namespace + namespaceDelimiter + longName
+		}
+
+		switch i := g.parent.(type) {
+		case *Command:
+			g = i.Group
+		case *Group:
+			g = i
+		case *Parser:
+			g = nil
+		}
+	}
+
+	return longName
+}
+
+// String converts an option to a human friendly readable string describing the
+// option.
+func (option *Option) String() string {
+	var s string
+	var short string
+
+	if option.ShortName != 0 {
+		data := make([]byte, utf8.RuneLen(option.ShortName))
+		utf8.EncodeRune(data, option.ShortName)
+		short = string(data)
+
+		if len(option.LongName) != 0 {
+			s = fmt.Sprintf("%s%s, %s%s",
+				string(defaultShortOptDelimiter), short,
+				defaultLongOptDelimiter, option.LongNameWithNamespace())
+		} else {
+			s = fmt.Sprintf("%s%s", string(defaultShortOptDelimiter), short)
+		}
+	} else if len(option.LongName) != 0 {
+		s = fmt.Sprintf("%s%s", defaultLongOptDelimiter, option.LongNameWithNamespace())
+	}
+
+	return s
+}
+
+// Value returns the option value as an interface{}.
+func (option *Option) Value() interface{} {
+	return option.value.Interface()
+}
+
+// IsSet returns true if option has been set
+func (option *Option) IsSet() bool {
+	return option.isSet
+}
+
+// Set the value of an option to the specified value. An error will be returned
+// if the specified value could not be converted to the corresponding option
+// value type.
+func (option *Option) set(value *string) error {
+	kind := option.value.Type().Kind()
+
+	if (kind == reflect.Map || kind == reflect.Slice) && !option.isSet {
+		option.empty()
+	}
+
+	option.isSet = true
+	option.preventDefault = true
+
+	if len(option.Choices) != 0 {
+		found := false
+
+		for _, choice := range option.Choices {
+			if choice == *value {
+				found = true
+				break
+			}
+		}
+
+		if !found {
+			allowed := strings.Join(option.Choices[0:len(option.Choices)-1], ", ")
+
+			if len(option.Choices) > 1 {
+				allowed += " or " + option.Choices[len(option.Choices)-1]
+			}
+
+			return newErrorf(ErrInvalidChoice,
+				"Invalid value `%s' for option `%s'. Allowed values are: %s",
+				*value, option, allowed)
+		}
+	}
+
+	if option.isFunc() {
+		return option.call(value)
+	} else if value != nil {
+		return convert(*value, option.value, option.tag)
+	}
+
+	return convert("", option.value, option.tag)
+}
+
+func (option *Option) canCli() bool {
+	return option.ShortName != 0 || len(option.LongName) != 0
+}
+
+func (option *Option) canArgument() bool {
+	if u := option.isUnmarshaler(); u != nil {
+		return true
+	}
+
+	return !option.isBool()
+}
+
+func (option *Option) emptyValue() reflect.Value {
+	tp := option.value.Type()
+
+	if tp.Kind() == reflect.Map {
+		return reflect.MakeMap(tp)
+	}
+
+	return reflect.Zero(tp)
+}
+
+func (option *Option) empty() {
+	if !option.isFunc() {
+		option.value.Set(option.emptyValue())
+	}
+}
+
+func (option *Option) clearDefault() {
+	usedDefault := option.Default
+
+	if envKey := option.EnvDefaultKey; envKey != "" {
+		// os.Getenv() makes no distinction between undefined and
+		// empty values, so we use syscall.Getenv()
+		if value, ok := syscall.Getenv(envKey); ok {
+			if option.EnvDefaultDelim != "" {
+				usedDefault = strings.Split(value,
+					option.EnvDefaultDelim)
+			} else {
+				usedDefault = []string{value}
+			}
+		}
+	}
+
+	if len(usedDefault) > 0 {
+		option.empty()
+
+		for _, d := range usedDefault {
+			option.set(&d)
+		}
+	} else {
+		tp := option.value.Type()
+
+		switch tp.Kind() {
+		case reflect.Map:
+			if option.value.IsNil() {
+				option.empty()
+			}
+		case reflect.Slice:
+			if option.value.IsNil() {
+				option.empty()
+			}
+		}
+	}
+}
+
+func (option *Option) valueIsDefault() bool {
+	// Check if the value of the option corresponds to its
+	// default value
+	emptyval := option.emptyValue()
+
+	checkvalptr := reflect.New(emptyval.Type())
+	checkval := reflect.Indirect(checkvalptr)
+
+	checkval.Set(emptyval)
+
+	if len(option.Default) != 0 {
+		for _, v := range option.Default {
+			convert(v, checkval, option.tag)
+		}
+	}
+
+	return reflect.DeepEqual(option.value.Interface(), checkval.Interface())
+}
+
+func (option *Option) isUnmarshaler() Unmarshaler {
+	v := option.value
+
+	for {
+		if !v.CanInterface() {
+			break
+		}
+
+		i := v.Interface()
+
+		if u, ok := i.(Unmarshaler); ok {
+			return u
+		}
+
+		if !v.CanAddr() {
+			break
+		}
+
+		v = v.Addr()
+	}
+
+	return nil
+}
+
+func (option *Option) isBool() bool {
+	tp := option.value.Type()
+
+	for {
+		switch tp.Kind() {
+		case reflect.Bool:
+			return true
+		case reflect.Slice:
+			return (tp.Elem().Kind() == reflect.Bool)
+		case reflect.Func:
+			return tp.NumIn() == 0
+		case reflect.Ptr:
+			tp = tp.Elem()
+		default:
+			return false
+		}
+	}
+}
+
+func (option *Option) isFunc() bool {
+	return option.value.Type().Kind() == reflect.Func
+}
+
+func (option *Option) call(value *string) error {
+	var retval []reflect.Value
+
+	if value == nil {
+		retval = option.value.Call(nil)
+	} else {
+		tp := option.value.Type().In(0)
+
+		val := reflect.New(tp)
+		val = reflect.Indirect(val)
+
+		if err := convert(*value, val, option.tag); err != nil {
+			return err
+		}
+
+		retval = option.value.Call([]reflect.Value{val})
+	}
+
+	if len(retval) == 1 && retval[0].Type() == reflect.TypeOf((*error)(nil)).Elem() {
+		if retval[0].Interface() == nil {
+			return nil
+		}
+
+		return retval[0].Interface().(error)
+	}
+
+	return nil
+}
+
+func (option *Option) updateDefaultLiteral() {
+	defs := option.Default
+	def := ""
+
+	if len(defs) == 0 && option.canArgument() {
+		var showdef bool
+
+		switch option.field.Type.Kind() {
+		case reflect.Func, reflect.Ptr:
+			showdef = !option.value.IsNil()
+		case reflect.Slice, reflect.String, reflect.Array:
+			showdef = option.value.Len() > 0
+		case reflect.Map:
+			showdef = !option.value.IsNil() && option.value.Len() > 0
+		default:
+			zeroval := reflect.Zero(option.field.Type)
+			showdef = !reflect.DeepEqual(zeroval.Interface(), option.value.Interface())
+		}
+
+		if showdef {
+			def, _ = convertToString(option.value, option.tag)
+		}
+	} else if len(defs) != 0 {
+		l := len(defs) - 1
+
+		for i := 0; i < l; i++ {
+			def += quoteIfNeeded(defs[i]) + ", "
+		}
+
+		def += quoteIfNeeded(defs[l])
+	}
+
+	option.defaultLiteral = def
+}
+
+func (option *Option) shortAndLongName() string {
+	ret := &bytes.Buffer{}
+
+	if option.ShortName != 0 {
+		ret.WriteRune(defaultShortOptDelimiter)
+		ret.WriteRune(option.ShortName)
+	}
+
+	if len(option.LongName) != 0 {
+		if option.ShortName != 0 {
+			ret.WriteRune('/')
+		}
+
+		ret.WriteString(option.LongName)
+	}
+
+	return ret.String()
+}

vendor/github.com/jessevdk/go-flags/optstyle_other.go

@@ -0,0 +1,67 @@
+// +build !windows
+
+package flags
+
+import (
+	"strings"
+)
+
+const (
+	defaultShortOptDelimiter = '-'
+	defaultLongOptDelimiter  = "--"
+	defaultNameArgDelimiter  = '='
+)
+
+func argumentStartsOption(arg string) bool {
+	return len(arg) > 0 && arg[0] == '-'
+}
+
+func argumentIsOption(arg string) bool {
+	if len(arg) > 1 && arg[0] == '-' && arg[1] != '-' {
+		return true
+	}
+
+	if len(arg) > 2 && arg[0] == '-' && arg[1] == '-' && arg[2] != '-' {
+		return true
+	}
+
+	return false
+}
+
+// stripOptionPrefix returns the option without the prefix and whether or
+// not the option is a long option or not.
+func stripOptionPrefix(optname string) (prefix string, name string, islong bool) {
+	if strings.HasPrefix(optname, "--") {
+		return "--", optname[2:], true
+	} else if strings.HasPrefix(optname, "-") {
+		return "-", optname[1:], false
+	}
+
+	return "", optname, false
+}
+
+// splitOption attempts to split the passed option into a name and an argument.
+// When there is no argument specified, nil will be returned for it.
+func splitOption(prefix string, option string, islong bool) (string, string, *string) {
+	pos := strings.Index(option, "=")
+
+	if (islong && pos >= 0) || (!islong && pos == 1) {
+		rest := option[pos+1:]
+		return option[:pos], "=", &rest
+	}
+
+	return option, "", nil
+}
+
+// addHelpGroup adds a new group that contains default help parameters.
+func (c *Command) addHelpGroup(showHelp func() error) *Group {
+	var help struct {
+		ShowHelp func() error `short:"h" long:"help" description:"Show this help message"`
+	}
+
+	help.ShowHelp = showHelp
+	ret, _ := c.AddGroup("Help Options", "", &help)
+	ret.isBuiltinHelp = true
+
+	return ret
+}