ghcr-publish.yml

name: Attest Image (GH Container Registry)

on:
  workflow_dispatch:

jobs:
  build-artifact-ghcr:
    name: Build/Attest Artifact (GHCR)
    runs-on: ubuntu-latest
    permissions:
      id-token: write
      attestations: write
      packages: write
    env:
      REGISTRY: ghcr.io
      IMAGE_NAME: ${{ github.repository }}
    steps:
      - name: Build artifact
        run: date > artifact.bin

      - name: Build Dockerfile
        run: |
          cat <<EOF > Dockerfile
          FROM scratch
          COPY artifact.bin .
          EOF

      - name: Set up QEMU
        uses: docker/setup-qemu-action@ce360397dd3f832beb865e1373c09c0e9f86d70a # v4.0.0

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

      - name: Login to GHCR
        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3.7.0
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Build and push
        id: build-and-push
        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v6.18.0
        with:
          context: .
          platforms: 'linux/amd64,linux/arm64'
          push: true
          tags: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest

      - name: Attest artifact
        uses: actions/attest-build-provenance@96278af6caaf10aea03fd8d33a09a777ca52d62f # v3.2.0
        with:
          subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          subject-digest: ${{ steps.build-and-push.outputs.digest }}
          push-to-registry: true

      - name: Verify OCI image
        env:
          GH_TOKEN: ${{ github.token }}
        run: gh attestation verify oci://${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest --owner "$GITHUB_REPOSITORY_OWNER"