build-pr.yml

name: Build container on pull request
on:
  pull_request:
    branches: [ '**' ]

jobs:
  build_commit:
    runs-on: ubuntu-latest
    environment: docker
    steps:
      - uses: actions/checkout@v2
      - name: Get shortsha
        id: vars
        run: |
          if [ -z "$EVENT_SHA" ]; then SHORT_SHA=${GITHUB_SHA::8}; else SHORT_SHA=${EVENT_SHA::8}; fi
          echo ::set-output name=sha_short::${SHORT_SHA}
        env:
          EVENT_SHA: ${{ github.event.client_payload.sha }} 
      - name: Print shortsha
        run: |
          echo $SHORTSHA
        env: 
          SHORTSHA: ${{ steps.vars.outputs.sha_short }}     
      - uses: mr-smithers-excellent/docker-build-push@v3
        name: Build & push commit tagged Docker image
        with:
          image: ${{ secrets.DOCKERHUB_REPO }}
          tag: ${{ steps.vars.outputs.sha_short }}   
          registry: docker.io
          dockerfile: Dockerfile
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}