docker-publish.yml

name: Publish Docker Image

# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.

on:
  workflow_dispatch:
  push:
    branches: [ master ]
    # Publish semver tags as releases.
    tags: [ '*.*.*' ]
  pull_request:
    branches: [ master ]

env:
  # Use docker.io for Docker Hub if empty
  REGISTRY: ghcr.io
  # github.repository as <account>/<repo>
  IMAGE_NAME: ${{ github.repository }}


jobs:
  build:

    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
      # This is used to complete the identity challenge
      # with sigstore/fulcio when running outside of PRs.
      id-token: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      # Install the cosign tool except on PR
      # https://github.com/sigstore/cosign-installer
      - name: Install cosign
        if: github.event_name != 'pull_request'
        uses: sigstore/cosign-installer@v3.6.0


      # Workaround: https://github.com/docker/build-push-action/issues/461
      - name: Setup Docker buildx
        uses: docker/setup-buildx-action@v3.6.1

      # Login against a Docker registry except on PR
      # https://github.com/docker/login-action
      - name: Log into registry ${{ env.REGISTRY }}
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3.3.0
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # Extract metadata (tags, labels) for Docker
      # https://github.com/docker/metadata-action
      - name: Extract Docker metadata
        id: meta
        uses: docker/metadata-action@v5.5.1
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      # Get the current Git tag if available, otherwise use branch name and commit hash
      - name: Get version
        id: get-version
        run: |
          TAG=$(git describe --tags --abbrev=0 2>/dev/null || echo "")
          if [ -z "$TAG" ]; then
            BRANCH=$(git rev-parse --abbrev-ref HEAD)
            COMMIT_HASH=$(git rev-parse --short HEAD)
            VERSION="${BRANCH}-${COMMIT_HASH}"
          else
            VERSION=$TAG
          fi
          echo "VERSION=$VERSION" >> $GITHUB_ENV

      # Build and push Docker image with Buildx (don't push on PR)
      # https://github.com/docker/build-push-action
      - name: Build and push Docker image
        id: build-and-push
        uses: docker/build-push-action@v6.7.0
        with:
          context: .
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          build-args: |
            VERSION=${{ env.VERSION }}

      # Sign the resulting Docker image digest except on PRs.
      # This will only write to the public Rekor transparency log when the Docker
      # repository is public to avoid leaking data.  If you would like to publish
      # transparency data even for private images, pass --force to cosign below.
      # https://github.com/sigstore/cosign
      #- name: Sign the published Docker image
      #  if: ${{ github.event_name != 'pull_request' }}
      #  env:
      #    COSIGN_EXPERIMENTAL: "true"
        # This step uses the identity token to provision an ephemeral certificate
        # against the sigstore community Fulcio instance.
      #  run: cosign sign ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}@${{ steps.build-and-push.outputs.digest }}