README

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:

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 metrics.Log(metrics.DefaultRegistry, 60e9, log.New(os.Stderr, "metrics: ", log.Lmicroseconds))

Periodically log every metric in slightly-more-parseable form to syslog:

w, _ := syslog.Dial("unixgram", "/dev/log", syslog.LOG_INFO, "metrics")
go metrics.Syslog(metrics.DefaultRegistry, 60e9, w)

Periodically emit every metric to Graphite:

addr, _ := net.ResolveTCPAddr("tcp", "127.0.0.1:2003")
go metrics.Graphite(metrics.DefaultRegistry, 10e9, "metrics", addr)

Periodically emit every metric to StatHat:

import "github.com/rcrowley/go-metrics/stathat"

stathat.Stathat(metrics.DefaultRegistry, 10e9, "example@example.com")

Installation

go get github.com/rcrowley/go-metrics

StatHat support additionally requires their Go client:

go get github.com/stathat/go
Expand ▾ Collapse ▴

Documentation

Overview

Go port of Coda Hale's Metrics library

<https://github.com/rcrowley/go-metrics>

Coda Hale's original work: <https://github.com/codahale/metrics>

Index

Examples

Constants

This section is empty.

Variables

var UseNilMetrics bool = false

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.


Functions

func CaptureDebugGCStats

func CaptureDebugGCStats(r Registry, d time.Duration)

Capture new values for the Go garbage collector statistics exported in debug.GCStats. This is designed to be called as a goroutine.

func CaptureDebugGCStatsOnce

func CaptureDebugGCStatsOnce(r Registry)

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 CaptureRuntimeMemStats

func CaptureRuntimeMemStats(r Registry, d time.Duration)

Capture new values for the Go runtime statistics exported in runtime.MemStats. This is designed to be called as a goroutine.

func CaptureRuntimeMemStatsOnce

func CaptureRuntimeMemStatsOnce(r Registry)

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 Each

func Each(f func(string, interface{}))

Call the given function for each registered metric.

func Get

func Get(name string) interface{}

Get the metric by the given name or nil if none is registered.

func GetOrRegister

func GetOrRegister(name string, i interface{}) interface{}

Gets an existing metric or creates and registers a new one. Threadsafe alternative to calling Get and Register on failure.

func Graphite

func Graphite(r Registry, d time.Duration, prefix string, addr *net.TCPAddr)

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.

Example

Code:

addr, _ := net.ResolveTCPAddr("net", ":2003")
go Graphite(DefaultRegistry, 1*time.Second, "some.prefix", addr)

func GraphiteWithConfig

func GraphiteWithConfig(c GraphiteConfig)

GraphiteWithConfig is a blocking exporter function just like Graphite, but it takes a GraphiteConfig instead.

Example

Code:

addr, _ := net.ResolveTCPAddr("net", ":2003")
go GraphiteWithConfig(GraphiteConfig{
	Addr:          addr,
	Registry:      DefaultRegistry,
	FlushInterval: 1 * time.Second,
	DurationUnit:  time.Millisecond,
})

func Log

func Log(r Registry, d time.Duration, l *log.Logger)

Output each metric in the given registry periodically using the given logger.

func Register

func Register(name string, i interface{})

Register the given metric under the given name.

func RegisterDebugGCStats

func RegisterDebugGCStats(r Registry)

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 RegisterRuntimeMemStats

func RegisterRuntimeMemStats(r Registry)

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 RunHealthchecks

func RunHealthchecks()

Run all registered healthchecks.

func SampleMax

func SampleMax(values []int64) int64

SampleMax returns the maximum value of the slice of int64.

func SampleMean

func SampleMean(values []int64) float64

SampleMean returns the mean value of the slice of int64.

func SampleMin

func SampleMin(values []int64) int64

SampleMin returns the minimum value of the slice of int64.

func SamplePercentile

func SamplePercentile(values int64Slice, p float64) float64

SamplePercentiles returns an arbitrary percentile of the slice of int64.

func SamplePercentiles

func SamplePercentiles(values int64Slice, ps []float64) []float64

SamplePercentiles returns a slice of arbitrary percentiles of the slice of int64.

func SampleStdDev

func SampleStdDev(values []int64) float64

SampleStdDev returns the standard deviation of the slice of int64.

func SampleSum

func SampleSum(values []int64) int64

SampleSum returns the sum of the slice of int64.

func SampleVariance

func SampleVariance(values []int64) float64

SampleVariance returns the variance of the slice of int64.

func Syslog

func Syslog(r Registry, d time.Duration, w *syslog.Writer)

Output each metric in the given registry to syslog periodically using the given syslogger.

func Unregister

func Unregister(name string)

Unregister the metric with the given name.

func Write

func Write(r Registry, d time.Duration, w io.Writer)

Output each metric in the given registry periodically using the given io.Writer.

func WriteOnce

func WriteOnce(r Registry, w io.Writer)

Types

type Counter

type Counter interface {
	Clear()
	Count() int64
	Dec(int64)
	Inc(int64)
	Snapshot() Counter
}

Counters hold an int64 value that can be incremented and decremented.

func GetOrRegisterCounter

func GetOrRegisterCounter(name string, r Registry) Counter

GetOrRegisterCounter returns an existing Counter or constructs and registers a new StandardCounter.

func NewCounter

func NewCounter() Counter

NewCounter constructs a new StandardCounter.

func NewRegisteredCounter

func NewRegisteredCounter(name string, r Registry) Counter

NewRegisteredCounter constructs and registers a new StandardCounter.

type CounterSnapshot

type CounterSnapshot int64

CounterSnapshot is a read-only copy of another Counter.

func (CounterSnapshot) Clear

func (CounterSnapshot) Clear()

Clear panics.

func (CounterSnapshot) Count

func (c CounterSnapshot) Count() int64

Count returns the count at the time the snapshot was taken.

func (CounterSnapshot) Dec

func (CounterSnapshot) Dec(int64)

Dec panics.

func (CounterSnapshot) Inc

func (CounterSnapshot) Inc(int64)

Inc panics.

func (CounterSnapshot) Snapshot

func (c CounterSnapshot) Snapshot() Counter

Snapshot returns the snapshot.

type EWMA

type EWMA interface {
	Rate() float64
	Snapshot() EWMA
	Tick()
	Update(int64)
}

EWMAs continuously calculate an exponentially-weighted moving average based on an outside source of clock ticks.

func NewEWMA

func NewEWMA(alpha float64) EWMA

NewEWMA constructs a new EWMA with the given alpha.

func NewEWMA1

func NewEWMA1() EWMA

NewEWMA1 constructs a new EWMA for a one-minute moving average.

func NewEWMA15

func NewEWMA15() EWMA

NewEWMA15 constructs a new EWMA for a fifteen-minute moving average.

func NewEWMA5

func NewEWMA5() EWMA

NewEWMA5 constructs a new EWMA for a five-minute moving average.

type EWMASnapshot

type EWMASnapshot float64

EWMASnapshot is a read-only copy of another EWMA.

func (EWMASnapshot) Rate

func (a EWMASnapshot) Rate() float64

Rate returns the rate of events per second at the time the snapshot was taken.

func (EWMASnapshot) Snapshot

func (a EWMASnapshot) Snapshot() EWMA

Snapshot returns the snapshot.

func (EWMASnapshot) Tick

func (EWMASnapshot) Tick()

Tick panics.

func (EWMASnapshot) Update

func (EWMASnapshot) Update(int64)

Update panics.

type ExpDecaySample

type ExpDecaySample struct {
	// contains filtered or unexported fields
}

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>

func (*ExpDecaySample) Clear

func (s *ExpDecaySample) Clear()

Clear clears all samples.

func (*ExpDecaySample) Count

func (s *ExpDecaySample) Count() int64

Count returns the number of samples recorded, which may exceed the reservoir size.

func (*ExpDecaySample) Max

func (s *ExpDecaySample) Max() int64

Max returns the maximum value in the sample, which may not be the maximum value ever to be part of the sample.

func (*ExpDecaySample) Mean

func (s *ExpDecaySample) Mean() float64

Mean returns the mean of the values in the sample.

func (*ExpDecaySample) Min

func (s *ExpDecaySample) Min() int64

Min returns the minimum value in the sample, which may not be the minimum value ever to be part of the sample.

func (*ExpDecaySample) Percentile

func (s *ExpDecaySample) Percentile(p float64) float64

Percentile returns an arbitrary percentile of values in the sample.

func (*ExpDecaySample) Percentiles

func (s *ExpDecaySample) Percentiles(ps []float64) []float64

Percentiles returns a slice of arbitrary percentiles of values in the sample.

func (*ExpDecaySample) Size

func (s *ExpDecaySample) Size() int

Size returns the size of the sample, which is at most the reservoir size.

func (*ExpDecaySample) Snapshot

func (s *ExpDecaySample) Snapshot() Sample

Snapshot returns a read-only copy of the sample.

func (*ExpDecaySample) StdDev

func (s *ExpDecaySample) StdDev() float64

StdDev returns the standard deviation of the values in the sample.

func (*ExpDecaySample) Sum

func (s *ExpDecaySample) Sum() int64

Sum returns the sum of the values in the sample.

func (*ExpDecaySample) Update

func (s *ExpDecaySample) Update(v int64)

Update samples a new value.

func (*ExpDecaySample) Values

func (s *ExpDecaySample) Values() []int64

Values returns a copy of the values in the sample.

func (*ExpDecaySample) Variance

func (s *ExpDecaySample) Variance() float64

Variance returns the variance of the values in the sample.

type Gauge

type Gauge interface {
	Snapshot() Gauge
	Update(int64)
	Value() int64
}

Gauges hold an int64 value that can be set arbitrarily.

func GetOrRegisterGauge

func GetOrRegisterGauge(name string, r Registry) Gauge

GetOrRegisterGauge returns an existing Gauge or constructs and registers a new StandardGauge.

func NewGauge

func NewGauge() Gauge

NewGauge constructs a new StandardGauge.

func NewRegisteredGauge

func NewRegisteredGauge(name string, r Registry) Gauge

NewRegisteredGauge constructs and registers a new StandardGauge.

type GaugeSnapshot

type GaugeSnapshot int64

GaugeSnapshot is a read-only copy of another Gauge.

func (GaugeSnapshot) Snapshot

func (g GaugeSnapshot) Snapshot() Gauge

Snapshot returns the snapshot.

func (GaugeSnapshot) Update

func (GaugeSnapshot) Update(int64)

Update panics.

func (GaugeSnapshot) Value

func (g GaugeSnapshot) Value() int64

Value returns the value at the time the snapshot was taken.

type GraphiteConfig

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
}

GraphiteConfig provides a container with configuration parameters for the Graphite exporter

type Healthcheck

type Healthcheck interface {
	Check()
	Error() error
	Healthy()
	Unhealthy(error)
}

Healthchecks hold an error value describing an arbitrary up/down status.

func NewHealthcheck

func NewHealthcheck(f func(Healthcheck)) Healthcheck

NewHealthcheck constructs a new Healthcheck which will use the given function to update its status.

type Histogram

type Histogram interface {
	Clear()
	Count() int64
	Max() int64
	Mean() float64
	Min() int64
	Percentile(float64) float64
	Percentiles([]float64) []float64
	Sample() Sample
	Snapshot() Histogram
	StdDev() float64
	Update(int64)
	Variance() float64
}

Histograms calculate distribution statistics from a series of int64 values.

func GetOrRegisterHistogram

func GetOrRegisterHistogram(name string, r Registry, s Sample) Histogram

GetOrRegisterHistogram returns an existing Histogram or constructs and registers a new StandardHistogram.

func NewHistogram

func NewHistogram(s Sample) Histogram

NewHistogram constructs a new StandardHistogram from a Sample.

func NewRegisteredHistogram

func NewRegisteredHistogram(name string, r Registry, s Sample) Histogram

NewRegisteredHistogram constructs and registers a new StandardHistogram from a Sample.

type HistogramSnapshot

type HistogramSnapshot struct {
	// contains filtered or unexported fields
}

HistogramSnapshot is a read-only copy of another Histogram.

func (*HistogramSnapshot) Clear

func (*HistogramSnapshot) Clear()

Clear panics.

func (*HistogramSnapshot) Count

func (h *HistogramSnapshot) Count() int64

Count returns the number of samples recorded at the time the snapshot was taken.

func (*HistogramSnapshot) Max

func (h *HistogramSnapshot) Max() int64

Max returns the maximum value in the sample at the time the snapshot was taken.

func (*HistogramSnapshot) Mean

func (h *HistogramSnapshot) Mean() float64

Mean returns the mean of the values in the sample at the time the snapshot was taken.

func (*HistogramSnapshot) Min

func (h *HistogramSnapshot) Min() int64

Min returns the minimum value in the sample at the time the snapshot was taken.

func (*HistogramSnapshot) Percentile

func (h *HistogramSnapshot) Percentile(p float64) float64

Percentile returns an arbitrary percentile of values in the sample at the time the snapshot was taken.

func (*HistogramSnapshot) Percentiles

func (h *HistogramSnapshot) Percentiles(ps []float64) []float64

Percentiles returns a slice of arbitrary percentiles of values in the sample at the time the snapshot was taken.

func (*HistogramSnapshot) Sample

func (h *HistogramSnapshot) Sample() Sample

Sample returns the Sample underlying the histogram.

func (*HistogramSnapshot) Snapshot

func (h *HistogramSnapshot) Snapshot() Histogram

Snapshot returns the snapshot.

func (*HistogramSnapshot) StdDev

func (h *HistogramSnapshot) StdDev() float64

StdDev returns the standard deviation of the values in the sample at the time the snapshot was taken.

func (*HistogramSnapshot) Update

func (*HistogramSnapshot) Update(int64)

Update panics.

func (*HistogramSnapshot) Variance

func (h *HistogramSnapshot) Variance() float64

Variance returns the variance of inputs at the time the snapshot was taken.

type Meter

type Meter interface {
	Count() int64
	Mark(int64)
	Rate1() float64
	Rate5() float64
	Rate15() float64
	RateMean() float64
	Snapshot() Meter
}

Meters count events to produce exponentially-weighted moving average rates at one-, five-, and fifteen-minutes and a mean rate.

func GetOrRegisterMeter

func GetOrRegisterMeter(name string, r Registry) Meter

GetOrRegisterMeter returns an existing Meter or constructs and registers a new StandardMeter.

func NewMeter

func NewMeter() Meter

NewMeter constructs a new StandardMeter and launches a goroutine.

func NewRegisteredMeter

func NewRegisteredMeter(name string, r Registry) Meter

NewMeter constructs and registers a new StandardMeter and launches a goroutine.

type MeterSnapshot

type MeterSnapshot struct {
	// contains filtered or unexported fields
}

MeterSnapshot is a read-only copy of another Meter.

func (*MeterSnapshot) Count

func (m *MeterSnapshot) Count() int64

Count returns the count of events at the time the snapshot was taken.

func (*MeterSnapshot) Mark

func (*MeterSnapshot) Mark(n int64)

Mark panics.

func (*MeterSnapshot) Rate1

func (m *MeterSnapshot) Rate1() float64

Rate1 returns the one-minute moving average rate of events per second at the time the snapshot was taken.

func (*MeterSnapshot) Rate15

func (m *MeterSnapshot) Rate15() float64

Rate15 returns the fifteen-minute moving average rate of events per second at the time the snapshot was taken.

func (*MeterSnapshot) Rate5

func (m *MeterSnapshot) Rate5() float64

Rate5 returns the five-minute moving average rate of events per second at the time the snapshot was taken.

func (*MeterSnapshot) RateMean

func (m *MeterSnapshot) RateMean() float64

RateMean returns the meter's mean rate of events per second at the time the snapshot was taken.

func (*MeterSnapshot) Snapshot

func (m *MeterSnapshot) Snapshot() Meter

Snapshot returns the snapshot.

type NilCounter

type NilCounter struct{}

NilCounter is a no-op Counter.

func (NilCounter) Clear

func (NilCounter) Clear()

Clear is a no-op.

func (NilCounter) Count

func (NilCounter) Count() int64

Count is a no-op.

func (NilCounter) Dec

func (NilCounter) Dec(i int64)

Dec is a no-op.

func (NilCounter) Inc

func (NilCounter) Inc(i int64)

Inc is a no-op.

func (NilCounter) Snapshot

func (NilCounter) Snapshot() Counter

Snapshot is a no-op.

type NilEWMA

type NilEWMA struct{}

NilEWMA is a no-op EWMA.

func (NilEWMA) Rate

func (NilEWMA) Rate() float64

Rate is a no-op.

func (NilEWMA) Snapshot

func (NilEWMA) Snapshot() EWMA

Snapshot is a no-op.

func (NilEWMA) Tick

func (NilEWMA) Tick()

Tick is a no-op.

func (NilEWMA) Update

func (NilEWMA) Update(n int64)

Update is a no-op.

type NilGauge

type NilGauge struct{}

NilGauge is a no-op Gauge.

func (NilGauge) Snapshot

func (NilGauge) Snapshot() Gauge

Snapshot is a no-op.

func (NilGauge) Update

func (NilGauge) Update(v int64)

Update is a no-op.

func (NilGauge) Value

func (NilGauge) Value() int64

Value is a no-op.

type NilHealthcheck

type NilHealthcheck struct{}

NilHealthcheck is a no-op.

func (NilHealthcheck) Check

func (NilHealthcheck) Check()

Check is a no-op.

func (NilHealthcheck) Error

func (NilHealthcheck) Error() error

Error is a no-op.

func (NilHealthcheck) Healthy

func (NilHealthcheck) Healthy()

Healthy is a no-op.

func (NilHealthcheck) Unhealthy

func (NilHealthcheck) Unhealthy(error)

Unhealthy is a no-op.

type NilHistogram

type NilHistogram struct{}

NilHistogram is a no-op Histogram.

func (NilHistogram) Clear

func (NilHistogram) Clear()

Clear is a no-op.

func (NilHistogram) Count

func (NilHistogram) Count() int64

Count is a no-op.

func (NilHistogram) Max

func (NilHistogram) Max() int64

Max is a no-op.

func (NilHistogram) Mean

func (NilHistogram) Mean() float64

Mean is a no-op.

func (NilHistogram) Min

func (NilHistogram) Min() int64

Min is a no-op.

func (NilHistogram) Percentile

func (NilHistogram) Percentile(p float64) float64

Percentile is a no-op.

func (NilHistogram) Percentiles

func (NilHistogram) Percentiles(ps []float64) []float64

Percentiles is a no-op.

func (NilHistogram) Sample

func (NilHistogram) Sample() Sample

Sample is a no-op.

func (NilHistogram) Snapshot

func (NilHistogram) Snapshot() Histogram

Snapshot is a no-op.

func (NilHistogram) StdDev

func (NilHistogram) StdDev() float64

StdDev is a no-op.

func (NilHistogram) Update

func (NilHistogram) Update(v int64)

Update is a no-op.

func (NilHistogram) Variance

func (NilHistogram) Variance() float64

Variance is a no-op.

type NilMeter

type NilMeter struct{}

NilMeter is a no-op Meter.

func (NilMeter) Count

func (NilMeter) Count() int64

Count is a no-op.

func (NilMeter) Mark

func (NilMeter) Mark(n int64)

Mark is a no-op.

func (NilMeter) Rate1

func (NilMeter) Rate1() float64

Rate1 is a no-op.

func (NilMeter) Rate15

func (NilMeter) Rate15() float64

Rate15is a no-op.

func (NilMeter) Rate5

func (NilMeter) Rate5() float64

Rate5 is a no-op.

func (NilMeter) RateMean

func (NilMeter) RateMean() float64

RateMean is a no-op.

func (NilMeter) Snapshot

func (NilMeter) Snapshot() Meter

Snapshot is a no-op.

type NilSample

type NilSample struct{}

NilSample is a no-op Sample.

func (NilSample) Clear

func (NilSample) Clear()

Clear is a no-op.

func (NilSample) Count

func (NilSample) Count() int64

Count is a no-op.

func (NilSample) Max

func (NilSample) Max() int64

Max is a no-op.

func (NilSample) Mean

func (NilSample) Mean() float64

Mean is a no-op.

func (NilSample) Min

func (NilSample) Min() int64

Min is a no-op.

func (NilSample) Percentile

func (NilSample) Percentile(p float64) float64

Percentile is a no-op.

func (NilSample) Percentiles

func (NilSample) Percentiles(ps []float64) []float64

Percentiles is a no-op.

func (NilSample) Size

func (NilSample) Size() int

Size is a no-op.

func (NilSample) Snapshot

func (NilSample) Snapshot() Sample

Sample is a no-op.

func (NilSample) StdDev

func (NilSample) StdDev() float64

StdDev is a no-op.

func (NilSample) Sum

func (NilSample) Sum() int64

Sum is a no-op.

func (NilSample) Update

func (NilSample) Update(v int64)

Update is a no-op.

func (NilSample) Values

func (NilSample) Values() []int64

Values is a no-op.

func (NilSample) Variance

func (NilSample) Variance() float64

Variance is a no-op.

type NilTimer

type NilTimer struct {
	// contains filtered or unexported fields
}

NilTimer is a no-op Timer.

func (NilTimer) Count

func (NilTimer) Count() int64

Count is a no-op.

func (NilTimer) Max

func (NilTimer) Max() int64

Max is a no-op.

func (NilTimer) Mean

func (NilTimer) Mean() float64

Mean is a no-op.

func (NilTimer) Min

func (NilTimer) Min() int64

Min is a no-op.

func (NilTimer) Percentile

func (NilTimer) Percentile(p float64) float64

Percentile is a no-op.

func (NilTimer) Percentiles

func (NilTimer) Percentiles(ps []float64) []float64

Percentiles is a no-op.

func (NilTimer) Rate1

func (NilTimer) Rate1() float64

Rate1 is a no-op.

func (NilTimer) Rate15

func (NilTimer) Rate15() float64

Rate15 is a no-op.

func (NilTimer) Rate5

func (NilTimer) Rate5() float64

Rate5 is a no-op.

func (NilTimer) RateMean

func (NilTimer) RateMean() float64

RateMean is a no-op.

func (NilTimer) Snapshot

func (NilTimer) Snapshot() Timer

Snapshot is a no-op.

func (NilTimer) StdDev

func (NilTimer) StdDev() float64

StdDev is a no-op.

func (NilTimer) Time

func (NilTimer) Time(func())

Time is a no-op.

func (NilTimer) Update

func (NilTimer) Update(time.Duration)

Update is a no-op.

func (NilTimer) UpdateSince

func (NilTimer) UpdateSince(time.Time)

UpdateSince is a no-op.

func (NilTimer) Variance

func (NilTimer) Variance() float64

Variance is a no-op.

type Registry

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 creates and registers a new one.
	GetOrRegister(string, interface{}) interface{}

	// Register the given metric under the given name.
	Register(string, interface{})

	// Run all registered healthchecks.
	RunHealthchecks()

	// Unregister the metric with the given name.
	Unregister(string)
}

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.

var DefaultRegistry Registry = NewRegistry()

func NewRegistry

func NewRegistry() Registry

Create a new registry.

type Sample

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
}

Samples maintain a statistically-significant selection of values from a stream.

func NewExpDecaySample

func NewExpDecaySample(reservoirSize int, alpha float64) Sample

NewExpDecaySample constructs a new exponentially-decaying sample with the given reservoir size and alpha.

func NewUniformSample

func NewUniformSample(reservoirSize int) Sample

NewUniformSample constructs a new uniform sample with the given reservoir size.

type SampleSnapshot

type SampleSnapshot struct {
	// contains filtered or unexported fields
}

SampleSnapshot is a read-only copy of another Sample.

func (*SampleSnapshot) Clear

func (*SampleSnapshot) Clear()

Clear panics.

func (*SampleSnapshot) Count

func (s *SampleSnapshot) Count() int64

Count returns the count of inputs at the time the snapshot was taken.

func (*SampleSnapshot) Max

func (s *SampleSnapshot) Max() int64

Max returns the maximal value at the time the snapshot was taken.

func (*SampleSnapshot) Mean

func (s *SampleSnapshot) Mean() float64

Mean returns the mean value at the time the snapshot was taken.

func (*SampleSnapshot) Min

func (s *SampleSnapshot) Min() int64

Min returns the minimal value at the time the snapshot was taken.

func (*SampleSnapshot) Percentile

func (s *SampleSnapshot) Percentile(p float64) float64

Percentile returns an arbitrary percentile of values at the time the snapshot was taken.

func (*SampleSnapshot) Percentiles

func (s *SampleSnapshot) Percentiles(ps []float64) []float64

Percentiles returns a slice of arbitrary percentiles of values at the time the snapshot was taken.

func (*SampleSnapshot) Size

func (s *SampleSnapshot) Size() int

Size returns the size of the sample at the time the snapshot was taken.

func (*SampleSnapshot) Snapshot

func (s *SampleSnapshot) Snapshot() Sample

Snapshot returns the snapshot.

func (*SampleSnapshot) StdDev

func (s *SampleSnapshot) StdDev() float64

StdDev returns the standard deviation of values at the time the snapshot was taken.

func (*SampleSnapshot) Sum

func (s *SampleSnapshot) Sum() int64

Sum returns the sum of values at the time the snapshot was taken.

func (*SampleSnapshot) Update

func (*SampleSnapshot) Update(int64)

Update panics.

func (*SampleSnapshot) Values

func (s *SampleSnapshot) Values() []int64

Values returns a copy of the values in the sample.

func (*SampleSnapshot) Variance

func (s *SampleSnapshot) Variance() float64

Variance returns the variance of values at the time the snapshot was taken.

type StandardCounter

type StandardCounter struct {
	// contains filtered or unexported fields
}

StandardCounter is the standard implementation of a Counter and uses the sync/atomic package to manage a single int64 value.

func (*StandardCounter) Clear

func (c *StandardCounter) Clear()

Clear sets the counter to zero.

func (*StandardCounter) Count

func (c *StandardCounter) Count() int64

Count returns the current count.

func (*StandardCounter) Dec

func (c *StandardCounter) Dec(i int64)

Dec decrements the counter by the given amount.

func (*StandardCounter) Inc

func (c *StandardCounter) Inc(i int64)

Inc increments the counter by the given amount.

func (*StandardCounter) Snapshot

func (c *StandardCounter) Snapshot() Counter

Snapshot returns a read-only copy of the counter.

type StandardEWMA

type StandardEWMA struct {
	// contains filtered or unexported fields
}

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.

func (*StandardEWMA) Rate

func (a *StandardEWMA) Rate() float64

Rate returns the moving average rate of events per second.

func (*StandardEWMA) Snapshot

func (a *StandardEWMA) Snapshot() EWMA

Snapshot returns a read-only copy of the EWMA.

func (*StandardEWMA) Tick

func (a *StandardEWMA) Tick()

Tick ticks the clock to update the moving average. It assumes it is called every five seconds.

func (*StandardEWMA) Update

func (a *StandardEWMA) Update(n int64)

Update adds n uncounted events.

type StandardGauge

type StandardGauge struct {
	// contains filtered or unexported fields
}

StandardGauge is the standard implementation of a Gauge and uses the sync/atomic package to manage a single int64 value.

func (*StandardGauge) Snapshot

func (g *StandardGauge) Snapshot() Gauge

Snapshot returns a read-only copy of the gauge.

func (*StandardGauge) Update

func (g *StandardGauge) Update(v int64)

Update updates the gauge's value.

func (*StandardGauge) Value

func (g *StandardGauge) Value() int64

Value returns the gauge's current value.

type StandardHealthcheck

type StandardHealthcheck struct {
	// contains filtered or unexported fields
}

StandardHealthcheck is the standard implementation of a Healthcheck and stores the status and a function to call to update the status.

func (*StandardHealthcheck) Check

func (h *StandardHealthcheck) Check()

Check runs the healthcheck function to update the healthcheck's status.

func (*StandardHealthcheck) Error

func (h *StandardHealthcheck) Error() error

Error returns the healthcheck's status, which will be nil if it is healthy.

func (*StandardHealthcheck) Healthy

func (h *StandardHealthcheck) Healthy()

Healthy marks the healthcheck as healthy.

func (*StandardHealthcheck) Unhealthy

func (h *StandardHealthcheck) Unhealthy(err error)

Unhealthy marks the healthcheck as unhealthy. The error is stored and may be retrieved by the Error method.

type StandardHistogram

type StandardHistogram struct {
	// contains filtered or unexported fields
}

StandardHistogram is the standard implementation of a Histogram and uses a Sample to bound its memory use.

func (*StandardHistogram) Clear

func (h *StandardHistogram) Clear()

Clear clears the histogram and its sample.

func (*StandardHistogram) Count

func (h *StandardHistogram) Count() int64

Count returns the number of samples recorded since the histogram was last cleared.

func (*StandardHistogram) Max

func (h *StandardHistogram) Max() int64

Max returns the maximum value in the sample.

func (*StandardHistogram) Mean

func (h *StandardHistogram) Mean() float64

Mean returns the mean of the values in the sample.

func (*StandardHistogram) Min

func (h *StandardHistogram) Min() int64

Min returns the minimum value in the sample.

func (*StandardHistogram) Percentile

func (h *StandardHistogram) Percentile(p float64) float64

Percentile returns an arbitrary percentile of the values in the sample.

func (*StandardHistogram) Percentiles

func (h *StandardHistogram) Percentiles(ps []float64) []float64

Percentiles returns a slice of arbitrary percentiles of the values in the sample.

func (*StandardHistogram) Sample

func (h *StandardHistogram) Sample() Sample

Sample returns the Sample underlying the histogram.

func (*StandardHistogram) Snapshot

func (h *StandardHistogram) Snapshot() Histogram

Snapshot returns a read-only copy of the histogram.

func (*StandardHistogram) StdDev

func (h *StandardHistogram) StdDev() float64

StdDev returns the standard deviation of the values in the sample.

func (*StandardHistogram) Update

func (h *StandardHistogram) Update(v int64)

Update samples a new value.

func (*StandardHistogram) Variance

func (h *StandardHistogram) Variance() float64

Variance returns the variance of the values in the sample.

type StandardMeter

type StandardMeter struct {
	// contains filtered or unexported fields
}

StandardMeter is the standard implementation of a Meter and uses a goroutine to synchronize its calculations and a time.Ticker to pass time.

func (*StandardMeter) Count

func (m *StandardMeter) Count() int64

Count returns the number of events recorded.

func (*StandardMeter) Mark

func (m *StandardMeter) Mark(n int64)

Mark records the occurance of n events.

func (*StandardMeter) Rate1

func (m *StandardMeter) Rate1() float64

Rate1 returns the one-minute moving average rate of events per second.

func (*StandardMeter) Rate15

func (m *StandardMeter) Rate15() float64

Rate15 returns the fifteen-minute moving average rate of events per second.

func (*StandardMeter) Rate5

func (m *StandardMeter) Rate5() float64

Rate5 returns the five-minute moving average rate of events per second.

func (*StandardMeter) RateMean

func (m *StandardMeter) RateMean() float64

RateMean returns the meter's mean rate of events per second.

func (*StandardMeter) Snapshot

func (m *StandardMeter) Snapshot() Meter

Snapshot returns a read-only copy of the meter.

type StandardRegistry

type StandardRegistry struct {
	// contains filtered or unexported fields
}

The standard implementation of a Registry is a mutex-protected map of names to metrics.

func (*StandardRegistry) Each

func (r *StandardRegistry) Each(f func(string, interface{}))

Call the given function for each registered metric.

func (*StandardRegistry) Get

func (r *StandardRegistry) Get(name string) interface{}

Get the metric by the given name or nil if none is registered.

func (*StandardRegistry) GetOrRegister

func (r *StandardRegistry) GetOrRegister(name string, i interface{}) interface{}

Gets an existing metric or creates and registers a new one. Threadsafe alternative to calling Get and Register on failure.

func (StandardRegistry) MarshalJSON

func (r StandardRegistry) MarshalJSON() ([]byte, error)

MarshalJSON returns a byte slice containing a JSON representation of all the metrics in the Registry.

func (*StandardRegistry) Register

func (r *StandardRegistry) Register(name string, i interface{})

Register the given metric under the given name.

func (*StandardRegistry) RunHealthchecks

func (r *StandardRegistry) RunHealthchecks()

Run all registered healthchecks.

func (*StandardRegistry) Unregister

func (r *StandardRegistry) Unregister(name string)

Unregister the metric with the given name.

type StandardTimer

type StandardTimer struct {
	// contains filtered or unexported fields
}

StandardTimer is the standard implementation of a Timer and uses a Histogram and Meter.

func (*StandardTimer) Count

func (t *StandardTimer) Count() int64

Count returns the number of events recorded.

func (*StandardTimer) Max

func (t *StandardTimer) Max() int64

Max returns the maximum value in the sample.

func (*StandardTimer) Mean

func (t *StandardTimer) Mean() float64

Mean returns the mean of the values in the sample.

func (*StandardTimer) Min

func (t *StandardTimer) Min() int64

Min returns the minimum value in the sample.

func (*StandardTimer) Percentile

func (t *StandardTimer) Percentile(p float64) float64

Percentile returns an arbitrary percentile of the values in the sample.

func (*StandardTimer) Percentiles

func (t *StandardTimer) Percentiles(ps []float64) []float64

Percentiles returns a slice of arbitrary percentiles of the values in the sample.

func (*StandardTimer) Rate1

func (t *StandardTimer) Rate1() float64

Rate1 returns the one-minute moving average rate of events per second.

func (*StandardTimer) Rate15

func (t *StandardTimer) Rate15() float64

Rate15 returns the fifteen-minute moving average rate of events per second.

func (*StandardTimer) Rate5

func (t *StandardTimer) Rate5() float64

Rate5 returns the five-minute moving average rate of events per second.

func (*StandardTimer) RateMean

func (t *StandardTimer) RateMean() float64

RateMean returns the meter's mean rate of events per second.

func (*StandardTimer) Snapshot

func (t *StandardTimer) Snapshot() Timer

Snapshot returns a read-only copy of the timer.

func (*StandardTimer) StdDev

func (t *StandardTimer) StdDev() float64

StdDev returns the standard deviation of the values in the sample.

func (*StandardTimer) Time

func (t *StandardTimer) Time(f func())

Record the duration of the execution of the given function.

func (*StandardTimer) Update

func (t *StandardTimer) Update(d time.Duration)

Record the duration of an event.

func (*StandardTimer) UpdateSince

func (t *StandardTimer) UpdateSince(ts time.Time)

Record the duration of an event that started at a time and ends now.

func (*StandardTimer) Variance

func (t *StandardTimer) Variance() float64

Variance returns the variance of the values in the sample.

type Timer

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
	Time(func())
	Update(time.Duration)
	UpdateSince(time.Time)
	Variance() float64
}

Timers capture the duration and rate of events.

func GetOrRegisterTimer

func GetOrRegisterTimer(name string, r Registry) Timer

GetOrRegisterTimer returns an existing Timer or constructs and registers a new StandardTimer.

func NewCustomTimer

func NewCustomTimer(h Histogram, m Meter) Timer

NewCustomTimer constructs a new StandardTimer from a Histogram and a Meter.

func NewRegisteredTimer

func NewRegisteredTimer(name string, r Registry) Timer

NewRegisteredTimer constructs and registers a new StandardTimer.

func NewTimer

func NewTimer() Timer

NewTimer constructs a new StandardTimer using an exponentially-decaying sample with the same reservoir size and alpha as UNIX load averages.

type TimerSnapshot

type TimerSnapshot struct {
	// contains filtered or unexported fields
}

TimerSnapshot is a read-only copy of another Timer.

func (*TimerSnapshot) Count

func (t *TimerSnapshot) Count() int64

Count returns the number of events recorded at the time the snapshot was taken.

func (*TimerSnapshot) Max

func (t *TimerSnapshot) Max() int64

Max returns the maximum value at the time the snapshot was taken.

func (*TimerSnapshot) Mean

func (t *TimerSnapshot) Mean() float64

Mean returns the mean value at the time the snapshot was taken.

func (*TimerSnapshot) Min

func (t *TimerSnapshot) Min() int64

Min returns the minimum value at the time the snapshot was taken.

func (*TimerSnapshot) Percentile

func (t *TimerSnapshot) Percentile(p float64) float64

Percentile returns an arbitrary percentile of sampled values at the time the snapshot was taken.

func (*TimerSnapshot) Percentiles

func (t *TimerSnapshot) Percentiles(ps []float64) []float64

Percentiles returns a slice of arbitrary percentiles of sampled values at the time the snapshot was taken.

func (*TimerSnapshot) Rate1

func (t *TimerSnapshot) Rate1() float64

Rate1 returns the one-minute moving average rate of events per second at the time the snapshot was taken.

func (*TimerSnapshot) Rate15

func (t *TimerSnapshot) Rate15() float64

Rate15 returns the fifteen-minute moving average rate of events per second at the time the snapshot was taken.

func (*TimerSnapshot) Rate5

func (t *TimerSnapshot) Rate5() float64

Rate5 returns the five-minute moving average rate of events per second at the time the snapshot was taken.

func (*TimerSnapshot) RateMean

func (t *TimerSnapshot) RateMean() float64

RateMean returns the meter's mean rate of events per second at the time the snapshot was taken.

func (*TimerSnapshot) Snapshot

func (t *TimerSnapshot) Snapshot() Timer

Snapshot returns the snapshot.

func (*TimerSnapshot) StdDev

func (t *TimerSnapshot) StdDev() float64

StdDev returns the standard deviation of the values at the time the snapshot was taken.

func (*TimerSnapshot) Time

func (*TimerSnapshot) Time(func())

Time panics.

func (*TimerSnapshot) Update

func (*TimerSnapshot) Update(time.Duration)

Update panics.

func (*TimerSnapshot) UpdateSince

func (*TimerSnapshot) UpdateSince(time.Time)

UpdateSince panics.

func (*TimerSnapshot) Variance

func (t *TimerSnapshot) Variance() float64

Variance returns the variance of the values at the time the snapshot was taken.

type UniformSample

type UniformSample struct {
	// contains filtered or unexported fields
}

A uniform sample using Vitter's Algorithm R.

<http://www.cs.umd.edu/~samir/498/vitter.pdf>

func (*UniformSample) Clear

func (s *UniformSample) Clear()

Clear clears all samples.

func (*UniformSample) Count

func (s *UniformSample) Count() int64

Count returns the number of samples recorded, which may exceed the reservoir size.

func (*UniformSample) Max

func (s *UniformSample) Max() int64

Max returns the maximum value in the sample, which may not be the maximum value ever to be part of the sample.

func (*UniformSample) Mean

func (s *UniformSample) Mean() float64

Mean returns the mean of the values in the sample.

func (*UniformSample) Min

func (s *UniformSample) Min() int64

Min returns the minimum value in the sample, which may not be the minimum value ever to be part of the sample.

func (*UniformSample) Percentile

func (s *UniformSample) Percentile(p float64) float64

Percentile returns an arbitrary percentile of values in the sample.

func (*UniformSample) Percentiles

func (s *UniformSample) Percentiles(ps []float64) []float64

Percentiles returns a slice of arbitrary percentiles of values in the sample.

func (*UniformSample) Size

func (s *UniformSample) Size() int

Size returns the size of the sample, which is at most the reservoir size.

func (*UniformSample) Snapshot

func (s *UniformSample) Snapshot() Sample

Snapshot returns a read-only copy of the sample.

func (*UniformSample) StdDev

func (s *UniformSample) StdDev() float64

StdDev returns the standard deviation of the values in the sample.

func (*UniformSample) Sum

func (s *UniformSample) Sum() int64

Sum returns the sum of the values in the sample.

func (*UniformSample) Update

func (s *UniformSample) Update(v int64)

Update samples a new value.

func (*UniformSample) Values

func (s *UniformSample) Values() []int64

Values returns a copy of the values in the sample.

func (*UniformSample) Variance

func (s *UniformSample) Variance() float64

Variance returns the variance of the values in the sample.

Directories

Path Synopsis
cmd/metrics-bench
cmd/metrics-example
cmd/never-read
librato
stathat Metrics output to StatHat.