metrics

package module
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 Go to latest Published: Dec 6, 2022 License: MIT Imports: 20 Imported by: 0

README

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metrics - lightweight package for exporting metrics in Prometheus format

Features
  • Lightweight. Has minimal number of third-party dependencies and all these deps are small. See this article for details.
  • Easy to use. See the API docs.
  • Fast.
  • Allows exporting distinct metric sets via distinct endpoints. See Set.
  • Supports easy-to-use histograms, which just work without any tuning. Read more about VictoriaMetrics histograms at this article.
  • Can push metrics to VictoriaMetrics or to any other remote storage, which accepts metrics in Prometheus text exposition format. See these docs.
Limitations
Usage
import "github.com/VictoriaMetrics/metrics"

// Register various metrics.
// Metric name may contain labels in Prometheus format - see below.
var (
	// Register counter without labels.
	requestsTotal = metrics.NewCounter("requests_total")

	// Register summary with a single label.
	requestDuration = metrics.NewSummary(`requests_duration_seconds{path="/foobar/baz"}`)

	// Register gauge with two labels.
	queueSize = metrics.NewGauge(`queue_size{queue="foobar",topic="baz"}`, func() float64 {
		return float64(foobarQueue.Len())
	})

	// Register histogram with a single label.
	responseSize = metrics.NewHistogram(`response_size{path="/foo/bar"}`)
)

// ...
func requestHandler() {
	// Increment requestTotal counter.
	requestsTotal.Inc()

	startTime := time.Now()
	processRequest()
	// Update requestDuration summary.
	requestDuration.UpdateDuration(startTime)

	// Update responseSize histogram.
	responseSize.Update(responseSize)
}

// Expose the registered metrics at `/metrics` path.
http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) {
	metrics.WritePrometheus(w, true)
})

// ... or push registered metrics every 10 seconds to http://victoria-metrics:8428/api/v1/import/prometheus
// with the added `instance="foobar"` label to all the pushed metrics.
metrics.InitPush("http://victoria-metrics:8428/api/v1/import/prometheus", 10*time.Second, `instance="foobar"`, true)

See docs for more info.

Users
FAQ
Why the metrics API isn't compatible with github.com/prometheus/client_golang?

Because the github.com/prometheus/client_golang is too complex and is hard to use.

Why the metrics.WritePrometheus doesn't expose documentation for each metric?

Because this documentation is ignored by Prometheus. The documentation is for users. Just give meaningful names to the exported metrics or add comments in the source code or in other suitable place explaining each metric exposed from your application.

How to implement CounterVec in metrics?

Just use GetOrCreateCounter instead of CounterVec.With. See this example for details.

Why Histogram buckets contain vmrange labels instead of le labels like in Prometheus histograms?

Buckets with vmrange labels occupy less disk space compared to Promethes-style buckets with le labels, because vmrange buckets don't include counters for the previous ranges. VictoriaMetrics provides prometheus_buckets function, which converts vmrange buckets to Prometheus-style buckets with le labels. This is useful for building heatmaps in Grafana. Additionally, its' histogram_quantile function transparently handles histogram buckets with vmrange labels.

Documentation

Overview

Package metrics implements Prometheus-compatible metrics for applications.

This package is lightweight alternative to https://github.com/prometheus/client_golang with simpler API and smaller dependencies.

Usage:

  1. Register the required metrics via New* functions.
  2. Expose them to `/metrics` page via WritePrometheus.
  3. Update the registered metrics during application lifetime.

The package has been extracted from https://victoriametrics.com/

Index

Examples

Constants

View Source 
const (
	FlagOfPushProcessMetrics = 1 // bit 0: use push process metrics
	FlagOfForbideGzip        = 2 // bit 1: not use gzip to post data
)

Variables

This section is empty.

Functions

func InitPush 

func InitPush(pushURL string, interval time.Duration, extraLabels string, pushProcessMetrics bool) error

InitPush sets up periodic push for globally registered metrics to the given pushURL with the given interval.

extraLabels may contain comma-separated list of `label="value"` labels, which will be added to all the metrics before pushing them to pushURL.

If pushProcessMetrics is set to true, then 'process_*' metrics are also pushed to pushURL.

The metrics are pushed to pushURL in Prometheus text exposition format. See https://github.com/prometheus/docs/blob/main/content/docs/instrumenting/exposition_formats.md#text-based-format

It is recommended pushing metrics to /api/v1/import/prometheus endpoint according to https://docs.victoriametrics.com/#how-to-import-data-in-prometheus-exposition-format

It is OK calling InitPush multiple times with different pushURL - in this case metrics are pushed to all the provided pushURL urls.

func InitPushExt 

func InitPushExt(pushURL string, interval time.Duration, extraLabels string, writeMetrics func(w io.Writer)) error

InitPushExt sets up periodic push for metrics obtained by calling writeMetrics with the given interval.

extraLabels may contain comma-separated list of `label="value"` labels, which will be added to all the metrics before pushing them to pushURL.

The writeMetrics callback must write metrics to w in Prometheus text exposition format without timestamps and trailing comments. See https://github.com/prometheus/docs/blob/main/content/docs/instrumenting/exposition_formats.md#text-based-format

It is recommended pushing metrics to /api/v1/import/prometheus endpoint according to https://docs.victoriametrics.com/#how-to-import-data-in-prometheus-exposition-format

It is OK calling InitPushExt multiple times with different pushURL - in this case metrics are pushed to all the provided pushURL urls.

It is OK calling InitPushExt multiple times with different writeMetrics - in this case all the metrics generated by writeMetrics callbacks are writte to pushURL.

func InitPushProcessMetrics 

func InitPushProcessMetrics(pushURL string, interval time.Duration, extraLabels string) error

InitPushProcessMetrics sets up periodic push for 'process_*' metrics to the given pushURL with the given interval.

extraLabels may contain comma-separated list of `label="value"` labels, which will be added to all the metrics before pushing them to pushURL.

The metrics are pushed to pushURL in Prometheus text exposition format. See https://github.com/prometheus/docs/blob/main/content/docs/instrumenting/exposition_formats.md#text-based-format

It is recommended pushing metrics to /api/v1/import/prometheus endpoint according to https://docs.victoriametrics.com/#how-to-import-data-in-prometheus-exposition-format

It is OK calling InitPushProcessMetrics multiple times with different pushURL - in this case metrics are pushed to all the provided pushURL urls.

func InitPushWithFlags 

func InitPushWithFlags(pushURL string, interval time.Duration, extraLabels string, flags uint64) error

InitPushWithFlags like `InitPush`, but user can use bit flags to add flags

func ListMetricNames 

func ListMetricNames() []string

ListMetricNames returns sorted list of all the metric names from default set.

func RegisterSet 

func RegisterSet(s *Set)

RegisterSet registers the given set s for metrics export via global WritePrometheus() call.

See also UnregisterSet.

func UnregisterAllMetrics 

func UnregisterAllMetrics()

UnregisterAllMetrics unregisters all the metrics from default set.

func UnregisterMetric 

func UnregisterMetric(name string) bool

UnregisterMetric removes metric with the given name from default set.

See also UnregisterAllMetrics.

func UnregisterSet 

func UnregisterSet(s *Set)

UnregisterSet stops exporting metrics for the given s via global WritePrometheus() call.

Call s.UnregisterAllMetrics() after unregistering s if it is no longer used.

func WriteFDMetrics 

func WriteFDMetrics(w io.Writer)

WriteFDMetrics writes `process_max_fds` and `process_open_fds` metrics to w.

func WriteProcessMetrics 

func WriteProcessMetrics(w io.Writer)

WriteProcessMetrics writes additional process metrics in Prometheus format to w.

The following `go_*` and `process_*` metrics are exposed for the currently running process. Below is a short description for the exposed `process_*` metrics:

  • process_cpu_seconds_system_total - CPU time spent in syscalls

  • process_cpu_seconds_user_total - CPU time spent in userspace

  • process_cpu_seconds_total - CPU time spent by the process

  • process_major_pagefaults_total - page faults resulted in disk IO

  • process_minor_pagefaults_total - page faults resolved without disk IO

  • process_resident_memory_bytes - recently accessed memory (aka RSS or resident memory)

  • process_resident_memory_peak_bytes - the maximum RSS memory usage

  • process_resident_memory_anon_bytes - RSS for memory-mapped files

  • process_resident_memory_file_bytes - RSS for memory allocated by the process

  • process_resident_memory_shared_bytes - RSS for memory shared between multiple processes

  • process_virtual_memory_bytes - virtual memory usage

  • process_virtual_memory_peak_bytes - the maximum virtual memory usage

  • process_num_threads - the number of threads

  • process_start_time_seconds - process start time as unix timestamp

  • process_io_read_bytes_total - the number of bytes read via syscalls

  • process_io_written_bytes_total - the number of bytes written via syscalls

  • process_io_read_syscalls_total - the number of read syscalls

  • process_io_write_syscalls_total - the number of write syscalls

  • process_io_storage_read_bytes_total - the number of bytes actually read from disk

  • process_io_storage_written_bytes_total - the number of bytes actually written to disk

  • go_memstats_alloc_bytes - memory usage for Go objects in the heap

  • go_memstats_alloc_bytes_total - the cumulative counter for total size of allocated Go objects

  • go_memstats_frees_total - the cumulative counter for number of freed Go objects

  • go_memstats_gc_cpu_fraction - the fraction of CPU spent in Go garbage collector

  • go_memstats_gc_sys_bytes - the size of Go garbage collector metadata

  • go_memstats_heap_alloc_bytes - the same as go_memstats_alloc_bytes

  • go_memstats_heap_idle_bytes - idle memory ready for new Go object allocations

  • go_memstats_heap_objects - the number of Go objects in the heap

  • go_memstats_heap_sys_bytes - memory requested for Go objects from the OS

  • go_memstats_mallocs_total - the number of allocations for Go objects

  • go_memstats_next_gc_bytes - the target heap size when the next garbage collection should start

  • go_memstats_stack_inuse_bytes - memory used for goroutine stacks

  • go_memstats_stack_sys_bytes - memory requested fromthe OS for goroutine stacks

  • go_memstats_sys_bytes - memory requested by Go runtime from the OS

The WriteProcessMetrics func is usually called in combination with writing Set metrics inside "/metrics" handler: 

http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) {
    mySet.WritePrometheus(w)
    metrics.WriteProcessMetrics(w)
})

See also WrteFDMetrics.

func WritePrometheus 

func WritePrometheus(w io.Writer, exposeProcessMetrics bool)

WritePrometheus writes all the metrics from default set and all the registered sets in Prometheus format to w.

Additional sets can be registered via RegisterSet() call.

If exposeProcessMetrics is true, then various `go_*` and `process_*` metrics are exposed for the current process.

The WritePrometheus func is usually called inside "/metrics" handler: 

http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) {
    metrics.WritePrometheus(w, true)
})
Example 
package main

import (
	"net/http"

	"github.com/VictoriaMetrics/metrics"
)

func main() {
	// Export all the registered metrics in Prometheus format at `/metrics` http path.
	http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) {
		metrics.WritePrometheus(w, true)
	})
}

Output:

Types

type Counter 

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

Counter is a counter.

It may be used as a gauge if Dec and Set are called.

Example 
package main

import (
	"fmt"
	"github.com/VictoriaMetrics/metrics"
)

func main() {
	// Define a counter in global scope.
	var c = metrics.NewCounter(`metric_total{label1="value1", label2="value2"}`)

	// Increment the counter when needed.
	for i := 0; i < 10; i++ {
		c.Inc()
	}
	n := c.Get()
	fmt.Println(n)

}

Output:

10
Example (Vec) 
package main

import (
	"fmt"
	"github.com/VictoriaMetrics/metrics"
)

func main() {
	for i := 0; i < 3; i++ {
		// Dynamically construct metric name and pass it to GetOrCreateCounter.
		name := fmt.Sprintf(`metric_total{label1=%q, label2="%d"}`, "value1", i)
		metrics.GetOrCreateCounter(name).Add(i + 1)
	}

	// Read counter values.
	for i := 0; i < 3; i++ {
		name := fmt.Sprintf(`metric_total{label1=%q, label2="%d"}`, "value1", i)
		n := metrics.GetOrCreateCounter(name).Get()
		fmt.Println(n)
	}

}

Output:

1
2
3

func GetOrCreateCounter 

func GetOrCreateCounter(name string) *Counter

GetOrCreateCounter returns registered counter with the given name or creates new counter if the registry doesn't contain counter with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned counter is safe to use from concurrent goroutines.

Performance tip: prefer NewCounter instead of GetOrCreateCounter.

func NewCounter 

func NewCounter(name string) *Counter

NewCounter registers and returns new counter with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned counter is safe to use from concurrent goroutines.

func (*Counter) Add 

func (c *Counter) Add(n int)

Add adds n to c.

func (*Counter) Dec 

func (c *Counter) Dec()

Dec decrements c.

func (*Counter) Get 

func (c *Counter) Get() uint64

Get returns the current value for c.

func (*Counter) Inc 

func (c *Counter) Inc()

Inc increments c.

func (*Counter) Set 

func (c *Counter) Set(n uint64)

Set sets c value to n.

type FloatCounter 

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

FloatCounter is a float64 counter guarded by RWmutex.

It may be used as a gauge if Add and Sub are called.

Example 
package main

import (
	"fmt"
	"github.com/VictoriaMetrics/metrics"
)

func main() {
	// Define a float64 counter in global scope.
	var fc = metrics.NewFloatCounter(`float_metric_total{label1="value1", label2="value2"}`)

	// Add to the counter when needed.
	for i := 0; i < 10; i++ {
		fc.Add(1.01)
	}
	n := fc.Get()
	fmt.Println(n)

}

Output:

10.1
Example (Vec) 
package main

import (
	"fmt"
	"github.com/VictoriaMetrics/metrics"
)

func main() {
	for i := 0; i < 3; i++ {
		// Dynamically construct metric name and pass it to GetOrCreateFloatCounter.
		name := fmt.Sprintf(`float_metric_total{label1=%q, label2="%d"}`, "value1", i)
		metrics.GetOrCreateFloatCounter(name).Add(float64(i) + 1.01)
	}

	// Read counter values.
	for i := 0; i < 3; i++ {
		name := fmt.Sprintf(`float_metric_total{label1=%q, label2="%d"}`, "value1", i)
		n := metrics.GetOrCreateFloatCounter(name).Get()
		fmt.Println(n)
	}

}

Output:

1.01
2.01
3.01

func GetOrCreateFloatCounter 

func GetOrCreateFloatCounter(name string) *FloatCounter

GetOrCreateFloatCounter returns registered FloatCounter with the given name or creates new FloatCounter if the registry doesn't contain FloatCounter with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned FloatCounter is safe to use from concurrent goroutines.

Performance tip: prefer NewFloatCounter instead of GetOrCreateFloatCounter.

func NewFloatCounter 

func NewFloatCounter(name string) *FloatCounter

NewFloatCounter registers and returns new counter of float64 type with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned counter is safe to use from concurrent goroutines.

func (*FloatCounter) Add 

func (fc *FloatCounter) Add(n float64)

Add adds n to fc.

func (*FloatCounter) Get 

func (fc *FloatCounter) Get() float64

Get returns the current value for fc.

func (*FloatCounter) Set 

func (fc *FloatCounter) Set(n float64)

Set sets fc value to n.

func (*FloatCounter) Sub 

func (fc *FloatCounter) Sub(n float64)

Sub substracts n from fc.

type Gauge 

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

Gauge is a float64 gauge.

See also Counter, which could be used as a gauge with Set and Dec calls.

Example 
package main

import (
	"fmt"
	"runtime"

	"github.com/VictoriaMetrics/metrics"
)

func main() {
	// Define a gauge exporting the number of goroutines.
	var g = metrics.NewGauge(`goroutines_count`, func() float64 {
		return float64(runtime.NumGoroutine())
	})

	// Obtain gauge value.
	fmt.Println(g.Get())
}

Output:
Example (Vec) 
package main

import (
	"fmt"

	"github.com/VictoriaMetrics/metrics"
)

func main() {
	for i := 0; i < 3; i++ {
		// Dynamically construct metric name and pass it to GetOrCreateGauge.
		name := fmt.Sprintf(`metric{label1=%q, label2="%d"}`, "value1", i)
		iLocal := i
		metrics.GetOrCreateGauge(name, func() float64 {
			return float64(iLocal + 1)
		})
	}

	// Read counter values.
	for i := 0; i < 3; i++ {
		name := fmt.Sprintf(`metric{label1=%q, label2="%d"}`, "value1", i)
		n := metrics.GetOrCreateGauge(name, func() float64 { return 0 }).Get()
		fmt.Println(n)
	}

}

Output:

1
2
3

func GetOrCreateGauge 

func GetOrCreateGauge(name string, f func() float64) *Gauge

GetOrCreateGauge returns registered gauge with the given name or creates new gauge if the registry doesn't contain gauge with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned gauge is safe to use from concurrent goroutines.

Performance tip: prefer NewGauge instead of GetOrCreateGauge.

See also FloatCounter for working with floating-point values.

func NewGauge 

func NewGauge(name string, f func() float64) *Gauge

NewGauge registers and returns gauge with the given name, which calls f to obtain gauge value.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

f must be safe for concurrent calls.

The returned gauge is safe to use from concurrent goroutines.

See also FloatCounter for working with floating-point values.

func (*Gauge) Get 

func (g *Gauge) Get() float64

Get returns the current value for g.

type Histogram 

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

Histogram is a histogram for non-negative values with automatically created buckets.

See https://medium.com/@valyala/improving-histogram-usability-for-prometheus-and-grafana-bc7e5df0e350

Each bucket contains a counter for values in the given range. Each non-empty bucket is exposed via the following metric: 

<metric_name>_bucket{<optional_tags>,vmrange="<start>...<end>"} <counter>

Where:

  • <metric_name> is the metric name passed to NewHistogram
  • <optional_tags> is optional tags for the <metric_name>, which are passed to NewHistogram
  • <start> and <end> - start and end values for the given bucket
  • <counter> - the number of hits to the given bucket during Update* calls

Histogram buckets can be converted to Prometheus-like buckets with `le` labels with `prometheus_buckets(<metric_name>_bucket)` function from PromQL extensions in VictoriaMetrics. (see https://github.com/VictoriaMetrics/VictoriaMetrics/wiki/MetricsQL ): 

prometheus_buckets(request_duration_bucket)

Time series produced by the Histogram have better compression ratio comparing to Prometheus histogram buckets with `le` labels, since they don't include counters for all the previous buckets.

Zero histogram is usable.

Example 
// Define a histogram in global scope.
var h = metrics.NewHistogram(`request_duration_seconds{path="/foo/bar"}`)

// Update the histogram with the duration of processRequest call.
startTime := time.Now()
processRequest()
h.UpdateDuration(startTime)

Output:
Example (Vec) 
for i := 0; i < 3; i++ {
	// Dynamically construct metric name and pass it to GetOrCreateHistogram.
	name := fmt.Sprintf(`response_size_bytes{path=%q}`, "/foo/bar")
	response := processRequest()
	metrics.GetOrCreateHistogram(name).Update(float64(len(response)))
}

Output:

func GetOrCreateHistogram 

func GetOrCreateHistogram(name string) *Histogram

GetOrCreateHistogram returns registered histogram with the given name or creates new histogram if the registry doesn't contain histogram with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned histogram is safe to use from concurrent goroutines.

Performance tip: prefer NewHistogram instead of GetOrCreateHistogram.

func NewHistogram 

func NewHistogram(name string) *Histogram

NewHistogram creates and returns new histogram with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned histogram is safe to use from concurrent goroutines.

func (*Histogram) Reset 

func (h *Histogram) Reset()

Reset resets the given histogram.

func (*Histogram) Update 

func (h *Histogram) Update(v float64)

Update updates h with v.

Negative values and NaNs are ignored.

func (*Histogram) UpdateDuration 

func (h *Histogram) UpdateDuration(startTime time.Time)

UpdateDuration updates request duration based on the given startTime.

func (*Histogram) VisitNonZeroBuckets 

func (h *Histogram) VisitNonZeroBuckets(f func(vmrange string, count uint64))

VisitNonZeroBuckets calls f for all buckets with non-zero counters.

vmrange contains "<start>...<end>" string with bucket bounds. The lower bound isn't included in the bucket, while the upper bound is included. This is required to be compatible with Prometheus-style histogram buckets with `le` (less or equal) labels.

type Set 

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

Set is a set of metrics.

Metrics belonging to a set are exported separately from global metrics.

Set.WritePrometheus must be called for exporting metrics from the set.

Example 
package main

import (
	"bytes"
	"fmt"
	"github.com/VictoriaMetrics/metrics"
)

func main() {
	// Create a set with a counter
	s := metrics.NewSet()
	sc := s.NewCounter("set_counter")
	sc.Inc()
	s.NewGauge(`set_gauge{foo="bar"}`, func() float64 { return 42 })

	// Dump metrics from s.
	var bb bytes.Buffer
	s.WritePrometheus(&bb)
	fmt.Printf("set metrics:\n%s\n", bb.String())

}

Output:

set metrics:
set_counter 1
set_gauge{foo="bar"} 42

func GetDefaultSet 

func GetDefaultSet() *Set

GetDefaultSet returns the default metrics set.

func NewSet 

func NewSet() *Set

NewSet creates new set of metrics.

Pass the set to RegisterSet() function in order to export its metrics via global WritePrometheus() call.

func (*Set) GetOrCreateCounter 

func (s *Set) GetOrCreateCounter(name string) *Counter

GetOrCreateCounter returns registered counter in s with the given name or creates new counter if s doesn't contain counter with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned counter is safe to use from concurrent goroutines.

Performance tip: prefer NewCounter instead of GetOrCreateCounter.

func (*Set) GetOrCreateFloatCounter 

func (s *Set) GetOrCreateFloatCounter(name string) *FloatCounter

GetOrCreateFloatCounter returns registered FloatCounter in s with the given name or creates new FloatCounter if s doesn't contain FloatCounter with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned FloatCounter is safe to use from concurrent goroutines.

Performance tip: prefer NewFloatCounter instead of GetOrCreateFloatCounter.

func (*Set) GetOrCreateGauge 

func (s *Set) GetOrCreateGauge(name string, f func() float64) *Gauge

GetOrCreateGauge returns registered gauge with the given name in s or creates new gauge if s doesn't contain gauge with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned gauge is safe to use from concurrent goroutines.

Performance tip: prefer NewGauge instead of GetOrCreateGauge.

func (*Set) GetOrCreateHistogram 

func (s *Set) GetOrCreateHistogram(name string) *Histogram

GetOrCreateHistogram returns registered histogram in s with the given name or creates new histogram if s doesn't contain histogram with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned histogram is safe to use from concurrent goroutines.

Performance tip: prefer NewHistogram instead of GetOrCreateHistogram.

func (*Set) GetOrCreateSummary 

func (s *Set) GetOrCreateSummary(name string) *Summary

GetOrCreateSummary returns registered summary with the given name in s or creates new summary if s doesn't contain summary with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned summary is safe to use from concurrent goroutines.

Performance tip: prefer NewSummary instead of GetOrCreateSummary.

func (*Set) GetOrCreateSummaryExt 

func (s *Set) GetOrCreateSummaryExt(name string, window time.Duration, quantiles []float64) *Summary

GetOrCreateSummaryExt returns registered summary with the given name, window and quantiles in s or creates new summary if s doesn't contain summary with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned summary is safe to use from concurrent goroutines.

Performance tip: prefer NewSummaryExt instead of GetOrCreateSummaryExt.

func (*Set) InitPush 

func (s *Set) InitPush(pushURL string, interval time.Duration, extraLabels string) error

InitPush sets up periodic push for metrics from s to the given pushURL with the given interval.

extraLabels may contain comma-separated list of `label="value"` labels, which will be added to all the metrics before pushing them to pushURL.

/ The metrics are pushed to pushURL in Prometheus text exposition format. See https://github.com/prometheus/docs/blob/main/content/docs/instrumenting/exposition_formats.md#text-based-format

It is recommended pushing metrics to /api/v1/import/prometheus endpoint according to https://docs.victoriametrics.com/#how-to-import-data-in-prometheus-exposition-format

It is OK calling InitPush multiple times with different pushURL - in this case metrics are pushed to all the provided pushURL urls.

func (*Set) ListMetricNames 

func (s *Set) ListMetricNames() []string

ListMetricNames returns sorted list of all the metrics in s.

func (*Set) NewCounter 

func (s *Set) NewCounter(name string) *Counter

NewCounter registers and returns new counter with the given name in the s.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned counter is safe to use from concurrent goroutines.

func (*Set) NewFloatCounter 

func (s *Set) NewFloatCounter(name string) *FloatCounter

NewFloatCounter registers and returns new FloatCounter with the given name in the s.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned FloatCounter is safe to use from concurrent goroutines.

func (*Set) NewGauge 

func (s *Set) NewGauge(name string, f func() float64) *Gauge

NewGauge registers and returns gauge with the given name in s, which calls f to obtain gauge value.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

f must be safe for concurrent calls.

The returned gauge is safe to use from concurrent goroutines.

func (*Set) NewHistogram 

func (s *Set) NewHistogram(name string) *Histogram

NewHistogram creates and returns new histogram in s with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned histogram is safe to use from concurrent goroutines.

func (*Set) NewSummary 

func (s *Set) NewSummary(name string) *Summary

NewSummary creates and returns new summary with the given name in s.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned summary is safe to use from concurrent goroutines.

func (*Set) NewSummaryExt 

func (s *Set) NewSummaryExt(name string, window time.Duration, quantiles []float64) *Summary

NewSummaryExt creates and returns new summary in s with the given name, window and quantiles.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned summary is safe to use from concurrent goroutines.

func (*Set) UnregisterAllMetrics 

func (s *Set) UnregisterAllMetrics()

UnregisterAllMetrics de-registers all metrics registered in s.

func (*Set) UnregisterMetric 

func (s *Set) UnregisterMetric(name string) bool

UnregisterMetric removes metric with the given name from s.

True is returned if the metric has been removed. False is returned if the given metric is missing in s.

func (*Set) WritePrometheus 

func (s *Set) WritePrometheus(w io.Writer)

WritePrometheus writes all the metrics from s to w in Prometheus format.

type Summary 

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

Summary implements summary.

Example 
package main

import (
	"time"

	"github.com/VictoriaMetrics/metrics"
)

func main() {
	// Define a summary in global scope.
	var s = metrics.NewSummary(`request_duration_seconds{path="/foo/bar"}`)

	// Update the summary with the duration of processRequest call.
	startTime := time.Now()
	processRequest()
	s.UpdateDuration(startTime)
}

func processRequest() string {
	return "foobar"
}

Output:
Example (Vec) 
package main

import (
	"fmt"

	"github.com/VictoriaMetrics/metrics"
)

func main() {
	for i := 0; i < 3; i++ {
		// Dynamically construct metric name and pass it to GetOrCreateSummary.
		name := fmt.Sprintf(`response_size_bytes{path=%q}`, "/foo/bar")
		response := processRequest()
		metrics.GetOrCreateSummary(name).Update(float64(len(response)))
	}
}

func processRequest() string {
	return "foobar"
}

Output:

func GetOrCreateSummary 

func GetOrCreateSummary(name string) *Summary

GetOrCreateSummary returns registered summary with the given name or creates new summary if the registry doesn't contain summary with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned summary is safe to use from concurrent goroutines.

Performance tip: prefer NewSummary instead of GetOrCreateSummary.

func GetOrCreateSummaryExt 

func GetOrCreateSummaryExt(name string, window time.Duration, quantiles []float64) *Summary

GetOrCreateSummaryExt returns registered summary with the given name, window and quantiles or creates new summary if the registry doesn't contain summary with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned summary is safe to use from concurrent goroutines.

Performance tip: prefer NewSummaryExt instead of GetOrCreateSummaryExt.

func NewSummary 

func NewSummary(name string) *Summary

NewSummary creates and returns new summary with the given name.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned summary is safe to use from concurrent goroutines.

func NewSummaryExt 

func NewSummaryExt(name string, window time.Duration, quantiles []float64) *Summary

NewSummaryExt creates and returns new summary with the given name, window and quantiles.

name must be valid Prometheus-compatible metric with possible labels. For instance,

  • foo
  • foo{bar="baz"}
  • foo{bar="baz",aaa="b"}

The returned summary is safe to use from concurrent goroutines.

func (*Summary) Update 

func (sm *Summary) Update(v float64)

Update updates the summary.

func (*Summary) UpdateDuration 

func (sm *Summary) UpdateDuration(startTime time.Time)

UpdateDuration updates request duration based on the given startTime.

Source Files

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