fix(api): make PollForMediaWikiJobsJob skip soft-deleted wikis

[dati18]

Bug: T433575

[tarrow]

looks close to ready to me apart from the new duplication in the resolver; I wonder if we need to any more tests or do you think that's not necessary?

[tarrow]

Thanks for removing the duplication

I wonder if we need to any more tests or do you think that's not necessary?

Did you have any thoughts about this?

[dati18]

@tarrow Sorry I couldn't reply sooner because of the outage yesterday. My 2cent is that the extra test would be testing getHostForDomain() returning all expected service hosts using the same helper function, so it's not about testing a behavior change, but a formatting test.
All existing focused tests cover the real contract of MediaWikiHostResolver.php, for example, successful backend host resolution or backend URL generation, etc. That is enough because the change was only about the host-formatting logic, not changing the mapping behavior itself.

[tarrow]

We talked about this in the daily @dati18 thinks that no more testing is required as per the above comment.

I'm still somewhat hesitant to approve this without doing some more thinking / manual testing to improve my confidence; I don't want us to get distracted from our main work if this Job running blows up (although by eye I don't see why it should)

Specifically I think it might be good to have tests that:

• cover any new public functions added to MediaWikiHostResolver
• cover the functionality of PollForMediaWikiJobsJob when errors are thrown by MediaWikiHostResolver

I didn't yet manage to find the time for some manual testing or to write these tests myself to improve my confidence.

[dati18]

@tarrow I took your hints and added a few test cases based on existing tests.

MediaWikiHostResolverTest:

• testResolverReturnsAllHostsForDomain — verifies getHostsForDomain() returns all service hosts with correct names
  testResolverBuildsBackendUrlForWiki — verifies getBackendUrlForWiki() builds the correct http:// URL when given a Wiki object.

PollForMediaWikiJobsJobTest:

• testSkipsWikiWhenResolverThrowsAndContinuesProcessing — verifies that when MediaWikiHostResolver throws UnknownDBVersionException for one wiki, the job logs a warning and skips it, without failing the whole job, then continues dispatching ProcessMediaWikiJobsJob for the remaining healthy wiki(s).

[tarrow]

looks good to me; let's make sure when we ship this to staging we ensure we properly try it though.

Make sure there are some jobs created on Wikis and that they run before we promote it to production.