Add multi reporters to support multiple backends for a single scope (#26

)

multi/README.md

@@ -0,0 +1,13 @@
+# A buffered multi reporter
+
+Combine reporters to emit to many backends.
+
+Multiple `tally.StatsReporter` as a single reporter:
+```go
+reporter := NewMultiReporter(statsdReporter, ...)
+```
+
+Multiple `tally.CachedStatsReporter` as a single reporter:
+```go
+reporter := NewMultiCachedReporter(m3Reporter, promReporter, ...)
+```

multi/reporter.go

@@ -0,0 +1,198 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// 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.
+
+package multi
+
+import (
+	"time"
+
+	"github.com/uber-go/tally"
+)
+
+type multi struct {
+	multiBaseReporters multiBaseReporters
+	reporters          []tally.StatsReporter
+}
+
+// NewMultiReporter creates a new multi tally.StatsReporter.
+func NewMultiReporter(
+	r ...tally.StatsReporter,
+) tally.StatsReporter {
+	var baseReporters multiBaseReporters
+	for _, r := range r {
+		baseReporters = append(baseReporters, r)
+	}
+	return &multi{
+		multiBaseReporters: baseReporters,
+		reporters:          r,
+	}
+}
+
+func (r *multi) ReportCounter(
+	name string,
+	tags map[string]string,
+	value int64,
+) {
+	for _, r := range r.reporters {
+		r.ReportCounter(name, tags, value)
+	}
+}
+
+func (r *multi) ReportGauge(
+	name string,
+	tags map[string]string,
+	value float64,
+) {
+	for _, r := range r.reporters {
+		r.ReportGauge(name, tags, value)
+	}
+}
+
+func (r *multi) ReportTimer(
+	name string,
+	tags map[string]string,
+	interval time.Duration,
+) {
+	for _, r := range r.reporters {
+		r.ReportTimer(name, tags, interval)
+	}
+}
+
+func (r *multi) Capabilities() tally.Capabilities {
+	return r.multiBaseReporters.Capabilities()
+}
+
+func (r *multi) Flush() {
+	r.multiBaseReporters.Flush()
+}
+
+type multiCached struct {
+	multiBaseReporters multiBaseReporters
+	reporters          []tally.CachedStatsReporter
+}
+
+// NewMultiCachedReporter creates a new multi tally.CachedStatsReporter.
+func NewMultiCachedReporter(
+	r ...tally.CachedStatsReporter,
+) tally.CachedStatsReporter {
+	var baseReporters multiBaseReporters
+	for _, r := range r {
+		baseReporters = append(baseReporters, r)
+	}
+	return &multiCached{
+		multiBaseReporters: baseReporters,
+		reporters:          r,
+	}
+}
+
+func (r *multiCached) AllocateCounter(
+	name string,
+	tags map[string]string,
+) tally.CachedCount {
+	metrics := make([]tally.CachedCount, 0, len(r.reporters))
+	for _, r := range r.reporters {
+		metrics = append(metrics, r.AllocateCounter(name, tags))
+	}
+	return multiMetric{counters: metrics}
+}
+
+func (r *multiCached) AllocateGauge(
+	name string,
+	tags map[string]string,
+) tally.CachedGauge {
+	metrics := make([]tally.CachedGauge, 0, len(r.reporters))
+	for _, r := range r.reporters {
+		metrics = append(metrics, r.AllocateGauge(name, tags))
+	}
+	return multiMetric{gauges: metrics}
+}
+
+func (r *multiCached) AllocateTimer(
+	name string,
+	tags map[string]string,
+) tally.CachedTimer {
+	metrics := make([]tally.CachedTimer, 0, len(r.reporters))
+	for _, r := range r.reporters {
+		metrics = append(metrics, r.AllocateTimer(name, tags))
+	}
+	return multiMetric{timers: metrics}
+}
+
+func (r *multiCached) Capabilities() tally.Capabilities {
+	return r.multiBaseReporters.Capabilities()
+}
+
+func (r *multiCached) Flush() {
+	r.multiBaseReporters.Flush()
+}
+
+type multiMetric struct {
+	counters []tally.CachedCount
+	gauges   []tally.CachedGauge
+	timers   []tally.CachedTimer
+}
+
+func (m multiMetric) ReportCount(value int64) {
+	for _, m := range m.counters {
+		m.ReportCount(value)
+	}
+}
+
+func (m multiMetric) ReportGauge(value float64) {
+	for _, m := range m.gauges {
+		m.ReportGauge(value)
+	}
+}
+
+func (m multiMetric) ReportTimer(interval time.Duration) {
+	for _, m := range m.timers {
+		m.ReportTimer(interval)
+	}
+}
+
+type multiBaseReporters []tally.BaseStatsReporter
+
+func (r multiBaseReporters) Capabilities() tally.Capabilities {
+	c := &capabilities{reporting: true, tagging: true}
+	for _, r := range r {
+		c.reporting = c.reporting && r.Capabilities().Reporting()
+		c.tagging = c.tagging && r.Capabilities().Tagging()
+	}
+	return c
+}
+
+func (r multiBaseReporters) Flush() {
+	for _, r := range r {
+		r.Flush()
+	}
+}
+
+type capabilities struct {
+	reporting bool
+	tagging   bool
+}
+
+func (c *capabilities) Reporting() bool {
+	return c.reporting
+}
+
+func (c *capabilities) Tagging() bool {
+	return c.tagging
+}