Using WebHooks and PR Comments to Launch a Multi‐Branch Jenkins Job

To configure a webhook to trigger a Jenkins Multi-Branch Pipeline from a PR comment, follow these steps:

Step-by-Step Plan

1. Set Up GitHub Webhook:

   • Go to your GitHub repository.
   • Navigate to Settings > Webhooks > Add webhook.
   • Set the Payload URL to your Jenkins server URL followed by /github-webhook/.
   • Set the Content type to application/json.
   • Select the Let me select individual events option and choose Issue comment.

2. Install Necessary Jenkins Plugins:

   • Ensure you have the following plugins installed:
     • GitHub Integration Plugin
     • GitHub Pull Request Builder Plugin
     • GitHub Plugin

3. Configure Jenkins Job:

   • In Jenkins, create or configure your Multi-Branch Pipeline job.
   • In the job configuration, under Branch Sources, add your GitHub repository.
   • Under Build Triggers, check GitHub Pull Request Builder.

4. Update Jenkinsfile:

   • Modify your Jenkinsfile to handle PR comments and trigger builds accordingly.

Example Jenkinsfile Update

pipeline {
    agent any

    triggers {
        issueCommentTrigger('.*test this please.*')
    }

    stages {
        stage('Build') {
            steps {
                echo 'Building...'
                // Add your build steps here
            }
        }
        stage('Test') {
            steps {
                echo 'Testing...'
                // Add your test steps here
            }
        }
        stage('Deploy') {
            steps {
                echo 'Deploying...'
                // Add your deploy steps here
            }
        }
    }
}

Detailed Steps

1. Set Up GitHub Webhook:

   • Go to your GitHub repository.
   • Navigate to Settings > Webhooks > Add webhook.
   • Set the Payload URL to your Jenkins server URL followed by /github-webhook/.
   • Set the Content type to application/json.
   • Select the Let me select individual events option and choose Issue comment.

2. Install Necessary Jenkins Plugins:

   • Go to Manage Jenkins > Manage Plugins.
   • Install the following plugins if not already installed:
     • GitHub Integration Plugin
     • GitHub Pull Request Builder Plugin
     • GitHub Plugin

3. Configure Jenkins Job:

   • In Jenkins, create or configure your Multi-Branch Pipeline job.
   • In the job configuration, under Branch Sources, add your GitHub repository.
   • Under Build Triggers, check GitHub Pull Request Builder.

4. Update Jenkinsfile:

   • Modify your Jenkinsfile to handle PR comments and trigger builds accordingly.

Example Jenkinsfile Update

pipeline {
    agent any

    triggers {
        issueCommentTrigger('.*test this please.*')
    }

    stages {
        stage('Build') {
            steps {
                echo 'Building...'
                // Add your build steps here
            }
        }
        stage('Test') {
            steps {
                echo 'Testing...'
                // Add your test steps here
            }
        }
        stage('Deploy') {
            steps {
                echo 'Deploying...'
                // Add your deploy steps here
            }
        }
    }
}

Summary

By following these steps, you can configure a webhook to trigger a Jenkins Multi-Branch Pipeline from a PR comment. This setup allows you to automate the process of running builds and tests based on specific comments in your pull requests.