Jenkins Pipeline

Jenkins Pipeline

Overview

Create enterprise-grade Jenkins pipelines using declarative and scripted approaches to automate building, testing, and deploying with advanced control flow.

When to Use

• Enterprise CI/CD infrastructure
• Complex multi-stage builds
• On-premise deployment automation
• Parameterized builds

Implementation Examples

1. Declarative Pipeline (Jenkinsfile)

pipeline {
    agent { label 'linux-docker' }
    environment {
        REGISTRY = 'docker.io'
        IMAGE_NAME = 'myapp'
    }
    parameters {
        string(name: 'DEPLOY_ENV', defaultValue: 'staging')
    }
    stages {
        stage('Checkout') { steps { checkout scm } }
        stage('Install') { steps { sh 'npm ci' } }
        stage('Lint') { steps { sh 'npm run lint' } }
        stage('Test') {
            steps {
                sh 'npm run test:coverage'
                junit 'test-results.xml'
            }
        }
        stage('Build') {
            steps {
                sh 'npm run build'
                archiveArtifacts artifacts: 'dist/**/*'
            }
        }
        stage('Deploy') {
            when { branch 'main' }
            steps {
                sh 'kubectl set image deployment/app app=${REGISTRY}/${IMAGE_NAME}:latest'
            }
        }
    }
    post {
        always { cleanWs() }
        failure { echo 'Pipeline failed!' }
    }
}

2. Scripted Pipeline (Groovy)

// Jenkinsfile - Scripted Pipeline

node('linux-docker') {
    def imageTag = sh(returnStdout: true, script: 'git rev-parse --short HEAD').trim()
    def registry = 'docker.io'

    try {
        stage('Checkout') { checkout scm }
        stage('Install') { sh 'npm ci' }
        stage('Test') { sh 'npm test' }
        stage('Build') { sh 'npm run build' }

        currentBuild.result = 'SUCCESS'
    } catch (Exception e) {
        currentBuild.result = 'FAILURE'
        error("Build failed: ${e.message}")
    }
}

3. Multi-Branch Pipeline

pipeline {
    agent any
    stages {
        stage('Build') { steps { sh 'npm run build' } }
        stage('Test') { steps { sh 'npm test' } }
        stage('Deploy') {
            when { branch 'main' }
            steps { sh 'npm run deploy:prod' }
        }
    }
}

4. Parameterized Pipeline

pipeline {
    agent any
    parameters {
        string(name: 'VERSION', defaultValue: '1.0.0', description: 'Version to release')
        choice(name: 'ENV', choices: ['staging', 'prod'], description: 'Deployment environment')
    }
    stages {
        stage('Build') { steps { sh 'npm run build' } }
        stage('Test') { steps { sh 'npm test' } }
        stage('Deploy') {
            steps { sh "npm run deploy:${params.ENV}" }
        }
    }
}

5. Pipeline with Credentials

pipeline {
    agent any
    environment {
        DOCKER_CREDS = credentials('docker-hub')
    }
    stages {
        stage('Build & Push') {
            steps {
                sh '''
                    echo $DOCKER_CREDS_PSW | docker login -u $DOCKER_CREDS_USR --password-stdin
                    docker build -t myapp:latest .
                    docker push myapp:latest
                '''
            }
        }
    }
}

Best Practices

✅ DO

• Use declarative pipelines for clarity
• Use credentials plugin for secrets
• Archive artifacts and reports
• Implement approval gates for production
• Keep pipelines modular and reusable

❌ DON'T

• Store credentials in pipeline code
• Ignore pipeline errors
• Skip test coverage reporting
• Use deprecated plugins

Resources

• Jenkins Pipeline Documentation
• Declarative Pipeline Syntax