docker.yaml

name: Docker

on:
  schedule:
    - cron: "15 14 * * *"
  push:
  pull_request:
    branches: ["main"]
  workflow_dispatch:

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: inputs.publish
        uses: sigstore/cosign-installer@v3
          
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3
        with:
          platforms: arm64

      # Workaround: https://github.com/docker/build-push-action/issues/461
      - name: Setup Docker buildx
        uses: docker/setup-buildx-action@v3
        with:
          platforms: linux/amd64,linux/arm64

      # Login against a Docker registry except on PR
      # https://github.com/docker/login-action
      - name: Log into registry ${{ env.REGISTRY }}
        if: inputs.publish
        uses: docker/login-action@v3
        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
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}

      # 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@v5
        with:
          context: base
          push: ${{ inputs.publish }}
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          platforms: linux/amd64,linux/arm64

      # 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: inputs.publish
        env:
          # https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-an-intermediate-environment-variable
          TAGS: ${{ steps.meta.outputs.tags }}
          DIGEST: ${{ steps.build-and-push.outputs.digest }}
        # This step uses the identity token to provision an ephemeral certificate
        # against the sigstore community Fulcio instance.
        run: echo "${TAGS}" | xargs -I {} cosign sign --yes {}@${DIGEST}