feat: allow to encode a registry in openmetrics without EOF

[Frando]

Description

MetricsSource::encode_openmetrics adds the # EOF\n marker at the end of the encoded openmetrics output. This is the expected last characters in the openmetrics text format. Currently, MetricsSource::encode_openmetrics is the only public API to encode a iroh_metrics::Registry into the openmetrics text format.

When combining output from different sources, users should be able to add the EOF marker themselves. This PR adds a public function Registry::encode_openmetrics_to_writer that encodes without the EOF.

For 1.0 we should revisit the MetricsSource trait, but the change in this PR is semver compatible so can be in a patch release, so that downstream users of [email protected] can make use of it.

Breaking Changes

Notes & open questions

Change checklist

• Self-review.
• Documentation updates following the style guide, if relevant.
• Tests if relevant.
• All breaking changes documented.

[github-actions]

Documentation for this PR has been generated and is available at: https://n0-computer.github.io/iroh-metrics/pr/27/docs/iroh_metrics/

Last updated: 2025-05-22T10:27:04Z