Add Dockerfile and related Github Action

.github/workflows/docker-image.yml

@@ -0,0 +1,123 @@
+name: Build and Publish Docker Image
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}  
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - platform: linux/amd64
+            os: ubuntu-latest
+
+          - platform: linux/arm64
+            os: ubuntu-24.04-arm
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - name: Prepare
+        run: |
+          platform=${{ matrix.platform }}
+          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV
+
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Create lowercased repo env
+        run: |
+          echo "REPO=${GITHUB_REPOSITORY@L}" >> "${GITHUB_ENV}"
+
+      - name: Extract metadata (tags, labels)
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ env.REPO }}
+          tags: |
+            type=ref,event=branch
+            type=raw,value=latest,enable={{is_default_branch}}
+
+      - name: Build and push by digest
+        id: build
+        uses: docker/build-push-action@v6
+        with:
+          platforms: ${{ matrix.platform }}
+          labels: ${{ steps.meta.outputs.labels }}
+          tags: ghcr.io/${{ env.REPO }}
+          outputs: type=image,push-by-digest=true,name-canonical=true,push=true
+
+      - name: Export digest
+        run: |
+          mkdir -p ${{ runner.temp }}/digests
+          digest="${{ steps.build.outputs.digest }}"
+          touch "${{ runner.temp }}/digests/${digest#sha256:}"
+
+      - name: Upload digest
+        uses: actions/upload-artifact@v4
+        with:
+          name: digests-${{ env.PLATFORM_PAIR }}
+          path: ${{ runner.temp }}/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+  merge:
+    runs-on: ubuntu-latest
+    needs:
+      - build
+    steps:
+      - name: Download digests
+        uses: actions/download-artifact@v4
+        with:
+          path: ${{ runner.temp }}/digests
+          pattern: digests-*
+          merge-multiple: true
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Create lowercased repo env
+        run: |
+          echo "REPO=${GITHUB_REPOSITORY@L}" >> "${GITHUB_ENV}"
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ env.REPO }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=pr
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+
+      - name: Create manifest list and push
+        working-directory: ${{ runner.temp }}/digests
+        run: |
+          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf 'ghcr.io/${{ env.REPO }}@sha256:%s ' *)
+
+      - name: Inspect image
+        run: |
+          docker buildx imagetools inspect ghcr.io/${{ env.REPO }}:${{ steps.meta.outputs.version }}

Dockerfile

@@ -0,0 +1,46 @@
+FROM debian:bookworm-slim AS build
+
+# Prevent initramfs and ldconfig runs in CI, speeds up the build
+RUN dpkg-divert --local --rename --add /usr/sbin/update-initramfs \
+    && dpkg-divert --local --rename --add /sbin/ldconfig \
+    && dpkg-divert --local --rename --add /usr/sbin/ldconfig \
+    && ln -sf /bin/true /usr/sbin/update-initramfs \
+    && ln -sf /bin/true /sbin/ldconfig \
+    && ln -sf /bin/true /usr/sbin/ldconfig
+
+# Install build dependencies
+# eatmydata ignores fsck calls which arent needed in CI, speeds up the build
+RUN apt update \
+    && apt install -o APT::Install-Suggests=false -y eatmydata \
+    && eatmydata apt install -o APT::Install-Suggests=false -y \
+                gcc \
+                meson \
+                libsocketcan-dev \
+                libconfig-dev
+
+# Build and strip
+WORKDIR /src
+COPY . .
+RUN meson setup -Dlibconfig=true --buildtype=release build \
+    && meson compile -C build \
+    && meson install -C build
+
+# Collect only needed runtime files (arch-independent)
+RUN mkdir -p /minimal-root/usr/local/sbin /minimal-root/lib /minimal-root/lib64 /minimal-root/etc \
+    # The binary
+    && cp /usr/local/sbin/socketcand /minimal-root/usr/local/sbin/ \
+    # Get interpreter from ELF header and copy
+    && interp=$(readelf -l /usr/local/sbin/socketcand | awk -F ': ' '/interpreter/ {print $2}' | tr -d ']') \
+    && mkdir -p "/minimal-root$(dirname $interp)" \
+    && cp "$interp" "/minimal-root$interp" \
+    # Copy linked shared libraries
+    && ldd /usr/local/sbin/socketcand | awk '{print $3}' | grep '^/' | sort -u | xargs -I '{}' cp -v --parents '{}' /minimal-root/ \
+    # Minimal /etc
+    && cp -a /etc/nsswitch.conf /minimal-root/etc/ \
+    && cp -a /etc/hosts /minimal-root/etc/ \
+    && cp -a /etc/resolv.conf /minimal-root/etc/
+
+# Build minimal image
+FROM scratch
+COPY --from=build /minimal-root/ /
+ENTRYPOINT ["/usr/local/sbin/socketcand"]

README.md

@@ -21,10 +21,14 @@ Execute the following commands to configure, build, and install the software:
     $ meson compile -C build
     $ meson install -C build
 
-Service discovery
------------------
-
-The daemon uses a simple UDP beacon mechanism for service discovery. A beacon containing the service name, type and address is sent to the broadcast address (port 42000) at minimum every 3 seconds. A client only has to listen for messages of this type to detect all SocketCAN daemons in the local network.
+Docker image
+------------
+Prebuild docker images are available.  
+Note this image still needs a host kernel with SocketCAN modules.  
+The CAN interface needs to be configured on the host and made available to the container using the `--network=host` option.  
+
+Example usage:  
+`docker run --rm --network=host -it ghcr.io/linux-can/socketcand:latest -v -i can0`
 
 Usage
 -----
@@ -46,6 +50,11 @@ Usage
 * **-d** (set this flag if you want log to syslog instead of STDOUT)
 * **-h** (prints this message)
 
+Service discovery
+-----------------
+
+The daemon uses a simple UDP beacon mechanism for service discovery. A beacon containing the service name, type and address is sent to the broadcast address (port 42000) at minimum every 3 seconds. A client only has to listen for messages of this type to detect all SocketCAN daemons in the local network.
+
 License
 -------