rust CI: explore if it's possible to free more disk space

[MarcoIeni]

We use the action free-disk-space to remove stuff from the free runners that we don't use.

The action doesn't seem maintained anymore. E.g. there are the following PRs where the maintained didn't reply:

• perf: speed up deletings jlumbroso/free-disk-space#26
• Remove snapd and microsoft-edge-stable jlumbroso/free-disk-space#24

Task: evaluate those PRs and if they are worth it, fork the github action and maintain it under rust-lang org

We could also check if more packages we don't use could be removed

[pietroalbini]

I would not fork it and maintain inside of the rust-lang org, as we are already stretched too thin to maintain it and make it work for other people outside of Rust. I'd rather recreate the script inside of our src/ci/scripts directory and invoke it there.

[MarcoIeni]

maintain it and make it work for other people outside of Rust

I wouldn't do this. Although it would be nice to have external contributors that remove more stuff that GitHub might add to the runners.

The reason why we might want to have it as an action instead of a script, is that other rust projects (rust analyzer, miri, etc.) might want to use it at some point.

[pietroalbini]

If at some point other repos start needing it we can extract the script out of rust-lang/rust, but IMO maintaining it as an in-tree script makes it easier to test it and tweak it.

[MarcoIeni]

I agree, let's start with an in-tree script then 👍

I'm putting the good first issue label if anyone wants to own this issue.

[whiteio]

Hey! Could this be assigned to me please?

[MarcoIeni]

Done!

I would proceed in the following order:

1. Copy paste the script and use it in rust-lang/rust. Verify in the pr ci that the saved space is the same as the action
2. Apply the PRs I linked in the first post and verify that they work by comparing timings and saved disk space
3. More optimizations. E.g. find new stuff that can be removed. Maybe the issue tracker of that project can be a good source of inspiration

Note

You don't need to deal with the action inputs. In rust-lang/rust we want to delete everything we can 👍