godeps: pull in go-metrics

This commit is contained in:
Péter Szilágyi 2015-06-22 12:00:55 +03:00
parent 7f92e708c5
commit 7bd71fa800
49 changed files with 5431 additions and 0 deletions

4
Godeps/Godeps.json generated

@ -65,6 +65,10 @@
"ImportPath": "github.com/rakyll/goini",
"Rev": "907cca0f578a5316fb864ec6992dc3d9730ec58c"
},
{
"ImportPath": "github.com/rcrowley/go-metrics",
"Rev": "a5cfc242a56ba7fa70b785f678d6214837bf93b9"
},
{
"ImportPath": "github.com/robertkrimen/otto",
"Rev": "dea31a3d392779af358ec41f77a07fcc7e9d04ba"

@ -0,0 +1,9 @@
*.[68]
*.a
*.out
*.swp
_obj
_testmain.go
cmd/metrics-bench/metrics-bench
cmd/metrics-example/metrics-example
cmd/never-read/never-read

@ -0,0 +1,29 @@
Copyright 2012 Richard Crowley. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. 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.
THIS SOFTWARE IS PROVIDED BY RICHARD CROWLEY ``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 RICHARD CROWLEY 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.
The views and conclusions contained in the software and documentation
are those of the authors and should not be interpreted as representing
official policies, either expressed or implied, of Richard Crowley.

@ -0,0 +1,104 @@
go-metrics
==========
Go port of Coda Hale's Metrics library: <https://github.com/codahale/metrics>.
Documentation: <http://godoc.org/github.com/rcrowley/go-metrics>.
Usage
-----
Create and update metrics:
```go
c := metrics.NewCounter()
metrics.Register("foo", c)
c.Inc(47)
g := metrics.NewGauge()
metrics.Register("bar", g)
g.Update(47)
s := metrics.NewExpDecaySample(1028, 0.015) // or metrics.NewUniformSample(1028)
h := metrics.NewHistogram(s)
metrics.Register("baz", h)
h.Update(47)
m := metrics.NewMeter()
metrics.Register("quux", m)
m.Mark(47)
t := metrics.NewTimer()
metrics.Register("bang", t)
t.Time(func() {})
t.Update(47)
```
Periodically log every metric in human-readable form to standard error:
```go
go metrics.Log(metrics.DefaultRegistry, 60e9, log.New(os.Stderr, "metrics: ", log.Lmicroseconds))
```
Periodically log every metric in slightly-more-parseable form to syslog:
```go
w, _ := syslog.Dial("unixgram", "/dev/log", syslog.LOG_INFO, "metrics")
go metrics.Syslog(metrics.DefaultRegistry, 60e9, w)
```
Periodically emit every metric to Graphite:
```go
addr, _ := net.ResolveTCPAddr("tcp", "127.0.0.1:2003")
go metrics.Graphite(metrics.DefaultRegistry, 10e9, "metrics", addr)
```
Periodically emit every metric into InfluxDB:
```go
import "github.com/rcrowley/go-metrics/influxdb"
go influxdb.Influxdb(metrics.DefaultRegistry, 10e9, &influxdb.Config{
Host: "127.0.0.1:8086",
Database: "metrics",
Username: "test",
Password: "test",
})
```
Periodically upload every metric to Librato:
```go
import "github.com/rcrowley/go-metrics/librato"
go librato.Librato(metrics.DefaultRegistry,
10e9, // interval
"example@example.com", // account owner email address
"token", // Librato API token
"hostname", // source
[]float64{0.95}, // precentiles to send
time.Millisecond, // time unit
)
```
Periodically emit every metric to StatHat:
```go
import "github.com/rcrowley/go-metrics/stathat"
go stathat.Stathat(metrics.DefaultRegistry, 10e9, "example@example.com")
```
Installation
------------
```sh
go get github.com/rcrowley/go-metrics
```
StatHat support additionally requires their Go client:
```sh
go get github.com/stathat/go
```

@ -0,0 +1,20 @@
package main
import (
"fmt"
"github.com/rcrowley/go-metrics"
"time"
)
func main() {
r := metrics.NewRegistry()
for i := 0; i < 10000; i++ {
r.Register(fmt.Sprintf("counter-%d", i), metrics.NewCounter())
r.Register(fmt.Sprintf("gauge-%d", i), metrics.NewGauge())
r.Register(fmt.Sprintf("gaugefloat64-%d", i), metrics.NewGaugeFloat64())
r.Register(fmt.Sprintf("histogram-uniform-%d", i), metrics.NewHistogram(metrics.NewUniformSample(1028)))
r.Register(fmt.Sprintf("histogram-exp-%d", i), metrics.NewHistogram(metrics.NewExpDecaySample(1028, 0.015)))
r.Register(fmt.Sprintf("meter-%d", i), metrics.NewMeter())
}
time.Sleep(600e9)
}

@ -0,0 +1,154 @@
package main
import (
"errors"
"github.com/rcrowley/go-metrics"
// "github.com/rcrowley/go-metrics/stathat"
"log"
"math/rand"
"os"
// "syslog"
"time"
)
const fanout = 10
func main() {
r := metrics.NewRegistry()
c := metrics.NewCounter()
r.Register("foo", c)
for i := 0; i < fanout; i++ {
go func() {
for {
c.Dec(19)
time.Sleep(300e6)
}
}()
go func() {
for {
c.Inc(47)
time.Sleep(400e6)
}
}()
}
g := metrics.NewGauge()
r.Register("bar", g)
for i := 0; i < fanout; i++ {
go func() {
for {
g.Update(19)
time.Sleep(300e6)
}
}()
go func() {
for {
g.Update(47)
time.Sleep(400e6)
}
}()
}
gf := metrics.NewGaugeFloat64()
r.Register("barfloat64", gf)
for i := 0; i < fanout; i++ {
go func() {
for {
g.Update(19.0)
time.Sleep(300e6)
}
}()
go func() {
for {
g.Update(47.0)
time.Sleep(400e6)
}
}()
}
hc := metrics.NewHealthcheck(func(h metrics.Healthcheck) {
if 0 < rand.Intn(2) {
h.Healthy()
} else {
h.Unhealthy(errors.New("baz"))
}
})
r.Register("baz", hc)
s := metrics.NewExpDecaySample(1028, 0.015)
//s := metrics.NewUniformSample(1028)
h := metrics.NewHistogram(s)
r.Register("bang", h)
for i := 0; i < fanout; i++ {
go func() {
for {
h.Update(19)
time.Sleep(300e6)
}
}()
go func() {
for {
h.Update(47)
time.Sleep(400e6)
}
}()
}
m := metrics.NewMeter()
r.Register("quux", m)
for i := 0; i < fanout; i++ {
go func() {
for {
m.Mark(19)
time.Sleep(300e6)
}
}()
go func() {
for {
m.Mark(47)
time.Sleep(400e6)
}
}()
}
t := metrics.NewTimer()
r.Register("hooah", t)
for i := 0; i < fanout; i++ {
go func() {
for {
t.Time(func() { time.Sleep(300e6) })
}
}()
go func() {
for {
t.Time(func() { time.Sleep(400e6) })
}
}()
}
metrics.RegisterDebugGCStats(r)
go metrics.CaptureDebugGCStats(r, 5e9)
metrics.RegisterRuntimeMemStats(r)
go metrics.CaptureRuntimeMemStats(r, 5e9)
metrics.Log(r, 60e9, log.New(os.Stderr, "metrics: ", log.Lmicroseconds))
/*
w, err := syslog.Dial("unixgram", "/dev/log", syslog.LOG_INFO, "metrics")
if nil != err { log.Fatalln(err) }
metrics.Syslog(r, 60e9, w)
*/
/*
addr, _ := net.ResolveTCPAddr("tcp", "127.0.0.1:2003")
metrics.Graphite(r, 10e9, "metrics", addr)
*/
/*
stathat.Stathat(r, 10e9, "example@example.com")
*/
}

@ -0,0 +1,22 @@
package main
import (
"log"
"net"
)
func main() {
addr, _ := net.ResolveTCPAddr("tcp", "127.0.0.1:2003")
l, err := net.ListenTCP("tcp", addr)
if nil != err {
log.Fatalln(err)
}
log.Println("listening", l.Addr())
for {
c, err := l.AcceptTCP()
if nil != err {
log.Fatalln(err)
}
log.Println("accepted", c.RemoteAddr())
}
}

@ -0,0 +1,112 @@
package metrics
import "sync/atomic"
// Counters hold an int64 value that can be incremented and decremented.
type Counter interface {
Clear()
Count() int64
Dec(int64)
Inc(int64)
Snapshot() Counter
}
// GetOrRegisterCounter returns an existing Counter or constructs and registers
// a new StandardCounter.
func GetOrRegisterCounter(name string, r Registry) Counter {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, NewCounter).(Counter)
}
// NewCounter constructs a new StandardCounter.
func NewCounter() Counter {
if UseNilMetrics {
return NilCounter{}
}
return &StandardCounter{0}
}
// NewRegisteredCounter constructs and registers a new StandardCounter.
func NewRegisteredCounter(name string, r Registry) Counter {
c := NewCounter()
if nil == r {
r = DefaultRegistry
}
r.Register(name, c)
return c
}
// CounterSnapshot is a read-only copy of another Counter.
type CounterSnapshot int64
// Clear panics.
func (CounterSnapshot) Clear() {
panic("Clear called on a CounterSnapshot")
}
// Count returns the count at the time the snapshot was taken.
func (c CounterSnapshot) Count() int64 { return int64(c) }
// Dec panics.
func (CounterSnapshot) Dec(int64) {
panic("Dec called on a CounterSnapshot")
}
// Inc panics.
func (CounterSnapshot) Inc(int64) {
panic("Inc called on a CounterSnapshot")
}
// Snapshot returns the snapshot.
func (c CounterSnapshot) Snapshot() Counter { return c }
// NilCounter is a no-op Counter.
type NilCounter struct{}
// Clear is a no-op.
func (NilCounter) Clear() {}
// Count is a no-op.
func (NilCounter) Count() int64 { return 0 }
// Dec is a no-op.
func (NilCounter) Dec(i int64) {}
// Inc is a no-op.
func (NilCounter) Inc(i int64) {}
// Snapshot is a no-op.
func (NilCounter) Snapshot() Counter { return NilCounter{} }
// StandardCounter is the standard implementation of a Counter and uses the
// sync/atomic package to manage a single int64 value.
type StandardCounter struct {
count int64
}
// Clear sets the counter to zero.
func (c *StandardCounter) Clear() {
atomic.StoreInt64(&c.count, 0)
}
// Count returns the current count.
func (c *StandardCounter) Count() int64 {
return atomic.LoadInt64(&c.count)
}
// Dec decrements the counter by the given amount.
func (c *StandardCounter) Dec(i int64) {
atomic.AddInt64(&c.count, -i)
}
// Inc increments the counter by the given amount.
func (c *StandardCounter) Inc(i int64) {
atomic.AddInt64(&c.count, i)
}
// Snapshot returns a read-only copy of the counter.
func (c *StandardCounter) Snapshot() Counter {
return CounterSnapshot(c.Count())
}

@ -0,0 +1,77 @@
package metrics
import "testing"
func BenchmarkCounter(b *testing.B) {
c := NewCounter()
b.ResetTimer()
for i := 0; i < b.N; i++ {
c.Inc(1)
}
}
func TestCounterClear(t *testing.T) {
c := NewCounter()
c.Inc(1)
c.Clear()
if count := c.Count(); 0 != count {
t.Errorf("c.Count(): 0 != %v\n", count)
}
}
func TestCounterDec1(t *testing.T) {
c := NewCounter()
c.Dec(1)
if count := c.Count(); -1 != count {
t.Errorf("c.Count(): -1 != %v\n", count)
}
}
func TestCounterDec2(t *testing.T) {
c := NewCounter()
c.Dec(2)
if count := c.Count(); -2 != count {
t.Errorf("c.Count(): -2 != %v\n", count)
}
}
func TestCounterInc1(t *testing.T) {
c := NewCounter()
c.Inc(1)
if count := c.Count(); 1 != count {
t.Errorf("c.Count(): 1 != %v\n", count)
}
}
func TestCounterInc2(t *testing.T) {
c := NewCounter()
c.Inc(2)
if count := c.Count(); 2 != count {
t.Errorf("c.Count(): 2 != %v\n", count)
}
}
func TestCounterSnapshot(t *testing.T) {
c := NewCounter()
c.Inc(1)
snapshot := c.Snapshot()
c.Inc(1)
if count := snapshot.Count(); 1 != count {
t.Errorf("c.Count(): 1 != %v\n", count)
}
}
func TestCounterZero(t *testing.T) {
c := NewCounter()
if count := c.Count(); 0 != count {
t.Errorf("c.Count(): 0 != %v\n", count)
}
}
func TestGetOrRegisterCounter(t *testing.T) {
r := NewRegistry()
NewRegisteredCounter("foo", r).Inc(47)
if c := GetOrRegisterCounter("foo", r); 47 != c.Count() {
t.Fatal(c)
}
}

@ -0,0 +1,76 @@
package metrics
import (
"runtime/debug"
"time"
)
var (
debugMetrics struct {
GCStats struct {
LastGC Gauge
NumGC Gauge
Pause Histogram
//PauseQuantiles Histogram
PauseTotal Gauge
}
ReadGCStats Timer
}
gcStats debug.GCStats
)
// Capture new values for the Go garbage collector statistics exported in
// debug.GCStats. This is designed to be called as a goroutine.
func CaptureDebugGCStats(r Registry, d time.Duration) {
for _ = range time.Tick(d) {
CaptureDebugGCStatsOnce(r)
}
}
// Capture new values for the Go garbage collector statistics exported in
// debug.GCStats. This is designed to be called in a background goroutine.
// Giving a registry which has not been given to RegisterDebugGCStats will
// panic.
//
// Be careful (but much less so) with this because debug.ReadGCStats calls
// the C function runtime·lock(runtime·mheap) which, while not a stop-the-world
// operation, isn't something you want to be doing all the time.
func CaptureDebugGCStatsOnce(r Registry) {
lastGC := gcStats.LastGC
t := time.Now()
debug.ReadGCStats(&gcStats)
debugMetrics.ReadGCStats.UpdateSince(t)
debugMetrics.GCStats.LastGC.Update(int64(gcStats.LastGC.UnixNano()))
debugMetrics.GCStats.NumGC.Update(int64(gcStats.NumGC))
if lastGC != gcStats.LastGC && 0 < len(gcStats.Pause) {
debugMetrics.GCStats.Pause.Update(int64(gcStats.Pause[0]))
}
//debugMetrics.GCStats.PauseQuantiles.Update(gcStats.PauseQuantiles)
debugMetrics.GCStats.PauseTotal.Update(int64(gcStats.PauseTotal))
}
// Register metrics for the Go garbage collector statistics exported in
// 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()
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
// normal operation.
func init() {
gcStats.Pause = make([]time.Duration, 11)
}

@ -0,0 +1,48 @@
package metrics
import (
"runtime"
"runtime/debug"
"testing"
"time"
)
func BenchmarkDebugGCStats(b *testing.B) {
r := NewRegistry()
RegisterDebugGCStats(r)
b.ResetTimer()
for i := 0; i < b.N; i++ {
CaptureDebugGCStatsOnce(r)
}
}
func TestDebugGCStatsBlocking(t *testing.T) {
if g := runtime.GOMAXPROCS(0); g < 2 {
t.Skipf("skipping TestDebugGCMemStatsBlocking with GOMAXPROCS=%d\n", g)
return
}
ch := make(chan int)
go testDebugGCStatsBlocking(ch)
var gcStats debug.GCStats
t0 := time.Now()
debug.ReadGCStats(&gcStats)
t1 := time.Now()
t.Log("i++ during debug.ReadGCStats:", <-ch)
go testDebugGCStatsBlocking(ch)
d := t1.Sub(t0)
t.Log(d)
time.Sleep(d)
t.Log("i++ during time.Sleep:", <-ch)
}
func testDebugGCStatsBlocking(ch chan int) {
i := 0
for {
select {
case ch <- i:
return
default:
i++
}
}
}

@ -0,0 +1,118 @@
package metrics
import (
"math"
"sync"
"sync/atomic"
)
// EWMAs continuously calculate an exponentially-weighted moving average
// based on an outside source of clock ticks.
type EWMA interface {
Rate() float64
Snapshot() EWMA
Tick()
Update(int64)
}
// NewEWMA constructs a new EWMA with the given alpha.
func NewEWMA(alpha float64) EWMA {
if UseNilMetrics {
return NilEWMA{}
}
return &StandardEWMA{alpha: alpha}
}
// NewEWMA1 constructs a new EWMA for a one-minute moving average.
func NewEWMA1() EWMA {
return NewEWMA(1 - math.Exp(-5.0/60.0/1))
}
// NewEWMA5 constructs a new EWMA for a five-minute moving average.
func NewEWMA5() EWMA {
return NewEWMA(1 - math.Exp(-5.0/60.0/5))
}
// NewEWMA15 constructs a new EWMA for a fifteen-minute moving average.
func NewEWMA15() EWMA {
return NewEWMA(1 - math.Exp(-5.0/60.0/15))
}
// EWMASnapshot is a read-only copy of another EWMA.
type EWMASnapshot float64
// Rate returns the rate of events per second at the time the snapshot was
// taken.
func (a EWMASnapshot) Rate() float64 { return float64(a) }
// Snapshot returns the snapshot.
func (a EWMASnapshot) Snapshot() EWMA { return a }
// Tick panics.
func (EWMASnapshot) Tick() {
panic("Tick called on an EWMASnapshot")
}
// Update panics.
func (EWMASnapshot) Update(int64) {
panic("Update called on an EWMASnapshot")
}
// NilEWMA is a no-op EWMA.
type NilEWMA struct{}
// Rate is a no-op.
func (NilEWMA) Rate() float64 { return 0.0 }
// Snapshot is a no-op.
func (NilEWMA) Snapshot() EWMA { return NilEWMA{} }
// Tick is a no-op.
func (NilEWMA) Tick() {}
// Update is a no-op.
func (NilEWMA) Update(n int64) {}
// StandardEWMA is the standard implementation of an EWMA and tracks the number
// of uncounted events and processes them on each tick. It uses the
// sync/atomic package to manage uncounted events.
type StandardEWMA struct {
uncounted int64 // /!\ this should be the first member to ensure 64-bit alignment
alpha float64
rate float64
init bool
mutex sync.Mutex
}
// Rate returns the moving average rate of events per second.
func (a *StandardEWMA) Rate() float64 {
a.mutex.Lock()
defer a.mutex.Unlock()
return a.rate * float64(1e9)
}
// Snapshot returns a read-only copy of the EWMA.
func (a *StandardEWMA) Snapshot() EWMA {
return EWMASnapshot(a.Rate())
}
// Tick ticks the clock to update the moving average. It assumes it is called
// every five seconds.
func (a *StandardEWMA) Tick() {
count := atomic.LoadInt64(&a.uncounted)
atomic.AddInt64(&a.uncounted, -count)
instantRate := float64(count) / float64(5e9)
a.mutex.Lock()
defer a.mutex.Unlock()
if a.init {
a.rate += a.alpha * (instantRate - a.rate)
} else {
a.init = true
a.rate = instantRate
}
}
// Update adds n uncounted events.
func (a *StandardEWMA) Update(n int64) {
atomic.AddInt64(&a.uncounted, n)
}

@ -0,0 +1,225 @@
package metrics
import "testing"
func BenchmarkEWMA(b *testing.B) {
a := NewEWMA1()
b.ResetTimer()
for i := 0; i < b.N; i++ {
a.Update(1)
a.Tick()
}
}
func TestEWMA1(t *testing.T) {
a := NewEWMA1()
a.Update(3)
a.Tick()
if rate := a.Rate(); 0.6 != rate {
t.Errorf("initial a.Rate(): 0.6 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.22072766470286553 != rate {
t.Errorf("1 minute a.Rate(): 0.22072766470286553 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.08120116994196772 != rate {
t.Errorf("2 minute a.Rate(): 0.08120116994196772 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.029872241020718428 != rate {
t.Errorf("3 minute a.Rate(): 0.029872241020718428 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.01098938333324054 != rate {
t.Errorf("4 minute a.Rate(): 0.01098938333324054 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.004042768199451294 != rate {
t.Errorf("5 minute a.Rate(): 0.004042768199451294 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.0014872513059998212 != rate {
t.Errorf("6 minute a.Rate(): 0.0014872513059998212 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.0005471291793327122 != rate {
t.Errorf("7 minute a.Rate(): 0.0005471291793327122 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.00020127757674150815 != rate {
t.Errorf("8 minute a.Rate(): 0.00020127757674150815 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 7.404588245200814e-05 != rate {
t.Errorf("9 minute a.Rate(): 7.404588245200814e-05 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 2.7239957857491083e-05 != rate {
t.Errorf("10 minute a.Rate(): 2.7239957857491083e-05 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 1.0021020474147462e-05 != rate {
t.Errorf("11 minute a.Rate(): 1.0021020474147462e-05 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 3.6865274119969525e-06 != rate {
t.Errorf("12 minute a.Rate(): 3.6865274119969525e-06 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 1.3561976441886433e-06 != rate {
t.Errorf("13 minute a.Rate(): 1.3561976441886433e-06 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 4.989172314621449e-07 != rate {
t.Errorf("14 minute a.Rate(): 4.989172314621449e-07 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 1.8354139230109722e-07 != rate {
t.Errorf("15 minute a.Rate(): 1.8354139230109722e-07 != %v\n", rate)
}
}
func TestEWMA5(t *testing.T) {
a := NewEWMA5()
a.Update(3)
a.Tick()
if rate := a.Rate(); 0.6 != rate {
t.Errorf("initial a.Rate(): 0.6 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.49123845184678905 != rate {
t.Errorf("1 minute a.Rate(): 0.49123845184678905 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.4021920276213837 != rate {
t.Errorf("2 minute a.Rate(): 0.4021920276213837 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.32928698165641596 != rate {
t.Errorf("3 minute a.Rate(): 0.32928698165641596 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.269597378470333 != rate {
t.Errorf("4 minute a.Rate(): 0.269597378470333 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.2207276647028654 != rate {
t.Errorf("5 minute a.Rate(): 0.2207276647028654 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.18071652714732128 != rate {
t.Errorf("6 minute a.Rate(): 0.18071652714732128 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.14795817836496392 != rate {
t.Errorf("7 minute a.Rate(): 0.14795817836496392 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.12113791079679326 != rate {
t.Errorf("8 minute a.Rate(): 0.12113791079679326 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.09917933293295193 != rate {
t.Errorf("9 minute a.Rate(): 0.09917933293295193 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.08120116994196763 != rate {
t.Errorf("10 minute a.Rate(): 0.08120116994196763 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.06648189501740036 != rate {
t.Errorf("11 minute a.Rate(): 0.06648189501740036 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.05443077197364752 != rate {
t.Errorf("12 minute a.Rate(): 0.05443077197364752 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.04456414692860035 != rate {
t.Errorf("13 minute a.Rate(): 0.04456414692860035 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.03648603757513079 != rate {
t.Errorf("14 minute a.Rate(): 0.03648603757513079 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.0298722410207183831020718428 != rate {
t.Errorf("15 minute a.Rate(): 0.0298722410207183831020718428 != %v\n", rate)
}
}
func TestEWMA15(t *testing.T) {
a := NewEWMA15()
a.Update(3)
a.Tick()
if rate := a.Rate(); 0.6 != rate {
t.Errorf("initial a.Rate(): 0.6 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.5613041910189706 != rate {
t.Errorf("1 minute a.Rate(): 0.5613041910189706 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.5251039914257684 != rate {
t.Errorf("2 minute a.Rate(): 0.5251039914257684 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.4912384518467888184678905 != rate {
t.Errorf("3 minute a.Rate(): 0.4912384518467888184678905 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.459557003018789 != rate {
t.Errorf("4 minute a.Rate(): 0.459557003018789 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.4299187863442732 != rate {
t.Errorf("5 minute a.Rate(): 0.4299187863442732 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.4021920276213831 != rate {
t.Errorf("6 minute a.Rate(): 0.4021920276213831 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.37625345116383313 != rate {
t.Errorf("7 minute a.Rate(): 0.37625345116383313 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.3519877317060185 != rate {
t.Errorf("8 minute a.Rate(): 0.3519877317060185 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.3292869816564153165641596 != rate {
t.Errorf("9 minute a.Rate(): 0.3292869816564153165641596 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.3080502714195546 != rate {
t.Errorf("10 minute a.Rate(): 0.3080502714195546 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.2881831806538789 != rate {
t.Errorf("11 minute a.Rate(): 0.2881831806538789 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.26959737847033216 != rate {
t.Errorf("12 minute a.Rate(): 0.26959737847033216 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.2522102307052083 != rate {
t.Errorf("13 minute a.Rate(): 0.2522102307052083 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.23594443252115815 != rate {
t.Errorf("14 minute a.Rate(): 0.23594443252115815 != %v\n", rate)
}
elapseMinute(a)
if rate := a.Rate(); 0.2207276647028646247028654470286553 != rate {
t.Errorf("15 minute a.Rate(): 0.2207276647028646247028654470286553 != %v\n", rate)
}
}
func elapseMinute(a EWMA) {
for i := 0; i < 12; i++ {
a.Tick()
}
}

@ -0,0 +1,84 @@
package metrics
import "sync/atomic"
// Gauges hold an int64 value that can be set arbitrarily.
type Gauge interface {
Snapshot() Gauge
Update(int64)
Value() int64
}
// GetOrRegisterGauge returns an existing Gauge or constructs and registers a
// new StandardGauge.
func GetOrRegisterGauge(name string, r Registry) Gauge {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, NewGauge).(Gauge)
}
// NewGauge constructs a new StandardGauge.
func NewGauge() Gauge {
if UseNilMetrics {
return NilGauge{}
}
return &StandardGauge{0}
}
// NewRegisteredGauge constructs and registers a new StandardGauge.
func NewRegisteredGauge(name string, r Registry) Gauge {
c := NewGauge()
if nil == r {
r = DefaultRegistry
}
r.Register(name, c)
return c
}
// GaugeSnapshot is a read-only copy of another Gauge.
type GaugeSnapshot int64
// Snapshot returns the snapshot.
func (g GaugeSnapshot) Snapshot() Gauge { return g }
// Update panics.
func (GaugeSnapshot) Update(int64) {
panic("Update called on a GaugeSnapshot")
}
// Value returns the value at the time the snapshot was taken.
func (g GaugeSnapshot) Value() int64 { return int64(g) }
// NilGauge is a no-op Gauge.
type NilGauge struct{}
// Snapshot is a no-op.
func (NilGauge) Snapshot() Gauge { return NilGauge{} }
// Update is a no-op.
func (NilGauge) Update(v int64) {}
// Value is a no-op.
func (NilGauge) Value() int64 { return 0 }
// StandardGauge is the standard implementation of a Gauge and uses the
// sync/atomic package to manage a single int64 value.
type StandardGauge struct {
value int64
}
// Snapshot returns a read-only copy of the gauge.
func (g *StandardGauge) Snapshot() Gauge {
return GaugeSnapshot(g.Value())
}
// Update updates the gauge's value.
func (g *StandardGauge) Update(v int64) {
atomic.StoreInt64(&g.value, v)
}
// Value returns the gauge's current value.
func (g *StandardGauge) Value() int64 {
return atomic.LoadInt64(&g.value)
}

@ -0,0 +1,91 @@
package metrics
import "sync"
// GaugeFloat64s hold a float64 value that can be set arbitrarily.
type GaugeFloat64 interface {
Snapshot() GaugeFloat64
Update(float64)
Value() float64
}
// GetOrRegisterGaugeFloat64 returns an existing GaugeFloat64 or constructs and registers a
// new StandardGaugeFloat64.
func GetOrRegisterGaugeFloat64(name string, r Registry) GaugeFloat64 {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, NewGaugeFloat64()).(GaugeFloat64)
}
// NewGaugeFloat64 constructs a new StandardGaugeFloat64.
func NewGaugeFloat64() GaugeFloat64 {
if UseNilMetrics {
return NilGaugeFloat64{}
}
return &StandardGaugeFloat64{
value: 0.0,
}
}
// NewRegisteredGaugeFloat64 constructs and registers a new StandardGaugeFloat64.
func NewRegisteredGaugeFloat64(name string, r Registry) GaugeFloat64 {
c := NewGaugeFloat64()
if nil == r {
r = DefaultRegistry
}
r.Register(name, c)
return c
}
// GaugeFloat64Snapshot is a read-only copy of another GaugeFloat64.
type GaugeFloat64Snapshot float64
// Snapshot returns the snapshot.
func (g GaugeFloat64Snapshot) Snapshot() GaugeFloat64 { return g }
// Update panics.
func (GaugeFloat64Snapshot) Update(float64) {
panic("Update called on a GaugeFloat64Snapshot")
}
// Value returns the value at the time the snapshot was taken.
func (g GaugeFloat64Snapshot) Value() float64 { return float64(g) }
// NilGauge is a no-op Gauge.
type NilGaugeFloat64 struct{}
// Snapshot is a no-op.
func (NilGaugeFloat64) Snapshot() GaugeFloat64 { return NilGaugeFloat64{} }
// Update is a no-op.
func (NilGaugeFloat64) Update(v float64) {}
// Value is a no-op.
func (NilGaugeFloat64) Value() float64 { return 0.0 }
// StandardGaugeFloat64 is the standard implementation of a GaugeFloat64 and uses
// sync.Mutex to manage a single float64 value.
type StandardGaugeFloat64 struct {
mutex sync.Mutex
value float64
}
// Snapshot returns a read-only copy of the gauge.
func (g *StandardGaugeFloat64) Snapshot() GaugeFloat64 {
return GaugeFloat64Snapshot(g.Value())
}
// Update updates the gauge's value.
func (g *StandardGaugeFloat64) Update(v float64) {
g.mutex.Lock()
defer g.mutex.Unlock()
g.value = v
}
// Value returns the gauge's current value.
func (g *StandardGaugeFloat64) Value() float64 {
g.mutex.Lock()
defer g.mutex.Unlock()
return g.value
}

@ -0,0 +1,38 @@
package metrics
import "testing"
func BenchmarkGuageFloat64(b *testing.B) {
g := NewGaugeFloat64()
b.ResetTimer()
for i := 0; i < b.N; i++ {
g.Update(float64(i))
}
}
func TestGaugeFloat64(t *testing.T) {
g := NewGaugeFloat64()
g.Update(float64(47.0))
if v := g.Value(); float64(47.0) != v {
t.Errorf("g.Value(): 47.0 != %v\n", v)
}
}
func TestGaugeFloat64Snapshot(t *testing.T) {
g := NewGaugeFloat64()
g.Update(float64(47.0))
snapshot := g.Snapshot()
g.Update(float64(0))
if v := snapshot.Value(); float64(47.0) != v {
t.Errorf("g.Value(): 47.0 != %v\n", v)
}
}
func TestGetOrRegisterGaugeFloat64(t *testing.T) {
r := NewRegistry()
NewRegisteredGaugeFloat64("foo", r).Update(float64(47.0))
t.Logf("registry: %v", r)
if g := GetOrRegisterGaugeFloat64("foo", r); float64(47.0) != g.Value() {
t.Fatal(g)
}
}

@ -0,0 +1,37 @@
package metrics
import "testing"
func BenchmarkGuage(b *testing.B) {
g := NewGauge()
b.ResetTimer()
for i := 0; i < b.N; i++ {
g.Update(int64(i))
}
}
func TestGauge(t *testing.T) {
g := NewGauge()
g.Update(int64(47))
if v := g.Value(); 47 != v {
t.Errorf("g.Value(): 47 != %v\n", v)
}
}
func TestGaugeSnapshot(t *testing.T) {
g := NewGauge()
g.Update(int64(47))
snapshot := g.Snapshot()
g.Update(int64(0))
if v := snapshot.Value(); 47 != v {
t.Errorf("g.Value(): 47 != %v\n", v)
}
}
func TestGetOrRegisterGauge(t *testing.T) {
r := NewRegistry()
NewRegisteredGauge("foo", r).Update(47)
if g := GetOrRegisterGauge("foo", r); 47 != g.Value() {
t.Fatal(g)
}
}

@ -0,0 +1,111 @@
package metrics
import (
"bufio"
"fmt"
"log"
"net"
"strconv"
"strings"
"time"
)
// GraphiteConfig provides a container with configuration parameters for
// the Graphite exporter
type GraphiteConfig struct {
Addr *net.TCPAddr // Network address to connect to
Registry Registry // Registry to be exported
FlushInterval time.Duration // Flush interval
DurationUnit time.Duration // Time conversion unit for durations
Prefix string // Prefix to be prepended to metric names
Percentiles []float64 // Percentiles to export from timers and histograms
}
// Graphite is a blocking exporter function which reports metrics in r
// to a graphite server located at addr, flushing them every d duration
// and prepending metric names with prefix.
func Graphite(r Registry, d time.Duration, prefix string, addr *net.TCPAddr) {
GraphiteWithConfig(GraphiteConfig{
Addr: addr,
Registry: r,
FlushInterval: d,
DurationUnit: time.Nanosecond,
Prefix: prefix,
Percentiles: []float64{0.5, 0.75, 0.95, 0.99, 0.999},
})
}
// GraphiteWithConfig is a blocking exporter function just like Graphite,
// but it takes a GraphiteConfig instead.
func GraphiteWithConfig(c GraphiteConfig) {
for _ = range time.Tick(c.FlushInterval) {
if err := graphite(&c); nil != err {
log.Println(err)
}
}
}
// GraphiteOnce performs a single submission to Graphite, returning a
// non-nil error on failed connections. This can be used in a loop
// similar to GraphiteWithConfig for custom error handling.
func GraphiteOnce(c GraphiteConfig) error {
return graphite(&c)
}
func graphite(c *GraphiteConfig) error {
now := time.Now().Unix()
du := float64(c.DurationUnit)
conn, err := net.DialTCP("tcp", nil, c.Addr)
if nil != err {
return err
}
defer conn.Close()
w := bufio.NewWriter(conn)
c.Registry.Each(func(name string, i interface{}) {
switch metric := i.(type) {
case Counter:
fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, metric.Count(), now)
case Gauge:
fmt.Fprintf(w, "%s.%s.value %d %d\n", c.Prefix, name, metric.Value(), now)
case GaugeFloat64:
fmt.Fprintf(w, "%s.%s.value %f %d\n", c.Prefix, name, metric.Value(), now)
case Histogram:
h := metric.Snapshot()
ps := h.Percentiles(c.Percentiles)
fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, h.Count(), now)
fmt.Fprintf(w, "%s.%s.min %d %d\n", c.Prefix, name, h.Min(), now)
fmt.Fprintf(w, "%s.%s.max %d %d\n", c.Prefix, name, h.Max(), now)
fmt.Fprintf(w, "%s.%s.mean %.2f %d\n", c.Prefix, name, h.Mean(), now)
fmt.Fprintf(w, "%s.%s.std-dev %.2f %d\n", c.Prefix, name, h.StdDev(), now)
for psIdx, psKey := range c.Percentiles {
key := strings.Replace(strconv.FormatFloat(psKey*100.0, 'f', -1, 64), ".", "", 1)
fmt.Fprintf(w, "%s.%s.%s-percentile %.2f %d\n", c.Prefix, name, key, ps[psIdx], now)
}
case Meter:
m := metric.Snapshot()
fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, m.Count(), now)
fmt.Fprintf(w, "%s.%s.one-minute %.2f %d\n", c.Prefix, name, m.Rate1(), now)
fmt.Fprintf(w, "%s.%s.five-minute %.2f %d\n", c.Prefix, name, m.Rate5(), now)
fmt.Fprintf(w, "%s.%s.fifteen-minute %.2f %d\n", c.Prefix, name, m.Rate15(), now)
fmt.Fprintf(w, "%s.%s.mean %.2f %d\n", c.Prefix, name, m.RateMean(), now)
case Timer:
t := metric.Snapshot()
ps := t.Percentiles(c.Percentiles)
fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, t.Count(), now)
fmt.Fprintf(w, "%s.%s.min %d %d\n", c.Prefix, name, t.Min()/int64(du), now)
fmt.Fprintf(w, "%s.%s.max %d %d\n", c.Prefix, name, t.Max()/int64(du), now)
fmt.Fprintf(w, "%s.%s.mean %.2f %d\n", c.Prefix, name, t.Mean()/du, now)
fmt.Fprintf(w, "%s.%s.std-dev %.2f %d\n", c.Prefix, name, t.StdDev()/du, now)
for psIdx, psKey := range c.Percentiles {
key := strings.Replace(strconv.FormatFloat(psKey*100.0, 'f', -1, 64), ".", "", 1)
fmt.Fprintf(w, "%s.%s.%s-percentile %.2f %d\n", c.Prefix, name, key, ps[psIdx], now)
}
fmt.Fprintf(w, "%s.%s.one-minute %.2f %d\n", c.Prefix, name, t.Rate1(), now)
fmt.Fprintf(w, "%s.%s.five-minute %.2f %d\n", c.Prefix, name, t.Rate5(), now)
fmt.Fprintf(w, "%s.%s.fifteen-minute %.2f %d\n", c.Prefix, name, t.Rate15(), now)
fmt.Fprintf(w, "%s.%s.mean-rate %.2f %d\n", c.Prefix, name, t.RateMean(), now)
}
w.Flush()
})
return nil
}

@ -0,0 +1,22 @@
package metrics
import (
"net"
"time"
)
func ExampleGraphite() {
addr, _ := net.ResolveTCPAddr("net", ":2003")
go Graphite(DefaultRegistry, 1*time.Second, "some.prefix", addr)
}
func ExampleGraphiteWithConfig() {
addr, _ := net.ResolveTCPAddr("net", ":2003")
go GraphiteWithConfig(GraphiteConfig{
Addr: addr,
Registry: DefaultRegistry,
FlushInterval: 1 * time.Second,
DurationUnit: time.Millisecond,
Percentiles: []float64{ 0.5, 0.75, 0.99, 0.999 },
})
}

@ -0,0 +1,61 @@
package metrics
// Healthchecks hold an error value describing an arbitrary up/down status.
type Healthcheck interface {
Check()
Error() error
Healthy()
Unhealthy(error)
}
// NewHealthcheck constructs a new Healthcheck which will use the given
// function to update its status.
func NewHealthcheck(f func(Healthcheck)) Healthcheck {
if UseNilMetrics {
return NilHealthcheck{}
}
return &StandardHealthcheck{nil, f}
}
// NilHealthcheck is a no-op.
type NilHealthcheck struct{}
// Check is a no-op.
func (NilHealthcheck) Check() {}
// Error is a no-op.
func (NilHealthcheck) Error() error { return nil }
// Healthy is a no-op.
func (NilHealthcheck) Healthy() {}
// Unhealthy is a no-op.
func (NilHealthcheck) Unhealthy(error) {}
// StandardHealthcheck is the standard implementation of a Healthcheck and
// stores the status and a function to call to update the status.
type StandardHealthcheck struct {
err error
f func(Healthcheck)
}
// Check runs the healthcheck function to update the healthcheck's status.
func (h *StandardHealthcheck) Check() {
h.f(h)
}
// Error returns the healthcheck's status, which will be nil if it is healthy.
func (h *StandardHealthcheck) Error() error {
return h.err
}
// Healthy marks the healthcheck as healthy.
func (h *StandardHealthcheck) Healthy() {
h.err = nil
}
// Unhealthy marks the healthcheck as unhealthy. The error is stored and
// may be retrieved by the Error method.
func (h *StandardHealthcheck) Unhealthy(err error) {
h.err = err
}

@ -0,0 +1,202 @@
package metrics
// Histograms calculate distribution statistics from a series of int64 values.
type Histogram interface {
Clear()
Count() int64
Max() int64
Mean() float64
Min() int64
Percentile(float64) float64
Percentiles([]float64) []float64
Sample() Sample
Snapshot() Histogram
StdDev() float64
Sum() int64
Update(int64)
Variance() float64
}
// GetOrRegisterHistogram returns an existing Histogram or constructs and
// registers a new StandardHistogram.
func GetOrRegisterHistogram(name string, r Registry, s Sample) Histogram {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, func() Histogram { return NewHistogram(s) }).(Histogram)
}
// NewHistogram constructs a new StandardHistogram from a Sample.
func NewHistogram(s Sample) Histogram {
if UseNilMetrics {
return NilHistogram{}
}
return &StandardHistogram{sample: s}
}
// NewRegisteredHistogram constructs and registers a new StandardHistogram from
// a Sample.
func NewRegisteredHistogram(name string, r Registry, s Sample) Histogram {
c := NewHistogram(s)
if nil == r {
r = DefaultRegistry
}
r.Register(name, c)
return c
}
// HistogramSnapshot is a read-only copy of another Histogram.
type HistogramSnapshot struct {
sample *SampleSnapshot
}
// Clear panics.
func (*HistogramSnapshot) Clear() {
panic("Clear called on a HistogramSnapshot")
}
// Count returns the number of samples recorded at the time the snapshot was
// taken.
func (h *HistogramSnapshot) Count() int64 { return h.sample.Count() }
// Max returns the maximum value in the sample at the time the snapshot was
// taken.
func (h *HistogramSnapshot) Max() int64 { return h.sample.Max() }
// Mean returns the mean of the values in the sample at the time the snapshot
// was taken.
func (h *HistogramSnapshot) Mean() float64 { return h.sample.Mean() }
// Min returns the minimum value in the sample at the time the snapshot was
// taken.
func (h *HistogramSnapshot) Min() int64 { return h.sample.Min() }
// Percentile returns an arbitrary percentile of values in the sample at the
// time the snapshot was taken.
func (h *HistogramSnapshot) Percentile(p float64) float64 {
return h.sample.Percentile(p)
}
// Percentiles returns a slice of arbitrary percentiles of values in the sample
// at the time the snapshot was taken.
func (h *HistogramSnapshot) Percentiles(ps []float64) []float64 {
return h.sample.Percentiles(ps)
}
// Sample returns the Sample underlying the histogram.
func (h *HistogramSnapshot) Sample() Sample { return h.sample }
// Snapshot returns the snapshot.
func (h *HistogramSnapshot) Snapshot() Histogram { return h }
// StdDev returns the standard deviation of the values in the sample at the
// time the snapshot was taken.
func (h *HistogramSnapshot) StdDev() float64 { return h.sample.StdDev() }
// Sum returns the sum in the sample at the time the snapshot was taken.
func (h *HistogramSnapshot) Sum() int64 { return h.sample.Sum() }
// Update panics.
func (*HistogramSnapshot) Update(int64) {
panic("Update called on a HistogramSnapshot")
}
// Variance returns the variance of inputs at the time the snapshot was taken.
func (h *HistogramSnapshot) Variance() float64 { return h.sample.Variance() }
// NilHistogram is a no-op Histogram.
type NilHistogram struct{}
// Clear is a no-op.
func (NilHistogram) Clear() {}
// Count is a no-op.
func (NilHistogram) Count() int64 { return 0 }
// Max is a no-op.
func (NilHistogram) Max() int64 { return 0 }
// Mean is a no-op.
func (NilHistogram) Mean() float64 { return 0.0 }
// Min is a no-op.
func (NilHistogram) Min() int64 { return 0 }
// Percentile is a no-op.
func (NilHistogram) Percentile(p float64) float64 { return 0.0 }
// Percentiles is a no-op.
func (NilHistogram) Percentiles(ps []float64) []float64 {
return make([]float64, len(ps))
}
// Sample is a no-op.
func (NilHistogram) Sample() Sample { return NilSample{} }
// Snapshot is a no-op.
func (NilHistogram) Snapshot() Histogram { return NilHistogram{} }
// StdDev is a no-op.
func (NilHistogram) StdDev() float64 { return 0.0 }
// Sum is a no-op.
func (NilHistogram) Sum() int64 { return 0 }
// Update is a no-op.
func (NilHistogram) Update(v int64) {}
// Variance is a no-op.
func (NilHistogram) Variance() float64 { return 0.0 }
// StandardHistogram is the standard implementation of a Histogram and uses a
// Sample to bound its memory use.
type StandardHistogram struct {
sample Sample
}
// Clear clears the histogram and its sample.
func (h *StandardHistogram) Clear() { h.sample.Clear() }
// Count returns the number of samples recorded since the histogram was last
// cleared.
func (h *StandardHistogram) Count() int64 { return h.sample.Count() }
// Max returns the maximum value in the sample.
func (h *StandardHistogram) Max() int64 { return h.sample.Max() }
// Mean returns the mean of the values in the sample.
func (h *StandardHistogram) Mean() float64 { return h.sample.Mean() }
// Min returns the minimum value in the sample.
func (h *StandardHistogram) Min() int64 { return h.sample.Min() }
// Percentile returns an arbitrary percentile of the values in the sample.
func (h *StandardHistogram) Percentile(p float64) float64 {
return h.sample.Percentile(p)
}
// Percentiles returns a slice of arbitrary percentiles of the values in the
// sample.
func (h *StandardHistogram) Percentiles(ps []float64) []float64 {
return h.sample.Percentiles(ps)
}
// Sample returns the Sample underlying the histogram.
func (h *StandardHistogram) Sample() Sample { return h.sample }
// Snapshot returns a read-only copy of the histogram.
func (h *StandardHistogram) Snapshot() Histogram {
return &HistogramSnapshot{sample: h.sample.Snapshot().(*SampleSnapshot)}
}
// StdDev returns the standard deviation of the values in the sample.
func (h *StandardHistogram) StdDev() float64 { return h.sample.StdDev() }
// Sum returns the sum in the sample.
func (h *StandardHistogram) Sum() int64 { return h.sample.Sum() }
// Update samples a new value.
func (h *StandardHistogram) Update(v int64) { h.sample.Update(v) }
// Variance returns the variance of the values in the sample.
func (h *StandardHistogram) Variance() float64 { return h.sample.Variance() }

@ -0,0 +1,95 @@
package metrics
import "testing"
func BenchmarkHistogram(b *testing.B) {
h := NewHistogram(NewUniformSample(100))
b.ResetTimer()
for i := 0; i < b.N; i++ {
h.Update(int64(i))
}
}
func TestGetOrRegisterHistogram(t *testing.T) {
r := NewRegistry()
s := NewUniformSample(100)
NewRegisteredHistogram("foo", r, s).Update(47)
if h := GetOrRegisterHistogram("foo", r, s); 1 != h.Count() {
t.Fatal(h)
}
}
func TestHistogram10000(t *testing.T) {
h := NewHistogram(NewUniformSample(100000))
for i := 1; i <= 10000; i++ {
h.Update(int64(i))
}
testHistogram10000(t, h)
}
func TestHistogramEmpty(t *testing.T) {
h := NewHistogram(NewUniformSample(100))
if count := h.Count(); 0 != count {
t.Errorf("h.Count(): 0 != %v\n", count)
}
if min := h.Min(); 0 != min {
t.Errorf("h.Min(): 0 != %v\n", min)
}
if max := h.Max(); 0 != max {
t.Errorf("h.Max(): 0 != %v\n", max)
}
if mean := h.Mean(); 0.0 != mean {
t.Errorf("h.Mean(): 0.0 != %v\n", mean)
}
if stdDev := h.StdDev(); 0.0 != stdDev {
t.Errorf("h.StdDev(): 0.0 != %v\n", stdDev)
}
ps := h.Percentiles([]float64{0.5, 0.75, 0.99})
if 0.0 != ps[0] {
t.Errorf("median: 0.0 != %v\n", ps[0])
}
if 0.0 != ps[1] {
t.Errorf("75th percentile: 0.0 != %v\n", ps[1])
}
if 0.0 != ps[2] {
t.Errorf("99th percentile: 0.0 != %v\n", ps[2])
}
}
func TestHistogramSnapshot(t *testing.T) {
h := NewHistogram(NewUniformSample(100000))
for i := 1; i <= 10000; i++ {
h.Update(int64(i))
}
snapshot := h.Snapshot()
h.Update(0)
testHistogram10000(t, snapshot)
}
func testHistogram10000(t *testing.T, h Histogram) {
if count := h.Count(); 10000 != count {
t.Errorf("h.Count(): 10000 != %v\n", count)
}
if min := h.Min(); 1 != min {
t.Errorf("h.Min(): 1 != %v\n", min)
}
if max := h.Max(); 10000 != max {
t.Errorf("h.Max(): 10000 != %v\n", max)
}
if mean := h.Mean(); 5000.5 != mean {
t.Errorf("h.Mean(): 5000.5 != %v\n", mean)
}
if stdDev := h.StdDev(); 2886.751331514372 != stdDev {
t.Errorf("h.StdDev(): 2886.751331514372 != %v\n", stdDev)
}
ps := h.Percentiles([]float64{0.5, 0.75, 0.99})
if 5000.5 != ps[0] {
t.Errorf("median: 5000.5 != %v\n", ps[0])
}
if 7500.75 != ps[1] {
t.Errorf("75th percentile: 7500.75 != %v\n", ps[1])
}
if 9900.99 != ps[2] {
t.Errorf("99th percentile: 9900.99 != %v\n", ps[2])
}
}

@ -0,0 +1,114 @@
package influxdb
import (
"fmt"
influxClient "github.com/influxdb/influxdb/client"
"github.com/rcrowley/go-metrics"
"log"
"time"
)
type Config struct {
Host string
Database string
Username string
Password string
}
func Influxdb(r metrics.Registry, d time.Duration, config *Config) {
client, err := influxClient.NewClient(&influxClient.ClientConfig{
Host: config.Host,
Database: config.Database,
Username: config.Username,
Password: config.Password,
})
if err != nil {
log.Println(err)
return
}
for _ = range time.Tick(d) {
if err := send(r, client); err != nil {
log.Println(err)
}
}
}
func send(r metrics.Registry, client *influxClient.Client) error {
series := []*influxClient.Series{}
r.Each(func(name string, i interface{}) {
now := getCurrentTime()
switch metric := i.(type) {
case metrics.Counter:
series = append(series, &influxClient.Series{
Name: fmt.Sprintf("%s.count", name),
Columns: []string{"time", "count"},
Points: [][]interface{}{
{now, metric.Count()},
},
})
case metrics.Gauge:
series = append(series, &influxClient.Series{
Name: fmt.Sprintf("%s.value", name),
Columns: []string{"time", "value"},
Points: [][]interface{}{
{now, metric.Value()},
},
})
case metrics.GaugeFloat64:
series = append(series, &influxClient.Series{
Name: fmt.Sprintf("%s.value", name),
Columns: []string{"time", "value"},
Points: [][]interface{}{
{now, metric.Value()},
},
})
case metrics.Histogram:
h := metric.Snapshot()
ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
series = append(series, &influxClient.Series{
Name: fmt.Sprintf("%s.histogram", name),
Columns: []string{"time", "count", "min", "max", "mean", "std-dev",
"50-percentile", "75-percentile", "95-percentile",
"99-percentile", "999-percentile"},
Points: [][]interface{}{
{now, h.Count(), h.Min(), h.Max(), h.Mean(), h.StdDev(),
ps[0], ps[1], ps[2], ps[3], ps[4]},
},
})
case metrics.Meter:
m := metric.Snapshot()
series = append(series, &influxClient.Series{
Name: fmt.Sprintf("%s.meter", name),
Columns: []string{"count", "one-minute",
"five-minute", "fifteen-minute", "mean"},
Points: [][]interface{}{
{m.Count(), m.Rate1(), m.Rate5(), m.Rate15(), m.RateMean()},
},
})
case metrics.Timer:
h := metric.Snapshot()
ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
series = append(series, &influxClient.Series{
Name: fmt.Sprintf("%s.timer", name),
Columns: []string{"count", "min", "max", "mean", "std-dev",
"50-percentile", "75-percentile", "95-percentile",
"99-percentile", "999-percentile", "one-minute", "five-minute", "fifteen-minute", "mean-rate"},
Points: [][]interface{}{
{h.Count(), h.Min(), h.Max(), h.Mean(), h.StdDev(),
ps[0], ps[1], ps[2], ps[3], ps[4],
h.Rate1(), h.Rate5(), h.Rate15(), h.RateMean()},
},
})
}
})
if err := client.WriteSeries(series); err != nil {
log.Println(err)
}
return nil
}
func getCurrentTime() int64 {
return time.Now().UnixNano() / 1000000
}

@ -0,0 +1,83 @@
package metrics
import (
"encoding/json"
"io"
"time"
)
// MarshalJSON returns a byte slice containing a JSON representation of all
// the metrics in the Registry.
func (r StandardRegistry) MarshalJSON() ([]byte, error) {
data := make(map[string]map[string]interface{})
r.Each(func(name string, i interface{}) {
values := make(map[string]interface{})
switch metric := i.(type) {
case Counter:
values["count"] = metric.Count()
case Gauge:
values["value"] = metric.Value()
case GaugeFloat64:
values["value"] = metric.Value()
case Healthcheck:
values["error"] = nil
metric.Check()
if err := metric.Error(); nil != err {
values["error"] = metric.Error().Error()
}
case Histogram:
h := metric.Snapshot()
ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
values["count"] = h.Count()
values["min"] = h.Min()
values["max"] = h.Max()
values["mean"] = h.Mean()
values["stddev"] = h.StdDev()
values["median"] = ps[0]
values["75%"] = ps[1]
values["95%"] = ps[2]
values["99%"] = ps[3]
values["99.9%"] = ps[4]
case Meter:
m := metric.Snapshot()
values["count"] = m.Count()
values["1m.rate"] = m.Rate1()
values["5m.rate"] = m.Rate5()
values["15m.rate"] = m.Rate15()
values["mean.rate"] = m.RateMean()
case Timer:
t := metric.Snapshot()
ps := t.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
values["count"] = t.Count()
values["min"] = t.Min()
values["max"] = t.Max()
values["mean"] = t.Mean()
values["stddev"] = t.StdDev()
values["median"] = ps[0]
values["75%"] = ps[1]
values["95%"] = ps[2]
values["99%"] = ps[3]
values["99.9%"] = ps[4]
values["1m.rate"] = t.Rate1()
values["5m.rate"] = t.Rate5()
values["15m.rate"] = t.Rate15()
values["mean.rate"] = t.RateMean()
}
data[name] = values
})
return json.Marshal(data)
}
// WriteJSON writes metrics from the given registry periodically to the
// specified io.Writer as JSON.
func WriteJSON(r Registry, d time.Duration, w io.Writer) {
for _ = range time.Tick(d) {
WriteJSONOnce(r, w)
}
}
// WriteJSONOnce writes metrics from the given registry to the specified
// io.Writer as JSON.
func WriteJSONOnce(r Registry, w io.Writer) {
json.NewEncoder(w).Encode(r)
}

@ -0,0 +1,28 @@
package metrics
import (
"bytes"
"encoding/json"
"testing"
)
func TestRegistryMarshallJSON(t *testing.T) {
b := &bytes.Buffer{}
enc := json.NewEncoder(b)
r := NewRegistry()
r.Register("counter", NewCounter())
enc.Encode(r)
if s := b.String(); "{\"counter\":{\"count\":0}}\n" != s {
t.Fatalf(s)
}
}
func TestRegistryWriteJSONOnce(t *testing.T) {
r := NewRegistry()
r.Register("counter", NewCounter())
b := &bytes.Buffer{}
WriteJSONOnce(r, b)
if s := b.String(); s != "{\"counter\":{\"count\":0}}\n" {
t.Fail()
}
}

@ -0,0 +1,102 @@
package librato
import (
"bytes"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
)
const Operations = "operations"
const OperationsShort = "ops"
type LibratoClient struct {
Email, Token string
}
// property strings
const (
// display attributes
Color = "color"
DisplayMax = "display_max"
DisplayMin = "display_min"
DisplayUnitsLong = "display_units_long"
DisplayUnitsShort = "display_units_short"
DisplayStacked = "display_stacked"
DisplayTransform = "display_transform"
// special gauge display attributes
SummarizeFunction = "summarize_function"
Aggregate = "aggregate"
// metric keys
Name = "name"
Period = "period"
Description = "description"
DisplayName = "display_name"
Attributes = "attributes"
// measurement keys
MeasureTime = "measure_time"
Source = "source"
Value = "value"
// special gauge keys
Count = "count"
Sum = "sum"
Max = "max"
Min = "min"
SumSquares = "sum_squares"
// batch keys
Counters = "counters"
Gauges = "gauges"
MetricsPostUrl = "https://metrics-api.librato.com/v1/metrics"
)
type Measurement map[string]interface{}
type Metric map[string]interface{}
type Batch struct {
Gauges []Measurement `json:"gauges,omitempty"`
Counters []Measurement `json:"counters,omitempty"`
MeasureTime int64 `json:"measure_time"`
Source string `json:"source"`
}
func (self *LibratoClient) PostMetrics(batch Batch) (err error) {
var (
js []byte
req *http.Request
resp *http.Response
)
if len(batch.Counters) == 0 && len(batch.Gauges) == 0 {
return nil
}
if js, err = json.Marshal(batch); err != nil {
return
}
if req, err = http.NewRequest("POST", MetricsPostUrl, bytes.NewBuffer(js)); err != nil {
return
}
req.Header.Set("Content-Type", "application/json")
req.SetBasicAuth(self.Email, self.Token)
if resp, err = http.DefaultClient.Do(req); err != nil {
return
}
if resp.StatusCode != http.StatusOK {
var body []byte
if body, err = ioutil.ReadAll(resp.Body); err != nil {
body = []byte(fmt.Sprintf("(could not fetch response body for error: %s)", err))
}
err = fmt.Errorf("Unable to post to Librato: %d %s %s", resp.StatusCode, resp.Status, string(body))
}
return
}

@ -0,0 +1,230 @@
package librato
import (
"fmt"
"log"
"math"
"regexp"
"time"
"github.com/rcrowley/go-metrics"
)
// a regexp for extracting the unit from time.Duration.String
var unitRegexp = regexp.MustCompile("[^\\d]+$")
// a helper that turns a time.Duration into librato display attributes for timer metrics
func translateTimerAttributes(d time.Duration) (attrs map[string]interface{}) {
attrs = make(map[string]interface{})
attrs[DisplayTransform] = fmt.Sprintf("x/%d", int64(d))
attrs[DisplayUnitsShort] = string(unitRegexp.Find([]byte(d.String())))
return
}
type Reporter struct {
Email, Token string
Source string
Interval time.Duration
Registry metrics.Registry
Percentiles []float64 // percentiles to report on histogram metrics
TimerAttributes map[string]interface{} // units in which timers will be displayed
intervalSec int64
}
func NewReporter(r metrics.Registry, d time.Duration, e string, t string, s string, p []float64, u time.Duration) *Reporter {
return &Reporter{e, t, s, d, r, p, translateTimerAttributes(u), int64(d / time.Second)}
}
func Librato(r metrics.Registry, d time.Duration, e string, t string, s string, p []float64, u time.Duration) {
NewReporter(r, d, e, t, s, p, u).Run()
}
func (self *Reporter) Run() {
ticker := time.Tick(self.Interval)
metricsApi := &LibratoClient{self.Email, self.Token}
for now := range ticker {
var metrics Batch
var err error
if metrics, err = self.BuildRequest(now, self.Registry); err != nil {
log.Printf("ERROR constructing librato request body %s", err)
continue
}
if err := metricsApi.PostMetrics(metrics); err != nil {
log.Printf("ERROR sending metrics to librato %s", err)
continue
}
}
}
// calculate sum of squares from data provided by metrics.Histogram
// see http://en.wikipedia.org/wiki/Standard_deviation#Rapid_calculation_methods
func sumSquares(s metrics.Sample) float64 {
count := float64(s.Count())
sumSquared := math.Pow(count*s.Mean(), 2)
sumSquares := math.Pow(count*s.StdDev(), 2) + sumSquared/count
if math.IsNaN(sumSquares) {
return 0.0
}
return sumSquares
}
func sumSquaresTimer(t metrics.Timer) float64 {
count := float64(t.Count())
sumSquared := math.Pow(count*t.Mean(), 2)
sumSquares := math.Pow(count*t.StdDev(), 2) + sumSquared/count
if math.IsNaN(sumSquares) {
return 0.0
}
return sumSquares
}
func (self *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot Batch, err error) {
snapshot = Batch{
// coerce timestamps to a stepping fn so that they line up in Librato graphs
MeasureTime: (now.Unix() / self.intervalSec) * self.intervalSec,
Source: self.Source,
}
snapshot.Gauges = make([]Measurement, 0)
snapshot.Counters = make([]Measurement, 0)
histogramGaugeCount := 1 + len(self.Percentiles)
r.Each(func(name string, metric interface{}) {
measurement := Measurement{}
measurement[Period] = self.Interval.Seconds()
switch m := metric.(type) {
case metrics.Counter:
if m.Count() > 0 {
measurement[Name] = fmt.Sprintf("%s.%s", name, "count")
measurement[Value] = float64(m.Count())
measurement[Attributes] = map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
}
snapshot.Counters = append(snapshot.Counters, measurement)
}
case metrics.Gauge:
measurement[Name] = name
measurement[Value] = float64(m.Value())
snapshot.Gauges = append(snapshot.Gauges, measurement)
case metrics.GaugeFloat64:
measurement[Name] = name
measurement[Value] = float64(m.Value())
snapshot.Gauges = append(snapshot.Gauges, measurement)
case metrics.Histogram:
if m.Count() > 0 {
gauges := make([]Measurement, histogramGaugeCount, histogramGaugeCount)
s := m.Sample()
measurement[Name] = fmt.Sprintf("%s.%s", name, "hist")
measurement[Count] = uint64(s.Count())
measurement[Max] = float64(s.Max())
measurement[Min] = float64(s.Min())
measurement[Sum] = float64(s.Sum())
measurement[SumSquares] = sumSquares(s)
gauges[0] = measurement
for i, p := range self.Percentiles {
gauges[i+1] = Measurement{
Name: fmt.Sprintf("%s.%.2f", measurement[Name], p),
Value: s.Percentile(p),
Period: measurement[Period],
}
}
snapshot.Gauges = append(snapshot.Gauges, gauges...)
}
case metrics.Meter:
measurement[Name] = name
measurement[Value] = float64(m.Count())
snapshot.Counters = append(snapshot.Counters, measurement)
snapshot.Gauges = append(snapshot.Gauges,
Measurement{
Name: fmt.Sprintf("%s.%s", name, "1min"),
Value: m.Rate1(),
Period: int64(self.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
Measurement{
Name: fmt.Sprintf("%s.%s", name, "5min"),
Value: m.Rate5(),
Period: int64(self.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
Measurement{
Name: fmt.Sprintf("%s.%s", name, "15min"),
Value: m.Rate15(),
Period: int64(self.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
)
case metrics.Timer:
measurement[Name] = name
measurement[Value] = float64(m.Count())
snapshot.Counters = append(snapshot.Counters, measurement)
if m.Count() > 0 {
libratoName := fmt.Sprintf("%s.%s", name, "timer.mean")
gauges := make([]Measurement, histogramGaugeCount, histogramGaugeCount)
gauges[0] = Measurement{
Name: libratoName,
Count: uint64(m.Count()),
Sum: m.Mean() * float64(m.Count()),
Max: float64(m.Max()),
Min: float64(m.Min()),
SumSquares: sumSquaresTimer(m),
Period: int64(self.Interval.Seconds()),
Attributes: self.TimerAttributes,
}
for i, p := range self.Percentiles {
gauges[i+1] = Measurement{
Name: fmt.Sprintf("%s.timer.%2.0f", name, p*100),
Value: m.Percentile(p),
Period: int64(self.Interval.Seconds()),
Attributes: self.TimerAttributes,
}
}
snapshot.Gauges = append(snapshot.Gauges, gauges...)
snapshot.Gauges = append(snapshot.Gauges,
Measurement{
Name: fmt.Sprintf("%s.%s", name, "rate.1min"),
Value: m.Rate1(),
Period: int64(self.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
Measurement{
Name: fmt.Sprintf("%s.%s", name, "rate.5min"),
Value: m.Rate5(),
Period: int64(self.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
Measurement{
Name: fmt.Sprintf("%s.%s", name, "rate.15min"),
Value: m.Rate15(),
Period: int64(self.Interval.Seconds()),
Attributes: map[string]interface{}{
DisplayUnitsLong: Operations,
DisplayUnitsShort: OperationsShort,
DisplayMin: "0",
},
},
)
}
}
})
return
}

@ -0,0 +1,70 @@
package metrics
import (
"log"
"time"
)
// Output each metric in the given registry periodically using the given
// logger.
func Log(r Registry, d time.Duration, l *log.Logger) {
for _ = range time.Tick(d) {
r.Each(func(name string, i interface{}) {
switch metric := i.(type) {
case Counter:
l.Printf("counter %s\n", name)
l.Printf(" count: %9d\n", metric.Count())
case Gauge:
l.Printf("gauge %s\n", name)
l.Printf(" value: %9d\n", metric.Value())
case GaugeFloat64:
l.Printf("gauge %s\n", name)
l.Printf(" value: %f\n", metric.Value())
case Healthcheck:
metric.Check()
l.Printf("healthcheck %s\n", name)
l.Printf(" error: %v\n", metric.Error())
case Histogram:
h := metric.Snapshot()
ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
l.Printf("histogram %s\n", name)
l.Printf(" count: %9d\n", h.Count())
l.Printf(" min: %9d\n", h.Min())
l.Printf(" max: %9d\n", h.Max())
l.Printf(" mean: %12.2f\n", h.Mean())
l.Printf(" stddev: %12.2f\n", h.StdDev())
l.Printf(" median: %12.2f\n", ps[0])
l.Printf(" 75%%: %12.2f\n", ps[1])
l.Printf(" 95%%: %12.2f\n", ps[2])
l.Printf(" 99%%: %12.2f\n", ps[3])
l.Printf(" 99.9%%: %12.2f\n", ps[4])
case Meter:
m := metric.Snapshot()
l.Printf("meter %s\n", name)
l.Printf(" count: %9d\n", m.Count())
l.Printf(" 1-min rate: %12.2f\n", m.Rate1())
l.Printf(" 5-min rate: %12.2f\n", m.Rate5())
l.Printf(" 15-min rate: %12.2f\n", m.Rate15())
l.Printf(" mean rate: %12.2f\n", m.RateMean())
case Timer:
t := metric.Snapshot()
ps := t.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
l.Printf("timer %s\n", name)
l.Printf(" count: %9d\n", t.Count())
l.Printf(" min: %9d\n", t.Min())
l.Printf(" max: %9d\n", t.Max())
l.Printf(" mean: %12.2f\n", t.Mean())
l.Printf(" stddev: %12.2f\n", t.StdDev())
l.Printf(" median: %12.2f\n", ps[0])
l.Printf(" 75%%: %12.2f\n", ps[1])
l.Printf(" 95%%: %12.2f\n", ps[2])
l.Printf(" 99%%: %12.2f\n", ps[3])
l.Printf(" 99.9%%: %12.2f\n", ps[4])
l.Printf(" 1-min rate: %12.2f\n", t.Rate1())
l.Printf(" 5-min rate: %12.2f\n", t.Rate5())
l.Printf(" 15-min rate: %12.2f\n", t.Rate15())
l.Printf(" mean rate: %12.2f\n", t.RateMean())
}
})
}
}

@ -0,0 +1,285 @@
Memory usage
============
(Highly unscientific.)
Command used to gather static memory usage:
```sh
grep ^Vm "/proc/$(ps fax | grep [m]etrics-bench | awk '{print $1}')/status"
```
Program used to gather baseline memory usage:
```go
package main
import "time"
func main() {
time.Sleep(600e9)
}
```
Baseline
--------
```
VmPeak: 42604 kB
VmSize: 42604 kB
VmLck: 0 kB
VmHWM: 1120 kB
VmRSS: 1120 kB
VmData: 35460 kB
VmStk: 136 kB
VmExe: 1020 kB
VmLib: 1848 kB
VmPTE: 36 kB
VmSwap: 0 kB
```
Program used to gather metric memory usage (with other metrics being similar):
```go
package main
import (
"fmt"
"metrics"
"time"
)
func main() {
fmt.Sprintf("foo")
metrics.NewRegistry()
time.Sleep(600e9)
}
```
1000 counters registered
------------------------
```
VmPeak: 44016 kB
VmSize: 44016 kB
VmLck: 0 kB
VmHWM: 1928 kB
VmRSS: 1928 kB
VmData: 36868 kB
VmStk: 136 kB
VmExe: 1024 kB
VmLib: 1848 kB
VmPTE: 40 kB
VmSwap: 0 kB
```
**1.412 kB virtual, TODO 0.808 kB resident per counter.**
100000 counters registered
--------------------------
```
VmPeak: 55024 kB
VmSize: 55024 kB
VmLck: 0 kB
VmHWM: 12440 kB
VmRSS: 12440 kB
VmData: 47876 kB
VmStk: 136 kB
VmExe: 1024 kB
VmLib: 1848 kB
VmPTE: 64 kB
VmSwap: 0 kB
```
**0.1242 kB virtual, 0.1132 kB resident per counter.**
1000 gauges registered
----------------------
```
VmPeak: 44012 kB
VmSize: 44012 kB
VmLck: 0 kB
VmHWM: 1928 kB
VmRSS: 1928 kB
VmData: 36868 kB
VmStk: 136 kB
VmExe: 1020 kB
VmLib: 1848 kB
VmPTE: 40 kB
VmSwap: 0 kB
```
**1.408 kB virtual, 0.808 kB resident per counter.**
100000 gauges registered
------------------------
```
VmPeak: 55020 kB
VmSize: 55020 kB
VmLck: 0 kB
VmHWM: 12432 kB
VmRSS: 12432 kB
VmData: 47876 kB
VmStk: 136 kB
VmExe: 1020 kB
VmLib: 1848 kB
VmPTE: 60 kB
VmSwap: 0 kB
```
**0.12416 kB virtual, 0.11312 resident per gauge.**
1000 histograms with a uniform sample size of 1028
--------------------------------------------------
```
VmPeak: 72272 kB
VmSize: 72272 kB
VmLck: 0 kB
VmHWM: 16204 kB
VmRSS: 16204 kB
VmData: 65100 kB
VmStk: 136 kB
VmExe: 1048 kB
VmLib: 1848 kB
VmPTE: 80 kB
VmSwap: 0 kB
```
**29.668 kB virtual, TODO 15.084 resident per histogram.**
10000 histograms with a uniform sample size of 1028
---------------------------------------------------
```
VmPeak: 256912 kB
VmSize: 256912 kB
VmLck: 0 kB
VmHWM: 146204 kB
VmRSS: 146204 kB
VmData: 249740 kB
VmStk: 136 kB
VmExe: 1048 kB
VmLib: 1848 kB
VmPTE: 448 kB
VmSwap: 0 kB
```
**21.4308 kB virtual, 14.5084 kB resident per histogram.**
50000 histograms with a uniform sample size of 1028
---------------------------------------------------
```
VmPeak: 908112 kB
VmSize: 908112 kB
VmLck: 0 kB
VmHWM: 645832 kB
VmRSS: 645588 kB
VmData: 900940 kB
VmStk: 136 kB
VmExe: 1048 kB
VmLib: 1848 kB
VmPTE: 1716 kB
VmSwap: 1544 kB
```
**17.31016 kB virtual, 12.88936 kB resident per histogram.**
1000 histograms with an exponentially-decaying sample size of 1028 and alpha of 0.015
-------------------------------------------------------------------------------------
```
VmPeak: 62480 kB
VmSize: 62480 kB
VmLck: 0 kB
VmHWM: 11572 kB
VmRSS: 11572 kB
VmData: 55308 kB
VmStk: 136 kB
VmExe: 1048 kB
VmLib: 1848 kB
VmPTE: 64 kB
VmSwap: 0 kB
```
**19.876 kB virtual, 10.452 kB resident per histogram.**
10000 histograms with an exponentially-decaying sample size of 1028 and alpha of 0.015
--------------------------------------------------------------------------------------
```
VmPeak: 153296 kB
VmSize: 153296 kB
VmLck: 0 kB
VmHWM: 101176 kB
VmRSS: 101176 kB
VmData: 146124 kB
VmStk: 136 kB
VmExe: 1048 kB
VmLib: 1848 kB
VmPTE: 240 kB
VmSwap: 0 kB
```
**11.0692 kB virtual, 10.0056 kB resident per histogram.**
50000 histograms with an exponentially-decaying sample size of 1028 and alpha of 0.015
--------------------------------------------------------------------------------------
```
VmPeak: 557264 kB
VmSize: 557264 kB
VmLck: 0 kB
VmHWM: 501056 kB
VmRSS: 501056 kB
VmData: 550092 kB
VmStk: 136 kB
VmExe: 1048 kB
VmLib: 1848 kB
VmPTE: 1032 kB
VmSwap: 0 kB
```
**10.2932 kB virtual, 9.99872 kB resident per histogram.**
1000 meters
-----------
```
VmPeak: 74504 kB
VmSize: 74504 kB
VmLck: 0 kB
VmHWM: 24124 kB
VmRSS: 24124 kB
VmData: 67340 kB
VmStk: 136 kB
VmExe: 1040 kB
VmLib: 1848 kB
VmPTE: 92 kB
VmSwap: 0 kB
```
**31.9 kB virtual, 23.004 kB resident per meter.**
10000 meters
------------
```
VmPeak: 278920 kB
VmSize: 278920 kB
VmLck: 0 kB
VmHWM: 227300 kB
VmRSS: 227300 kB
VmData: 271756 kB
VmStk: 136 kB
VmExe: 1040 kB
VmLib: 1848 kB
VmPTE: 488 kB
VmSwap: 0 kB
```
**23.6316 kB virtual, 22.618 kB resident per meter.**

@ -0,0 +1,233 @@
package metrics
import (
"sync"
"time"
)
// Meters count events to produce exponentially-weighted moving average rates
// at one-, five-, and fifteen-minutes and a mean rate.
type Meter interface {
Count() int64
Mark(int64)
Rate1() float64
Rate5() float64
Rate15() float64
RateMean() float64
Snapshot() Meter
}
// GetOrRegisterMeter returns an existing Meter or constructs and registers a
// new StandardMeter.
func GetOrRegisterMeter(name string, r Registry) Meter {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, NewMeter).(Meter)
}
// NewMeter constructs a new StandardMeter and launches a goroutine.
func NewMeter() Meter {
if UseNilMetrics {
return NilMeter{}
}
m := newStandardMeter()
arbiter.Lock()
defer arbiter.Unlock()
arbiter.meters = append(arbiter.meters, m)
if !arbiter.started {
arbiter.started = true
go arbiter.tick()
}
return m
}
// NewMeter constructs and registers a new StandardMeter and launches a
// goroutine.
func NewRegisteredMeter(name string, r Registry) Meter {
c := NewMeter()
if nil == r {
r = DefaultRegistry
}
r.Register(name, c)
return c
}
// MeterSnapshot is a read-only copy of another Meter.
type MeterSnapshot struct {
count int64
rate1, rate5, rate15, rateMean float64
}
// Count returns the count of events at the time the snapshot was taken.
func (m *MeterSnapshot) Count() int64 { return m.count }
// Mark panics.
func (*MeterSnapshot) Mark(n int64) {
panic("Mark called on a MeterSnapshot")
}
// Rate1 returns the one-minute moving average rate of events per second at the
// time the snapshot was taken.
func (m *MeterSnapshot) Rate1() float64 { return m.rate1 }
// Rate5 returns the five-minute moving average rate of events per second at
// the time the snapshot was taken.
func (m *MeterSnapshot) Rate5() float64 { return m.rate5 }
// Rate15 returns the fifteen-minute moving average rate of events per second
// at the time the snapshot was taken.
func (m *MeterSnapshot) Rate15() float64 { return m.rate15 }
// RateMean returns the meter's mean rate of events per second at the time the
// snapshot was taken.
func (m *MeterSnapshot) RateMean() float64 { return m.rateMean }
// Snapshot returns the snapshot.
func (m *MeterSnapshot) Snapshot() Meter { return m }
// NilMeter is a no-op Meter.
type NilMeter struct{}
// Count is a no-op.
func (NilMeter) Count() int64 { return 0 }
// Mark is a no-op.
func (NilMeter) Mark(n int64) {}
// Rate1 is a no-op.
func (NilMeter) Rate1() float64 { return 0.0 }
// Rate5 is a no-op.
func (NilMeter) Rate5() float64 { return 0.0 }
// Rate15is a no-op.
func (NilMeter) Rate15() float64 { return 0.0 }
// RateMean is a no-op.
func (NilMeter) RateMean() float64 { return 0.0 }
// Snapshot is a no-op.
func (NilMeter) Snapshot() Meter { return NilMeter{} }
// StandardMeter is the standard implementation of a Meter.
type StandardMeter struct {
lock sync.RWMutex
snapshot *MeterSnapshot
a1, a5, a15 EWMA
startTime time.Time
}
func newStandardMeter() *StandardMeter {
return &StandardMeter{
snapshot: &MeterSnapshot{},
a1: NewEWMA1(),
a5: NewEWMA5(),
a15: NewEWMA15(),
startTime: time.Now(),
}
}
// Count returns the number of events recorded.
func (m *StandardMeter) Count() int64 {
m.lock.RLock()
count := m.snapshot.count
m.lock.RUnlock()
return count
}
// Mark records the occurance of n events.
func (m *StandardMeter) Mark(n int64) {
m.lock.Lock()
defer m.lock.Unlock()
m.snapshot.count += n
m.a1.Update(n)
m.a5.Update(n)
m.a15.Update(n)
m.updateSnapshot()
}
// Rate1 returns the one-minute moving average rate of events per second.
func (m *StandardMeter) Rate1() float64 {
m.lock.RLock()
rate1 := m.snapshot.rate1
m.lock.RUnlock()
return rate1
}
// Rate5 returns the five-minute moving average rate of events per second.
func (m *StandardMeter) Rate5() float64 {
m.lock.RLock()
rate5 := m.snapshot.rate5
m.lock.RUnlock()
return rate5
}
// Rate15 returns the fifteen-minute moving average rate of events per second.
func (m *StandardMeter) Rate15() float64 {
m.lock.RLock()
rate15 := m.snapshot.rate15
m.lock.RUnlock()
return rate15
}
// RateMean returns the meter's mean rate of events per second.
func (m *StandardMeter) RateMean() float64 {
m.lock.RLock()
rateMean := m.snapshot.rateMean
m.lock.RUnlock()
return rateMean
}
// Snapshot returns a read-only copy of the meter.
func (m *StandardMeter) Snapshot() Meter {
m.lock.RLock()
snapshot := *m.snapshot
m.lock.RUnlock()
return &snapshot
}
func (m *StandardMeter) updateSnapshot() {
// should run with write lock held on m.lock
snapshot := m.snapshot
snapshot.rate1 = m.a1.Rate()
snapshot.rate5 = m.a5.Rate()
snapshot.rate15 = m.a15.Rate()
snapshot.rateMean = float64(snapshot.count) / time.Since(m.startTime).Seconds()
}
func (m *StandardMeter) tick() {
m.lock.Lock()
defer m.lock.Unlock()
m.a1.Tick()
m.a5.Tick()
m.a15.Tick()
m.updateSnapshot()
}
type meterArbiter struct {
sync.RWMutex
started bool
meters []*StandardMeter
ticker *time.Ticker
}
var arbiter = meterArbiter{ticker: time.NewTicker(5e9)}
// Ticks meters on the scheduled interval
func (ma *meterArbiter) tick() {
for {
select {
case <-ma.ticker.C:
ma.tickMeters()
}
}
}
func (ma *meterArbiter) tickMeters() {
ma.RLock()
defer ma.RUnlock()
for _, meter := range ma.meters {
meter.tick()
}
}

@ -0,0 +1,60 @@
package metrics
import (
"testing"
"time"
)
func BenchmarkMeter(b *testing.B) {
m := NewMeter()
b.ResetTimer()
for i := 0; i < b.N; i++ {
m.Mark(1)
}
}
func TestGetOrRegisterMeter(t *testing.T) {
r := NewRegistry()
NewRegisteredMeter("foo", r).Mark(47)
if m := GetOrRegisterMeter("foo", r); 47 != m.Count() {
t.Fatal(m)
}
}
func TestMeterDecay(t *testing.T) {
ma := meterArbiter{
ticker: time.NewTicker(1),
}
m := newStandardMeter()
ma.meters = append(ma.meters, m)
go ma.tick()
m.Mark(1)
rateMean := m.RateMean()
time.Sleep(1)
if m.RateMean() >= rateMean {
t.Error("m.RateMean() didn't decrease")
}
}
func TestMeterNonzero(t *testing.T) {
m := NewMeter()
m.Mark(3)
if count := m.Count(); 3 != count {
t.Errorf("m.Count(): 3 != %v\n", count)
}
}
func TestMeterSnapshot(t *testing.T) {
m := NewMeter()
m.Mark(1)
if snapshot := m.Snapshot(); m.RateMean() != snapshot.RateMean() {
t.Fatal(snapshot)
}
}
func TestMeterZero(t *testing.T) {
m := NewMeter()
if count := m.Count(); 0 != count {
t.Errorf("m.Count(): 0 != %v\n", count)
}
}

@ -0,0 +1,13 @@
// Go port of Coda Hale's Metrics library
//
// <https://github.com/rcrowley/go-metrics>
//
// Coda Hale's original work: <https://github.com/codahale/metrics>
package metrics
// UseNilMetrics is checked by the constructor functions for all of the
// standard metrics. If it is true, the metric returned is a stub.
//
// This global kill-switch helps quantify the observer effect and makes
// for less cluttered pprof profiles.
var UseNilMetrics bool = false

@ -0,0 +1,107 @@
package metrics
import (
"io/ioutil"
"log"
"sync"
"testing"
)
const FANOUT = 128
// Stop the compiler from complaining during debugging.
var (
_ = ioutil.Discard
_ = log.LstdFlags
)
func BenchmarkMetrics(b *testing.B) {
r := NewRegistry()
c := NewRegisteredCounter("counter", r)
g := NewRegisteredGauge("gauge", r)
gf := NewRegisteredGaugeFloat64("gaugefloat64", r)
h := NewRegisteredHistogram("histogram", r, NewUniformSample(100))
m := NewRegisteredMeter("meter", r)
t := NewRegisteredTimer("timer", r)
RegisterDebugGCStats(r)
RegisterRuntimeMemStats(r)
b.ResetTimer()
ch := make(chan bool)
wgD := &sync.WaitGroup{}
/*
wgD.Add(1)
go func() {
defer wgD.Done()
//log.Println("go CaptureDebugGCStats")
for {
select {
case <-ch:
//log.Println("done CaptureDebugGCStats")
return
default:
CaptureDebugGCStatsOnce(r)
}
}
}()
//*/
wgR := &sync.WaitGroup{}
//*
wgR.Add(1)
go func() {
defer wgR.Done()
//log.Println("go CaptureRuntimeMemStats")
for {
select {
case <-ch:
//log.Println("done CaptureRuntimeMemStats")
return
default:
CaptureRuntimeMemStatsOnce(r)
}
}
}()
//*/
wgW := &sync.WaitGroup{}
/*
wgW.Add(1)
go func() {
defer wgW.Done()
//log.Println("go Write")
for {
select {
case <-ch:
//log.Println("done Write")
return
default:
WriteOnce(r, ioutil.Discard)
}
}
}()
//*/
wg := &sync.WaitGroup{}
wg.Add(FANOUT)
for i := 0; i < FANOUT; i++ {
go func(i int) {
defer wg.Done()
//log.Println("go", i)
for i := 0; i < b.N; i++ {
c.Inc(1)
g.Update(int64(i))
gf.Update(float64(i))
h.Update(int64(i))
m.Mark(1)
t.Update(1)
}
//log.Println("done", i)
}(i)
}
wg.Wait()
close(ch)
wgD.Wait()
wgR.Wait()
wgW.Wait()
}

@ -0,0 +1,119 @@
package metrics
import (
"bufio"
"fmt"
"log"
"net"
"os"
"strings"
"time"
)
var shortHostName string = ""
// OpenTSDBConfig provides a container with configuration parameters for
// the OpenTSDB exporter
type OpenTSDBConfig struct {
Addr *net.TCPAddr // Network address to connect to
Registry Registry // Registry to be exported
FlushInterval time.Duration // Flush interval
DurationUnit time.Duration // Time conversion unit for durations
Prefix string // Prefix to be prepended to metric names
}
// OpenTSDB is a blocking exporter function which reports metrics in r
// to a TSDB server located at addr, flushing them every d duration
// and prepending metric names with prefix.
func OpenTSDB(r Registry, d time.Duration, prefix string, addr *net.TCPAddr) {
OpenTSDBWithConfig(OpenTSDBConfig{
Addr: addr,
Registry: r,
FlushInterval: d,
DurationUnit: time.Nanosecond,
Prefix: prefix,
})
}
// OpenTSDBWithConfig is a blocking exporter function just like OpenTSDB,
// but it takes a OpenTSDBConfig instead.
func OpenTSDBWithConfig(c OpenTSDBConfig) {
for _ = range time.Tick(c.FlushInterval) {
if err := openTSDB(&c); nil != err {
log.Println(err)
}
}
}
func getShortHostname() string {
if shortHostName == "" {
host, _ := os.Hostname()
if index := strings.Index(host, "."); index > 0 {
shortHostName = host[:index]
} else {
shortHostName = host
}
}
return shortHostName
}
func openTSDB(c *OpenTSDBConfig) error {
shortHostname := getShortHostname()
now := time.Now().Unix()
du := float64(c.DurationUnit)
conn, err := net.DialTCP("tcp", nil, c.Addr)
if nil != err {
return err
}
defer conn.Close()
w := bufio.NewWriter(conn)
c.Registry.Each(func(name string, i interface{}) {
switch metric := i.(type) {
case Counter:
fmt.Fprintf(w, "put %s.%s.count %d %d host=%s\n", c.Prefix, name, now, metric.Count(), shortHostname)
case Gauge:
fmt.Fprintf(w, "put %s.%s.value %d %d host=%s\n", c.Prefix, name, now, metric.Value(), shortHostname)
case GaugeFloat64:
fmt.Fprintf(w, "put %s.%s.value %d %f host=%s\n", c.Prefix, name, now, metric.Value(), shortHostname)
case Histogram:
h := metric.Snapshot()
ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
fmt.Fprintf(w, "put %s.%s.count %d %d host=%s\n", c.Prefix, name, now, h.Count(), shortHostname)
fmt.Fprintf(w, "put %s.%s.min %d %d host=%s\n", c.Prefix, name, now, h.Min(), shortHostname)
fmt.Fprintf(w, "put %s.%s.max %d %d host=%s\n", c.Prefix, name, now, h.Max(), shortHostname)
fmt.Fprintf(w, "put %s.%s.mean %d %.2f host=%s\n", c.Prefix, name, now, h.Mean(), shortHostname)
fmt.Fprintf(w, "put %s.%s.std-dev %d %.2f host=%s\n", c.Prefix, name, now, h.StdDev(), shortHostname)
fmt.Fprintf(w, "put %s.%s.50-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[0], shortHostname)
fmt.Fprintf(w, "put %s.%s.75-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[1], shortHostname)
fmt.Fprintf(w, "put %s.%s.95-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[2], shortHostname)
fmt.Fprintf(w, "put %s.%s.99-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[3], shortHostname)
fmt.Fprintf(w, "put %s.%s.999-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[4], shortHostname)
case Meter:
m := metric.Snapshot()
fmt.Fprintf(w, "put %s.%s.count %d %d host=%s\n", c.Prefix, name, now, m.Count(), shortHostname)
fmt.Fprintf(w, "put %s.%s.one-minute %d %.2f host=%s\n", c.Prefix, name, now, m.Rate1(), shortHostname)
fmt.Fprintf(w, "put %s.%s.five-minute %d %.2f host=%s\n", c.Prefix, name, now, m.Rate5(), shortHostname)
fmt.Fprintf(w, "put %s.%s.fifteen-minute %d %.2f host=%s\n", c.Prefix, name, now, m.Rate15(), shortHostname)
fmt.Fprintf(w, "put %s.%s.mean %d %.2f host=%s\n", c.Prefix, name, now, m.RateMean(), shortHostname)
case Timer:
t := metric.Snapshot()
ps := t.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
fmt.Fprintf(w, "put %s.%s.count %d %d host=%s\n", c.Prefix, name, now, t.Count(), shortHostname)
fmt.Fprintf(w, "put %s.%s.min %d %d host=%s\n", c.Prefix, name, now, t.Min()/int64(du), shortHostname)
fmt.Fprintf(w, "put %s.%s.max %d %d host=%s\n", c.Prefix, name, now, t.Max()/int64(du), shortHostname)
fmt.Fprintf(w, "put %s.%s.mean %d %.2f host=%s\n", c.Prefix, name, now, t.Mean()/du, shortHostname)
fmt.Fprintf(w, "put %s.%s.std-dev %d %.2f host=%s\n", c.Prefix, name, now, t.StdDev()/du, shortHostname)
fmt.Fprintf(w, "put %s.%s.50-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[0]/du, shortHostname)
fmt.Fprintf(w, "put %s.%s.75-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[1]/du, shortHostname)
fmt.Fprintf(w, "put %s.%s.95-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[2]/du, shortHostname)
fmt.Fprintf(w, "put %s.%s.99-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[3]/du, shortHostname)
fmt.Fprintf(w, "put %s.%s.999-percentile %d %.2f host=%s\n", c.Prefix, name, now, ps[4]/du, shortHostname)
fmt.Fprintf(w, "put %s.%s.one-minute %d %.2f host=%s\n", c.Prefix, name, now, t.Rate1(), shortHostname)
fmt.Fprintf(w, "put %s.%s.five-minute %d %.2f host=%s\n", c.Prefix, name, now, t.Rate5(), shortHostname)
fmt.Fprintf(w, "put %s.%s.fifteen-minute %d %.2f host=%s\n", c.Prefix, name, now, t.Rate15(), shortHostname)
fmt.Fprintf(w, "put %s.%s.mean-rate %d %.2f host=%s\n", c.Prefix, name, now, t.RateMean(), shortHostname)
}
w.Flush()
})
return nil
}

@ -0,0 +1,22 @@
package metrics
import (
"net"
"time"
)
func ExampleOpenTSDB() {
addr, _ := net.ResolveTCPAddr("net", ":2003")
go OpenTSDB(DefaultRegistry, 1*time.Second, "some.prefix", addr)
}
func ExampleOpenTSDBWithConfig() {
addr, _ := net.ResolveTCPAddr("net", ":2003")
go OpenTSDBWithConfig(OpenTSDBConfig{
Addr: addr,
Registry: DefaultRegistry,
FlushInterval: 1 * time.Second,
DurationUnit: time.Millisecond,
})
}

@ -0,0 +1,180 @@
package metrics
import (
"fmt"
"reflect"
"sync"
)
// DuplicateMetric is the error returned by Registry.Register when a metric
// already exists. If you mean to Register that metric you must first
// Unregister the existing metric.
type DuplicateMetric string
func (err DuplicateMetric) Error() string {
return fmt.Sprintf("duplicate metric: %s", string(err))
}
// A Registry holds references to a set of metrics by name and can iterate
// over them, calling callback functions provided by the user.
//
// This is an interface so as to encourage other structs to implement
// the Registry API as appropriate.
type Registry interface {
// Call the given function for each registered metric.
Each(func(string, interface{}))
// Get the metric by the given name or nil if none is registered.
Get(string) interface{}
// Gets an existing metric or registers the given one.
// The interface can be the metric to register if not found in registry,
// or a function returning the metric for lazy instantiation.
GetOrRegister(string, interface{}) interface{}
// Register the given metric under the given name.
Register(string, interface{}) error
// Run all registered healthchecks.
RunHealthchecks()
// Unregister the metric with the given name.
Unregister(string)
// Unregister all metrics. (Mostly for testing.)
UnregisterAll()
}
// The standard implementation of a Registry is a mutex-protected map
// of names to metrics.
type StandardRegistry struct {
metrics map[string]interface{}
mutex sync.Mutex
}
// Create a new registry.
func NewRegistry() Registry {
return &StandardRegistry{metrics: make(map[string]interface{})}
}
// Call the given function for each registered metric.
func (r *StandardRegistry) Each(f func(string, interface{})) {
for name, i := range r.registered() {
f(name, i)
}
}
// Get the metric by the given name or nil if none is registered.
func (r *StandardRegistry) Get(name string) interface{} {
r.mutex.Lock()
defer r.mutex.Unlock()
return r.metrics[name]
}
// Gets an existing metric or creates and registers a new one. Threadsafe
// alternative to calling Get and Register on failure.
// The interface can be the metric to register if not found in registry,
// or a function returning the metric for lazy instantiation.
func (r *StandardRegistry) GetOrRegister(name string, i interface{}) interface{} {
r.mutex.Lock()
defer r.mutex.Unlock()
if metric, ok := r.metrics[name]; ok {
return metric
}
if v := reflect.ValueOf(i); v.Kind() == reflect.Func {
i = v.Call(nil)[0].Interface()
}
r.register(name, i)
return i
}
// Register the given metric under the given name. Returns a DuplicateMetric
// if a metric by the given name is already registered.
func (r *StandardRegistry) Register(name string, i interface{}) error {
r.mutex.Lock()
defer r.mutex.Unlock()
return r.register(name, i)
}
// Run all registered healthchecks.
func (r *StandardRegistry) RunHealthchecks() {
r.mutex.Lock()
defer r.mutex.Unlock()
for _, i := range r.metrics {
if h, ok := i.(Healthcheck); ok {
h.Check()
}
}
}
// Unregister the metric with the given name.
func (r *StandardRegistry) Unregister(name string) {
r.mutex.Lock()
defer r.mutex.Unlock()
delete(r.metrics, name)
}
// Unregister all metrics. (Mostly for testing.)
func (r *StandardRegistry) UnregisterAll() {
r.mutex.Lock()
defer r.mutex.Unlock()
for name, _ := range r.metrics {
delete(r.metrics, name)
}
}
func (r *StandardRegistry) register(name string, i interface{}) error {
if _, ok := r.metrics[name]; ok {
return DuplicateMetric(name)
}
switch i.(type) {
case Counter, Gauge, GaugeFloat64, Healthcheck, Histogram, Meter, Timer:
r.metrics[name] = i
}
return nil
}
func (r *StandardRegistry) registered() map[string]interface{} {
r.mutex.Lock()
defer r.mutex.Unlock()
metrics := make(map[string]interface{}, len(r.metrics))
for name, i := range r.metrics {
metrics[name] = i
}
return metrics
}
var DefaultRegistry Registry = NewRegistry()
// Call the given function for each registered metric.
func Each(f func(string, interface{})) {
DefaultRegistry.Each(f)
}
// Get the metric by the given name or nil if none is registered.
func Get(name string) interface{} {
return DefaultRegistry.Get(name)
}
// Gets an existing metric or creates and registers a new one. Threadsafe
// alternative to calling Get and Register on failure.
func GetOrRegister(name string, i interface{}) interface{} {
return DefaultRegistry.GetOrRegister(name, i)
}
// Register the given metric under the given name. Returns a DuplicateMetric
// if a metric by the given name is already registered.
func Register(name string, i interface{}) error {
return DefaultRegistry.Register(name, i)
}
// Run all registered healthchecks.
func RunHealthchecks() {
DefaultRegistry.RunHealthchecks()
}
// Unregister the metric with the given name.
func Unregister(name string) {
DefaultRegistry.Unregister(name)
}

@ -0,0 +1,118 @@
package metrics
import "testing"
func BenchmarkRegistry(b *testing.B) {
r := NewRegistry()
r.Register("foo", NewCounter())
b.ResetTimer()
for i := 0; i < b.N; i++ {
r.Each(func(string, interface{}) {})
}
}
func TestRegistry(t *testing.T) {
r := NewRegistry()
r.Register("foo", NewCounter())
i := 0
r.Each(func(name string, iface interface{}) {
i++
if "foo" != name {
t.Fatal(name)
}
if _, ok := iface.(Counter); !ok {
t.Fatal(iface)
}
})
if 1 != i {
t.Fatal(i)
}
r.Unregister("foo")
i = 0
r.Each(func(string, interface{}) { i++ })
if 0 != i {
t.Fatal(i)
}
}
func TestRegistryDuplicate(t *testing.T) {
r := NewRegistry()
if err := r.Register("foo", NewCounter()); nil != err {
t.Fatal(err)
}
if err := r.Register("foo", NewGauge()); nil == err {
t.Fatal(err)
}
i := 0
r.Each(func(name string, iface interface{}) {
i++
if _, ok := iface.(Counter); !ok {
t.Fatal(iface)
}
})
if 1 != i {
t.Fatal(i)
}
}
func TestRegistryGet(t *testing.T) {
r := NewRegistry()
r.Register("foo", NewCounter())
if count := r.Get("foo").(Counter).Count(); 0 != count {
t.Fatal(count)
}
r.Get("foo").(Counter).Inc(1)
if count := r.Get("foo").(Counter).Count(); 1 != count {
t.Fatal(count)
}
}
func TestRegistryGetOrRegister(t *testing.T) {
r := NewRegistry()
// First metric wins with GetOrRegister
_ = r.GetOrRegister("foo", NewCounter())
m := r.GetOrRegister("foo", NewGauge())
if _, ok := m.(Counter); !ok {
t.Fatal(m)
}
i := 0
r.Each(func(name string, iface interface{}) {
i++
if name != "foo" {
t.Fatal(name)
}
if _, ok := iface.(Counter); !ok {
t.Fatal(iface)
}
})
if i != 1 {
t.Fatal(i)
}
}
func TestRegistryGetOrRegisterWithLazyInstantiation(t *testing.T) {
r := NewRegistry()
// First metric wins with GetOrRegister
_ = r.GetOrRegister("foo", NewCounter)
m := r.GetOrRegister("foo", NewGauge)
if _, ok := m.(Counter); !ok {
t.Fatal(m)
}
i := 0
r.Each(func(name string, iface interface{}) {
i++
if name != "foo" {
t.Fatal(name)
}
if _, ok := iface.(Counter); !ok {
t.Fatal(iface)
}
})
if i != 1 {
t.Fatal(i)
}
}

@ -0,0 +1,200 @@
package metrics
import (
"runtime"
"time"
)
var (
memStats runtime.MemStats
runtimeMetrics struct {
MemStats struct {
Alloc Gauge
BuckHashSys Gauge
DebugGC Gauge
EnableGC Gauge
Frees Gauge
HeapAlloc Gauge
HeapIdle Gauge
HeapInuse Gauge
HeapObjects Gauge
HeapReleased Gauge
HeapSys Gauge
LastGC Gauge
Lookups Gauge
Mallocs Gauge
MCacheInuse Gauge
MCacheSys Gauge
MSpanInuse Gauge
MSpanSys Gauge
NextGC Gauge
NumGC Gauge
PauseNs Histogram
PauseTotalNs Gauge
StackInuse Gauge
StackSys Gauge
Sys Gauge
TotalAlloc Gauge
}
NumCgoCall Gauge
NumGoroutine Gauge
ReadMemStats Timer
}
frees uint64
lookups uint64
mallocs uint64
numGC uint32
numCgoCalls int64
)
// Capture new values for the Go runtime statistics exported in
// runtime.MemStats. This is designed to be called as a goroutine.
func CaptureRuntimeMemStats(r Registry, d time.Duration) {
for _ = range time.Tick(d) {
CaptureRuntimeMemStatsOnce(r)
}
}
// Capture new values for the Go runtime statistics exported in
// runtime.MemStats. This is designed to be called in a background
// goroutine. Giving a registry which has not been given to
// RegisterRuntimeMemStats will panic.
//
// Be very careful with this because runtime.ReadMemStats calls the C
// functions runtime·semacquire(&runtime·worldsema) and runtime·stoptheworld()
// and that last one does what it says on the tin.
func CaptureRuntimeMemStatsOnce(r Registry) {
t := time.Now()
runtime.ReadMemStats(&memStats) // This takes 50-200us.
runtimeMetrics.ReadMemStats.UpdateSince(t)
runtimeMetrics.MemStats.Alloc.Update(int64(memStats.Alloc))
runtimeMetrics.MemStats.BuckHashSys.Update(int64(memStats.BuckHashSys))
if memStats.DebugGC {
runtimeMetrics.MemStats.DebugGC.Update(1)
} else {
runtimeMetrics.MemStats.DebugGC.Update(0)
}
if memStats.EnableGC {
runtimeMetrics.MemStats.EnableGC.Update(1)
} else {
runtimeMetrics.MemStats.EnableGC.Update(0)
}
runtimeMetrics.MemStats.Frees.Update(int64(memStats.Frees - frees))
runtimeMetrics.MemStats.HeapAlloc.Update(int64(memStats.HeapAlloc))
runtimeMetrics.MemStats.HeapIdle.Update(int64(memStats.HeapIdle))
runtimeMetrics.MemStats.HeapInuse.Update(int64(memStats.HeapInuse))
runtimeMetrics.MemStats.HeapObjects.Update(int64(memStats.HeapObjects))
runtimeMetrics.MemStats.HeapReleased.Update(int64(memStats.HeapReleased))
runtimeMetrics.MemStats.HeapSys.Update(int64(memStats.HeapSys))
runtimeMetrics.MemStats.LastGC.Update(int64(memStats.LastGC))
runtimeMetrics.MemStats.Lookups.Update(int64(memStats.Lookups - lookups))
runtimeMetrics.MemStats.Mallocs.Update(int64(memStats.Mallocs - mallocs))
runtimeMetrics.MemStats.MCacheInuse.Update(int64(memStats.MCacheInuse))
runtimeMetrics.MemStats.MCacheSys.Update(int64(memStats.MCacheSys))
runtimeMetrics.MemStats.MSpanInuse.Update(int64(memStats.MSpanInuse))
runtimeMetrics.MemStats.MSpanSys.Update(int64(memStats.MSpanSys))
runtimeMetrics.MemStats.NextGC.Update(int64(memStats.NextGC))
runtimeMetrics.MemStats.NumGC.Update(int64(memStats.NumGC - numGC))
// <https://code.google.com/p/go/source/browse/src/pkg/runtime/mgc0.c>
i := numGC % uint32(len(memStats.PauseNs))
ii := memStats.NumGC % uint32(len(memStats.PauseNs))
if memStats.NumGC-numGC >= uint32(len(memStats.PauseNs)) {
for i = 0; i < uint32(len(memStats.PauseNs)); i++ {
runtimeMetrics.MemStats.PauseNs.Update(int64(memStats.PauseNs[i]))
}
} else {
if i > ii {
for ; i < uint32(len(memStats.PauseNs)); i++ {
runtimeMetrics.MemStats.PauseNs.Update(int64(memStats.PauseNs[i]))
}
i = 0
}
for ; i < ii; i++ {
runtimeMetrics.MemStats.PauseNs.Update(int64(memStats.PauseNs[i]))
}
}
frees = memStats.Frees
lookups = memStats.Lookups
mallocs = memStats.Mallocs
numGC = memStats.NumGC
runtimeMetrics.MemStats.PauseTotalNs.Update(int64(memStats.PauseTotalNs))
runtimeMetrics.MemStats.StackInuse.Update(int64(memStats.StackInuse))
runtimeMetrics.MemStats.StackSys.Update(int64(memStats.StackSys))
runtimeMetrics.MemStats.Sys.Update(int64(memStats.Sys))
runtimeMetrics.MemStats.TotalAlloc.Update(int64(memStats.TotalAlloc))
currentNumCgoCalls := numCgoCall()
runtimeMetrics.NumCgoCall.Update(currentNumCgoCalls - numCgoCalls)
numCgoCalls = currentNumCgoCalls
runtimeMetrics.NumGoroutine.Update(int64(runtime.NumGoroutine()))
}
// Register runtimeMetrics for the Go runtime statistics exported in runtime and
// 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.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.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.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.ReadMemStats", runtimeMetrics.ReadMemStats)
}

@ -0,0 +1,10 @@
// +build cgo
// +build !appengine
package metrics
import "runtime"
func numCgoCall() int64 {
return runtime.NumCgoCall()
}

@ -0,0 +1,7 @@
// +build !cgo appengine
package metrics
func numCgoCall() int64 {
return 0
}

@ -0,0 +1,78 @@
package metrics
import (
"runtime"
"testing"
"time"
)
func BenchmarkRuntimeMemStats(b *testing.B) {
r := NewRegistry()
RegisterRuntimeMemStats(r)
b.ResetTimer()
for i := 0; i < b.N; i++ {
CaptureRuntimeMemStatsOnce(r)
}
}
func TestRuntimeMemStats(t *testing.T) {
r := NewRegistry()
RegisterRuntimeMemStats(r)
CaptureRuntimeMemStatsOnce(r)
zero := runtimeMetrics.MemStats.PauseNs.Count() // Get a "zero" since GC may have run before these tests.
runtime.GC()
CaptureRuntimeMemStatsOnce(r)
if count := runtimeMetrics.MemStats.PauseNs.Count(); 1 != count-zero {
t.Fatal(count - zero)
}
runtime.GC()
runtime.GC()
CaptureRuntimeMemStatsOnce(r)
if count := runtimeMetrics.MemStats.PauseNs.Count(); 3 != count-zero {
t.Fatal(count - zero)
}
for i := 0; i < 256; i++ {
runtime.GC()
}
CaptureRuntimeMemStatsOnce(r)
if count := runtimeMetrics.MemStats.PauseNs.Count(); 259 != count-zero {
t.Fatal(count - zero)
}
for i := 0; i < 257; i++ {
runtime.GC()
}
CaptureRuntimeMemStatsOnce(r)
if count := runtimeMetrics.MemStats.PauseNs.Count(); 515 != count-zero { // We lost one because there were too many GCs between captures.
t.Fatal(count - zero)
}
}
func TestRuntimeMemStatsBlocking(t *testing.T) {
if g := runtime.GOMAXPROCS(0); g < 2 {
t.Skipf("skipping TestRuntimeMemStatsBlocking with GOMAXPROCS=%d\n", g)
}
ch := make(chan int)
go testRuntimeMemStatsBlocking(ch)
var memStats runtime.MemStats
t0 := time.Now()
runtime.ReadMemStats(&memStats)
t1 := time.Now()
t.Log("i++ during runtime.ReadMemStats:", <-ch)
go testRuntimeMemStatsBlocking(ch)
d := t1.Sub(t0)
t.Log(d)
time.Sleep(d)
t.Log("i++ during time.Sleep:", <-ch)
}
func testRuntimeMemStatsBlocking(ch chan int) {
i := 0
for {
select {
case ch <- i:
return
default:
i++
}
}
}

@ -0,0 +1,609 @@
package metrics
import (
"math"
"math/rand"
"sort"
"sync"
"time"
)
const rescaleThreshold = time.Hour
// Samples maintain a statistically-significant selection of values from
// a stream.
type Sample interface {
Clear()
Count() int64
Max() int64
Mean() float64
Min() int64
Percentile(float64) float64
Percentiles([]float64) []float64
Size() int
Snapshot() Sample
StdDev() float64
Sum() int64
Update(int64)
Values() []int64
Variance() float64
}
// ExpDecaySample is an exponentially-decaying sample using a forward-decaying
// priority reservoir. See Cormode et al's "Forward Decay: A Practical Time
// Decay Model for Streaming Systems".
//
// <http://www.research.att.com/people/Cormode_Graham/library/publications/CormodeShkapenyukSrivastavaXu09.pdf>
type ExpDecaySample struct {
alpha float64
count int64
mutex sync.Mutex
reservoirSize int
t0, t1 time.Time
values *expDecaySampleHeap
}
// NewExpDecaySample constructs a new exponentially-decaying sample with the
// given reservoir size and alpha.
func NewExpDecaySample(reservoirSize int, alpha float64) Sample {
if UseNilMetrics {
return NilSample{}
}
s := &ExpDecaySample{
alpha: alpha,
reservoirSize: reservoirSize,
t0: time.Now(),
values: newExpDecaySampleHeap(reservoirSize),
}
s.t1 = s.t0.Add(rescaleThreshold)
return s
}
// Clear clears all samples.
func (s *ExpDecaySample) Clear() {
s.mutex.Lock()
defer s.mutex.Unlock()
s.count = 0
s.t0 = time.Now()
s.t1 = s.t0.Add(rescaleThreshold)
s.values.Clear()
}
// Count returns the number of samples recorded, which may exceed the
// reservoir size.
func (s *ExpDecaySample) Count() int64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return s.count
}
// Max returns the maximum value in the sample, which may not be the maximum
// value ever to be part of the sample.
func (s *ExpDecaySample) Max() int64 {
return SampleMax(s.Values())
}
// Mean returns the mean of the values in the sample.
func (s *ExpDecaySample) Mean() float64 {
return SampleMean(s.Values())
}
// Min returns the minimum value in the sample, which may not be the minimum
// value ever to be part of the sample.
func (s *ExpDecaySample) Min() int64 {
return SampleMin(s.Values())
}
// Percentile returns an arbitrary percentile of values in the sample.
func (s *ExpDecaySample) Percentile(p float64) float64 {
return SamplePercentile(s.Values(), p)
}
// Percentiles returns a slice of arbitrary percentiles of values in the
// sample.
func (s *ExpDecaySample) Percentiles(ps []float64) []float64 {
return SamplePercentiles(s.Values(), ps)
}
// Size returns the size of the sample, which is at most the reservoir size.
func (s *ExpDecaySample) Size() int {
s.mutex.Lock()
defer s.mutex.Unlock()
return s.values.Size()
}
// Snapshot returns a read-only copy of the sample.
func (s *ExpDecaySample) Snapshot() Sample {
s.mutex.Lock()
defer s.mutex.Unlock()
vals := s.values.Values()
values := make([]int64, len(vals))
for i, v := range vals {
values[i] = v.v
}
return &SampleSnapshot{
count: s.count,
values: values,
}
}
// StdDev returns the standard deviation of the values in the sample.
func (s *ExpDecaySample) StdDev() float64 {
return SampleStdDev(s.Values())
}
// Sum returns the sum of the values in the sample.
func (s *ExpDecaySample) Sum() int64 {
return SampleSum(s.Values())
}
// Update samples a new value.
func (s *ExpDecaySample) Update(v int64) {
s.update(time.Now(), v)
}
// Values returns a copy of the values in the sample.
func (s *ExpDecaySample) Values() []int64 {
s.mutex.Lock()
defer s.mutex.Unlock()
vals := s.values.Values()
values := make([]int64, len(vals))
for i, v := range vals {
values[i] = v.v
}
return values
}
// Variance returns the variance of the values in the sample.
func (s *ExpDecaySample) Variance() float64 {
return SampleVariance(s.Values())
}
// update samples a new value at a particular timestamp. This is a method all
// its own to facilitate testing.
func (s *ExpDecaySample) update(t time.Time, v int64) {
s.mutex.Lock()
defer s.mutex.Unlock()
s.count++
if s.values.Size() == s.reservoirSize {
s.values.Pop()
}
s.values.Push(expDecaySample{
k: math.Exp(t.Sub(s.t0).Seconds()*s.alpha) / rand.Float64(),
v: v,
})
if t.After(s.t1) {
values := s.values.Values()
t0 := s.t0
s.values.Clear()
s.t0 = t
s.t1 = s.t0.Add(rescaleThreshold)
for _, v := range values {
v.k = v.k * math.Exp(-s.alpha*s.t0.Sub(t0).Seconds())
s.values.Push(v)
}
}
}
// NilSample is a no-op Sample.
type NilSample struct{}
// Clear is a no-op.
func (NilSample) Clear() {}
// Count is a no-op.
func (NilSample) Count() int64 { return 0 }
// Max is a no-op.
func (NilSample) Max() int64 { return 0 }
// Mean is a no-op.
func (NilSample) Mean() float64 { return 0.0 }
// Min is a no-op.
func (NilSample) Min() int64 { return 0 }
// Percentile is a no-op.
func (NilSample) Percentile(p float64) float64 { return 0.0 }
// Percentiles is a no-op.
func (NilSample) Percentiles(ps []float64) []float64 {
return make([]float64, len(ps))
}
// Size is a no-op.
func (NilSample) Size() int { return 0 }
// Sample is a no-op.
func (NilSample) Snapshot() Sample { return NilSample{} }
// StdDev is a no-op.
func (NilSample) StdDev() float64 { return 0.0 }
// Sum is a no-op.
func (NilSample) Sum() int64 { return 0 }
// Update is a no-op.
func (NilSample) Update(v int64) {}
// Values is a no-op.
func (NilSample) Values() []int64 { return []int64{} }
// Variance is a no-op.
func (NilSample) Variance() float64 { return 0.0 }
// SampleMax returns the maximum value of the slice of int64.
func SampleMax(values []int64) int64 {
if 0 == len(values) {
return 0
}
var max int64 = math.MinInt64
for _, v := range values {
if max < v {
max = v
}
}
return max
}
// SampleMean returns the mean value of the slice of int64.
func SampleMean(values []int64) float64 {
if 0 == len(values) {
return 0.0
}
return float64(SampleSum(values)) / float64(len(values))
}
// SampleMin returns the minimum value of the slice of int64.
func SampleMin(values []int64) int64 {
if 0 == len(values) {
return 0
}
var min int64 = math.MaxInt64
for _, v := range values {
if min > v {
min = v
}
}
return min
}
// SamplePercentiles returns an arbitrary percentile of the slice of int64.
func SamplePercentile(values int64Slice, p float64) float64 {
return SamplePercentiles(values, []float64{p})[0]
}
// SamplePercentiles returns a slice of arbitrary percentiles of the slice of
// int64.
func SamplePercentiles(values int64Slice, ps []float64) []float64 {
scores := make([]float64, len(ps))
size := len(values)
if size > 0 {
sort.Sort(values)
for i, p := range ps {
pos := p * float64(size+1)
if pos < 1.0 {
scores[i] = float64(values[0])
} else if pos >= float64(size) {
scores[i] = float64(values[size-1])
} else {
lower := float64(values[int(pos)-1])
upper := float64(values[int(pos)])
scores[i] = lower + (pos-math.Floor(pos))*(upper-lower)
}
}
}
return scores
}
// SampleSnapshot is a read-only copy of another Sample.
type SampleSnapshot struct {
count int64
values []int64
}
// Clear panics.
func (*SampleSnapshot) Clear() {
panic("Clear called on a SampleSnapshot")
}
// Count returns the count of inputs at the time the snapshot was taken.
func (s *SampleSnapshot) Count() int64 { return s.count }
// Max returns the maximal value at the time the snapshot was taken.
func (s *SampleSnapshot) Max() int64 { return SampleMax(s.values) }
// Mean returns the mean value at the time the snapshot was taken.
func (s *SampleSnapshot) Mean() float64 { return SampleMean(s.values) }
// Min returns the minimal value at the time the snapshot was taken.
func (s *SampleSnapshot) Min() int64 { return SampleMin(s.values) }
// Percentile returns an arbitrary percentile of values at the time the
// snapshot was taken.
func (s *SampleSnapshot) Percentile(p float64) float64 {
return SamplePercentile(s.values, p)
}
// Percentiles returns a slice of arbitrary percentiles of values at the time
// the snapshot was taken.
func (s *SampleSnapshot) Percentiles(ps []float64) []float64 {
return SamplePercentiles(s.values, ps)
}
// Size returns the size of the sample at the time the snapshot was taken.
func (s *SampleSnapshot) Size() int { return len(s.values) }
// Snapshot returns the snapshot.
func (s *SampleSnapshot) Snapshot() Sample { return s }
// StdDev returns the standard deviation of values at the time the snapshot was
// taken.
func (s *SampleSnapshot) StdDev() float64 { return SampleStdDev(s.values) }
// Sum returns the sum of values at the time the snapshot was taken.
func (s *SampleSnapshot) Sum() int64 { return SampleSum(s.values) }
// Update panics.
func (*SampleSnapshot) Update(int64) {
panic("Update called on a SampleSnapshot")
}
// Values returns a copy of the values in the sample.
func (s *SampleSnapshot) Values() []int64 {
values := make([]int64, len(s.values))
copy(values, s.values)
return values
}
// Variance returns the variance of values at the time the snapshot was taken.
func (s *SampleSnapshot) Variance() float64 { return SampleVariance(s.values) }
// SampleStdDev returns the standard deviation of the slice of int64.
func SampleStdDev(values []int64) float64 {
return math.Sqrt(SampleVariance(values))
}
// SampleSum returns the sum of the slice of int64.
func SampleSum(values []int64) int64 {
var sum int64
for _, v := range values {
sum += v
}
return sum
}
// SampleVariance returns the variance of the slice of int64.
func SampleVariance(values []int64) float64 {
if 0 == len(values) {
return 0.0
}
m := SampleMean(values)
var sum float64
for _, v := range values {
d := float64(v) - m
sum += d * d
}
return sum / float64(len(values))
}
// A uniform sample using Vitter's Algorithm R.
//
// <http://www.cs.umd.edu/~samir/498/vitter.pdf>
type UniformSample struct {
count int64
mutex sync.Mutex
reservoirSize int
values []int64
}
// NewUniformSample constructs a new uniform sample with the given reservoir
// size.
func NewUniformSample(reservoirSize int) Sample {
if UseNilMetrics {
return NilSample{}
}
return &UniformSample{
reservoirSize: reservoirSize,
values: make([]int64, 0, reservoirSize),
}
}
// Clear clears all samples.
func (s *UniformSample) Clear() {
s.mutex.Lock()
defer s.mutex.Unlock()
s.count = 0
s.values = make([]int64, 0, s.reservoirSize)
}
// Count returns the number of samples recorded, which may exceed the
// reservoir size.
func (s *UniformSample) Count() int64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return s.count
}
// Max returns the maximum value in the sample, which may not be the maximum
// value ever to be part of the sample.
func (s *UniformSample) Max() int64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return SampleMax(s.values)
}
// Mean returns the mean of the values in the sample.
func (s *UniformSample) Mean() float64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return SampleMean(s.values)
}
// Min returns the minimum value in the sample, which may not be the minimum
// value ever to be part of the sample.
func (s *UniformSample) Min() int64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return SampleMin(s.values)
}
// Percentile returns an arbitrary percentile of values in the sample.
func (s *UniformSample) Percentile(p float64) float64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return SamplePercentile(s.values, p)
}
// Percentiles returns a slice of arbitrary percentiles of values in the
// sample.
func (s *UniformSample) Percentiles(ps []float64) []float64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return SamplePercentiles(s.values, ps)
}
// Size returns the size of the sample, which is at most the reservoir size.
func (s *UniformSample) Size() int {
s.mutex.Lock()
defer s.mutex.Unlock()
return len(s.values)
}
// Snapshot returns a read-only copy of the sample.
func (s *UniformSample) Snapshot() Sample {
s.mutex.Lock()
defer s.mutex.Unlock()
values := make([]int64, len(s.values))
copy(values, s.values)
return &SampleSnapshot{
count: s.count,
values: values,
}
}
// StdDev returns the standard deviation of the values in the sample.
func (s *UniformSample) StdDev() float64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return SampleStdDev(s.values)
}
// Sum returns the sum of the values in the sample.
func (s *UniformSample) Sum() int64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return SampleSum(s.values)
}
// Update samples a new value.
func (s *UniformSample) Update(v int64) {
s.mutex.Lock()
defer s.mutex.Unlock()
s.count++
if len(s.values) < s.reservoirSize {
s.values = append(s.values, v)
} else {
r := rand.Int63n(s.count)
if r < int64(len(s.values)) {
s.values[int(r)] = v
}
}
}
// Values returns a copy of the values in the sample.
func (s *UniformSample) Values() []int64 {
s.mutex.Lock()
defer s.mutex.Unlock()
values := make([]int64, len(s.values))
copy(values, s.values)
return values
}
// Variance returns the variance of the values in the sample.
func (s *UniformSample) Variance() float64 {
s.mutex.Lock()
defer s.mutex.Unlock()
return SampleVariance(s.values)
}
// expDecaySample represents an individual sample in a heap.
type expDecaySample struct {
k float64
v int64
}
func newExpDecaySampleHeap(reservoirSize int) *expDecaySampleHeap {
return &expDecaySampleHeap{make([]expDecaySample, 0, reservoirSize)}
}
// expDecaySampleHeap is a min-heap of expDecaySamples.
// The internal implementation is copied from the standard library's container/heap
type expDecaySampleHeap struct {
s []expDecaySample
}
func (h *expDecaySampleHeap) Clear() {
h.s = h.s[:0]
}
func (h *expDecaySampleHeap) Push(s expDecaySample) {
n := len(h.s)
h.s = h.s[0 : n+1]
h.s[n] = s
h.up(n)
}
func (h *expDecaySampleHeap) Pop() expDecaySample {
n := len(h.s) - 1
h.s[0], h.s[n] = h.s[n], h.s[0]
h.down(0, n)
n = len(h.s)
s := h.s[n-1]
h.s = h.s[0 : n-1]
return s
}
func (h *expDecaySampleHeap) Size() int {
return len(h.s)
}
func (h *expDecaySampleHeap) Values() []expDecaySample {
return h.s
}
func (h *expDecaySampleHeap) up(j int) {
for {
i := (j - 1) / 2 // parent
if i == j || !(h.s[j].k < h.s[i].k) {
break
}
h.s[i], h.s[j] = h.s[j], h.s[i]
j = i
}
}
func (h *expDecaySampleHeap) down(i, n int) {
for {
j1 := 2*i + 1
if j1 >= n || j1 < 0 { // j1 < 0 after int overflow
break
}
j := j1 // left child
if j2 := j1 + 1; j2 < n && !(h.s[j1].k < h.s[j2].k) {
j = j2 // = 2*i + 2 // right child
}
if !(h.s[j].k < h.s[i].k) {
break
}
h.s[i], h.s[j] = h.s[j], h.s[i]
i = j
}
}
type int64Slice []int64
func (p int64Slice) Len() int { return len(p) }
func (p int64Slice) Less(i, j int) bool { return p[i] < p[j] }
func (p int64Slice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }

@ -0,0 +1,363 @@
package metrics
import (
"math/rand"
"runtime"
"testing"
"time"
)
// Benchmark{Compute,Copy}{1000,1000000} demonstrate that, even for relatively
// expensive computations like Variance, the cost of copying the Sample, as
// approximated by a make and copy, is much greater than the cost of the
// computation for small samples and only slightly less for large samples.
func BenchmarkCompute1000(b *testing.B) {
s := make([]int64, 1000)
for i := 0; i < len(s); i++ {
s[i] = int64(i)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
SampleVariance(s)
}
}
func BenchmarkCompute1000000(b *testing.B) {
s := make([]int64, 1000000)
for i := 0; i < len(s); i++ {
s[i] = int64(i)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
SampleVariance(s)
}
}
func BenchmarkCopy1000(b *testing.B) {
s := make([]int64, 1000)
for i := 0; i < len(s); i++ {
s[i] = int64(i)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
sCopy := make([]int64, len(s))
copy(sCopy, s)
}
}
func BenchmarkCopy1000000(b *testing.B) {
s := make([]int64, 1000000)
for i := 0; i < len(s); i++ {
s[i] = int64(i)
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
sCopy := make([]int64, len(s))
copy(sCopy, s)
}
}
func BenchmarkExpDecaySample257(b *testing.B) {
benchmarkSample(b, NewExpDecaySample(257, 0.015))
}
func BenchmarkExpDecaySample514(b *testing.B) {
benchmarkSample(b, NewExpDecaySample(514, 0.015))
}
func BenchmarkExpDecaySample1028(b *testing.B) {
benchmarkSample(b, NewExpDecaySample(1028, 0.015))
}
func BenchmarkUniformSample257(b *testing.B) {
benchmarkSample(b, NewUniformSample(257))
}
func BenchmarkUniformSample514(b *testing.B) {
benchmarkSample(b, NewUniformSample(514))
}
func BenchmarkUniformSample1028(b *testing.B) {
benchmarkSample(b, NewUniformSample(1028))
}
func TestExpDecaySample10(t *testing.T) {
rand.Seed(1)
s := NewExpDecaySample(100, 0.99)
for i := 0; i < 10; i++ {
s.Update(int64(i))
}
if size := s.Count(); 10 != size {
t.Errorf("s.Count(): 10 != %v\n", size)
}
if size := s.Size(); 10 != size {
t.Errorf("s.Size(): 10 != %v\n", size)
}
if l := len(s.Values()); 10 != l {
t.Errorf("len(s.Values()): 10 != %v\n", l)
}
for _, v := range s.Values() {
if v > 10 || v < 0 {
t.Errorf("out of range [0, 10): %v\n", v)
}
}
}
func TestExpDecaySample100(t *testing.T) {
rand.Seed(1)
s := NewExpDecaySample(1000, 0.01)
for i := 0; i < 100; i++ {
s.Update(int64(i))
}
if size := s.Count(); 100 != size {
t.Errorf("s.Count(): 100 != %v\n", size)
}
if size := s.Size(); 100 != size {
t.Errorf("s.Size(): 100 != %v\n", size)
}
if l := len(s.Values()); 100 != l {
t.Errorf("len(s.Values()): 100 != %v\n", l)
}
for _, v := range s.Values() {
if v > 100 || v < 0 {
t.Errorf("out of range [0, 100): %v\n", v)
}
}
}
func TestExpDecaySample1000(t *testing.T) {
rand.Seed(1)
s := NewExpDecaySample(100, 0.99)
for i := 0; i < 1000; i++ {
s.Update(int64(i))
}
if size := s.Count(); 1000 != size {
t.Errorf("s.Count(): 1000 != %v\n", size)
}
if size := s.Size(); 100 != size {
t.Errorf("s.Size(): 100 != %v\n", size)
}
if l := len(s.Values()); 100 != l {
t.Errorf("len(s.Values()): 100 != %v\n", l)
}
for _, v := range s.Values() {
if v > 1000 || v < 0 {
t.Errorf("out of range [0, 1000): %v\n", v)
}
}
}
// This test makes sure that the sample's priority is not amplified by using
// nanosecond duration since start rather than second duration since start.
// The priority becomes +Inf quickly after starting if this is done,
// effectively freezing the set of samples until a rescale step happens.
func TestExpDecaySampleNanosecondRegression(t *testing.T) {
rand.Seed(1)
s := NewExpDecaySample(100, 0.99)
for i := 0; i < 100; i++ {
s.Update(10)
}
time.Sleep(1 * time.Millisecond)
for i := 0; i < 100; i++ {
s.Update(20)
}
v := s.Values()
avg := float64(0)
for i := 0; i < len(v); i++ {
avg += float64(v[i])
}
avg /= float64(len(v))
if avg > 16 || avg < 14 {
t.Errorf("out of range [14, 16]: %v\n", avg)
}
}
func TestExpDecaySampleRescale(t *testing.T) {
s := NewExpDecaySample(2, 0.001).(*ExpDecaySample)
s.update(time.Now(), 1)
s.update(time.Now().Add(time.Hour+time.Microsecond), 1)
for _, v := range s.values.Values() {
if v.k == 0.0 {
t.Fatal("v.k == 0.0")
}
}
}
func TestExpDecaySampleSnapshot(t *testing.T) {
now := time.Now()
rand.Seed(1)
s := NewExpDecaySample(100, 0.99)
for i := 1; i <= 10000; i++ {
s.(*ExpDecaySample).update(now.Add(time.Duration(i)), int64(i))
}
snapshot := s.Snapshot()
s.Update(1)
testExpDecaySampleStatistics(t, snapshot)
}
func TestExpDecaySampleStatistics(t *testing.T) {
now := time.Now()
rand.Seed(1)
s := NewExpDecaySample(100, 0.99)
for i := 1; i <= 10000; i++ {
s.(*ExpDecaySample).update(now.Add(time.Duration(i)), int64(i))
}
testExpDecaySampleStatistics(t, s)
}
func TestUniformSample(t *testing.T) {
rand.Seed(1)
s := NewUniformSample(100)
for i := 0; i < 1000; i++ {
s.Update(int64(i))
}
if size := s.Count(); 1000 != size {
t.Errorf("s.Count(): 1000 != %v\n", size)
}
if size := s.Size(); 100 != size {
t.Errorf("s.Size(): 100 != %v\n", size)
}
if l := len(s.Values()); 100 != l {
t.Errorf("len(s.Values()): 100 != %v\n", l)
}
for _, v := range s.Values() {
if v > 1000 || v < 0 {
t.Errorf("out of range [0, 100): %v\n", v)
}
}
}
func TestUniformSampleIncludesTail(t *testing.T) {
rand.Seed(1)
s := NewUniformSample(100)
max := 100
for i := 0; i < max; i++ {
s.Update(int64(i))
}
v := s.Values()
sum := 0
exp := (max - 1) * max / 2
for i := 0; i < len(v); i++ {
sum += int(v[i])
}
if exp != sum {
t.Errorf("sum: %v != %v\n", exp, sum)
}
}
func TestUniformSampleSnapshot(t *testing.T) {
s := NewUniformSample(100)
for i := 1; i <= 10000; i++ {
s.Update(int64(i))
}
snapshot := s.Snapshot()
s.Update(1)
testUniformSampleStatistics(t, snapshot)
}
func TestUniformSampleStatistics(t *testing.T) {
rand.Seed(1)
s := NewUniformSample(100)
for i := 1; i <= 10000; i++ {
s.Update(int64(i))
}
testUniformSampleStatistics(t, s)
}
func benchmarkSample(b *testing.B, s Sample) {
var memStats runtime.MemStats
runtime.ReadMemStats(&memStats)
pauseTotalNs := memStats.PauseTotalNs
b.ResetTimer()
for i := 0; i < b.N; i++ {
s.Update(1)
}
b.StopTimer()
runtime.GC()
runtime.ReadMemStats(&memStats)
b.Logf("GC cost: %d ns/op", int(memStats.PauseTotalNs-pauseTotalNs)/b.N)
}
func testExpDecaySampleStatistics(t *testing.T, s Sample) {
if count := s.Count(); 10000 != count {
t.Errorf("s.Count(): 10000 != %v\n", count)
}
if min := s.Min(); 107 != min {
t.Errorf("s.Min(): 107 != %v\n", min)
}
if max := s.Max(); 10000 != max {
t.Errorf("s.Max(): 10000 != %v\n", max)
}
if mean := s.Mean(); 4965.98 != mean {
t.Errorf("s.Mean(): 4965.98 != %v\n", mean)
}
if stdDev := s.StdDev(); 2959.825156930727 != stdDev {
t.Errorf("s.StdDev(): 2959.825156930727 != %v\n", stdDev)
}
ps := s.Percentiles([]float64{0.5, 0.75, 0.99})
if 4615 != ps[0] {
t.Errorf("median: 4615 != %v\n", ps[0])
}
if 7672 != ps[1] {
t.Errorf("75th percentile: 7672 != %v\n", ps[1])
}
if 9998.99 != ps[2] {
t.Errorf("99th percentile: 9998.99 != %v\n", ps[2])
}
}
func testUniformSampleStatistics(t *testing.T, s Sample) {
if count := s.Count(); 10000 != count {
t.Errorf("s.Count(): 10000 != %v\n", count)
}
if min := s.Min(); 37 != min {
t.Errorf("s.Min(): 37 != %v\n", min)
}
if max := s.Max(); 9989 != max {
t.Errorf("s.Max(): 9989 != %v\n", max)
}
if mean := s.Mean(); 4748.14 != mean {
t.Errorf("s.Mean(): 4748.14 != %v\n", mean)
}
if stdDev := s.StdDev(); 2826.684117548333 != stdDev {
t.Errorf("s.StdDev(): 2826.684117548333 != %v\n", stdDev)
}
ps := s.Percentiles([]float64{0.5, 0.75, 0.99})
if 4599 != ps[0] {
t.Errorf("median: 4599 != %v\n", ps[0])
}
if 7380.5 != ps[1] {
t.Errorf("75th percentile: 7380.5 != %v\n", ps[1])
}
if 9986.429999999998 != ps[2] {
t.Errorf("99th percentile: 9986.429999999998 != %v\n", ps[2])
}
}
// TestUniformSampleConcurrentUpdateCount would expose data race problems with
// concurrent Update and Count calls on Sample when test is called with -race
// argument
func TestUniformSampleConcurrentUpdateCount(t *testing.T) {
if testing.Short() {
t.Skip("skipping in short mode")
}
s := NewUniformSample(100)
for i := 0; i < 100; i++ {
s.Update(int64(i))
}
quit := make(chan struct{})
go func() {
t := time.NewTicker(10 * time.Millisecond)
for {
select {
case <-t.C:
s.Update(rand.Int63())
case <-quit:
t.Stop()
return
}
}
}()
for i := 0; i < 1000; i++ {
s.Count()
time.Sleep(5 * time.Millisecond)
}
quit <- struct{}{}
}

@ -0,0 +1,69 @@
// Metrics output to StatHat.
package stathat
import (
"github.com/rcrowley/go-metrics"
"github.com/stathat/go"
"log"
"time"
)
func Stathat(r metrics.Registry, d time.Duration, userkey string) {
for {
if err := sh(r, userkey); nil != err {
log.Println(err)
}
time.Sleep(d)
}
}
func sh(r metrics.Registry, userkey string) error {
r.Each(func(name string, i interface{}) {
switch metric := i.(type) {
case metrics.Counter:
stathat.PostEZCount(name, userkey, int(metric.Count()))
case metrics.Gauge:
stathat.PostEZValue(name, userkey, float64(metric.Value()))
case metrics.GaugeFloat64:
stathat.PostEZValue(name, userkey, float64(metric.Value()))
case metrics.Histogram:
h := metric.Snapshot()
ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
stathat.PostEZCount(name+".count", userkey, int(h.Count()))
stathat.PostEZValue(name+".min", userkey, float64(h.Min()))
stathat.PostEZValue(name+".max", userkey, float64(h.Max()))
stathat.PostEZValue(name+".mean", userkey, float64(h.Mean()))
stathat.PostEZValue(name+".std-dev", userkey, float64(h.StdDev()))
stathat.PostEZValue(name+".50-percentile", userkey, float64(ps[0]))
stathat.PostEZValue(name+".75-percentile", userkey, float64(ps[1]))
stathat.PostEZValue(name+".95-percentile", userkey, float64(ps[2]))
stathat.PostEZValue(name+".99-percentile", userkey, float64(ps[3]))
stathat.PostEZValue(name+".999-percentile", userkey, float64(ps[4]))
case metrics.Meter:
m := metric.Snapshot()
stathat.PostEZCount(name+".count", userkey, int(m.Count()))
stathat.PostEZValue(name+".one-minute", userkey, float64(m.Rate1()))
stathat.PostEZValue(name+".five-minute", userkey, float64(m.Rate5()))
stathat.PostEZValue(name+".fifteen-minute", userkey, float64(m.Rate15()))
stathat.PostEZValue(name+".mean", userkey, float64(m.RateMean()))
case metrics.Timer:
t := metric.Snapshot()
ps := t.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
stathat.PostEZCount(name+".count", userkey, int(t.Count()))
stathat.PostEZValue(name+".min", userkey, float64(t.Min()))
stathat.PostEZValue(name+".max", userkey, float64(t.Max()))
stathat.PostEZValue(name+".mean", userkey, float64(t.Mean()))
stathat.PostEZValue(name+".std-dev", userkey, float64(t.StdDev()))
stathat.PostEZValue(name+".50-percentile", userkey, float64(ps[0]))
stathat.PostEZValue(name+".75-percentile", userkey, float64(ps[1]))
stathat.PostEZValue(name+".95-percentile", userkey, float64(ps[2]))
stathat.PostEZValue(name+".99-percentile", userkey, float64(ps[3]))
stathat.PostEZValue(name+".999-percentile", userkey, float64(ps[4]))
stathat.PostEZValue(name+".one-minute", userkey, float64(t.Rate1()))
stathat.PostEZValue(name+".five-minute", userkey, float64(t.Rate5()))
stathat.PostEZValue(name+".fifteen-minute", userkey, float64(t.Rate15()))
stathat.PostEZValue(name+".mean-rate", userkey, float64(t.RateMean()))
}
})
return nil
}

@ -0,0 +1,78 @@
// +build !windows
package metrics
import (
"fmt"
"log/syslog"
"time"
)
// Output each metric in the given registry to syslog periodically using
// the given syslogger.
func Syslog(r Registry, d time.Duration, w *syslog.Writer) {
for _ = range time.Tick(d) {
r.Each(func(name string, i interface{}) {
switch metric := i.(type) {
case Counter:
w.Info(fmt.Sprintf("counter %s: count: %d", name, metric.Count()))
case Gauge:
w.Info(fmt.Sprintf("gauge %s: value: %d", name, metric.Value()))
case GaugeFloat64:
w.Info(fmt.Sprintf("gauge %s: value: %f", name, metric.Value()))
case Healthcheck:
metric.Check()
w.Info(fmt.Sprintf("healthcheck %s: error: %v", name, metric.Error()))
case Histogram:
h := metric.Snapshot()
ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
w.Info(fmt.Sprintf(
"histogram %s: count: %d min: %d max: %d mean: %.2f stddev: %.2f median: %.2f 75%%: %.2f 95%%: %.2f 99%%: %.2f 99.9%%: %.2f",
name,
h.Count(),
h.Min(),
h.Max(),
h.Mean(),
h.StdDev(),
ps[0],
ps[1],
ps[2],
ps[3],
ps[4],
))
case Meter:
m := metric.Snapshot()
w.Info(fmt.Sprintf(
"meter %s: count: %d 1-min: %.2f 5-min: %.2f 15-min: %.2f mean: %.2f",
name,
m.Count(),
m.Rate1(),
m.Rate5(),
m.Rate15(),
m.RateMean(),
))
case Timer:
t := metric.Snapshot()
ps := t.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
w.Info(fmt.Sprintf(
"timer %s: count: %d min: %d max: %d mean: %.2f stddev: %.2f median: %.2f 75%%: %.2f 95%%: %.2f 99%%: %.2f 99.9%%: %.2f 1-min: %.2f 5-min: %.2f 15-min: %.2f mean-rate: %.2f",
name,
t.Count(),
t.Min(),
t.Max(),
t.Mean(),
t.StdDev(),
ps[0],
ps[1],
ps[2],
ps[3],
ps[4],
t.Rate1(),
t.Rate5(),
t.Rate15(),
t.RateMean(),
))
}
})
}
}

@ -0,0 +1,311 @@
package metrics
import (
"sync"
"time"
)
// Timers capture the duration and rate of events.
type Timer interface {
Count() int64
Max() int64
Mean() float64
Min() int64
Percentile(float64) float64
Percentiles([]float64) []float64
Rate1() float64
Rate5() float64
Rate15() float64
RateMean() float64
Snapshot() Timer
StdDev() float64
Sum() int64
Time(func())
Update(time.Duration)
UpdateSince(time.Time)
Variance() float64
}
// GetOrRegisterTimer returns an existing Timer or constructs and registers a
// new StandardTimer.
func GetOrRegisterTimer(name string, r Registry) Timer {
if nil == r {
r = DefaultRegistry
}
return r.GetOrRegister(name, NewTimer).(Timer)
}
// NewCustomTimer constructs a new StandardTimer from a Histogram and a Meter.
func NewCustomTimer(h Histogram, m Meter) Timer {
if UseNilMetrics {
return NilTimer{}
}
return &StandardTimer{
histogram: h,
meter: m,
}
}
// NewRegisteredTimer constructs and registers a new StandardTimer.
func NewRegisteredTimer(name string, r Registry) Timer {
c := NewTimer()
if nil == r {
r = DefaultRegistry
}
r.Register(name, c)
return c
}
// NewTimer constructs a new StandardTimer using an exponentially-decaying
// sample with the same reservoir size and alpha as UNIX load averages.
func NewTimer() Timer {
if UseNilMetrics {
return NilTimer{}
}
return &StandardTimer{
histogram: NewHistogram(NewExpDecaySample(1028, 0.015)),
meter: NewMeter(),
}
}
// NilTimer is a no-op Timer.
type NilTimer struct {
h Histogram
m Meter
}
// Count is a no-op.
func (NilTimer) Count() int64 { return 0 }
// Max is a no-op.
func (NilTimer) Max() int64 { return 0 }
// Mean is a no-op.
func (NilTimer) Mean() float64 { return 0.0 }
// Min is a no-op.
func (NilTimer) Min() int64 { return 0 }
// Percentile is a no-op.
func (NilTimer) Percentile(p float64) float64 { return 0.0 }
// Percentiles is a no-op.
func (NilTimer) Percentiles(ps []float64) []float64 {
return make([]float64, len(ps))
}
// Rate1 is a no-op.
func (NilTimer) Rate1() float64 { return 0.0 }
// Rate5 is a no-op.
func (NilTimer) Rate5() float64 { return 0.0 }
// Rate15 is a no-op.
func (NilTimer) Rate15() float64 { return 0.0 }
// RateMean is a no-op.
func (NilTimer) RateMean() float64 { return 0.0 }
// Snapshot is a no-op.
func (NilTimer) Snapshot() Timer { return NilTimer{} }
// StdDev is a no-op.
func (NilTimer) StdDev() float64 { return 0.0 }
// Sum is a no-op.
func (NilTimer) Sum() int64 { return 0 }
// Time is a no-op.
func (NilTimer) Time(func()) {}
// Update is a no-op.
func (NilTimer) Update(time.Duration) {}
// UpdateSince is a no-op.
func (NilTimer) UpdateSince(time.Time) {}
// Variance is a no-op.
func (NilTimer) Variance() float64 { return 0.0 }
// StandardTimer is the standard implementation of a Timer and uses a Histogram
// and Meter.
type StandardTimer struct {
histogram Histogram
meter Meter
mutex sync.Mutex
}
// Count returns the number of events recorded.
func (t *StandardTimer) Count() int64 {
return t.histogram.Count()
}
// Max returns the maximum value in the sample.
func (t *StandardTimer) Max() int64 {
return t.histogram.Max()
}
// Mean returns the mean of the values in the sample.
func (t *StandardTimer) Mean() float64 {
return t.histogram.Mean()
}
// Min returns the minimum value in the sample.
func (t *StandardTimer) Min() int64 {
return t.histogram.Min()
}
// Percentile returns an arbitrary percentile of the values in the sample.
func (t *StandardTimer) Percentile(p float64) float64 {
return t.histogram.Percentile(p)
}
// Percentiles returns a slice of arbitrary percentiles of the values in the
// sample.
func (t *StandardTimer) Percentiles(ps []float64) []float64 {
return t.histogram.Percentiles(ps)
}
// Rate1 returns the one-minute moving average rate of events per second.
func (t *StandardTimer) Rate1() float64 {
return t.meter.Rate1()
}
// Rate5 returns the five-minute moving average rate of events per second.
func (t *StandardTimer) Rate5() float64 {
return t.meter.Rate5()
}
// Rate15 returns the fifteen-minute moving average rate of events per second.
func (t *StandardTimer) Rate15() float64 {
return t.meter.Rate15()
}
// RateMean returns the meter's mean rate of events per second.
func (t *StandardTimer) RateMean() float64 {
return t.meter.RateMean()
}
// Snapshot returns a read-only copy of the timer.
func (t *StandardTimer) Snapshot() Timer {
t.mutex.Lock()
defer t.mutex.Unlock()
return &TimerSnapshot{
histogram: t.histogram.Snapshot().(*HistogramSnapshot),
meter: t.meter.Snapshot().(*MeterSnapshot),
}
}
// StdDev returns the standard deviation of the values in the sample.
func (t *StandardTimer) StdDev() float64 {
return t.histogram.StdDev()
}
// Sum returns the sum in the sample.
func (t *StandardTimer) Sum() int64 {
return t.histogram.Sum()
}
// Record the duration of the execution of the given function.
func (t *StandardTimer) Time(f func()) {
ts := time.Now()
f()
t.Update(time.Since(ts))
}
// Record the duration of an event.
func (t *StandardTimer) Update(d time.Duration) {
t.mutex.Lock()
defer t.mutex.Unlock()
t.histogram.Update(int64(d))
t.meter.Mark(1)
}
// Record the duration of an event that started at a time and ends now.
func (t *StandardTimer) UpdateSince(ts time.Time) {
t.mutex.Lock()
defer t.mutex.Unlock()
t.histogram.Update(int64(time.Since(ts)))
t.meter.Mark(1)
}
// Variance returns the variance of the values in the sample.
func (t *StandardTimer) Variance() float64 {
return t.histogram.Variance()
}
// TimerSnapshot is a read-only copy of another Timer.
type TimerSnapshot struct {
histogram *HistogramSnapshot
meter *MeterSnapshot
}
// Count returns the number of events recorded at the time the snapshot was
// taken.
func (t *TimerSnapshot) Count() int64 { return t.histogram.Count() }
// Max returns the maximum value at the time the snapshot was taken.
func (t *TimerSnapshot) Max() int64 { return t.histogram.Max() }
// Mean returns the mean value at the time the snapshot was taken.
func (t *TimerSnapshot) Mean() float64 { return t.histogram.Mean() }
// Min returns the minimum value at the time the snapshot was taken.
func (t *TimerSnapshot) Min() int64 { return t.histogram.Min() }
// Percentile returns an arbitrary percentile of sampled values at the time the
// snapshot was taken.
func (t *TimerSnapshot) Percentile(p float64) float64 {
return t.histogram.Percentile(p)
}
// Percentiles returns a slice of arbitrary percentiles of sampled values at
// the time the snapshot was taken.
func (t *TimerSnapshot) Percentiles(ps []float64) []float64 {
return t.histogram.Percentiles(ps)
}
// Rate1 returns the one-minute moving average rate of events per second at the
// time the snapshot was taken.
func (t *TimerSnapshot) Rate1() float64 { return t.meter.Rate1() }
// Rate5 returns the five-minute moving average rate of events per second at
// the time the snapshot was taken.
func (t *TimerSnapshot) Rate5() float64 { return t.meter.Rate5() }
// Rate15 returns the fifteen-minute moving average rate of events per second
// at the time the snapshot was taken.
func (t *TimerSnapshot) Rate15() float64 { return t.meter.Rate15() }
// RateMean returns the meter's mean rate of events per second at the time the
// snapshot was taken.
func (t *TimerSnapshot) RateMean() float64 { return t.meter.RateMean() }
// Snapshot returns the snapshot.
func (t *TimerSnapshot) Snapshot() Timer { return t }
// StdDev returns the standard deviation of the values at the time the snapshot
// was taken.
func (t *TimerSnapshot) StdDev() float64 { return t.histogram.StdDev() }
// Sum returns the sum at the time the snapshot was taken.
func (t *TimerSnapshot) Sum() int64 { return t.histogram.Sum() }
// Time panics.
func (*TimerSnapshot) Time(func()) {
panic("Time called on a TimerSnapshot")
}
// Update panics.
func (*TimerSnapshot) Update(time.Duration) {
panic("Update called on a TimerSnapshot")
}
// UpdateSince panics.
func (*TimerSnapshot) UpdateSince(time.Time) {
panic("UpdateSince called on a TimerSnapshot")
}
// Variance returns the variance of the values at the time the snapshot was
// taken.
func (t *TimerSnapshot) Variance() float64 { return t.histogram.Variance() }

@ -0,0 +1,81 @@
package metrics
import (
"math"
"testing"
"time"
)
func BenchmarkTimer(b *testing.B) {
tm := NewTimer()
b.ResetTimer()
for i := 0; i < b.N; i++ {
tm.Update(1)
}
}
func TestGetOrRegisterTimer(t *testing.T) {
r := NewRegistry()
NewRegisteredTimer("foo", r).Update(47)
if tm := GetOrRegisterTimer("foo", r); 1 != tm.Count() {
t.Fatal(tm)
}
}
func TestTimerExtremes(t *testing.T) {
tm := NewTimer()
tm.Update(math.MaxInt64)
tm.Update(0)
if stdDev := tm.StdDev(); 4.611686018427388e+18 != stdDev {
t.Errorf("tm.StdDev(): 4.611686018427388e+18 != %v\n", stdDev)
}
}
func TestTimerFunc(t *testing.T) {
tm := NewTimer()
tm.Time(func() { time.Sleep(50e6) })
if max := tm.Max(); 45e6 > max || max > 55e6 {
t.Errorf("tm.Max(): 45e6 > %v || %v > 55e6\n", max, max)
}
}
func TestTimerZero(t *testing.T) {
tm := NewTimer()
if count := tm.Count(); 0 != count {
t.Errorf("tm.Count(): 0 != %v\n", count)
}
if min := tm.Min(); 0 != min {
t.Errorf("tm.Min(): 0 != %v\n", min)
}
if max := tm.Max(); 0 != max {
t.Errorf("tm.Max(): 0 != %v\n", max)
}
if mean := tm.Mean(); 0.0 != mean {
t.Errorf("tm.Mean(): 0.0 != %v\n", mean)
}
if stdDev := tm.StdDev(); 0.0 != stdDev {
t.Errorf("tm.StdDev(): 0.0 != %v\n", stdDev)
}
ps := tm.Percentiles([]float64{0.5, 0.75, 0.99})
if 0.0 != ps[0] {
t.Errorf("median: 0.0 != %v\n", ps[0])
}
if 0.0 != ps[1] {
t.Errorf("75th percentile: 0.0 != %v\n", ps[1])
}
if 0.0 != ps[2] {
t.Errorf("99th percentile: 0.0 != %v\n", ps[2])
}
if rate1 := tm.Rate1(); 0.0 != rate1 {
t.Errorf("tm.Rate1(): 0.0 != %v\n", rate1)
}
if rate5 := tm.Rate5(); 0.0 != rate5 {
t.Errorf("tm.Rate5(): 0.0 != %v\n", rate5)
}
if rate15 := tm.Rate15(); 0.0 != rate15 {
t.Errorf("tm.Rate15(): 0.0 != %v\n", rate15)
}
if rateMean := tm.RateMean(); 0.0 != rateMean {
t.Errorf("tm.RateMean(): 0.0 != %v\n", rateMean)
}
}

@ -0,0 +1,100 @@
package metrics
import (
"fmt"
"io"
"sort"
"time"
)
// Write sorts writes each metric in the given registry periodically to the
// given io.Writer.
func Write(r Registry, d time.Duration, w io.Writer) {
for _ = range time.Tick(d) {
WriteOnce(r, w)
}
}
// WriteOnce sorts and writes metrics in the given registry to the given
// io.Writer.
func WriteOnce(r Registry, w io.Writer) {
var namedMetrics namedMetricSlice
r.Each(func(name string, i interface{}) {
namedMetrics = append(namedMetrics, namedMetric{name, i})
})
sort.Sort(namedMetrics)
for _, namedMetric := range namedMetrics {
switch metric := namedMetric.m.(type) {
case Counter:
fmt.Fprintf(w, "counter %s\n", namedMetric.name)
fmt.Fprintf(w, " count: %9d\n", metric.Count())
case Gauge:
fmt.Fprintf(w, "gauge %s\n", namedMetric.name)
fmt.Fprintf(w, " value: %9d\n", metric.Value())
case GaugeFloat64:
fmt.Fprintf(w, "gauge %s\n", namedMetric.name)
fmt.Fprintf(w, " value: %f\n", metric.Value())
case Healthcheck:
metric.Check()
fmt.Fprintf(w, "healthcheck %s\n", namedMetric.name)
fmt.Fprintf(w, " error: %v\n", metric.Error())
case Histogram:
h := metric.Snapshot()
ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
fmt.Fprintf(w, "histogram %s\n", namedMetric.name)
fmt.Fprintf(w, " count: %9d\n", h.Count())
fmt.Fprintf(w, " min: %9d\n", h.Min())
fmt.Fprintf(w, " max: %9d\n", h.Max())
fmt.Fprintf(w, " mean: %12.2f\n", h.Mean())
fmt.Fprintf(w, " stddev: %12.2f\n", h.StdDev())
fmt.Fprintf(w, " median: %12.2f\n", ps[0])
fmt.Fprintf(w, " 75%%: %12.2f\n", ps[1])
fmt.Fprintf(w, " 95%%: %12.2f\n", ps[2])
fmt.Fprintf(w, " 99%%: %12.2f\n", ps[3])
fmt.Fprintf(w, " 99.9%%: %12.2f\n", ps[4])
case Meter:
m := metric.Snapshot()
fmt.Fprintf(w, "meter %s\n", namedMetric.name)
fmt.Fprintf(w, " count: %9d\n", m.Count())
fmt.Fprintf(w, " 1-min rate: %12.2f\n", m.Rate1())
fmt.Fprintf(w, " 5-min rate: %12.2f\n", m.Rate5())
fmt.Fprintf(w, " 15-min rate: %12.2f\n", m.Rate15())
fmt.Fprintf(w, " mean rate: %12.2f\n", m.RateMean())
case Timer:
t := metric.Snapshot()
ps := t.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})
fmt.Fprintf(w, "timer %s\n", namedMetric.name)
fmt.Fprintf(w, " count: %9d\n", t.Count())
fmt.Fprintf(w, " min: %9d\n", t.Min())
fmt.Fprintf(w, " max: %9d\n", t.Max())
fmt.Fprintf(w, " mean: %12.2f\n", t.Mean())
fmt.Fprintf(w, " stddev: %12.2f\n", t.StdDev())
fmt.Fprintf(w, " median: %12.2f\n", ps[0])
fmt.Fprintf(w, " 75%%: %12.2f\n", ps[1])
fmt.Fprintf(w, " 95%%: %12.2f\n", ps[2])
fmt.Fprintf(w, " 99%%: %12.2f\n", ps[3])
fmt.Fprintf(w, " 99.9%%: %12.2f\n", ps[4])
fmt.Fprintf(w, " 1-min rate: %12.2f\n", t.Rate1())
fmt.Fprintf(w, " 5-min rate: %12.2f\n", t.Rate5())
fmt.Fprintf(w, " 15-min rate: %12.2f\n", t.Rate15())
fmt.Fprintf(w, " mean rate: %12.2f\n", t.RateMean())
}
}
}
type namedMetric struct {
name string
m interface{}
}
// namedMetricSlice is a slice of namedMetrics that implements sort.Interface.
type namedMetricSlice []namedMetric
func (nms namedMetricSlice) Len() int { return len(nms) }
func (nms namedMetricSlice) Swap(i, j int) { nms[i], nms[j] = nms[j], nms[i] }
func (nms namedMetricSlice) Less(i, j int) bool {
return nms[i].name < nms[j].name
}

@ -0,0 +1,22 @@
package metrics
import (
"sort"
"testing"
)
func TestMetricsSorting(t *testing.T) {
var namedMetrics = namedMetricSlice{
{name: "zzz"},
{name: "bbb"},
{name: "fff"},
{name: "ggg"},
}
sort.Sort(namedMetrics)
for i, name := range []string{"bbb", "fff", "ggg", "zzz"} {
if namedMetrics[i].name != name {
t.Fail()
}
}
}