Merge branch 'master' into each_no_copy

README.md

@@ -157,6 +157,7 @@ Publishing Metrics
 
 Clients are available for the following destinations:
 
+* AppOptics - https://github.com/ysamlan/go-metrics-appoptics
 * Librato - https://github.com/mihasya/go-metrics-librato
 * Graphite - https://github.com/cyberdelia/go-metrics-graphite
 * InfluxDB - https://github.com/vrischmann/go-metrics-influxdb

debug.go

@@ -2,6 +2,7 @@ package metrics
 
 import (
 	"runtime/debug"
+	"sync"
 	"time"
 )
 
@@ -16,7 +17,8 @@ var (
 		}
 		ReadGCStats Timer
 	}
-	gcStats debug.GCStats
+	gcStats                  debug.GCStats
+	registerDebugMetricsOnce = sync.Once{}
 )
 
 // Capture new values for the Go garbage collector statistics exported in
@@ -54,19 +56,21 @@ func CaptureDebugGCStatsOnce(r Registry) {
 // debug.GCStats.  The metrics are named by their fully-qualified Go symbols,
 // i.e. debug.GCStats.PauseTotal.
 func RegisterDebugGCStats(r Registry) {
-	debugMetrics.GCStats.LastGC = NewGauge()
-	debugMetrics.GCStats.NumGC = NewGauge()
-	debugMetrics.GCStats.Pause = NewHistogram(NewExpDecaySample(1028, 0.015))
-	//debugMetrics.GCStats.PauseQuantiles = NewHistogram(NewExpDecaySample(1028, 0.015))
-	debugMetrics.GCStats.PauseTotal = NewGauge()
-	debugMetrics.ReadGCStats = NewTimer()
+	registerDebugMetricsOnce.Do(func() {
+		debugMetrics.GCStats.LastGC = NewGauge()
+		debugMetrics.GCStats.NumGC = NewGauge()
+		debugMetrics.GCStats.Pause = NewHistogram(NewExpDecaySample(1028, 0.015))
+		//debugMetrics.GCStats.PauseQuantiles = NewHistogram(NewExpDecaySample(1028, 0.015))
+		debugMetrics.GCStats.PauseTotal = NewGauge()
+		debugMetrics.ReadGCStats = NewTimer()
 
-	r.Register("debug.GCStats.LastGC", debugMetrics.GCStats.LastGC)
-	r.Register("debug.GCStats.NumGC", debugMetrics.GCStats.NumGC)
-	r.Register("debug.GCStats.Pause", debugMetrics.GCStats.Pause)
-	//r.Register("debug.GCStats.PauseQuantiles", debugMetrics.GCStats.PauseQuantiles)
-	r.Register("debug.GCStats.PauseTotal", debugMetrics.GCStats.PauseTotal)
-	r.Register("debug.ReadGCStats", debugMetrics.ReadGCStats)
+		r.Register("debug.GCStats.LastGC", debugMetrics.GCStats.LastGC)
+		r.Register("debug.GCStats.NumGC", debugMetrics.GCStats.NumGC)
+		r.Register("debug.GCStats.Pause", debugMetrics.GCStats.Pause)
+		//r.Register("debug.GCStats.PauseQuantiles", debugMetrics.GCStats.PauseQuantiles)
+		r.Register("debug.GCStats.PauseTotal", debugMetrics.GCStats.PauseTotal)
+		r.Register("debug.ReadGCStats", debugMetrics.ReadGCStats)
+	})
 }
 
 // Allocate an initial slice for gcStats.Pause to avoid allocations during

debug_test.go

@@ -46,3 +46,26 @@ func testDebugGCStatsBlocking(ch chan int) {
 		}
 	}
 }
+
+func TestDebugGCStatsDoubleRegister(t *testing.T) {
+	r := NewRegistry()
+	RegisterDebugGCStats(r)
+	var storedGauge = (r.Get("debug.GCStats.LastGC")).(Gauge)
+
+	runtime.GC()
+	CaptureDebugGCStatsOnce(r)
+
+	firstGC := storedGauge.Value()
+	if 0 == firstGC {
+		t.Errorf("firstGC got %d, expected > 0", firstGC)
+	}
+
+	time.Sleep(time.Millisecond)
+
+	RegisterDebugGCStats(r)
+	runtime.GC()
+	CaptureDebugGCStatsOnce(r)
+	if lastGC := storedGauge.Value(); firstGC == lastGC {
+		t.Errorf("lastGC got %d, expected a higher timestamp value", lastGC)
+	}
+}

log.go

@@ -8,17 +8,37 @@ type Logger interface {
 	Printf(format string, v ...interface{})
 }
 
+// Log outputs each metric in the given registry periodically using the given logger.
 func Log(r Registry, freq time.Duration, l Logger) {
 	LogScaled(r, freq, time.Nanosecond, l)
 }
 
-// Output each metric in the given registry periodically using the given
+// LogOnCue outputs each metric in the given registry on demand through the channel
+// using the given logger
+func LogOnCue(r Registry, ch chan interface{}, l Logger) {
+	LogScaledOnCue(r, ch, time.Nanosecond, l)
+}
+
+// LogScaled outputs each metric in the given registry periodically using the given
 // logger. Print timings in `scale` units (eg time.Millisecond) rather than nanos.
 func LogScaled(r Registry, freq time.Duration, scale time.Duration, l Logger) {
+	ch := make(chan interface{})
+	go func(channel chan interface{}) {
+		for _ = range time.Tick(freq) {
+			channel <- struct{}{}
+		}
+	}(ch)
+	LogScaledOnCue(r, ch, scale, l)
+}
+
+// LogScaledOnCue outputs each metric in the given registry on demand through the channel
+// using the given logger. Print timings in `scale` units (eg time.Millisecond) rather
+// than nanos.
+func LogScaledOnCue(r Registry, ch chan interface{}, scale time.Duration, l Logger) {
 	du := float64(scale)
 	duSuffix := scale.String()[1:]
 
-	for _ = range time.Tick(freq) {
+	for _ = range ch {
 		r.Each(func(name string, i interface{}) {
 			switch metric := i.(type) {
 			case Counter:

meter.go

@@ -126,8 +126,6 @@ func (NilMeter) Stop() {}
 
 // StandardMeter is the standard implementation of a Meter.
 type StandardMeter struct {
-	// Only used on stop.
-	lock        sync.Mutex
 	snapshot    *MeterSnapshot
 	a1, a5, a15 EWMA
 	startTime   time.Time
@@ -146,11 +144,7 @@ func newStandardMeter() *StandardMeter {
 
 // Stop stops the meter, Mark() will be a no-op if you use it after being stopped.
 func (m *StandardMeter) Stop() {
-	m.lock.Lock()
-	stopped := m.stopped
-	m.stopped = 1
-	m.lock.Unlock()
-	if stopped != 1 {
+	if atomic.CompareAndSwapUint32(&m.stopped, 0, 1) {
 		arbiter.Lock()
 		delete(arbiter.meters, m)
 		arbiter.Unlock()

meter_test.go

@@ -43,6 +43,11 @@ func TestMeterConcurrency(t *testing.T) {
 			m.Mark(1)
 			wg.Done()
 		}(m, wg)
+		wg.Add(1)
+		go func(m Meter, wg *sync.WaitGroup) {
+			m.Stop()
+			wg.Done()
+		}(m, wg)
 	}
 	wg.Wait()
 }

registry.go

@@ -220,8 +220,8 @@ type metricKV struct {
 
 func (r *StandardRegistry) registered() []metricKV {
 	metrics := make([]metricKV, 0, len(r.metrics))
-	r.mutex.Lock()
-	defer r.mutex.Unlock()
+	r.mutex.RLock()
+	defer r.mutex.RUnlock()
 	for name, i := range r.metrics {
 		metrics = append(metrics, metricKV{
 			name:  name,
@@ -230,6 +230,7 @@ func (r *StandardRegistry) registered() []metricKV {
 	}
 	return metrics
 }
+
 func (r *StandardRegistry) stop(name string) {
 	if i, ok := r.metrics[name]; ok {
 		if s, ok := i.(Stoppable); ok {

runtime.go

@@ -3,6 +3,7 @@ package metrics
 import (
 	"runtime"
 	"runtime/pprof"
+	"sync"
 	"time"
 )
 
@@ -49,7 +50,8 @@ var (
 	numGC       uint32
 	numCgoCalls int64
 
-	threadCreateProfile = pprof.Lookup("threadcreate")
+	threadCreateProfile        = pprof.Lookup("threadcreate")
+	registerRuntimeMetricsOnce = sync.Once{}
 )
 
 // Capture new values for the Go runtime statistics exported in
@@ -146,67 +148,69 @@ func CaptureRuntimeMemStatsOnce(r Registry) {
 // specifically runtime.MemStats.  The runtimeMetrics are named by their
 // fully-qualified Go symbols, i.e. runtime.MemStats.Alloc.
 func RegisterRuntimeMemStats(r Registry) {
-	runtimeMetrics.MemStats.Alloc = NewGauge()
-	runtimeMetrics.MemStats.BuckHashSys = NewGauge()
-	runtimeMetrics.MemStats.DebugGC = NewGauge()
-	runtimeMetrics.MemStats.EnableGC = NewGauge()
-	runtimeMetrics.MemStats.Frees = NewGauge()
-	runtimeMetrics.MemStats.HeapAlloc = NewGauge()
-	runtimeMetrics.MemStats.HeapIdle = NewGauge()
-	runtimeMetrics.MemStats.HeapInuse = NewGauge()
-	runtimeMetrics.MemStats.HeapObjects = NewGauge()
-	runtimeMetrics.MemStats.HeapReleased = NewGauge()
-	runtimeMetrics.MemStats.HeapSys = NewGauge()
-	runtimeMetrics.MemStats.LastGC = NewGauge()
-	runtimeMetrics.MemStats.Lookups = NewGauge()
-	runtimeMetrics.MemStats.Mallocs = NewGauge()
-	runtimeMetrics.MemStats.MCacheInuse = NewGauge()
-	runtimeMetrics.MemStats.MCacheSys = NewGauge()
-	runtimeMetrics.MemStats.MSpanInuse = NewGauge()
-	runtimeMetrics.MemStats.MSpanSys = NewGauge()
-	runtimeMetrics.MemStats.NextGC = NewGauge()
-	runtimeMetrics.MemStats.NumGC = NewGauge()
-	runtimeMetrics.MemStats.GCCPUFraction = NewGaugeFloat64()
-	runtimeMetrics.MemStats.PauseNs = NewHistogram(NewExpDecaySample(1028, 0.015))
-	runtimeMetrics.MemStats.PauseTotalNs = NewGauge()
-	runtimeMetrics.MemStats.StackInuse = NewGauge()
-	runtimeMetrics.MemStats.StackSys = NewGauge()
-	runtimeMetrics.MemStats.Sys = NewGauge()
-	runtimeMetrics.MemStats.TotalAlloc = NewGauge()
-	runtimeMetrics.NumCgoCall = NewGauge()
-	runtimeMetrics.NumGoroutine = NewGauge()
-	runtimeMetrics.NumThread = NewGauge()
-	runtimeMetrics.ReadMemStats = NewTimer()
+	registerRuntimeMetricsOnce.Do(func() {
+		runtimeMetrics.MemStats.Alloc = NewGauge()
+		runtimeMetrics.MemStats.BuckHashSys = NewGauge()
+		runtimeMetrics.MemStats.DebugGC = NewGauge()
+		runtimeMetrics.MemStats.EnableGC = NewGauge()
+		runtimeMetrics.MemStats.Frees = NewGauge()
+		runtimeMetrics.MemStats.HeapAlloc = NewGauge()
+		runtimeMetrics.MemStats.HeapIdle = NewGauge()
+		runtimeMetrics.MemStats.HeapInuse = NewGauge()
+		runtimeMetrics.MemStats.HeapObjects = NewGauge()
+		runtimeMetrics.MemStats.HeapReleased = NewGauge()
+		runtimeMetrics.MemStats.HeapSys = NewGauge()
+		runtimeMetrics.MemStats.LastGC = NewGauge()
+		runtimeMetrics.MemStats.Lookups = NewGauge()
+		runtimeMetrics.MemStats.Mallocs = NewGauge()
+		runtimeMetrics.MemStats.MCacheInuse = NewGauge()
+		runtimeMetrics.MemStats.MCacheSys = NewGauge()
+		runtimeMetrics.MemStats.MSpanInuse = NewGauge()
+		runtimeMetrics.MemStats.MSpanSys = NewGauge()
+		runtimeMetrics.MemStats.NextGC = NewGauge()
+		runtimeMetrics.MemStats.NumGC = NewGauge()
+		runtimeMetrics.MemStats.GCCPUFraction = NewGaugeFloat64()
+		runtimeMetrics.MemStats.PauseNs = NewHistogram(NewExpDecaySample(1028, 0.015))
+		runtimeMetrics.MemStats.PauseTotalNs = NewGauge()
+		runtimeMetrics.MemStats.StackInuse = NewGauge()
+		runtimeMetrics.MemStats.StackSys = NewGauge()
+		runtimeMetrics.MemStats.Sys = NewGauge()
+		runtimeMetrics.MemStats.TotalAlloc = NewGauge()
+		runtimeMetrics.NumCgoCall = NewGauge()
+		runtimeMetrics.NumGoroutine = NewGauge()
+		runtimeMetrics.NumThread = NewGauge()
+		runtimeMetrics.ReadMemStats = NewTimer()
 
-	r.Register("runtime.MemStats.Alloc", runtimeMetrics.MemStats.Alloc)
-	r.Register("runtime.MemStats.BuckHashSys", runtimeMetrics.MemStats.BuckHashSys)
-	r.Register("runtime.MemStats.DebugGC", runtimeMetrics.MemStats.DebugGC)
-	r.Register("runtime.MemStats.EnableGC", runtimeMetrics.MemStats.EnableGC)
-	r.Register("runtime.MemStats.Frees", runtimeMetrics.MemStats.Frees)
-	r.Register("runtime.MemStats.HeapAlloc", runtimeMetrics.MemStats.HeapAlloc)
-	r.Register("runtime.MemStats.HeapIdle", runtimeMetrics.MemStats.HeapIdle)
-	r.Register("runtime.MemStats.HeapInuse", runtimeMetrics.MemStats.HeapInuse)
-	r.Register("runtime.MemStats.HeapObjects", runtimeMetrics.MemStats.HeapObjects)
-	r.Register("runtime.MemStats.HeapReleased", runtimeMetrics.MemStats.HeapReleased)
-	r.Register("runtime.MemStats.HeapSys", runtimeMetrics.MemStats.HeapSys)
-	r.Register("runtime.MemStats.LastGC", runtimeMetrics.MemStats.LastGC)
-	r.Register("runtime.MemStats.Lookups", runtimeMetrics.MemStats.Lookups)
-	r.Register("runtime.MemStats.Mallocs", runtimeMetrics.MemStats.Mallocs)
-	r.Register("runtime.MemStats.MCacheInuse", runtimeMetrics.MemStats.MCacheInuse)
-	r.Register("runtime.MemStats.MCacheSys", runtimeMetrics.MemStats.MCacheSys)
-	r.Register("runtime.MemStats.MSpanInuse", runtimeMetrics.MemStats.MSpanInuse)
-	r.Register("runtime.MemStats.MSpanSys", runtimeMetrics.MemStats.MSpanSys)
-	r.Register("runtime.MemStats.NextGC", runtimeMetrics.MemStats.NextGC)
-	r.Register("runtime.MemStats.NumGC", runtimeMetrics.MemStats.NumGC)
-	r.Register("runtime.MemStats.GCCPUFraction", runtimeMetrics.MemStats.GCCPUFraction)
-	r.Register("runtime.MemStats.PauseNs", runtimeMetrics.MemStats.PauseNs)
-	r.Register("runtime.MemStats.PauseTotalNs", runtimeMetrics.MemStats.PauseTotalNs)
-	r.Register("runtime.MemStats.StackInuse", runtimeMetrics.MemStats.StackInuse)
-	r.Register("runtime.MemStats.StackSys", runtimeMetrics.MemStats.StackSys)
-	r.Register("runtime.MemStats.Sys", runtimeMetrics.MemStats.Sys)
-	r.Register("runtime.MemStats.TotalAlloc", runtimeMetrics.MemStats.TotalAlloc)
-	r.Register("runtime.NumCgoCall", runtimeMetrics.NumCgoCall)
-	r.Register("runtime.NumGoroutine", runtimeMetrics.NumGoroutine)
-	r.Register("runtime.NumThread", runtimeMetrics.NumThread)
-	r.Register("runtime.ReadMemStats", runtimeMetrics.ReadMemStats)
+		r.Register("runtime.MemStats.Alloc", runtimeMetrics.MemStats.Alloc)
+		r.Register("runtime.MemStats.BuckHashSys", runtimeMetrics.MemStats.BuckHashSys)
+		r.Register("runtime.MemStats.DebugGC", runtimeMetrics.MemStats.DebugGC)
+		r.Register("runtime.MemStats.EnableGC", runtimeMetrics.MemStats.EnableGC)
+		r.Register("runtime.MemStats.Frees", runtimeMetrics.MemStats.Frees)
+		r.Register("runtime.MemStats.HeapAlloc", runtimeMetrics.MemStats.HeapAlloc)
+		r.Register("runtime.MemStats.HeapIdle", runtimeMetrics.MemStats.HeapIdle)
+		r.Register("runtime.MemStats.HeapInuse", runtimeMetrics.MemStats.HeapInuse)
+		r.Register("runtime.MemStats.HeapObjects", runtimeMetrics.MemStats.HeapObjects)
+		r.Register("runtime.MemStats.HeapReleased", runtimeMetrics.MemStats.HeapReleased)
+		r.Register("runtime.MemStats.HeapSys", runtimeMetrics.MemStats.HeapSys)
+		r.Register("runtime.MemStats.LastGC", runtimeMetrics.MemStats.LastGC)
+		r.Register("runtime.MemStats.Lookups", runtimeMetrics.MemStats.Lookups)
+		r.Register("runtime.MemStats.Mallocs", runtimeMetrics.MemStats.Mallocs)
+		r.Register("runtime.MemStats.MCacheInuse", runtimeMetrics.MemStats.MCacheInuse)
+		r.Register("runtime.MemStats.MCacheSys", runtimeMetrics.MemStats.MCacheSys)
+		r.Register("runtime.MemStats.MSpanInuse", runtimeMetrics.MemStats.MSpanInuse)
+		r.Register("runtime.MemStats.MSpanSys", runtimeMetrics.MemStats.MSpanSys)
+		r.Register("runtime.MemStats.NextGC", runtimeMetrics.MemStats.NextGC)
+		r.Register("runtime.MemStats.NumGC", runtimeMetrics.MemStats.NumGC)
+		r.Register("runtime.MemStats.GCCPUFraction", runtimeMetrics.MemStats.GCCPUFraction)
+		r.Register("runtime.MemStats.PauseNs", runtimeMetrics.MemStats.PauseNs)
+		r.Register("runtime.MemStats.PauseTotalNs", runtimeMetrics.MemStats.PauseTotalNs)
+		r.Register("runtime.MemStats.StackInuse", runtimeMetrics.MemStats.StackInuse)
+		r.Register("runtime.MemStats.StackSys", runtimeMetrics.MemStats.StackSys)
+		r.Register("runtime.MemStats.Sys", runtimeMetrics.MemStats.Sys)
+		r.Register("runtime.MemStats.TotalAlloc", runtimeMetrics.MemStats.TotalAlloc)
+		r.Register("runtime.NumCgoCall", runtimeMetrics.NumCgoCall)
+		r.Register("runtime.NumGoroutine", runtimeMetrics.NumGoroutine)
+		r.Register("runtime.NumThread", runtimeMetrics.NumThread)
+		r.Register("runtime.ReadMemStats", runtimeMetrics.ReadMemStats)
+	})
 }

runtime_test.go

@@ -6,6 +6,29 @@ import (
 	"time"
 )
 
+func TestRuntimeMemStatsDoubleRegister(t *testing.T) {
+	r := NewRegistry()
+	RegisterRuntimeMemStats(r)
+	storedGauge := r.Get("runtime.MemStats.LastGC").(Gauge)
+
+	runtime.GC()
+	CaptureRuntimeMemStatsOnce(r)
+
+	firstGC := storedGauge.Value()
+	if 0 == firstGC {
+		t.Errorf("firstGC got %d, expected timestamp > 0", firstGC)
+	}
+
+	time.Sleep(time.Millisecond)
+
+	RegisterRuntimeMemStats(r)
+	runtime.GC()
+	CaptureRuntimeMemStatsOnce(r)
+	if lastGC := storedGauge.Value(); firstGC == lastGC {
+		t.Errorf("lastGC got %d, expected a higher timestamp value", lastGC)
+	}
+}
+
 func BenchmarkRuntimeMemStats(b *testing.B) {
 	r := NewRegistry()
 	RegisterRuntimeMemStats(r)