Using Jenkins to build a C++ app

Introduction

This tutorial demonstrates how to build a simple C++ Casino Number Guessing Game using Jenkins. The game generates a random number depending on the chosen difficulty level, and players win a prize if they guess the correct number.

Requirements

• Docker
• Docker compose
• Git
• VS Code

Fork and clone the sample repository

First, fork the sample repository containing the Casino Number Guessing Game’s C++ code to your GitHub account. Then, clone your fork to your local machine.

• Sign into your GitHub account
• Fork the casino-number-guessing-game from GitHub into your GitHub account
• Click Create fork
• clone the forked repository using VS Code by running the following command git clone [repo-URL]

To get repo-URL, click code and copy HTTPS url.

NOTE:Make sure to create a folder before running the command.

Start your Jenkins controller

• Clone the quickstart-tutorials repository to get the latest preconfigured Jenkins deployment by running the command

git clone https://github.com/jenkins-docs/quickstart-tutorials.git

• Run the following command after cloning. Make sure to cd into quickstart-tutorials directory before running it.

docker compose --profile cpp up -d

• After confirming the containers are running with docker compose ps, access the controller at http://localhost:8080.
• Log in with admin as username and password.

Create your Pipeline project in Jenkins

• In Jenkins UI, select New Item under Dashboard.
• Give a name to your Pipeline, select Pipeline under Select an item type section and click OK.
• Enter a Pipeline Description.

Create your initial Pipeline as a Jenkinsfile

You are now ready to automate your C++ application build by creating a Jenkins Pipeline. This pipeline will be defined in a Jenkinsfile that you will commit to your local Git repository (casino-number-guessing-game).

• When you forked our sample repository, you already have an empty Jenkinsfile.
• Copy the Declarative Pipeline code below and paste it into your Jenkinsfile:

pipeline {
    agent any
    stages {
        stage('Build') { 
            steps {
                sh 'rm -rf build'
                sh 'cmake -B build -S .' 
                sh 'cmake --build build'
            }
        }
    }
}

• Save and commit the edited Jenkinsfile into your local casino-number-guessing-game Git repository. cd into casino-number-guessing-game directory if you have not done so and run the following command:

git  add .

git commit -m "Add initial Jenkinsfile"

git push

• Back at Jenkins UI, select Build Now
• If your Pipeline run successfully, you will see a green check mark and #1 on the left side and the Build stage completed in the main view.
• You can now click on #1 to view the build details, where you'll see both the queue wait time and actual execution time for your build - this helps monitor performance and identify potential delays for future runs.
• On the left, you can click on Pipeline Overview to see the stages of the Pipeline.
• Click the Build stage to view detailed logs, including the cmake command output (click the green cmake section to expand it). This helps verify your build executed correctly.
• To return to your pipeline's main page, simply select 'casino-number-guessing-game' (or the name you’ve chosen for your pipeline) from the top left.

Add a test stage to your Pipeline

• Head back to Jenkins UI and open Jenkinsfile.
• Copy and paste the following Declarative Pipeline syntax under Build stage of your Jenkinsfile.

stage('Test') {
            steps {
                sh './build/casino_game'
                sh './build/test_game'
            }
        }

Your Jenkinsfile should look like this:

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'rm -rf build'
                sh 'cmake -B build -S .'
                sh 'cmake --build build'
            }
        }
        stage('Test') { 
            steps {
                sh './build/casino_game' 
                sh './build/test_game'
            }
        }
    }
}

• Save your Jenkinsfile and push the new changes to your remote Jenkinsfile for Jenkins to access by running the following command:

git add .

git commit -m "Add 'Test' stage"

git push

• Click Build Now to launch another build
• After some time, a new column called 'Test' should appear in the Stage View.
• Click on #2 or the number corresponding to your most recent build on the left, under Build History, to view the build details.
• Select Pipeline overview to see the stages of the Pipeline.
• Take note of the new 'Test' stage. You can select the checkmark next to 'Test' to view the output from that stage.

Add a final delivery stage to your Pipeline

• Back at your VS Code with Jenkinsfile opened.
• Copy and paste the following Declarative Pipeline syntax under Test stage of your Jenkinsfile.

stage('Deliver') {
            steps {
                sh 'tar -czf casino_game.tar.gz build/casino_game'
                archiveArtifacts artifacts: 'casino_game.tar.gz', fingerprint: true
            }
        }

Your Jenkinsfile will look like this:

pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                sh 'rm -rf build'
                sh 'cmake -B build -S .'
                sh 'cmake --build build'
            }
        }
        stage('Test') {
            steps {
                sh './build/casino_game'
                sh './build/test_game'
            }
        }
        stage('Deliver') { 
            steps {
                sh 'tar -czf casino_game.tar.gz build/casino_game' 
                archiveArtifacts artifacts: 'casino_game.tar.gz', fingerprint: true 
            }
        }
    }
}

• Save your Jenkinsfile and push the new changes to your remote Jenkinsfile for Jenkins to access by running the following command:

git add .

git commit -m "Add 'Test' stage"

git push

• Click on 'Build Now' on the left. After a short wait, a new column labeled 'Deliver' should appear in the Stage View.
• Click on #3 or the number for your most recent build in the left pane under Build History to view the build details.
• Select Pipeline Overview to see the stages of the Pipeline.
• Select the Deliver stage. You will then see a green part displaying tar -czf casino_game.tar.gz build/casino_game, which represents the successful execution of the tar command.
• You can see the full stage view by clicking on the "Full Stage View" in the left menu.

Thanks for staying till the end