Add monitoring linter

[assafad]

What this PR does / why we need it:

Monitoring Linter is a Golang linter designed to ensure that in Kubernetes operator projects,
monitoring-related practices are implemented within the pkg/monitoring directory using operator-observability methods. It verifies that all metrics, alerts and recording rules registrations are centralized in this directory.
The use of Prometheus registration methods is restricted across the entire project.

Fixes https://issues.redhat.com/browse/CNV-36760.

Checklist

This checklist is not enforcing, but it's a reminder of items that could be relevant to every PR.
Approvers are expected to review this list.

• Design: A design document was considered and is present (link) or not required
• PR: The PR description is expressive enough and will help future contributors
• Code: Write code that humans can understand and Keep it simple
• Refactor: You have left the code cleaner than you found it (Boy Scout Rule)
• Upgrade: Impact of this change on upgrade flows was considered and addressed if required
• Testing: New code requires new unit tests. New features and bug fixes require at least on e2e test
• Documentation: A user-guide update was considered and is present (link) or not required. You want a user-guide update if it's a user facing feature / API change.
• Community: Announcement to kubevirt-dev was considered

Release note:

None

[nunnatsa]

Did preliminary quick review. Added some comments

[machadovilaca]

just a small nit, otherwise good progress so far!

[machadovilaca]

although this is a package that executes testing, it is nonetheless a package to be distributed/imported by other projects
therefore I think it should be in cmd/ pkg/ dirs

test/monitoringlocationlinter/analyzer.go should be pkg/monitoringlocationlinter/analyzer.go
and
test/monitoringlocationlinter/cmd/monitoringlocationlinter/main.go should be cmd/monitoringlocationlinter/main.go

code in test/ should be used to test the code in the own repo cmd/, pkg/, internal/, etc... dirs

wdyt @nunnatsa?

[nunnatsa]

although this is a package that executes testing, it is nonetheless a package to be distributed/imported by other projects therefore I think it should be in cmd/ pkg/ dirs

test/monitoringlocationlinter/analyzer.go should be pkg/monitoringlocationlinter/analyzer.go and test/monitoringlocationlinter/cmd/monitoringlocationlinter/main.go should be cmd/monitoringlocationlinter/main.go

code in test/ should be used to test the code in the own repo cmd/, pkg/, internal/, etc... dirs

wdyt @nunnatsa?

It should not be in tests for sure. But I would add everything under one directory, e.g.

(and by the way, "monitoringlocationlinter" limit you to only check locations. What if you'll want to add additional rules?)

WDYT about this?

monitoringlinter/
+ -- go.mod
+ -- go.sum
+---> cmd/
          + main.go
+---> analyzer/
          +---> testdata/
                    ...
          + -- analyzer.go
          + -- analyzer_test.go

[nunnatsa]

@nunnatsa +1 for changing to monitoringlinter. Are you suggesting to have its dir under the root dir?

yes, new directory named monitoringlinter under the repo root dir.

[assafad]

Hi @nunnatsa, @machadovilaca, can you please review again?
I updated the PR with the following changes:

• Changed the linter name to monitoringlinter and moved its dir to the root dir, as discussed.
  I find the current linter dir structure the most convenient, but let me know if don't agree.
• Following @machadovilaca's comment, to add checks for operator-observability packages, I changed analyzer.go, please have a look at it again.
• Updated all required docs and tests following this changes (e.g. added unit tests and files to the testdata).

[nunnatsa]

/lgtm
/approve