Pipeline SCM Triggers in Jenkins

1. Introduction

In Jenkins, SCM (Source Code Management) triggers are used to automate the build process by polling the source code repository for changes. This lesson covers how to configure and use SCM triggers in Jenkins pipelines.

2. SCM Triggers Overview

SCM triggers allow Jenkins to automatically start a build when changes are detected in the source code repository. Key concepts include:

• Polling the SCM for changes
• Webhook triggers
• Handling multiple branches

3. Configuring SCM Triggers

To configure SCM triggers in a Jenkins pipeline, follow these steps:

1. Open your Jenkins dashboard and create a new pipeline job.
2. In the pipeline configuration page, navigate to the "Pipeline" section.
3. Under "Definition", select "Pipeline script".
4. Use the following example Jenkinsfile to configure SCM triggers:

pipeline {
    agent any
    triggers {
        pollSCM('H/5 * * * *') // Polls SCM every 5 minutes
    }
    stages {
        stage('Build') {
            steps {
                echo 'Building...'
            }
        }
        stage('Test') {
            steps {
                echo 'Testing...'
            }
        }
    }
}

4. Best Practices

• Minimize polling frequency to reduce load on the SCM server.
• Use webhooks if your SCM supports them for immediate triggers.
• Implement branch-specific triggers for multi-branch pipelines.

5. FAQ