Shared Libraries in Jenkins¶

Shared libraries in Jenkins are reusable code components that centralize common logic, making pipelines modular, maintainable, and consistent. They address key problems like:

• Avoiding Code Duplication: Centralizes repetitive logic across multiple pipelines.
• Simplifying Maintenance: Updates to shared libraries automatically propagate to dependent pipelines.
• Improving Modularity: Keeps Jenkinsfiles clean by abstracting complex or repetitive steps.
• Enhancing Collaboration: Allows teams to manage reusable logic separately.

Directory Structure¶

Shared libraries have two main directories: vars/ and src/.

vars/¶

• Contains global Groovy scripts (<file-name>.groovy) that are directly callable in pipelines.
• Use Case: Simple, globally accessible functions.
• Example:

  // vars/deployApp.groovy
  def call() {
      echo 'Deploying application...'
  }
  

src/¶

• Contains reusable classes organized in a Java-like package structure (e.g., src/org/example).

• Requires explicit imports in pipeline scripts or vars functions.

• Use Case: Encapsulating complex logic in classes.

• Example:

  // src/org/example/MyUtils.groovy
  package org.example
  
  class MyUtils {
      def performTask() {
          echo 'Performing task...'
      }
  }
  

Key Differences¶

ibtisam@mint-dell:/media/ibtisam/L-Mint/git/jenkins_shared_library$ tree
.
├── resources
│   └── config.txt
├── src
│   └── org
│       └── example
│           └── myLibrary.groovy
└── vars
    ├── install.groovy
    ├── myFunction.groovy
    ├── pkgwithskiptest.groovy
    └── sonar-analysis.groovy

6 directories, 6 files

ibtisam@mint-dell:/media/ibtisam/L-Mint/git/jenkins_shared_library$ cat vars/myFunction.groovy 
// vars/myFunction.groovy
def call(name) {
    echo "Hello ${name} from myFunction!"

}

ibtisam@mint-dell:/media/ibtisam/L-Mint/git/jenkins_shared_library$ cat vars/pkgwithskiptest.groovy 
def call() {   
     sh 'mvn package -DskipTests=true'      

}

Steps¶

1. Configure the Github repo as following:

1. Write the pipeline as following:

@Library ("it_can_be_any_name")_

pipeline {
    agent any

    tools { 
        maven "maven3"
    } 

    stages {
        stage('Git Checkout') {
            steps {
                git branch: 'master', url: 'https://github.com/ibtisam-iq/secretsanta-generator.git'
            }
        }

        stage('Hello') {
            steps {
                script {
                    myFunction("Ibtisam")
                    pkgwithskiptest
                }
            }
        }
    }
}