Jenkins with Git/GitHub — SCM Config and PR Builds

Jenkins and Git are best friends. Every pipeline starts with pulling code from Git. But there is more to it than just entering a URL. You need to configure credentials, branch strategies, and PR builds. Let us set it up properly.

Adding Git Credentials to Jenkins

Configure Git Credentials

1. Go to Manage Jenkins > Credentials > System > Global credentials.
2. Click "Add Credentials."
3. Kind: "Username with password" (for HTTPS) or "SSH Username with private key" (for SSH).
4. For HTTPS: Username = your GitHub username. Password = your GitHub Personal Access Token (not your GitHub password!).
5. For SSH: Paste your private key (~/.ssh/id_rsa content).
6. ID: give it a memorable name like "github-creds."
7. Save.

SCM Configuration in Pipeline

pipeline {
    agent any

    stages {
        stage('Checkout') {
            steps {
                // Option 1: Simple — uses the repo configured in job settings
                checkout scm

                // Option 2: Explicit — checkout a specific repo and branch
                git branch: 'main',
                    credentialsId: 'github-creds',
                    url: 'https://github.com/yourorg/automation-tests.git'
            }
        }
    }
}

Multibranch Pipeline — Build Every PR

A regular Pipeline job builds one branch. But what if developers create feature branches and PRs? You do not want to create a separate job for each branch. Multibranch Pipeline solves this. It automatically discovers branches and PRs and runs the Jenkinsfile from each.

Set Up Multibranch Pipeline

1. New Item > enter name > select "Multibranch Pipeline" > OK.
2. Branch Sources > Add source > GitHub.
3. Enter credentials and repository URL.
4. Behaviors: Add "Discover branches" and "Discover pull requests from origin."
5. Build Configuration: Script Path = Jenkinsfile.
6. Scan Multibranch Pipeline Triggers: Set interval (e.g., 1 minute) or use webhook.
7. Save. Jenkins scans the repo and creates a job for each branch that has a Jenkinsfile.

Now when a developer opens a PR, Jenkins automatically runs the Selenium suite against that PR branch. The test results show up as a status check on the PR in GitHub. Green checkmark = tests passed. Red X = tests failed. The reviewer can see test results before merging.