CI/CD for C++ Projects: Setting Up GitHub Actions

CI/CD for C++ Projects: Complete Guide to Setting Up GitHub Actions

In modern software development, automation of build, testing, and deployment processes has become not just a convenience but a necessity. For C++ projects, which often feature complex build systems and dependencies, implementing CI/CD (Continuous Integration / Continuous Deployment) is especially relevant. In this article, we will thoroughly examine how to set up a CI/CD pipeline for C++ projects using GitHub Actions — a powerful and built-in automation tool.

What is GitHub Actions and why is it suitable for C++?

GitHub Actions is a platform for automating workflows that allows you to create CI/CD pipelines directly in your GitHub repository. For C++ developers, this is an ideal solution for several reasons:

• Free build minutes for public repositories.
• Support for Linux, macOS, and Windows — you can test cross-platform builds.
• Flexible configuration via YAML files.
• Huge ecosystem of ready-made actions for installing compilers, dependencies, and tools.

The main element is a workflow, which is described in a file .github/workflows/*.yml. Each workflow consists of one or more jobs that run on virtual machines (runners).

Setting up a basic pipeline: build and test

Let's start with the simplest — create a workflow that will build your C++ project using CMake and run tests every time you push changes to the main branch or create a Pull Request.

Create a file .github/workflows/build.yml in the root of your repository and add the following code to it:

name: C++ CI Build

on:  push:    branches: [ "main" ]  pull_request:    branches: [ "main" ]

jobs:  build:    runs-on: ubuntu-latest

    steps:    - name: Checkout repository      uses: actions/checkout@v4

    - name: Install dependencies      run: |        sudo apt-get update        sudo apt-get install -y cmake g++ libgtest-dev

    - name: Configure CMake      run: cmake -B build -DCMAKE_BUILD_TYPE=Release

    - name: Build      run: cmake --build build --config Release

    - name: Run tests      working-directory: ./build      run: ctest --output-on-failure

Let's break down this code step by step:

• name — the name of the workflow that will be displayed in the GitHub interface.
• on — triggers that start the workflow (push and pull_request to main).
• runs-on — the operating system of the runner (ubuntu-latest, windows-latest, macos-latest).
• actions/checkout — a standard action that clones your repository.
• Install dependencies — installs CMake, the GCC compiler, and the Google Test library for unit tests.
• Configure, Build, Run tests — standard CMake commands for building and running tests.

Optimization: caching and matrix build

The basic pipeline works, but it can be significantly improved. Two key techniques are dependency caching and matrix build.

Caching to speed up builds

Each time a workflow runs, the runner downloads all dependencies from scratch. This takes time. Use actions/cache to save the CMake cache and installed packages:

    - name: Cache CMake build      uses: actions/cache@v3      with:        path: |          build          /usr/l