Docker image workflow (publish on `ghcr.io`) (#14230)

.github/workflows/docker_image.yml

@@ -0,0 +1,89 @@
+---
+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 (but do not publish)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

.github/workflows/linux.yml

@@ -151,13 +151,3 @@ jobs:
       - name: Test
         run: |
           ./bin/minetestserver --run-unittests
-
-  docker:
-    name: "Docker image"
-    runs-on: ubuntu-20.04
-    steps:
-      - uses: actions/checkout@v4
-      - name: Build docker image
-        run: |
-          docker build . -t minetest:latest
-          docker run --rm minetest:latest /usr/local/bin/minetestserver --version

README.md

@@ -127,9 +127,7 @@ Docker
 ------
 
 - [Developing minetestserver with Docker](doc/developing/docker.md)
-
-We provide a Dockerfile that can be used to build the server.
-
+- [Running a server with Docker](doc/docker_server.md)
 
 Version scheme
 --------------

doc/docker_server.md

@@ -0,0 +1,46 @@
+# Docker Server
+
+We provide Minetest server Docker images using the GitHub container registry.
+
+Images are built on each commit and available using the following tag scheme:
+
+* `ghcr.io/minetest/minetest:master` (latest build)
+* `ghcr.io/minetest/minetest:<tag>` (specific Git tag)
+* `ghcr.io/minetest/minetest:latest` (latest Git tag, which is the stable release)
+
+See [here](https://github.com/minetest/minetest/pkgs/container/minetest) for all available tags.
+
+For a quick test you can easily run:
+
+```shell
+docker run ghcr.io/minetest/minetest:master
+```
+
+To use it in a production environment, you should use volumes bound to the Docker host to persist data and modify the configuration:
+
+```shell
+docker create -v /home/minetest/data/:/var/lib/minetest/ -v /home/minetest/conf/:/etc/minetest/ ghcr.io/minetest/minetest:master
+```
+
+You may also want to use [Docker Compose](https://docs.docker.com/compose):
+
+```yaml
+---
+version: "2"
+services:
+  minetest_server:
+    image: ghcr.io/minetest/minetest:master
+    restart: always
+    networks:
+      - default
+    volumes:
+      - /home/minetest/data/:/var/lib/minetest/
+      - /home/minetest/conf/:/etc/minetest/
+    ports:
+      - "30000:30000/udp"
+      - "127.0.0.1:30000:30000/tcp"
+```
+
+Data will be written to `/home/minetest/data` on the host, and configuration will be read from `/home/minetest/conf/minetest.conf`.
+
+**Note:** If you don't understand the previous commands please read the [official Docker documentation](https://docs.docker.com) before use.