add basic metrics to the store package

store/metrics.gen.go

@@ -0,0 +1,32 @@
+// Code generated by metricsgen. DO NOT EDIT.
+
+package store
+
+import (
+	"github.com/go-kit/kit/metrics/discard"
+	prometheus "github.com/go-kit/kit/metrics/prometheus"
+	stdprometheus "github.com/prometheus/client_golang/prometheus"
+)
+
+func PrometheusMetrics(namespace string, labelsAndValues ...string) *Metrics {
+	labels := []string{}
+	for i := 0; i < len(labelsAndValues); i += 2 {
+		labels = append(labels, labelsAndValues[i])
+	}
+	return &Metrics{
+		BlockStoreAccessDurationSeconds: prometheus.NewHistogramFrom(stdprometheus.HistogramOpts{
+			Namespace: namespace,
+			Subsystem: MetricsSubsystem,
+			Name:      "block_store_access_duration_seconds",
+			Help:      "The duration of accesses to the state store labeled by which method was called on the store.",
+
+			Buckets: stdprometheus.ExponentialBuckets(0.01, 2, 5),
+		}, append(labels, "method")).With(labelsAndValues...),
+	}
+}
+
+func NopMetrics() *Metrics {
+	return &Metrics{
+		BlockStoreAccessDurationSeconds: discard.NewHistogram(),
+	}
+}

store/metrics.go

@@ -0,0 +1,20 @@
+package store
+
+import (
+	"github.com/go-kit/kit/metrics"
+)
+
+const (
+	// MetricsSubsystem is a subsystem shared by all metrics exposed by this
+	// package.
+	MetricsSubsystem = "store"
+)
+
+//go:generate go run ../scripts/metricsgen -struct=Metrics
+
+// Metrics contains metrics exposed by this package.
+type Metrics struct {
+	// The duration of accesses to the state store labeled by which method
+	// was called on the store.
+	BlockStoreAccessDurationSeconds metrics.Histogram `metrics_buckettype:"exp" metrics_bucketsizes:"0.01, 2, 5" metrics_labels:"method"`
+}

store/store.go

@@ -35,6 +35,8 @@ The store can be assumed to contain all contiguous blocks between base and heigh
 type BlockStore struct {
 	db dbm.DB
 
+	metrics *Metrics
+
 	// mtx guards access to the struct fields listed below it. We rely on the database to enforce
 	// fine-grained concurrency control for its data, and thus this mutex does not apply to
 	// database contents. The only reason for keeping these fields in the struct is that the data