build-grpcio: limit resource usage

Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>

Author: threexc

.github/workflows/build-grpcio.yml

@@ -33,26 +33,36 @@ jobs:
     runs-on: ubuntu-24.04-riscv
     strategy:
       fail-fast: false
+      # grpc's C++ core is the expensive part of this build. Limit it to avoid
+      # runner resource exhaustion.
+      max-parallel: 4
       matrix:
         # grpcio doesn't advertise free-threaded support yet
         # (src/python/grpcio/python_version.py lists only 3.10-3.14), so
         # 3.14t is dropped from the usual default matrix.
         # See also: https://github.com/grpc/grpc/issues/38762
         python: ["cp312", "cp313", "cp314"]
 
+    env:
+      CCACHE_DIR: ${{ github.workspace }}/.ccache
+      CCACHE_BASEDIR: "/project"
+      CCACHE_COMPILERCHECK: "content"
+
     steps:
       - name: Checkout grpc v${{ env.GRPCIO_VERSION }}
         uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7.0.0
         with:
           repository: grpc/grpc
           ref: v${{ env.GRPCIO_VERSION }}
           submodules: true
+          fetch-depth: 1  # grpc's submodules (boringssl, abseil, re2, ...) are large; skip history
           persist-credentials: false
 
       - name: Checkout python-wheels
         uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7.0.0
         with:
           path: python-wheels
+          fetch-depth: 1
           persist-credentials: false
 
       # install_all_python_modules.sh (run below via CIBW_TEST_COMMAND) would
@@ -61,15 +71,32 @@ jobs:
       - name: Patch grpc source
         run: git apply python-wheels/patches/grpcio/${{ env.GRPCIO_VERSION }}/00*.patch
 
+      # The C++ core is identical across cp312/cp313/cp314; share ccache across
+      # builds assuming that the package version is the same.
+      - name: Restore compilation cache
+        uses: actions/cache/restore@27d5ce7f107fe9357f9df03efb73ab90386fccae  # v5.0.5
+        with:
+          path: ${{ env.CCACHE_DIR }}
+          key: ccache-wheels-grpcio-v${{ env.GRPCIO_VERSION }}-manylinux_riscv64-${{ matrix.python }}
+          restore-keys: |
+            ccache-wheels-grpcio-v${{ env.GRPCIO_VERSION }}-manylinux_riscv64-
+
       - name: Build wheels
         uses: pypa/cibuildwheel@294735312765b09d24a2fbec22660ce817587d55  # v4.1.0
         env:
           CIBW_BUILD: ${{ matrix.python }}-manylinux_riscv64
           CIBW_MANYLINUX_RISCV64_IMAGE: ${{ env.MANYLINUX_RISCV64_IMAGE }}
-          # Enables grpc's optional systemd socket-activation feature (see
-          # src/python/grpcio/README.rst); needs libsystemd-devel present.
-          CIBW_ENVIRONMENT: GRPC_PYTHON_BUILD_WITH_SYSTEMD=1
-          CIBW_BEFORE_ALL: dnf install -y systemd-devel
+          CIBW_BEFORE_ALL: |
+            set -eux
+            CCACHE_VERSION=4.13.6
+            curl -fsSL https://github.com/ccache/ccache/releases/download/v${CCACHE_VERSION}/ccache-${CCACHE_VERSION}-linux-$(uname -m)-musl-static.tar.gz | \
+              tar -xvzf - --strip-components 1 -C /usr/local/bin ccache-${CCACHE_VERSION}-linux-$(uname -m)-musl-static/ccache
+            ccache --version
+            ccache --zero-stats
+          CIBW_ENVIRONMENT_PASS_LINUX: >-
+            CCACHE_BASEDIR
+            CCACHE_COMPILERCHECK
+          CIBW_CONTAINER_ENGINE: "docker; create_args: --volume ${{ env.CCACHE_DIR }}:/root/.ccache"
           CIBW_BEFORE_BUILD: pip install -r requirements.txt
           CIBW_REPAIR_WHEEL_COMMAND: auditwheel repair --strip -w {dest_dir} {wheel}
           CIBW_TEST_REQUIRES: setuptools
@@ -78,6 +105,13 @@ jobs:
             PIP_NO_BUILD_ISOLATION=0 ./install_all_python_modules.sh &&
             cd {project}/src && python python/grpcio_tests/setup.py test_lite
 
+      - name: Save compilation cache
+        if: always() && github.ref == 'refs/heads/main'
+        uses: actions/cache/save@27d5ce7f107fe9357f9df03efb73ab90386fccae  # v5.0.5
+        with:
+          path: ${{ env.CCACHE_DIR }}
+          key: ccache-wheels-grpcio-v${{ env.GRPCIO_VERSION }}-manylinux_riscv64-${{ matrix.python }}
+
       - uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a  # v7.0.1
         with:
           name: grpcio-${{ env.GRPCIO_VERSION }}-${{ matrix.python }}-manylinux_riscv64