Annotations not working as expected to add descriptions

[arya062000]

👋🏼 I came across this document on adding annotations to images pushed via buildkit for the index manifest https://github.com/moby/buildkit/blob/master/docs/annotations.md. I tried using this to add descriptions to an image but was not able to.

[jedevc]

Heya, thanks for the report! 🎉

Could you explain what you're trying to do, and what you're expecting to happen? If you could also share what version of buildkit you're using, that would be great as well!

Annotations haven't made it into a release yet, so unless you're using the master or nightly builds, the feature isn't yet available - though it will be in 0.11 when we release soon.

[arya062000]

I'm using : https://github.com/docker/setup-buildx-action i.e. GitHub Action to set up Docker Buildx. Annotations are being added like this in the github actions. And passing annotations to the output param.

[arya062000]

And passing annotations as:

outputs: type=image,name=target,annotation-index.org.opencontainers.image.description=DESCRIPTION

[jedevc]

Can you share your GitHub workflow? At least the part that contains your setup-buildx-action step?

[arya062000]

name: CI

on:
  push:
    branches: [ master ]
  workflow_dispatch:
  # schedule:
  #  - cron:  '0,15,30,45 * * * *'

env:
  # Use docker.io for Docker Hub if empty
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository_owner }}/example-buildx-push

jobs:
  build:  
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write

    strategy:
      matrix:
        number: [0, 1]
        include:
          - driver-opts: ""
          - number: 0
            platforms: ""
            tag: single-platform
          - number: 1
            platforms: "linux/386,linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64,linux/ppc64le"
            tag: multi-platform

    timeout-minutes: 5

    steps:
      - name: Checkout repository
        uses: actions/checkout@v2
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v1

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
        with:
          buildkitd-flags: --debug
          driver-opts: |
            image=moby/buildkit:master
            ${{ matrix.driver-opts }}
      - name: Log into registry ${{ env.REGISTRY }}
        uses: docker/login-action@v1
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # Build and push Docker image with Buildx (don't push on PR)
      # https://github.com/docker/build-push-action@v2
      - name: Build and push Docker image
        uses: docker/build-push-action@v2
        with:
          context: .
          file: ./Dockerfile
          platforms: ${{ matrix.platforms }}
          push: true
          tags: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ matrix.tag }}
          outputs: type=image,name=target,annotation-index.org.opencontainers.image.description=DESCRIPTION

[jedevc]

So I think this is probably an issue with the single-platform in your matrix - if its also occurring with multi-platform in that same matrix, I'm not quite sure what the problem is. If you could share the results of docker buildx imagetools inspect --raw <registry>/<image>:<tag> for the images that you expect to have the index annotation, I can confirm.

Annotations for single platforms generate a manifest, so the annotation is silently discarded. That's weird behavior, so we should probably explicitly errored - I've linked a PR that will cause this to explicitly (instead of silently) fail.