gem-hunter

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.

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.

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!

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.

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.

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.

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

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

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

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