metrics/README.md

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.

Limitations

• It doesn't implement advanced functionality from github.com/prometheus/client_golang/prometheus.

Usage

import "github.com/VictoriaMetrics/metrics"

// Register various time series.
// Time series 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{handler="/my/super/handler"}`)

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

// ...
func requestHandler() {
	startTime := time.Now()
	// ...
	requestsTotal.Inc()
	requestDuration.UpdateDuration(startTime)
}
// ...

// `/metrics` handler for exposing the registered metrics.
http.HandleFunc("/metrics", func(w http.ResponseWriter, req *http.Request) {
	metrics.WritePrometheus(w, true)
})

See docs for more info.

Users

• Metrics has been extracted from VictoriaMetrics sources. See this article for more info about VictoriaMetrics.