docmachine-containers/.github/workflows/build-and-publish.yml

---
name: "Build and Publish"

on:
  # run it on push to the default repository branch
  push:
    branches: [master]
  # run it during pull request
  pull_request:

defaults:
  # define job to build and publish docker image
  build-and-push-docker-image:
    name: Build Docker image and push to repositories
    # run only when code is compiling and tests are passing
    runs-on: ubuntu-latest

    # steps to perform in job
    steps:
      - name: Checkout code
        uses: actions/checkout@v2

      # setup Docker buld action
      - name: Set up Docker Buildx
        id: buildx
        uses: docker/setup-buildx-action@v1

      - name: Login to DockerHub
        uses: docker/login-action@v1
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Build image and push to Docker Hub and GitHub Container Registry
        uses: docker/build-push-action@v2
        with:
          # relative path to the place where source code with Dockerfile
          # is located
          context: ./src/samples/simple
          # Note: tags has to be all lower-case
          tags: |
            glenux/teaching-boilerplate:latest
          # build on feature branches, push only on main branch
          push: ${{ github.ref == 'refs/heads/master' }}

      - name: Image digest
        run: echo ${{ steps.docker_build.outputs.digest }}