TopolearnWith many repositories, a shared library keeps pipelines short and lets one team fix the build logic everywhere.
A shared library is a Git repository with a fixed layout:
vars/: eachname.groovyfile defines a global step calledname, implemented by itscall(...)method. This is the most common part.src/: Groovy classes in packages, imported normally.resources/: non-Groovy files loaded withlibraryResource.
Register the library under Manage Jenkins, System, Global Trusted Pipeline Libraries (or on a folder) with a name and a default version. A Jenkinsfile loads it with @Library('ci-lib@v2.1') _; the trailing underscore is an annotation target. With the default version configured as implicit, no annotation is needed at all.
A vars step can wrap a whole declarative pipeline, so an application's Jenkinsfile shrinks to standardJavaPipeline(deploy: true). Taking a Map of options keeps the call site readable and extensible.
Pin versions with tags in production and test library changes by pointing a single job at a branch. Libraries configured globally are trusted: they run outside the Groovy sandbox and can call any Jenkins API, so changes to them deserve the same review as changes to Jenkins itself. Folder-level libraries run in the sandbox.
Example
// ci-lib repository: vars/standardPipeline.groovy
def call(Map cfg = [:]) {
pipeline {
agent { docker { image "${cfg.image ?: 'maven:3.9-eclipse-temurin-21'}" } }
stages {
stage('Build') { steps { sh 'mvn -B verify' } }
stage('Deploy') {
when { expression { cfg.deploy && env.BRANCH_NAME == 'main' } }
steps { sh "./deploy.sh ${cfg.app}" }
}
}
post { always { junit allowEmptyResults: true, testResults: 'target/surefire-reports/*.xml' } }
}
}
// Application repository: Jenkinsfile (the whole file)
@Library('ci-lib@v2.1') _
standardPipeline(app: 'shop', deploy: true)Remember
- vars/name.groovy with call() becomes a pipeline step called name
- Load with @Library('lib@version') _ and pin versions
- Global libraries are trusted and bypass the sandbox; review them carefully
Watch out for
- Loading libraries from a moving branch in production; one bad commit breaks every pipeline.