Implement ghcr.io expiration for images and cache layers

[jiridanek]

It appears that ghcr.io does not support setting expiration. The only way is to periodically delete old images. This is probably a good thing to do, just to avoid excessive storage usage.

Although there does not seem to be any limit for us, it seems to be a good practice to clean up after ourselves.

• https://github.com/WoozyMasta/quay-expiration
• https://github.com/eumel8/expire-action
• https://github.com/snok/container-retention-policy/blob/main/main.py

[caponetto]

One more option: https://github.com/marketplace/actions/ghcr-pruning

[jiridanek]

@caponetto do you have a favorite? I'm unfamiliar with the options, so I'm inclined to pick yours

[caponetto]

Hey @jiridanek,
I was looking at the options and the container-retention-policy that you found looks better in terms of activity and popularity in the community. Also, I saw that there will be a new major release (v3) coming out soon, which is being developed on this branch.