publish-container.yml

name: Publish container image

on:
  push:
    tags: [ 'v*' ]


jobs:
  publish-container:
    name: Build and Push
    runs-on: ubuntu-latest
    steps:

    - uses: actions/checkout@v2

    - name: Login to ghcr.io Docker registry
      uses: docker/login-action@v1
      with:
        registry: ghcr.io
        username: ${{ github.repository_owner }}
        password: ${{ secrets.GITHUB_TOKEN }}

    - name: Compute Docker container image addresses
      run: |
        DOCKER_REPOSITORY="ghcr.io/${GITHUB_REPOSITORY,,}"
        DOCKER_TAG="${GITHUB_REF:11}"

        echo "DOCKER_REPOSITORY=${DOCKER_REPOSITORY}" >> $GITHUB_ENV
        echo "DOCKER_TAG=${DOCKER_TAG}" >> $GITHUB_ENV

        echo "Using: ${DOCKER_REPOSITORY}/*:${DOCKER_TAG}"

    - name: 'Pull previous Docker container image: app:latest'
      run: docker pull "${DOCKER_REPOSITORY}/app:latest" || true

    - name: 'Build Docker container image: app:latest'
      run: |
        docker build \
            --cache-from "${DOCKER_REPOSITORY}/app:latest" \
            --tag "${DOCKER_REPOSITORY}/app:latest" \
            --tag "${DOCKER_REPOSITORY}/app:${DOCKER_TAG}" \
            .

    - name: Push Docker container image app:latest"
      run: docker push "${DOCKER_REPOSITORY}/app:latest"

    - name: Push Docker container image app:v*"
      run: docker push "${DOCKER_REPOSITORY}/app:${DOCKER_TAG}"