build.yml

# <https://docs.github.com/en/actions/publishing-packages/publishing-docker-images>
name: Create and publish a Docker image

on:
  push:
    branches:
      - main

env:
  IMAGE_NAME: ${{ github.repository }}
  REGISTRY: ghcr.io

jobs:
  build-and-push-image:
    permissions:
      attestations: write
      contents: read
      id-token: write
      packages: write
    runs-on: ubuntu-latest
    steps:

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

      - name: Log in to the Container registry
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - id: meta
        name: Extract metadata (tags, labels) for Docker
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          tags: type=sha

      - id: push
        name: Build and push Docker image
        uses: docker/build-push-action@v6
        with:
          context: .
          labels: ${{ steps.meta.outputs.labels }}
          #platforms: linux/amd64,linux/arm64 # TODO support ARM, too, with this and a different "driver"
          push: true
          tags: ${{ steps.meta.outputs.tags }}

      - name: Generate artifact attestation
        uses: actions/attest-build-provenance@v1
        with:
          push-to-registry: true
          subject-digest: ${{ steps.push.outputs.digest }}
          subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME}}