CI/CD for C++ Projects: GitHub Actions Advanced Level

Advanced CI/CD for C++ Projects on GitHub Actions

When a simple "build — run tests — deploy" pipeline is no longer sufficient, it's time for advanced techniques. In this article, we'll look at how to configure GitHub Actions for C++ projects at a professional level: dependency caching, build matrix for different compilers, static code analysis, artifacts, and smart triggers. All examples are given in C++ using CMake.

1. Dependency Caching and Build Acceleration

Each workflow run starts with a clean virtual machine. Without caching, you will download and build the same library (e.g., Boost or Google Test) every time. The solution is to use built-in GitHub Actions caching.

name: CI for C++ (advanced)on: [push, pull_request]

jobs:  build:    runs-on: ubuntu-latest    steps:      - uses: actions/checkout@v4

      - name: Cache dependencies        uses: actions/cache@v3        with:          path: |            ~/.cache            build/_deps          key: ${{ runner.os }}-c++-${{ hashFiles('CMakeLists.txt', '**/*.cmake') }}          restore-keys: |            ${{ runner.os }}-c++-

      - name: Install system dependencies        run: sudo apt-get update && sudo apt-get install -y libboost-all-dev

      - name: Build        run: |          cmake -B build -DCMAKE_BUILD_TYPE=Release          cmake --build build -j$(nproc)

The key is formed based on the hash of CMakeLists.txt — when the dependency list changes, the cache is automatically invalidated. The restore-keys parameter allows partial cache restoration if an exact key is not found.

2. Build Matrix: Multiple Compilers and Platforms

When developing a cross-platform C++ application, it's important to verify the build under different compilers. GitHub Actions supports a matrix strategy.

jobs:  build:    strategy:      matrix:        os: [ubuntu-latest, windows-latest, macos-latest]        compiler: [gcc, clang, msvc]        exclude:          - os: ubuntu-latest            compiler: msvc          - os: windows-latest            compiler: clang          - os: macos-latest            compiler: msvc

    runs-on: ${{ matrix.os }}

    steps:      - uses: actions/checkout@v4

      - name: Configure compiler (Linux)        if: runner.os == 'Linux'        run: |          if [ "${{ matrix.compiler }}" == "gcc" ]; then            echo "CC=gcc" >> $GITHUB_ENV            echo "CXX=g++" >> $GITHUB_ENV          elif [ "${{ matrix.compiler }}" == "clang" ]; then            echo "CC=clang" >> $GITHUB_ENV            echo "CXX=clang++" >> $GITHUB_ENV          fi

      - name: Build with CMake        run: |          cmake -B build -DCMAKE_BUILD_TYPE=Debug          cmake --build build

The matrix automatically generates 6 jobs (3 OS × 2 compilers after excluding invalid combinations). This allows you to quickly detect issues specific to a particular compiler or platform.

3. Static Analysis and Linters

C++ code quality is critical. Integrate static analysis into your pipeline using Clang-Tidy, Cppcheck, or SonarCloud. Let's look at an example with Clang-Tidy.

jobs:  static-analysis:    runs-on: ubuntu-latest    steps:      - uses: actions/checkout@v4

      - name: Install tools        run: |          sudo apt-get install -y clang-tidy cppcheck          pip install compiledb

      - name: Generate compile_commands.json        run: |          cmake -B build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON          compiledb -o build/compile_commands.json make -C build

      - name: Run Clang-Tidy        run: |          find . -name '*.cpp' -o -name '*.hpp' | xargs clang-tidy -p build --checks='*,-modernize-use