[Bug]: oci_python_image / py_layers unnecessarily rebuilds all layers

[gfrankliu]

What happened?

py_layers creates three tar files for layers = ["interpreter", "packages", "app"]

If you make a small change to your app, bazel build will recreate all three tar files, even though there is no change in "interpreter", "packages".

This is especially a problem if you have a large packages file (eg: pytorch and friends will be many GB), and it takes more than 5 minutes to tar/compress the packages unnecessarily when you only make a small change in your app.

To make things worse, gzip compression doesn't support multicore, so only a single cpu is being used.

Version

bazel v7.4.1

How to reproduce

No response

Any other information?

No response

[gfrankliu]

The issue is fixed with this patch: #372 (comment)