Precompile creates log files which land in the final image

[thedarkside]

After upgrading to jammy builder and to rails 7.0 (including sprockets-rails upgrade) i am observing a difference in the built image contents. The /log directory now contains empty log files!
I believe it is due to sprockets-rails loading now the complete environment during assets:precompile resulting in those log files being created.

And because the jammy builder runs the build env with a different user id then the run env, the permissions don't allow writing those files which leads to a crash on startup.

"log to stdout" doesnt help me here either, because my stack outputs multiple log streams. I simply can not mix them in just one STDOUT stream. So i need those files writable during runtime!

Describe the Enhancement

After thinking about different solutions i came to the conclusion that the most elegant one would be to execute a "cleanup" task after compilation in this buildpack.
I mean, if we assume that after executing precompilation some logs getting written, it makes sense to solve this by cleaning up this directory leaving a clean image.

Possible Solution

Just a simple rm -rf /workspace/log/* after precompile would solve it. Or it could be rollback'ed to the previous state by taking a snapshot before the precompilation and copying over the snapshot after the precompilation.

[sophiewigmore]

@thedarkside sorry you're having issues upgrading to Jammy. I think your idea of doing a log cleanup makes sense - unless for some reason a user might want to look at those logs at runtime? Or they might want to look at logs in the case of a failed build