build-and-push.yaml

# see: https://docs.github.com/en/actions/publishing-packages/publishing-docker-images#publishing-images-to-github-packages
name: Build and push

on:
  push:
    branches: ["master"]

env:
  REGISTRY: ghcr.io

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

    steps:
      - name: Checkout repository
        uses: actions/checkout@v2

      - name: Set some environment variables for later use
        run: |
          # Get the short git hash
          echo "SHORT_HASH=$(git rev-parse --short HEAD)" >>${GITHUB_ENV}

          # Use the lowercase version of the repository name as the image name,
          # because docker does not allow uppercase characters
          echo "IMAGE_NAME=${REGISTRY}/${GITHUB_REPOSITORY,,}" >>${GITHUB_ENV}

      - name: Log in to the Container registry
        uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Build the Docker image
        # see: https://docs.docker.com/engine/reference/commandline/image_build/#usage
        run: docker image build --tag '${{ env.IMAGE_NAME }}:latest' --tag '${{ env.IMAGE_NAME }}:${{ env.SHORT_HASH }}' .

      - name: Push the Docker image
        run: docker image push --all-tags '${{ env.IMAGE_NAME }}'