Moved to google.golang.org/genproto/googleapis/api/annotations

Fixes #52

vendor/github.com/go-kit/kit/metrics/graphite/graphite.go

@@ -0,0 +1,203 @@
+// Package graphite provides a Graphite backend for metrics. Metrics are batched
+// and emitted in the plaintext protocol. For more information, see
+// http://graphite.readthedocs.io/en/latest/feeding-carbon.html#the-plaintext-protocol
+//
+// Graphite does not have a native understanding of metric parameterization, so
+// label values not supported. Use distinct metrics for each unique combination
+// of label values.
+package graphite
+
+import (
+	"fmt"
+	"io"
+	"sync"
+	"time"
+
+	"github.com/go-kit/kit/log"
+	"github.com/go-kit/kit/metrics"
+	"github.com/go-kit/kit/metrics/generic"
+	"github.com/go-kit/kit/util/conn"
+)
+
+// Graphite receives metrics observations and forwards them to a Graphite server.
+// Create a Graphite object, use it to create metrics, and pass those metrics as
+// dependencies to the components that will use them.
+//
+// All metrics are buffered until WriteTo is called. Counters and gauges are
+// aggregated into a single observation per timeseries per write. Histograms are
+// exploded into per-quantile gauges and reported once per write.
+//
+// To regularly report metrics to an io.Writer, use the WriteLoop helper method.
+// To send to a Graphite server, use the SendLoop helper method.
+type Graphite struct {
+	mtx        sync.RWMutex
+	prefix     string
+	counters   map[string]*Counter
+	gauges     map[string]*Gauge
+	histograms map[string]*Histogram
+	logger     log.Logger
+}
+
+// New returns a Graphite object that may be used to create metrics. Prefix is
+// applied to all created metrics. Callers must ensure that regular calls to
+// WriteTo are performed, either manually or with one of the helper methods.
+func New(prefix string, logger log.Logger) *Graphite {
+	return &Graphite{
+		prefix:     prefix,
+		counters:   map[string]*Counter{},
+		gauges:     map[string]*Gauge{},
+		histograms: map[string]*Histogram{},
+		logger:     logger,
+	}
+}
+
+// NewCounter returns a counter. Observations are aggregated and emitted once
+// per write invocation.
+func (g *Graphite) NewCounter(name string) *Counter {
+	c := NewCounter(g.prefix + name)
+	g.mtx.Lock()
+	g.counters[g.prefix+name] = c
+	g.mtx.Unlock()
+	return c
+}
+
+// NewGauge returns a gauge. Observations are aggregated and emitted once per
+// write invocation.
+func (g *Graphite) NewGauge(name string) *Gauge {
+	ga := NewGauge(g.prefix + name)
+	g.mtx.Lock()
+	g.gauges[g.prefix+name] = ga
+	g.mtx.Unlock()
+	return ga
+}
+
+// NewHistogram returns a histogram. Observations are aggregated and emitted as
+// per-quantile gauges, once per write invocation. 50 is a good default value
+// for buckets.
+func (g *Graphite) NewHistogram(name string, buckets int) *Histogram {
+	h := NewHistogram(g.prefix+name, buckets)
+	g.mtx.Lock()
+	g.histograms[g.prefix+name] = h
+	g.mtx.Unlock()
+	return h
+}
+
+// WriteLoop is a helper method that invokes WriteTo to the passed writer every
+// time the passed channel fires. This method blocks until the channel is
+// closed, so clients probably want to run it in its own goroutine. For typical
+// usage, create a time.Ticker and pass its C channel to this method.
+func (g *Graphite) WriteLoop(c <-chan time.Time, w io.Writer) {
+	for range c {
+		if _, err := g.WriteTo(w); err != nil {
+			g.logger.Log("during", "WriteTo", "err", err)
+		}
+	}
+}
+
+// SendLoop is a helper method that wraps WriteLoop, passing a managed
+// connection to the network and address. Like WriteLoop, this method blocks
+// until the channel is closed, so clients probably want to start it in its own
+// goroutine. For typical usage, create a time.Ticker and pass its C channel to
+// this method.
+func (g *Graphite) SendLoop(c <-chan time.Time, network, address string) {
+	g.WriteLoop(c, conn.NewDefaultManager(network, address, g.logger))
+}
+
+// WriteTo flushes the buffered content of the metrics to the writer, in
+// Graphite plaintext format. WriteTo abides best-effort semantics, so
+// observations are lost if there is a problem with the write. Clients should be
+// sure to call WriteTo regularly, ideally through the WriteLoop or SendLoop
+// helper methods.
+func (g *Graphite) WriteTo(w io.Writer) (count int64, err error) {
+	g.mtx.RLock()
+	defer g.mtx.RUnlock()
+	now := time.Now().Unix()
+
+	for name, c := range g.counters {
+		n, err := fmt.Fprintf(w, "%s %f %d\n", name, c.c.ValueReset(), now)
+		if err != nil {
+			return count, err
+		}
+		count += int64(n)
+	}
+
+	for name, ga := range g.gauges {
+		n, err := fmt.Fprintf(w, "%s %f %d\n", name, ga.g.Value(), now)
+		if err != nil {
+			return count, err
+		}
+		count += int64(n)
+	}
+
+	for name, h := range g.histograms {
+		for _, p := range []struct {
+			s string
+			f float64
+		}{
+			{"50", 0.50},
+			{"90", 0.90},
+			{"95", 0.95},
+			{"99", 0.99},
+		} {
+			n, err := fmt.Fprintf(w, "%s.p%s %f %d\n", name, p.s, h.h.Quantile(p.f), now)
+			if err != nil {
+				return count, err
+			}
+			count += int64(n)
+		}
+	}
+
+	return count, err
+}
+
+// Counter is a Graphite counter metric.
+type Counter struct {
+	c *generic.Counter
+}
+
+// NewCounter returns a new usable counter metric.
+func NewCounter(name string) *Counter {
+	return &Counter{generic.NewCounter(name)}
+}
+
+// With is a no-op.
+func (c *Counter) With(...string) metrics.Counter { return c }
+
+// Add implements counter.
+func (c *Counter) Add(delta float64) { c.c.Add(delta) }
+
+// Gauge is a Graphite gauge metric.
+type Gauge struct {
+	g *generic.Gauge
+}
+
+// NewGauge returns a new usable Gauge metric.
+func NewGauge(name string) *Gauge {
+	return &Gauge{generic.NewGauge(name)}
+}
+
+// With is a no-op.
+func (g *Gauge) With(...string) metrics.Gauge { return g }
+
+// Set implements gauge.
+func (g *Gauge) Set(value float64) { g.g.Set(value) }
+
+// Add implements metrics.Gauge.
+func (g *Gauge) Add(delta float64) { g.g.Add(delta) }
+
+// Histogram is a Graphite histogram metric. Observations are bucketed into
+// per-quantile gauges.
+type Histogram struct {
+	h *generic.Histogram
+}
+
+// NewHistogram returns a new usable Histogram metric.
+func NewHistogram(name string, buckets int) *Histogram {
+	return &Histogram{generic.NewHistogram(name, buckets)}
+}
+
+// With is a no-op.
+func (h *Histogram) With(...string) metrics.Histogram { return h }
+
+// Observe implements histogram.
+func (h *Histogram) Observe(value float64) { h.h.Observe(value) }