Cache docker layers

.github/workflows/docker-test.yml

@@ -18,6 +18,7 @@ jobs:
     env:
       SOURCE_ROOT: ${{ github.workspace }}
       ENTRYPOINT: ${{ github.workspace }}/docker/default-entry.sh
+      DOCKER_CACHE_DEST: ${{ github.workspace }}/.docker/buildx-cache
     steps:
     - uses: actions/checkout@v4
       with:
@@ -29,24 +30,43 @@ jobs:
         echo "OWNER_LC=$OWNER_LC" >>${GITHUB_ENV}
         echo "IMAGE=ghcr.io/$OWNER_LC/vs-fltk:build-env" >>${GITHUB_ENV}
 
-    - name: Install dependencies
-      run: sudo apt install -y docker-compose
-
     - name: Check if Dockerfile has changed
       run: |
-        FILES=$(git log -1 -p ./ | grep +++ | cut -d '/' -f 2-| sed -e 's|dev/null||g')
-        if echo "$FILES" | grep -qE "^(Dockerfile)$"; then
-          echo "changed=true" >> $GITHUB_ENV
-        else
-          echo "changed=false" >> $GITHUB_ENV
+        echo "do_build=false" >> $GITHUB_ENV
+        if [ "${{ github.ref }}" != "refs/heads/master" ]; then
+          FILES=$(git diff --name-only HEAD~1 HEAD)
+          if echo "$FILES" | grep -qE "^docker/Dockerfile$"; then
+            echo "do_build=true" >> $GITHUB_ENV
+          fi
         fi
 
+    - name: Cache Docker layers
+      if: ${{ env.do_build == 'true' }}
+      id: docker-cache
+      uses: actions/cache@v3
+      with:
+        path: ${{ env.DOCKER_CACHE_DEST }}
+        key: ${{ runner.os }}-docker-${{ github.ref_name }}
+        restore-keys: |
+          ${{ runner.os }}-docker-
+
+    - name: Set up Docker Buildx
+      if: ${{ env.do_build == 'true' }}
+      uses: docker/setup-buildx-action@v3
+
     - name: Build Docker image
-      if: ${{ env.changed == 'true' }}
-      run: docker build -t $IMAGE -f docker/Dockerfile ./docker
+      if: ${{ env.do_build == 'true' }}
+      run: |
+        docker buildx build \
+          ./docker \
+          -f docker/Dockerfile
+          -t $IMAGE \
+          --cache-to=type=local,dest=${{ env.DOCKER_CACHE_DEST }} \
+          --cache-from=type=local,src=${{ env.DOCKER_CACHE_DEST }} \
+          --load
 
     - name: Run commands in Docker container
       run: |
         export HOSTUID=$(id -u)
         export HOSTGID=$(id -g)
-        docker-compose -f docker/docker-compose.yml run --rm  dev
+        docker compose -f docker/docker-compose.yml run --rm  dev

docker/Dockerfile

@@ -24,8 +24,7 @@ RUN \
         sudo \
         swiftlang \
         unzip \
-        wget && \
-    update-ca-certificates -f
+        wget
 
 RUN useradd -m builder && passwd -d builder
 RUN echo "builder ALL=(ALL) ALL" >> /etc/sudoers