main.yml

# This requires
# vars.DOCKERHUB_USERNAME for the result image account
# secrets.DOCKERHUB_USERNAME for the account that pushes the image
# secrets.DOCKERHUB_TOKEN for the account password that pushes the image

name: Docker
on:
  push:
    branches:
    - main
  # We want to monthly update the base image for security
  # TODO Can we avoid building the same image?
  schedule:
    # min hour dom month dow
    - cron: '42 3 2 * *'
  workflow_dispatch:

permissions:
  contents: read

jobs:
  build:
    runs-on: ${{ matrix.platform == 'linux/arm64' && 'ubuntu-24.04-arm' || 'ubuntu-24.04' }}
    strategy:
      matrix:
        torch: ['2.9.1']
        python: ['3.14.2', '3.14.2-slim']
        index: [cu126,cpu]
        platform: [linux/amd64, linux/arm64]
        exclude:
        - index: cpu
          platform: linux/arm64
        - index: cpu
          python: '3.14.2-slim'
    permissions:
      contents: read
      id-token: write  # Needed for actions/attest-build-provenance build predicate
      attestations: write  # Needed for actions/attest-build-provenance attestation upload to repository
      artifact-metadata: write # Needed for actions/attest-build-provenance artifact metadata storage records
    steps:
    - id: created
      run: echo "created=$(date --utc +%Y-%m-%dT%H:%M:%SZ)" >> $GITHUB_OUTPUT

    - uses: actions/checkout@v6

    - name: Set up Docker Buildx
      uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3.12.0

    - name: Log in to Docker Hub
      uses: docker/login-action@5e57cd118135c172c3672efd75eb46360885c0ef # v3.6.0
      if: github.ref == 'refs/heads/main'
      with:
        username: ${{ secrets.DOCKERHUB_USERNAME }}
        password: ${{ secrets.DOCKERHUB_TOKEN }}

    - name: Build Tag
      id: build-tag
      # Tags have limited set of valid character, '+' not included
      # https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pulling-manifests
      run: |
        echo "tag=$(echo -n "${{ matrix.torch }}${{ matrix.index && format('-{0}', matrix.index) || '' }}-${{ matrix.python }}${PLATFORM:+-}${PLATFORM#*/}" | tr -c 'a-zA-Z0-9._-' '[-*]')" >> $GITHUB_OUTPUT
      env:
        PLATFORM: ${{ matrix.index != 'cpu' && matrix.platform || '' }}

    - uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
      id: build-push
      with:
        context: .
        push: ${{ github.ref == 'refs/heads/main' }}
        build-args: |
          CREATED=${{ steps.created.outputs.created }}
          SOURCE_COMMIT=${{ github.sha }}
          PYTHON=${{ matrix.python }}
          TORCH=${{ matrix.torch }}
          TORCH_REQUIREMENT=${{ matrix.url || format('torch=={0}', matrix.torch) }}
          TORCH_WHEEL_SOURCE=${{ matrix.torch-wheel-tag && format('{0}/torch-wheels:{1}', vars.DOCKERHUB_USERNAME, matrix.torch-wheel-tag) || 'scratch'}}
          TORCHVISION_WHEEL_SOURCE=${{ matrix.torchvision && format('{0}/torchvision-wheels:{1}', vars.DOCKERHUB_USERNAME, matrix.torchvision) || 'scratch'}}
          EXTRA_INDEX_URL=${{ matrix.extra-index-url || format('https://download.pytorch.org/whl/{0}/', matrix.index) }}
          CONSTRAINTS=constraints-${{ matrix.torch }}.txt
        # TODO add the latest tag, maybe somehow via docker/metadata-action
        tags: |
          ${{ vars.DOCKERHUB_USERNAME }}/python-torch:${{ steps.build-tag.outputs.tag }}
        # https://docs.docker.com/build/ci/github-actions/cache/
        cache-from: type=gha,scope=${{ matrix.torch }}-${{ matrix.python }}
        cache-to: type=gha,scope=${{ matrix.torch }}-${{ matrix.python }},mode=max
        platforms: ${{ matrix.platform }}

    - name: Create attestation for the image
      uses: actions/attest-build-provenance@v3
      with:
        subject-name: docker.io/${{ vars.DOCKERHUB_USERNAME }}/python-torch
        subject-digest: ${{ steps.build-push.outputs.digest }}
        push-to-registry: true

  merge:
    needs: build
    runs-on: ubuntu-latest
    strategy:
      matrix:
        torch: ['2.9.1']
        python: ['3.14.2', '3.14.2-slim']
        index: [cu126]
    permissions:
      id-token: write  # Needed for actions/attest-build-provenance build predicate
      attestations: write  # Needed for actions/attest-build-provenance attestation upload to repository
      artifact-metadata: write # Needed for actions/attest-build-provenance artifact metadata storage records
    steps:
    - name: Login to Docker Hub
      uses: docker/login-action@5e57cd118135c172c3672efd75eb46360885c0ef # v3.6.0
      with:
        username: ${{ secrets.DOCKERHUB_USERNAME }}
        password: ${{ secrets.DOCKERHUB_TOKEN }}

    - name: Merge platform images using manifest tool
      id: manifest
      run: |
        # This must match the build job tag generation
        tag="$(echo -n "${{ matrix.torch }}${{ matrix.index && format('-{0}', matrix.index) || '' }}-${{ matrix.python }}" | tr -c 'a-zA-Z0-9._-' '[-*]')"
        echo "tag=$tag" >> $GITHUB_OUTPUT
        repository="docker.io/$DOCKERHUB_USERNAME/python-torch"
        echo "repository=$repository" >> $GITHUB_OUTPUT
        name="$repository:$tag"
        echo "name=$name" >> $GITHUB_OUTPUT
        verify() {
          gh attestation verify oci://$repository@$1 \
            --repo $GITHUB_REPOSITORY \
            --signer-workflow $GITHUB_WORKFLOW_REF \
            --source-digest $GITHUB_SHA
        }
        amd64_digest=$(docker buildx imagetools inspect "$name-amd64" --format '{{ print .Manifest.Digest }}')
        verify $amd64_digest
        arm64_digest=$(docker buildx imagetools inspect "$name-arm64" --format '{{ print .Manifest.Digest }}')
        verify $arm64_digest
        docker buildx imagetools create \
          --tag $name \
          $repository@$amd64_digest \
          $repository@$arm64_digest 2>&1 | tee $RUNNER_TEMP/create_output.txt
        # Would be too easy, if create output the digest to stdout directly
        digest=$(sed -ne 's/.*pushing \(sha256:[a-f0-9]\+\).*/\1/p' $RUNNER_TEMP/create_output.txt)
        echo "digest=$digest" >> $GITHUB_OUTPUT
      env:
        DOCKERHUB_USERNAME: ${{ vars.DOCKERHUB_USERNAME }}
        GH_TOKEN: ${{ github.token }}

    - name: Create attestation for the manifest
      uses: actions/attest-build-provenance@v3
      with:
        subject-name: ${{ steps.manifest.outputs.repository }}
        subject-digest: ${{ steps.manifest.outputs.digest }}
        push-to-registry: true

  description:
    needs: merge
    # https://github.com/actions/runner-images/blob/main/images/ubuntu-slim/ubuntu-slim-Readme.md
    runs-on: ubuntu-slim
    if: github.ref == 'refs/heads/main'
    permissions:
      contents: write  # For the tag creation
    steps:
    # With org.opencontainers.image.source pointing to this repository Dockerfile FROM updates in pull requests can be scanned
    # if the commits have matching tags with the image.
    # https://github.blog/changelog/2023-04-13-dependabot-now-supports-fetching-release-notes-and-changelogs-for-docker-images/
    # https://octokit.github.io/rest.js/v19#git-create-ref
    # https://octokit.github.io/rest.js/v19#git-update-ref
    - name: Tag the commit or update tag
      if: github.ref == 'refs/heads/main'
      uses: actions/github-script@v8
      with:
        script: |
          try {
            await github.rest.git.createRef({
              owner: context.repo.owner,
              repo: context.repo.repo,
              ref: 'refs/tags/${{ steps.build-tag.outputs.tag }}',
              sha: context.sha,
            });
          } catch(e) {
            if (e.status === 422) {
              await github.rest.git.updateRef({
                owner: context.repo.owner,
                repo: context.repo.repo,
                ref: 'tags/${{ steps.build-tag.outputs.tag }}',
                sha: context.sha,
                force: true,
              });
            }
          }

      # Can not use Personal Access Token to update the README. Returns FORBIDDEN.
    - name: Docker Hub Description
      uses: peter-evans/dockerhub-description@1b9a80c056b620d92cedb9d9b5a223409c68ddfa # v5.0.0
      with:
        username: ${{ secrets.DOCKERHUB_USERNAME }}
        password: ${{ secrets.DOCKERHUB_TOKEN }}
        repository: ${{ vars.DOCKERHUB_USERNAME }}/python-torch