Add module for cockroachdb

[jsoriano]

Depends on #12465, module implemented as light module (#12270).

Collect metrics from cochroachdb, from its Prometheus endpoint.
All metrics are collected as they are and stored under prometheus.metrics.

An overview dashboard is added:

Pending:

• tests
• fields.yml (there will be follow up, see Generate fields.yml from prometheus response jsoriano/beats#3)
• dashboard

[exekias]

I see the pending point of fields.yml. This one is interesting, as already present Prometheus fields.yml gives us the right mapping already, still, there are no docs for the fields that we will get from the module. Is that why it's on the list?

[jsoriano]

I see the pending point of fields.yml. This one is interesting, as already present Prometheus fields.yml gives us the right mapping already, still, there are no docs for the fields that we will get from the module. Is that why it's on the list?

Yeah, I'd like to explore the possibility of getting the documentation for these fields automatically. If not it will require at least an empty fields.yml to pass our tests (or we have to change the tests).

[ruflin]

@jsoriano Is there a way to also have generated files for these light modules? This would be nice for testing, docs but also for us to see if the generated events outside the prometheus metrics contain the correct values (for example event.dataset).

[jsoriano]

@jsoriano Is there a way to also have generated files for these light modules? This would be nice for testing, docs but also for us to see if the generated events outside the prometheus metrics contain the correct values (for example event.dataset).

I would use by now the tools we already have, it should be possible to use current prometheus helpers to test this module and generate the data.json file. I wrote a bit about testing and tooling in the proposal.

[ruflin]

@jsoriano Would be great to have the generated file directly as part of this PR to make sure we generate the right data. Great if the current tools already work.

[kaiyan-sheng]

Just curious, when there are changes made in prometheus module, for example Pablo's le change on histogram, will tests fail in modules like cockroachdb?

[jsoriano]

Just curious, when there are changes made in prometheus module, for example Pablo's le change on histogram, will tests fail in modules like cockroachdb?

Yes, tests will fail and affected files will need to be regenerated. This would be similar to other changes we do in the framework that require regenerating golden files.

[jsoriano]

Dashboard added, screenshot uploaded to issue description.

[jsoriano]

@exekias I have been playing with the possibility of generating fields.yml and docs for fields from the prometheus response, find here the changes over this PR: jsoriano#3
I think that using these fields for the mapping can be a bit excesive as they are hundreds of new fields and we already have the wildcards, but it could be nice for the documentation. But this would require more changes in the doc generator.
What do you think? Does it worth it? or I leave the fields undocumented by now?

[exekias]

Leaving them for another PR sounds reasonable to me, will comment there!

Is this one ready for review?

[jsoriano]

Opening for review, there are some things pending but they are mostly for tests and docs, we can do them in future PRs.