action does not use cached layers when rebuilding image

[johanneszellinger]

Trying to used the following step in a GitHub workflow to build an image on an Enterprise server:

  - name: Build image
    uses: docker/build-push-action@v4
    with:
      context: .
      file: ./src/Dockerfile
      push: true
      tags: ${{ env.REGISTRY }}/${{ env.REGISTRY_PATH }}/image:latest
      cache-from: type=gha
      cache-to: type=gha, mode=max

Running the workflow and building the image works fine, however I would expect that the build layers are cached on the GitHub server and re-running the same workflow without changing the Dockerfile should be faster and also show CACHED in the unchanged steps.

I can see that the layers are actually cached on the server:

However, it does not seem, that the caches are used. For example the base image is python:3.11 which gets downloaded every time (although this should be the cache with 190MB in the image above I think).

Searching the action logs for any "cache" entry only shows:

#12 importing cache manifest from gha:14508570815286874220
#12 DONE 0.0s

What might be the reason the caches are not used for rebuilding the image?

[igor47]

I'm having the same issue. I have a very full cache, that never seems to be used.