[RamReso]

What is done?

• resolves Report the rust compiler version used in the prometheus metrics #19403
• Adds build-time Rust compiler detection and captures the rustc --version value during the build.
• Exposes the captured compiler version from the Rust extension via a new Python-callable function.
• Exports a new Prometheus metric for rustc version.

How to test?

• compile poetry install
• add enable_metrics: true and

    resources:
    - compress: false
      names:
      - client
      - federation
      - metrics

to homeserver.yaml

• start synapse
• find the rustc version at http://localhost:8008/_synapse/metrics

Pull Request Checklist

• Pull request is based on the develop branch
• Pull request includes a changelog file. The entry should:
  • Be a short description of your change which makes sense to users. "Fixed a bug that prevented receiving messages from other servers." instead of "Moved X method from EventStore to EventWorkerStore.".
  • Use markdown where necessary, mostly for code blocks.
  • End with either a period (.) or an exclamation mark (!).
  • Start with a capital letter.
  • Feel free to credit yourself, by adding a sentence "Contributed by @github_username." or "Contributed by [Your Name]." to the end of the entry.
• Code style is correct (run the linters)

[sandhose]

Thanks for this contribution, this is definitely useful!

[RamReso]

The test tests.rest.admin.test_user.UserRedactionBackgroundTaskTestCase.test_redact_messages_all_rooms fails, but I don't know why. On my machine the tests run without a failure. The failing test also looks unrelated to my PR.

[sandhose]

The test tests.rest.admin.test_user.UserRedactionBackgroundTaskTestCase.test_redact_messages_all_rooms fails, but I don't know why. On my machine the tests run without a failure. The failing test also looks unrelated to my PR.

This is just one of our usual test flake unfortunately, don't worry about that :)

Thanks for doing all this!