feat: composite action for labeled buildkitd + remote buildx driver

The default docker-container driver of docker/setup-buildx-action ignores driver-opts labels (container created with labels={}) and the Docker API cannot PATCH labels on existing containers. Start a privileged, labeled buildkitd ourselves (idempotent, restart unless-stopped) and connect via driver: remote endpoint docker-container://<name>.
2026-09-01 11:52:19 +02:00
commit 69d77d4ca0
1 changed files with 47 additions and 0 deletions
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+name: 'Setup BuildKit (with labels)'
+description: 'Idempotently start a labeled buildkitd container and point buildx at it via the remote driver. The default docker-container driver cannot set container labels, and the Docker API has no PATCH-labels for existing containers — so we manage the container ourselves and Watchtower/Dockhand see the labels.'
+inputs:
+  container_name:
+    description: 'Name of the buildkitd container'
+    required: false
+    default: 'buildkitd'
+  image:
+    description: 'BuildKit image'
+    required: false
+    default: 'moby/buildkit:buildx-stable-1'
+  monitor_only:
+    description: 'Value for com.centurylinklabs.watchtower.monitor-only'
+    required: false
+    default: 'false'
+  dockhand_notify:
+    description: 'Value for dockhand.notify'
+    required: false
+    default: 'false'
+  cleanup:
+    description: 'Stop the buildkitd container after the job (only for single-job runners; leave false on shared runners — concurrent jobs may be using it)'
+    required: false
+    default: 'false'
+
+runs:
+  using: 'composite'
+  steps:
+    - name: Start BuildKit container (with labels)
+      shell: bash
+      run: |
+        docker ps -a --format '{{.Names}}' | grep -qx '${{ inputs.container_name }}' || \
+        docker run -d --name ${{ inputs.container_name }} --privileged \
+          --restart unless-stopped \
+          --label com.centurylinklabs.watchtower.monitor-only=${{ inputs.monitor_only }} \
+          --label dockhand.notify=${{ inputs.dockhand_notify }} \
+          ${{ inputs.image }}
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v4
+      with:
+        driver: remote
+        endpoint: docker-container://${{ inputs.container_name }}
+
+    - name: Stop BuildKit (idle cleanup)
+      if: ${{ inputs.cleanup == 'true' && always() }}
+      shell: bash
+      run: docker stop ${{ inputs.container_name }} || true