# What is done?
- resolves#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
```yaml
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
<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->
* [x] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
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.
* [x] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct (run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))
---------
Co-authored-by: Quentin Gliech <quenting@element.io>
Noah Markert