techblog/.forgejo/workflows/docker-build.yml

name: Build and Push Docker Image

on:
  push:
    branches:
      - main
  workflow_dispatch:

jobs:
  build-and-push:
    runs-on: ubuntu-latest
    permissions:
      packages: write
      contents: read
    steps:
      - name: Checkout code
        uses: actions/checkout@v4

      - name: Show commit and Dockerfile
        run: git log --oneline -1 && echo "---" && head -35 Dockerfile

      - name: Clear Docker build cache
        run: docker builder prune -af

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Derive registry from server URL
        run: |
          REGISTRY=$(echo "${{ github.server_url }}" | sed 's|https://||' | sed 's|http://||')
          echo "REGISTRY=${REGISTRY}" >> $GITHUB_ENV
          echo "IMAGE=${REGISTRY}/${{ github.repository }}" >> $GITHUB_ENV

      - name: Log in to Forgejo container registry
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.REGISTRY_TOKEN }}

      - name: Extract metadata (tags, labels)
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.IMAGE }}
          tags: |
            type=sha,prefix=,format=short
            type=raw,value=latest,enable={{is_default_branch}}
          labels: |
            org.opencontainers.image.source=${{ github.server_url }}/${{ github.repository }}

      - name: Build and push Docker image
        uses: docker/build-push-action@v5
        with:
          context: .
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          secrets: |
            composer_auth=${{ secrets.COMPOSER_AUTH }}
          no-cache: true