tools: cache V8 builds

Author: aduh95

.github/workflows/test-shared.yml

@@ -141,8 +141,54 @@ jobs:
           path: '*.tar.gz'
           compression-level: 0
 
-  build:
+  build-v8:
     needs: build-tarball
+    runs-on: ubuntu-24.04-arm
+    name: 'aarch64-linux: Cache V8 build'
+    steps:
+      - name: Check if Cachix is available
+        id: cachix-check
+        run: echo 'IS_AVAILABLE=${{ secrets.CACHIX_AUTH_TOKEN && 'true' }}' >> "$GITUHB_OUTPUT"
+
+      - uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c  # v8.0.1
+        if: ${{ steps.cachix-check.outputs.IS_AVAILABLE == 'true' }}
+        with:
+          name: tarballs
+          path: tarballs
+
+      - name: Extract tarball
+        if: ${{ steps.cachix-check.outputs.IS_AVAILABLE == 'true' }}
+        shell: bash
+        run: |
+          tar xzf tarballs/*.tar.gz -C "$RUNNER_TEMP"
+          echo "TAR_DIR=$RUNNER_TEMP/$(basename tarballs/*.tar.gz .tar.gz)" >> "$GITHUB_ENV"
+
+      - uses: cachix/install-nix-action@96951a368ba55167b55f1c916f7d416bac6505fe  # v31.10.3
+        if: ${{ steps.cachix-check.outputs.IS_AVAILABLE == 'true' }}
+        with:
+          extra_nix_config: sandbox = true
+
+      - uses: cachix/cachix-action@1eb2ef646ac0255473d23a5907ad7b04ce94065c  # v17
+        if: ${{ steps.cachix-check.outputs.IS_AVAILABLE == 'true' }}
+        with:
+          name: nodejs
+          authToken: ${{ secrets.CACHIX_AUTH_TOKEN }}
+
+      - name: Build V8
+        if: ${{ steps.cachix-check.outputs.IS_AVAILABLE == 'true' }}
+        shell: bash
+        run: |
+          nix-shell \
+            -I "nixpkgs=$TAR_DIR/tools/nix/pkgs.nix" \
+            --pure \
+            --arg useSeparateDerivationForV8 true \
+            --arg ccache "${NIX_SCCACHE:-null}" \
+            --arg devTools '[]' \
+            --arg benchmarkTools '[]' \
+            --run ';'
+
+  build:
+    needs: build-v8
     strategy:
       fail-fast: false
       matrix:
@@ -181,21 +227,24 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
         with:
           persist-credentials: false
-          sparse-checkout: tools/nix
+          sparse-checkout: tools/nix/openssl-matrix.json
           sparse-checkout-cone-mode: false
       - id: query
         run: |
-          matrix=$(jq -c . tools/nix/openssl-matrix.json)
-          echo "matrix=$matrix" >> "$GITHUB_OUTPUT"
-
+          {
+            echo 'matrix<<EOF'
+            cat tools/nix/openssl-matrix.json
+            echo 'EOF'
+          } >> "$GITHUB_OUTPUT"
+  
   # Builds and tests Node.js with shared libraries against every supported
   # OpenSSL release version available in the repo-pinned nixpkgs. The default
   # shared `openssl` from tools/nix/sharedLibDeps.nix is overridden per matrix
   # entry, while all other shared libs remain at their defaults. Only runs on
   # a single runner/system (aarch64-linux) to keep the matrix to a minimum.
   build-openssl:
     needs:
-      - build-tarball
+      - build-v8
       - collect-openssl-versions
     strategy:
       fail-fast: false