Return image digest as action output

[ngraef]

To better support image pinning, this action should output the image digest after pushing to a registry. The digest could then be used as a parameter for a future step in the workflow, like triggering a deployment.

[EronWright]

Here's a workaround to use in combination with the tag_with_sha option. Simply put, compute the git short SHA and use it.

      - name: Get Git Short SHA
        id: slug
        run: echo "::set-output name=sha7::$(echo ${{ github.sha }} | cut -c1-7)"

      - name: Publish Docker Image
        uses: docker/build-push-action@v1
        with:
          repository: myorg/myrepository
          tag_with_sha: true

      - name: Use Docker Image (Example)
        run: docker pull "myorg/myrepository:sha-${{ steps.slug.outputs.sha7 }}"

[crazy-max]

This will be available through build-push-action v2 (#92).
You can already try it by combining it with:

• https://github.com/docker/setup-buildx-action
• https://github.com/docker/setup-qemu-action
• https://github.com/docker/login-action

[meekrosoft]

Fantastic news, looking forward to this landing!

[crazy-max]

Version 2 has been merged to the main branch and is therefore available via uses: docker/build-push-action@v2 (mutable tag).

As a reminder, this new version changes drastically and works with 3 new actions (login, setup-buildx and setup-qemu) that we have created. Many usage examples have been added to handle most use cases.

And it should fix this current issue. Don't hesitate if you have any questions.

[meekrosoft]

Brilliant, many thanks!