I’m trying to create a Github Action workflow to build a Docker image, then unless all layers use cache (no rebuild), continue to push the result and cache.

With this workflow it always pushes the result and cache.

on: [push]
jobs:

  build:
    permissions:
      packages: write
    runs-on: ubuntu-latest
    steps:
      - uses: docker/setup-buildx-action@v3
      - uses: docker/login-action@v3
        with:
          registry: ghcr.io
          password: ${{ secrets.GITHUB_TOKEN }}
          username: ${{ github.repository_owner }}
      - uses: docker/build-push-action@v6
        with:
          push: true
          tags: ghcr.io/<user>/<name>
          cache-from: type=registry,ref=ghcr.io/<user>/<name>:build-cache
          cache-to: type=registry,ref=ghcr.io/<user>/<name>:build-cache

How to make docker pushes the build result and cache unless all layers use cache?

I can’t find a way to add such check into docker/build-push-action@v6. My approach is remove push and cache-to from the action, and manually push after checking the image id with docker image ls -q -f=reference=ghcr.io/<user>/<name> but not sure about detailed steps.