Simplify lock acquire

[stsewd]

Currently we are acquiring 3 locks.
We should only have 2 (we can't have only one because of #5672)

Basically I'm removing the locks from setup_python_env and build_docs to only acquire the lock in a central place (run_build)

[stsewd]

I still want to test this more locally before merging :)

[stsewd]

Locking is working, this is ready for review.

[humitos]

Why not to acquire the lock immediately inside the run method of the build task so the whole build process (API query, setup, build docs, etc) is inside the lock?

Otherwise, the clean_build_task from #5680 could clean these files while we are performing the run_setup step.

[stsewd]

That's the trick, the lock needs to be acquired inside the with self.build_env context manager. Because build_env catch the VersionLocked error, otherwise the task will not shown as failed and would be retying without showing anything to the user.

[humitos]

Yeah, but we can create the self.build_env (or self.setup_env, it's the same for this) immediately after getting the project, version, build and env vars from the API. That's all what we need to create it and we can use the context manager after that wrapping the rest of the execution. Don't you think?

[stsewd]

There are two build environments, that's why we need two locks.

build_env_1 -> lock
build_env_2 -> lock

Nesting isn't possible due how build_env works and expects lock to be inside the build env context manager.

Also, the second build_env depends on the first, which gets the config file to initialize the next build_env with the correct docker image.

[ericholscher]

This makes a lot more sense 💯