metrics

Documentation

Overview

Package metrics implements support for exposing metrics using different providers

To create a new Metrics, use either NewPrometheus() or NewNone(). From there, call the New*() functions to obtain a metric and use them.

Index

• Variables
• type CounterVec
• type GaugeVec
• type HistogramVec
• type Labels
• type MetricOpts
• type Metrics
  • func NewNone() Metrics
  • func NewPrometheus(httpPort int) Metrics
• type SummaryVec

Variables

var (
	// ErrServerClosed is the error returned by Serve when the Metrics
	// server is closed.
	ErrServerClosed = http.ErrServerClosed
)

Types

type CounterVec

type CounterVec interface {
	Inc(labelValues ...string)
	Add(v float64, labelValues ...string)
}

CounterVec implements a Counter which can only increase in value. Notice that the amount of label values must match the number of label names used when creating the CounterVec.

type GaugeVec

type GaugeVec interface {
	Set(v float64, labelValues ...string)
	Inc(labelValues ...string)
	Add(v float64, labelValues ...string)
}

GaugeVec implements a Gauge that might increase or decrease in value over time. Notice that the amount of label values must match the number of label names used when creating the GaugeVec.

type HistogramVec

type HistogramVec interface {
	Observe(v float64, labelValues ...string)
}

A HistogramVec interface represents a histogram vector. Notice that the amount of label values must match the number of label names used when creating the HistogramVec.

type Labels

type Labels map[string]string

type MetricOpts

type MetricOpts struct {
	Namespace   string
	Subsystem   string
	Name        string
	Help        string
	ConstLabels Labels
}

MetricOpts represents the options used by all types of metrics. See https://prometheus.io/docs/practices/naming/ for choosing a metric name.

type Metrics

type Metrics interface {
	// NewCounterVec returns a CounterVec with the given options and labels.
	// See CounterVec for more information.
	NewCounterVec(opts MetricOpts, labelNames ...string) CounterVec
	// NewGaugeVec returns a GaugeVec with the given options and labels.
	// See GaugeVec for more information.
	NewGaugeVec(opts MetricOpts, labelNames ...string) GaugeVec
	// NewHistogramVec returns a HistogramVec with the given options and labels.
	// See HistogramVec for more information.
	NewHistogramVec(opts MetricOpts, labelNames ...string) HistogramVec
	// NewSummaryVec returns a HistogramVec with the given options and labels.
	// See SummaryVec for more information.
	NewSummaryVec(opts MetricOpts, labelNames ...string) SummaryVec
	// Serve starts serving the metrics collected by this Metrics, in a blocking way.
	// After shutdown, it will return ErrShutdown.
	Serve() error
	// Close stops serving the metrics immediately and invalidates all previously
	// create metrics (counters, gauges, etc...)
	Close() error
	// Shutdown works like Close(), but it awaits for any clients reading the
	// metrics to be done
	Shutdown(ctx context.Context) error
}

Metrics is an interface which wraps a metrics generator. To create a Metrics use one of the New*() functions in this package. After that, create any metrics you need using the New*() functions in this interface. To serve the metrics call Serve() at some point. Finally, call Shutdown() to exit cleanly.

func NewNone

func NewNone() Metrics

NewNone returns a metrics provider that does nothing

func NewPrometheus

func NewPrometheus(httpPort int) Metrics

NewPrometheus returns a metrics provider that exposes the metrics via Prometheus on the given port, at /metrics

type SummaryVec

type SummaryVec interface {
	Observe(v float64, labelValues ...string)
}