Documentation of existing CI behavior

[kevinburke]

Looking in the source code it's clear that there's a build runner that is supposed to be running the rustls tests, however, it's difficult to actually find that build because it's not linked in Github's checks UI. Further the fact that Github checks reports ~45 different tests made me think that I just wasn't looking hard enough and it must be there somewhere.

It turns out there is a whole other builder suite at https://curl.zuul.vexxhost.dev/builds?job_name=curl-debug-rustls (and maybe others?) that is running CI tests. While there are issues with that builder (#7522) we could probably do a better job of documenting the different CI jobs that are running currently.

I propose adding tests/CI.md with documentation on:

• The different locations that CI checks are run
• Which location runs which subset of tests
• Where you should look to verify your PR did not introduce regressions
• Who owns keys or knows how to set up CI (maybe the answer is just @bagder)

I'd also like to add a link in zuul.d/jobs.yaml with a link to the curl.zuul.vexxhost.dev page, just to make that link more explicit.

I would be happy to take a first stab at this.

[kevinburke]

It might also be helpful to include a few lines about how to get Zuul to show console logs. I am trying to view the results of this run - https://curl.zuul.vexxhost.dev/build/59ab8531336b4f5d93c405ade2c2079f - but alternately getting a CORS error or a NoSuchBucket error when I try to view the test logs.

[kevinburke]

Aha. I found https://github.com/curl/curl/blob/master/docs/CONTRIBUTE.md#about-pull-requests, but missed it the first time I looked because it didn't have the words I was searching for ("zuul", "azure", "github actions") to find info about the CI environment.

[bagder]

The zuul builds are "screwed up" for the moment (#7522), as they are supposed to show up with a line among the CI builds like all the others but they don't and this is causing us big problems since we miss failed builds and more! I fear that we need to move over jobs from zuul to other services soon unless someone helps us fix this situation.

Otherwise I sympathize with your idea. Maybe we should move the CI specifics from CONTRIBUTE.d into a separate CI.md and work on populating it with all the info that should be there!?