minetest/.github/workflows/docker_image.yml

---
name: docker_image

# https://docs.github.com/en/actions/publishing-packages/publishing-docker-images
# https://docs.docker.com/build/ci/github-actions/multi-platform
# https://github.com/opencontainers/image-spec/blob/main/annotations.md

on:
  push:
    branches: [ "master" ]
    # Publish semver tags as releases.
    tags: [ "*.*.*" ]
  pull_request:
    # Build docker image on pull requests. (but do not publish)
    paths:
      - 'lib/**.[ch]'
      - 'lib/**.cpp'
      - 'src/**.[ch]'
      - 'src/**.cpp'
      - '**/CMakeLists.txt'
      - 'cmake/Modules/**'
      - 'util/ci/**'
      - 'misc/irrlichtmt_tag.txt'
      - 'Dockerfile'
      - '.dockerignore'
      - '.github/workflows/docker_image.yml'
  workflow_dispatch:

env:
  REGISTRY: ghcr.io
  # github.repository as <account>/<repo>
  IMAGE_NAME: ${{ github.repository }}

jobs:
  publish:
    runs-on: ubuntu-latest

    permissions:
      contents: read
      packages: write

    steps:
      - name: Check out repository
        uses: actions/checkout@v4

      - name: Setup Docker buildx
        uses: docker/setup-buildx-action@v3.0.0

      # Login against the Docker registry except on PR
      # https://github.com/docker/login-action
      - name: Log into registry ${{ env.REGISTRY }}
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v3.0.0
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # Extract metadata (tags, labels) for Docker
      # https://github.com/docker/metadata-action
      - name: Extract Docker metadata
        id: meta
        uses: docker/metadata-action@v5.5.0
        with:
          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
          labels: |
            org.opencontainers.image.title=Minetest
            org.opencontainers.image.vendor=Minetest
            org.opencontainers.image.licenses=LGPL-2.1-only

      # Build and push Docker image
      # https://github.com/docker/build-push-action
      # No arm support for now. Require cross-compilation support in Dockerfile to not use QEMU.
      - name: Build and push Docker image
        uses: docker/build-push-action@v5.1.0
        with:
          context: .
          platforms: linux/amd64
          push: ${{ github.event_name != 'pull_request' }}
          load: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max

      - name: Test Docker Image
        run: |
          docker run --rm $(cut -d, -f1 <<<"$DOCKER_METADATA_OUTPUT_TAGS") minetestserver --version
        shell: bash