build_app_docker_image.yml

name: Auto-build Docker image of app and push to Docker Hub
on:
  workflow_dispatch:

  push:
    paths:
      - '**.java'
      - '**/pom.xml'
      - '**/application*.yml'
      - 'Dockerfile'
  
jobs:
  build_docker_image:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v4
    
    - name: Set up JDK 17
      uses: actions/setup-java@v4
      with:
        java-version: '17'
        distribution: 'temurin'
        cache: maven

    - name: Log in to Docker Hub
      uses: docker/login-action@v3
      with:
        username: ${{ secrets.DOCKER_HUB_USER }}
        password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}

    - name: Extract metadata (tags, labels) for Docker
      id: meta
      uses: docker/metadata-action@v5
      with:
          images: dspweick/springintroduction

    - name: Build and push Docker image
      uses: docker/build-push-action@v5
      with:
        context: .
        file: ./Dockerfile
        push: ${{ github.ref_name == 'main' }}
        tags: ${{ steps.meta.outputs.tags }}
        labels: ${{ steps.meta.outputs.labels }}