build.yml

name: Build and push latest image

on:
  push:
    branches:
      - main
      - stable
  schedule:
    # We run it every 4 hours, starting at 02:15.
    # Note that this will only update the 'latest' tag (not the 'stable' tag).
    # Ideally, we would update the image every time the base image
    # (p4lang/third-party) is updated, but we deem this good enough.
    - cron: '15 2-23/4 * * *' # "At minute 15 past every 4th hour from 2 through 23."

jobs:
  build:
    if: ${{ github.repository == 'p4lang/PI' }}
    runs-on: [ubuntu-latest]
    steps:
    - uses: actions/checkout@v4
      with:
        submodules: recursive
    - name: Determine Docker image tag
      id: get-tag
      shell: bash
      run: |
        TAG=""
        if [[ "$GITHUB_REF" =~ "main" ]]; then
            TAG="latest"
        elif [[ "$GITHUB_REF" =~ "stable" ]]; then
            TAG="stable"
        else
            echo "Invalid Github ref $GITHUB_REF"
            exit 1
        fi
        echo "Tag is $TAG"
        echo "::set-output name=tag::$TAG"
    - name: Set up Docker Buildx
      uses: docker/setup-buildx-action@v3
    - name: Login to DockerHub
      uses: docker/login-action@v3
      with:
        username: ${{ secrets.DOCKER_USERNAME }}
        password: ${{ secrets.DOCKER_PASSWORD }}
    - name: Build and push Docker image to registry
      uses: docker/build-push-action@v6
      with:
        context: .
        push: true
        tags: p4lang/pi:${{ steps.get-tag.outputs.tag }}
        cache-from: type=gha
        cache-to: type=gha,mode=max