cache modules?

.github/workflows/ci-workflow.yml

@@ -113,20 +113,25 @@ jobs:
 #          flags: integration-tests-${{ matrix.node }}-${{ matrix.os }}-${{ matrix.arch }}
 
   test_linux_arm:
+    # Skip this group if the PR doesn't originate from the main repo.
+    # Trying to run this on standard runners is just going to fail due to
+    # lack of CPU resources.
+    if: ${{ vars.NR_RUNNER != '' }}
     strategy:
       max-parallel: 1
       matrix:
         node: [ 16, 18, 20 ]
-#    runs-on: ${{ vars.NR_RUNNER || 'ubuntu-latest' }}
     runs-on: ${{ vars.NR_RUNNER }}
-#    concurrency:
-#      group: linux_arm-${{ github.workflow }}-${{ github.ref }}
     name: Linux / Node ${{ matrix.node }} arm64
     timeout-minutes: 15
     steps:
-      - run: cat /proc/cpuinfo
       - name: Checkout
         uses: actions/checkout@v4
+      - name: Restore modules cache
+        uses: actions/cache@v4
+        with:
+          path: ${{ github.workspace }}/node_modules
+          key: linux-arm-node-${{ matrix.node }}-${{ hashFiles('**/package-lock.json') }}
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
         with:
@@ -148,8 +153,16 @@ jobs:
         uses: addnab/docker-run-action@v3
         with:
           image: linux_arm:node-${{ matrix.node }}
-          options: --platform linux/arm64
+          options: --platform linux/arm64 -v ${{ github.workspace }}:/host
           run: |
+            cp -R /host/node_modules . 2>/dev/null
+            rm -rf /host/node_modules 2>/dev/null
             npm install --verbose
+            cp -R node_modules /host/
             npm run unit
             npm run integration
+      - name: Update modules cache
+        uses: actions/cache@v4
+        with:
+          path: ${{ github.workspace }}/node_modules
+          key: linux-arm-node-${{ matrix.node }}-${{ hashFiles('**/package-lock.json') }}