Set up cross compiling for a Docker container that runs on Raspberry Pi

.github/workflows/flow--new-master.yml

@@ -7,11 +7,48 @@ jobs:
   test:
     uses: ./.github/workflows/job--test-and-lint.yml
 
-  build:
+  build-server:
     uses: ./.github/workflows/job--build-and-tag.yml
     needs: test
     with:
-      TAG: latest
+      BASE_IMAGE: node:16-slim
+      DOCKER_DIRECTORY: docker/server
+      DOCKER_IMAGE: cimonitor/server:latest
+    secrets:
+      DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+      DOCKER_TOKEN: ${{ secrets.DOCKER_TOKEN }}
+
+  build-server-arm:
+    uses: ./.github/workflows/job--build-and-tag.yml
+    needs: test
+    with:
+      BASE_IMAGE: arm32v7/node:16-slim
+      DOCKER_DIRECTORY: docker/server
+      DOCKER_IMAGE: cimonitor/server:latest-arm
+      QEMU_ARCH: arm
+    secrets:
+      DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+      DOCKER_TOKEN: ${{ secrets.DOCKER_TOKEN }}
+
+  build-module-client:
+    uses: ./.github/workflows/job--build-and-tag.yml
+    needs: test
+    with:
+      BASE_IMAGE: node:16-slim
+      DOCKER_DIRECTORY: docker/module-client
+      DOCKER_IMAGE: cimonitor/module-client:latest
+    secrets:
+      DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+      DOCKER_TOKEN: ${{ secrets.DOCKER_TOKEN }}
+
+  build-module-client-arm:
+    uses: ./.github/workflows/job--build-and-tag.yml
+    needs: test
+    with:
+      BASE_IMAGE: arm32v7/node:16-slim
+      DOCKER_DIRECTORY: docker/module-client
+      DOCKER_IMAGE: cimonitor/module-client:latest-arm
+      QEMU_ARCH: arm
     secrets:
       DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
       DOCKER_TOKEN: ${{ secrets.DOCKER_TOKEN }}

.github/workflows/flow--new-version.yml

@@ -7,11 +7,48 @@ jobs:
   test:
     uses: ./.github/workflows/job--test-and-lint.yml
 
-  build:
+  build-server:
     uses: ./.github/workflows/job--build-and-tag.yml
     needs: test
     with:
-      TAG: ${GITHUB_REF/refs\/tags\//}
+      BASE_IMAGE: node:16-slim
+      DOCKER_DIRECTORY: docker/server
+      DOCKER_IMAGE: cimonitor/server:${GITHUB_REF/refs\/tags\//}
+    secrets:
+      DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+      DOCKER_TOKEN: ${{ secrets.DOCKER_TOKEN }}
+
+  build-server-arm:
+    uses: ./.github/workflows/job--build-and-tag.yml
+    needs: test
+    with:
+      BASE_IMAGE: arm32v7/node:16-slim
+      DOCKER_DIRECTORY: docker/server
+      DOCKER_IMAGE: cimonitor/server:${GITHUB_REF/refs\/tags\//}-arm
+      QEMU_ARCH: arm
+    secrets:
+      DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+      DOCKER_TOKEN: ${{ secrets.DOCKER_TOKEN }}
+
+  build-module-client:
+    uses: ./.github/workflows/job--build-and-tag.yml
+    needs: test
+    with:
+      BASE_IMAGE: node:16-slim
+      DOCKER_DIRECTORY: docker/module-client
+      DOCKER_IMAGE: cimonitor/module-client:${GITHUB_REF/refs\/tags\//}
+    secrets:
+      DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
+      DOCKER_TOKEN: ${{ secrets.DOCKER_TOKEN }}
+
+  build-module-client-arm:
+    uses: ./.github/workflows/job--build-and-tag.yml
+    needs: test
+    with:
+      BASE_IMAGE: arm32v7/node:16-slim
+      DOCKER_DIRECTORY: docker/module-client
+      DOCKER_IMAGE: cimonitor/module-client:${GITHUB_REF/refs\/tags\//}-arm
+      QEMU_ARCH: arm
     secrets:
       DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
       DOCKER_TOKEN: ${{ secrets.DOCKER_TOKEN }}

.github/workflows/job--build-and-tag.yml

@@ -2,7 +2,17 @@ name: Build and tag CIMonitor container
 on:
   workflow_call:
     inputs:
-      TAG:
+      BASE_IMAGE:
+        required: true
+        type: string
+      DOCKER_DIRECTORY:
+        default: docker/server
+        required: false
+        type: string
+      QEMU_ARCH:
+        required: false
+        type: string
+      DOCKER_IMAGE:
         required: true
         type: string
     secrets:
@@ -27,8 +37,19 @@ jobs:
       - name: Install production dependencies
         run: yarn install --production --ignore-scripts
 
+      - name : Install QEMU emulator
+        run: |
+          if [ -n "${{ inputs.QEMU_ARCH }}" ]; then
+            wget -q https://github.com/multiarch/qemu-user-static/releases/download/v3.0.0/x86_64_qemu-${{ inputs.QEMU_ARCH }}-static.tar.gz
+            tar xfvz x86_64_qemu-${{ inputs.QEMU_ARCH }}-static.tar.gz
+            docker run --rm --privileged multiarch/qemu-user-static:register --reset
+          fi
+
+      - name: Copy Docker files
+        run: cp ${{ inputs.DOCKER_DIRECTORY }}/Dockerfile ${{ inputs.DOCKER_DIRECTORY }}/.dockerignore .
+
       - name: Build CIMonitor image
-        run: docker build --target production --tag cimonitor/server:${{ inputs.TAG }} .
+        run: docker build --target production --tag ${{ inputs.DOCKER_IMAGE }} --build-arg BASE_IMAGE=${{ inputs.BASE_IMAGE }} --build-arg QEMU_BINARY=qemu-${{ inputs.QEMU_ARCH }}-static .
 
       - name: Log in to Docker Hub
         uses: docker/login-action@v1
@@ -37,4 +58,4 @@ jobs:
           password: ${{ secrets.DOCKER_TOKEN }}
 
       - name: Push docker image to the hub
-        run: docker push cimonitor/server:${{ inputs.TAG }}
+        run: docker push ${{ inputs.DOCKER_IMAGE }}

docker-compose.yml

@@ -4,7 +4,7 @@ services:
 
   server:
     build:
-      context: .
+      context: docker/server
       target: server
     volumes:
       - .:/CIMonitor
@@ -15,16 +15,16 @@ services:
 
   module-client:
     build:
-      context: .
-      target: server
+      context: docker/module-client
+      target: module-client
     volumes:
       - .:/CIMonitor
     user: ${USERID}:${GROUPID}
     command: sh -c "npm run module-client"
 
   dashboard:
     build:
-      context: .
+      context: docker/server
       target: dashboard
     volumes:
       - .:/CIMonitor

docker/module-client/.dockerignore

@@ -0,0 +1,10 @@
+# Ignore everything...
+**
+
+# ...but keep files/dirs:
+!/app
+!/node_modules
+!/package.json
+
+# ... and also keep the QEMU emulator for cross compiling:
+!/qemu-*-static

docker/module-client/Dockerfile

@@ -0,0 +1,51 @@
+ARG QEMU_BINARY=notset
+ARG BASE_IMAGE=node:16-slim
+
+# ==================================
+# Base stage
+# ==================================
+
+FROM ${BASE_IMAGE} as base
+
+WORKDIR /CIMonitor
+
+# ==================================
+# Local development module-client
+# ==================================
+
+FROM base as module-client
+
+ENV NODE_PATH=/CIMonitor
+
+CMD ["npm", "run", "module-client"]
+
+# ==================================
+# Production build - QEMU emulator
+# ==================================
+
+FROM base as production-qemu
+
+COPY ./${QEMU_BINARY}* /usr/bin/
+
+RUN echo "deb http://deb.debian.org/debian unstable main contrib non-free" >> /etc/apt/sources.list \
+    && apt-get update \
+    && apt-get install dumb-init
+
+# ==================================
+# Production
+# ==================================
+
+FROM base as production
+
+ENV NODE_ENV=production
+ENV NODE_PATH=/CIMonitor/app
+
+# Copy dumb-init from the QEMU stage
+COPY --from=production-qemu /usr/bin/dumb-init /usr/bin/dumb-init
+
+# Make sure "yarn build" is ran before building the production container
+COPY . /CIMonitor
+
+ENTRYPOINT ["/usr/bin/dumb-init", "--"]
+
+CMD ["npm", "run", "start-client"]

.dockerignore → docker/server/.dockerignore

@@ -1,8 +1,11 @@
 # Ignore everything...
-*
+**
 
 # ...but keep files/dirs:
 !/app
 !/dashboard
 !/node_modules
 !/package.json
+
+# ... and also keep the QEMU emulator for cross compiling:
+!/qemu-*-static

Dockerfile → docker/server/Dockerfile

@@ -1,8 +1,11 @@
+ARG QEMU_BINARY=notset
+ARG BASE_IMAGE=node:16-slim
+
 # ==================================
 # Base stage
 # ==================================
 
-FROM node:16-alpine as base
+FROM ${BASE_IMAGE} as base
 
 WORKDIR /CIMonitor
 
@@ -24,21 +27,33 @@ FROM base as dashboard
 
 CMD ["npm", "run", "dashboard"]
 
+# ==================================
+# Production build - QEMU emulator
+# ==================================
+
+FROM base as production-qemu
+
+COPY ./${QEMU_BINARY}* /usr/bin/
+
+RUN echo "deb http://deb.debian.org/debian unstable main contrib non-free" >> /etc/apt/sources.list \
+    && apt-get update \
+    && apt-get install dumb-init
+
 # ==================================
 # Production
 # ==================================
 
 FROM base as production
 
 ENV NODE_ENV=production
-
 ENV NODE_PATH=/CIMonitor/app
 
+# Copy dumb-init from the QEMU stage
+COPY --from=production-qemu /usr/bin/dumb-init /usr/bin/dumb-init
+
 # Make sure "yarn build" is ran before building the production container
 COPY . /CIMonitor
 
-RUN apk add --no-cache dumb-init
-
 ENTRYPOINT ["/usr/bin/dumb-init", "--"]
 
 CMD ["npm", "run", "start"]