theme.park/.github/workflows/auto-build.yml

name: publishmultipledockerimages
on:
  push:
    branches: [ docker-mods ]
    paths:
      - '**/Dockerfile'

jobs:
  job1:
    runs-on: ubuntu-latest
    steps:
      - name: checkout
        uses: actions/checkout@v2
        with:
          fetch-depth: 0

      - name: get changed files
        id: getfile
        run: |
          echo "::set-output name=files::$(git diff-tree --no-commit-id --name-only -r ${{ github.sha }}| xargs)"          

      - name: Login to GitHub Container Registry
        uses: docker/login-action@v1
        with:
          registry: ghcr.io
          username: ${{ github.repository_owner }}
          password: ${{ secrets.PERSONAL_TOKEN }}
  
      - name: echo the changed files and build&push
        uses: docker/build-push-action@v2
        run: |
          for i in ${{ steps.getfile.outputs.files }}
            do
              directory="$( echo $i | cut -d'/' -f1 -s )"
              if [ -z "$directory" ]; then
                continue # Skip root dir
              elif [ "$i" == *.md ]; then
                continue # Skip markdown files
              docker build . --file $i --tag theme.park:$directory
              docker push ghcr.io/gilbn/theme.park:$directory
            done