Add nested owners files to automate labeling pull requests

[jmhbnz]

This pull request proposes adding an initial set of nested OWNERS files with labels: populated in order to automate labeling for pull requests now that we have enabled the owners-label prow plugin in kubernetes/test-infra#32589.

I've structured the OWNERS files with the assumption that inheritance works, we need to test/verify this. For example, a pull request for tools/rw-heatmaps should in theory be allocated both the area/tooling and area/performance labels based on the inheritance.

Moving forward we can also use the nested OWNERS files to further delegate approvers and reviewers for specific directories of etcd-io/etcd code.

Fixes: #17970

[serathius]

The documentation directory is no longer used in the original way. Originally it included https://github.com/etcd-io/website. Now the remaining documentation is more of contributor documentation, using "area/documentation" label for this directory might be misleading.

[jmhbnz]

Yes that directory is rather awkward. I think we have a larger decision to make on if we will shift to serving our contributor facing documentation to a new area of etcd-io/website.

To be transparent I would be in favor of this. It's something k8s has been doing for a while https://kubernetes.io/docs/contribute/docs.

I don't want to force that decision in this pr though, happy to come back to it later, perhaps as a topic for one of our upcoming community calls.

[serathius]

Yes that directory is rather awkward. I think we have a larger decision to make on if we will shift to serving our contributor facing documentation to a new area of etcd-io/website.

eee, I was pushing for a reverse direction. etcd-io/website#569

The contributors documentation was moved with website, however I reversed the decision because it immediately became unmaintained and outdated. I don't like K8s direction, I think the contributor documentation should be in the same repo as project and be unit tested to ensure it's up to date.

Example of documentation testing in python https://docs.python.org/3/library/doctest.html#simple-usage-checking-examples-in-docstrings

[jmhbnz]

Based on when the linked pr was merged I would guess the unmaintained issue was a reflection of the state the project was in at that point in time around 2022? We are in a better position now in my view with more contributors available for website maintenance.

I like the idea of having better testing for documentation, and actually this isn't limited to contributor docs, I think many of the docs pages for our user facing documentation should have automated testing to ensure they are correct. In the ~2 years since that pr you linked was merged I don't believe we added unit tests for any of the files under our Documentation/ directory. However if we want to do this there is no reason we can't have scheduled prow job for etcd-io/website to let us know if something is broken.

Let's shift this discussion to a community meeting sometime and properly explore some pros/cons. At the end of the day I want our documentation to be the best it can be, irrespective of which git repo it is stored in.

[liangyuanpeng]

LGTM

[ivanvc]

/retest

[liangyuanpeng]

how about add an OWNERs file for .github/workflows, and label can be github_actions,it is also using by dependabot .

[ahrtr]

LGTM

Thanks