What is Continuous Integration in Jenkins - Hands-On Activity

What is Continuous Integration

📖 Scenario: You are working as a developer in a team. Your team wants to make sure that every change made to the code is tested automatically to avoid bugs. This helps the team deliver better software faster.

🎯 Goal: Learn the basic concept of Continuous Integration (CI) by setting up a simple Jenkins pipeline that runs a test command automatically whenever code changes are made.

📋 What You'll Learn

Create a Jenkins pipeline script with a basic structure

Add a stage to run a simple shell command simulating tests

Configure the pipeline to trigger on code changes

Print a message showing the test result

💡 Why This Matters

🌍 Real World

Continuous Integration helps teams catch bugs early by automatically testing code changes. Jenkins is a popular tool to automate this process.

💼 Career

Understanding CI pipelines is essential for DevOps roles and software developers to ensure code quality and faster delivery.

1

Create a basic Jenkins pipeline

Create a Jenkins pipeline script with a pipeline block and an empty stages section.

Jenkins

pipeline {
    agent any
    stages {
        // Your code here
    }
}

Need a hint?

Start by writing the pipeline block with agent any and an empty stages block.

2

Add a test stage to the pipeline

Inside the stages block, add a stage named Test that runs a shell command echo Running tests.

Jenkins

pipeline {
    agent any
    stages {
        // Add a stage named 'Test' that runs 'echo Running tests'
    }
}

Need a hint?

Use stage('Test') with steps and inside it run sh 'echo Running tests'.

3

Configure the pipeline to trigger on code changes

Add a triggers block inside the pipeline that uses pollSCM('* * * * *') to check for code changes every minute.

Jenkins

pipeline {
    agent any
    triggers {
        // Add pollSCM trigger here
    }
    stages {
        stage('Test') {
            steps {
                sh 'echo Running tests'
            }
        }
    }
}

Need a hint?

Inside pipeline, add triggers { pollSCM('* * * * *') } to poll for changes every minute.

4

Print a message showing the test result

Add a post block inside the pipeline that prints echo 'Tests completed successfully' when the pipeline succeeds.

Jenkins

pipeline {
    agent any
    triggers {
        pollSCM('* * * * *')
    }
    stages {
        stage('Test') {
            steps {
                sh 'echo Running tests'
            }
        }
    }
    // Add a post block to print a success message
}

Need a hint?

Use post { success { echo 'Tests completed successfully' } } inside the pipeline to print after success.