Gostats

gostats is a Go metrics library with support for Counters, Gauges, and Timers.

Installation

go get github.com/lyft/gostats

Building & Testing

go test ./...

Usage

In order to start using gostats, import it into your project with:

import "github.com/lyft/gostats"

Bounding memory from high-cardinality tags

By default, gostats never forgets a counter or timer name once it sees one, even after the value stops changing. Don't tag one with a high-cardinality value: that grows memory without limit. GOSTATS_PRUNE_IDLE_SECONDS limits the growth. See docs/idle-pruning.md for how it works and how to pick a value.

Mocking

A thread-safe mock sink is provided by the gostats/mock package. The mock sink also provides methods that are useful for testing (as demonstrated below).

package mock_test

import (
	"testing"

	"github.com/lyft/gostats"
	"github.com/lyft/gostats/mock"
)

type Config struct {
	Stats stats.Store
}

func TestMockExample(t *testing.T) {
	sink := mock.NewSink()
	conf := Config{
		Stats: stats.NewStore(sink, false),
	}
	conf.Stats.NewCounter("name").Inc()
	conf.Stats.Flush()
	sink.AssertCounterEquals(t, "name", 1)
}

If you do not need to assert on the contents of the sink the below example can be used to quickly create a thread-safe stats.Scope:

package config

import (
	"github.com/lyft/gostats"
	"github.com/lyft/gostats/mock"
)

type Config struct {
	Stats stats.Store
}

func NewConfig() *Config {
	return &Config{
		Stats: stats.NewDefaultStore(),
	}
}

func NewMockConfig() *Config {
	sink := mock.NewSink()
	return &Config{
		Stats: stats.NewStore(sink, false),
	}
}