ci: Docker release crashes or times out under arm64 emulation

.github/workflows/ci.yml

@@ -60,24 +60,18 @@ jobs:
         include:
           - name: Docker linux/amd64
             DOCKER_PLATFORM: linux/amd64
+            CACHE_SCOPE: docker-amd64
+            RUNNER_TYPE: ubuntu-latest
+          - name: Docker linux/arm64/v8
+            DOCKER_PLATFORM: linux/arm64/v8
+            CACHE_SCOPE: docker-arm64
             RUNNER_TYPE: ubuntu-latest
-          # - name: Docker linux/arm64/v8
-          #   DOCKER_PLATFORM: linux/arm64/v8
-          #   # Replace this with a native arm linux runner when available, presumably by EOY 2024, see:
-          #   # https://github.com/orgs/community/discussions/19197#discussioncomment-10550689
-          #   # The conditional setup of QEMU may need to be adapted to not run on native arm,
-          #   # which will speed up the build process for arm64/v8 since no emulation will be needed.
-          #   RUNNER_TYPE: ubuntu-latest
       fail-fast: false
     name: ${{ matrix.name }}
     timeout-minutes: 45
     runs-on: ${{ matrix.RUNNER_TYPE }}
     steps:
       - uses: actions/checkout@v4
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v2
-        # Only set up QEMU if not running on native arm
-        if: ${{ matrix.DOCKER_PLATFORM != 'linux/amd64' && matrix.RUNNER_TYPE == 'ubuntu-latest' }}
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v2
         with:
@@ -86,8 +80,8 @@ jobs:
         uses: docker/build-push-action@v3
         with:
           platforms: ${{ matrix.DOCKER_PLATFORM }}
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-from: type=gha,scope=${{ matrix.CACHE_SCOPE }}
+          cache-to: type=gha,mode=max,scope=${{ matrix.CACHE_SCOPE }}
   check-lock-file-version:
     name: NPM Lock File Version
     timeout-minutes: 5

.github/workflows/release-automated.yml

@@ -45,9 +45,6 @@ jobs:
         uses: actions/checkout@v2
         with:
           ref: ${{ needs.release.outputs.current_tag }}
-      - name: Set up QEMU
-        id: qemu
-        uses: docker/setup-qemu-action@v2
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v2
         with:

.github/workflows/release-manual-docker.yml

@@ -27,9 +27,6 @@ jobs:
         uses: actions/checkout@v2
         with:
           ref: ${{ github.event.inputs.ref }}
-      - name: Set up QEMU
-        id: qemu
-        uses: docker/setup-qemu-action@v2
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v2
         with:

Dockerfile

@@ -1,32 +1,50 @@
 ############################################################
 # Build stage
 ############################################################
-FROM node:20.19.0-alpine3.20 AS build
+# Runs on the platform of the build machine, also when building the image for
+# another platform, so that no code runs under emulation; Node.js running under
+# QEMU emulation can crash with an illegal instruction. Builders that don't set
+# BUILDPLATFORM, like the legacy Docker builder, run it on their own platform.
+FROM --platform=${BUILDPLATFORM:-linux} node:20.19.0-alpine3.20 AS build
 
 RUN apk --no-cache add git
 WORKDIR /src
 
 # Copy package.json first to benefit from layer caching
 COPY package*.json ./
 
-# Install without scripts otherwise webpack will fail
-RUN npm ci --omit=dev --ignore-scripts
+# Architecture of the image to build, set by BuildKit; builders that don't set
+# it build the image for their own platform
+ARG TARGETARCH
+
+# Install production dependencies for the image platform without scripts
+# otherwise webpack will fail
+RUN arch="${TARGETARCH:-$(uname -m)}" \
+ && case "$arch" in \
+      amd64|x86_64) cpu=x64 ;; \
+      arm64|aarch64) cpu=arm64 ;; \
+      arm|armv6l|armv7l) cpu=arm ;; \
+      ppc64le) cpu=ppc64 ;; \
+      s390x) cpu=s390x ;; \
+      *) echo "Unsupported target architecture: '$arch'" >&2; exit 1 ;; \
+    esac \
+ && npm ci --omit=dev --ignore-scripts --os=linux --cpu="$cpu" --libc=musl
 
 # Copy production node_modules aside for later
 RUN cp -R node_modules prod_node_modules
 
 # Copy src to have webpack config files ready for install
 COPY . /src
 
-# Install remaining dev dependencies
+# Install remaining dev dependencies; this also runs the prepare script, which
+# builds the bundles of the image
 RUN npm ci
 
-# Run all webpack build steps
-RUN npm run prepare && npm run build
-
 ############################################################
 # Release stage
 ############################################################
+# Must not contain RUN instructions, because building the image for another
+# platform than the one of the build machine would then require emulation.
 FROM node:20.19.0-alpine3.20 AS release
 WORKDIR /src