client_golang Documentation

Technical Documentation: prometheus/client_golang

ℹ️ Provenance: Multi-Tier Ingestion · CodeWiki Reference

Overview (`README.md`) Copy Section

Prometheus Go client library

This is the Go client library for
Prometheus. It has two separate parts, one for
instrumenting application code, and one for creating clients that talk to the
Prometheus HTTP API.

Version Compatibility Copy Chapter

This library supports the two most recent major releases of Go. While it may function with older versions, we only provide fixes and support for the currently supported Go releases.

[!NOTE]
See our Release Process for details on compatibility and support policies.

Important note about releases and stability Copy Chapter

This repository generally follows Semantic
Versioning. However, the API client in
prometheus/client_golang/api/… is still considered experimental. Breaking
changes of the API client will not trigger a new major release. The same is
true for selected other new features explicitly marked as EXPERIMENTAL in
CHANGELOG.md.

Features that require breaking changes in the stable parts of the repository
are being batched up and tracked in the v2
milestone, but plans for further development of v2 at the moment.

NOTE: The initial v2 attempt is in a separate branch. We also started
experimenting on a new prometheus.V2.* APIs in the 1.x's V2 struct. Help wanted!

Instrumenting applications Copy Chapter

The
prometheus directory
contains the instrumentation library. See the
guide on the Prometheus
website to learn more about instrumenting applications.

The
examples directory
contains simple examples of instrumented code.

Pushing metrics via OpenTelemetry OTLP Copy Chapter

Applications instrumented with client_golang can also export their
metrics via the OpenTelemetry OTLP push protocol without re-instrumenting
against a different metric API. The
go.opentelemetry.io/contrib/bridges/prometheus
module wraps a prometheus.Registry as an OpenTelemetry metric producer,
which an OTLP exporter (HTTP or gRPC) can then push to an OTel collector
or OTLP-accepting backend. This is useful for batch jobs or environments
where pull-based /metrics scraping is not an option.

Pull-based collection via promhttp remains the recommended default for
reliability, central discovery, and failover. The bridge is intended as
an additional option, not a replacement.

See the bridge's Go reference
and source
for setup details.

Client for the Prometheus HTTP API Copy Chapter

The
api/prometheus directory
contains the client for the
Prometheus HTTP API. It allows you
to write Go applications that query time series data from a Prometheus
server. It is still in alpha stage.

Where is `model`, `extraction`, and `text`? Copy Chapter

The model packages has been moved to
prometheus/common/model.

The extraction and text packages are now contained in
prometheus/common/expfmt.

Contributing and community Copy Chapter

See the contributing guidelines and the
Community section of the homepage.

client_golang community is also present on the CNCF Slack #prometheus-client_golang.

Overview (`exp/README.md`) Copy Section

client_golang experimental module

Contains experimental utilities and APIs for Prometheus.

Packages within this module are listed below.

Remote Copy Chapter

This module contains production quality code with explicitly unstable API. Any code in this module can change its API or be removed; use with care.

The intention is that, with maturity some of the packages would graduate to stable version of client_golang module.

Packages within this module are listed below.

Remote Copy Chapter

NOTE: The api/remote package is used by prometheus/prometheus. Any changes to this package should ensure Prometheus is not affected (e.g. does not break Prometheus on upgrade or if it breaks, the Prometheus gets updated soon.
Implements bindings from Prometheus remote APIs (remote write v1 and v2 for now).

Contains flexible method for building API clients, that can send remote write protocol messages.

import (
        "github.com/prometheus/client_golang/exp/api/remote"
    )
    ...

	remoteAPI, err := remote.NewAPI(
		"https://your-remote-endpoint",
		remote.WithAPIHTTPClient(httpClient),
		remote.WithAPILogger(logger.With("component", "remote_write_api")),
	)
    ...

    stats, err := remoteAPI.Write(ctx, remote.WriteV2MessageType, protoWriteReq)

Also contains handler methods for applications that would like to handle and store remote write requests.

import (
        "net/http"
        "log"

        "github.com/prometheus/client_golang/exp/api/remote"
    )
    ...
    
    type db {}

    func NewStorage() *db {}

    func (d *db) Store(ctx context.Context, msgType remote.WriteMessageType, req *http.Request) (*remote.WriteResponse, error) {}
    ...

	mux := http.NewServeMux()

	remoteWriteHandler := remote.NewHandler(storage, remote.WithHandlerLogger(logger.With("component", "remote_write_handler")))
	mux.Handle("/api/v1/write", remoteWriteHandler)

	server := &http.Server{
		Addr:    ":8080",
		Handler: mux,
	}
	if err := server.ListenAndServe(); err != nil {
		log.Fatal(err)
	}

For more details, see go doc.

Overview (`prometheus/README.md`) Copy Section

See .

Overview (`tutorials/whatsup/README.md`) Copy Section

client_golang Tutorial: "WhatsUp"

See slides

Overview (`internal/github.com/golang/gddo/README.md`) Copy Section

This source code is a stripped down version from the archived repository https://github.com/golang/gddo and licensed under BSD.

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