How to Use Shared Library in Jenkins Pipeline

To use a shared library in a Jenkins pipeline, first define the library in Jenkins global configuration, then load it in your Jenkinsfile using @Library annotation or library() step. This allows you to call reusable functions or classes from the shared library inside your pipeline code.

Syntax

The shared library is loaded in a Jenkins pipeline using the @Library annotation or the library() step.

• @Library('libraryName') _: Loads the shared library named libraryName at the top of the Jenkinsfile.
• library('libraryName'): Loads the shared library dynamically inside a pipeline stage or step.
• After loading, you can call functions or classes defined in the shared library.

groovy

@Library('my-shared-lib') _
pipeline {
    agent any
    stages {
        stage('Example') {
            steps {
                script {
                    mySharedFunction()
                }
            }
        }
    }
}

Example

This example shows how to use a shared library named my-shared-lib that contains a function mySharedFunction. The Jenkinsfile loads the library and calls the function inside a pipeline stage.

groovy

@Library('my-shared-lib') _
pipeline {
    agent any
    stages {
        stage('Call Shared Library') {
            steps {
                script {
                    mySharedFunction()
                }
            }
        }
    }
}

// In the shared library (vars/mySharedFunction.groovy):
// def call() {
//     echo 'Hello from shared library!'
// }

Output

[Pipeline] echo
Hello from shared library!
[Pipeline] End of Pipeline

Common Pitfalls

• Library not configured: Forgetting to add the shared library in Jenkins global configuration causes loading errors.
• Incorrect library name: Using a wrong library name in @Library or library() leads to failure.
• Missing underscore: When using @Library annotation, forgetting the trailing underscore _ causes syntax errors.
• Function not found: Calling a function not defined in the shared library will fail at runtime.

groovy

/* Wrong usage: missing underscore */
@Library('my-shared-lib')
pipeline {
    agent any
    stages {
        stage('Test') {
            steps {
                script {
                    mySharedFunction()
                }
            }
        }
    }
}

/* Correct usage: with underscore */
@Library('my-shared-lib') _
pipeline {
    agent any
    stages {
        stage('Test') {
            steps {
                script {
                    mySharedFunction()
                }
            }
        }
    }
}

Quick Reference

Concept	Usage	Notes
Define Shared Library	Manage Jenkins > Configure System > Global Pipeline Libraries	Add library name, source code repo, default version
Load Library in Jenkinsfile	@Library('libName') _	Use underscore after annotation
Call Library Function	myFunction()	Function defined in vars/ directory of library
Dynamic Load	library('libName')	Load library inside pipeline steps
Common Error	Missing underscore	Causes syntax error

Key Takeaways

Always configure your shared library in Jenkins global settings before use.

Use @Library('libraryName') _ at the top of your Jenkinsfile to load the shared library.

Call functions or classes defined in the shared library directly after loading it.

Remember the trailing underscore _ after @Library annotation to avoid syntax errors.

Check library name and function names carefully to prevent runtime failures.