[prometheuswritereceiver] target info

[perebaj]

Description

Cache target_info metrics so it can be used to populate metrics' Resource Attributes.

Link to tracking issue

Partially fixes #37277

[ArthurSens]

Good start, but there are a few things not going in the right direction. Added a few comments below

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[perebaj]

@ArthurSens I adapted the tests to use the forked version that fixes that snappy compression. But now I think that we have a different problem.

How we will validate the multiple requests' behavior? This because, the way that you explain to me that this code should be done, is using the MockConsumer. The issue with this approach, is if we use a unit test, we won't be able to have the snappy working, because the middleware it's just initialized when we start the real Server, like you did here.

Besides that, I think that in the response of the /api/v1/write we don't have access to the translated metric. So, how can use validate that the target_info is working between different requests?

[perebaj]

@ArthurSens I adapted the tests to use the forked version that fixes that snappy compression. But now I think that we have a different problem.

How we will validate the multiple requests' behavior? This because, the way that you explain to me that this code should be done, is using the MockConsumer. The issue with this approach, is if we use a unit test, we won't be able to have the snappy working, because the middleware it's just initialized when we start the real Server, like you did here.

Besides that, I think that in the response of the /api/v1/write we don't have access to the translated metric. So, how can use validate that the target_info is working between different requests?

The answer was in my front of me the whole time

5a08906#diff-946c2dc5f6b3b6d865be9b13c57625f05b095c373d8dcc960fa4357985903058R519

I can pass the mockConsumer for the factory.CreateMetric 😊. Test done and working!

[ArthurSens]

Awesome progress, I think we're almost done :)

A few comments

[ArthurSens]

Just one very small comment, otherwise LGTM!

[ArthurSens]

Thank you! The hardest part of the mentorship is done 🎉