Loading the Shared Library in Pipeline

This guide demonstrates how to replace inline methods with a centrally managed Shared Library in Jenkins. By loading common steps—like Slack notifications—from a library, you simplify maintenance, enforce consistency, and version your pipeline logic.

Prerequisites

• Jenkins instance with Global Pipeline Libraries configured
• Access to the Git repository hosting your shared library
• Slack Plugin installed and a valid Slack bot token

Verify that your library appears under Manage Jenkins » Configure System » Global Pipeline Libraries:

After you save and refresh, Jenkins connects to your Git repo and displays the commit ID from the default branch—confirming connectivity.

1. Inline Slack Notification (Before)

In a typical Jenkinsfile, you might define a slackNotificationMethod inline:

def slackNotificationMethod(String buildStatus = 'STARTED') {
    buildStatus = buildStatus ?: 'SUCCESS'
    def color = (buildStatus == 'SUCCESS')  ? '#47ec05' :
                (buildStatus == 'UNSTABLE') ? '#d5ee0d' :
                                              '#ec2805'
    def msg = "${buildStatus}: '${env.JOB_NAME}' #${env.BUILD_NUMBER}\n${env.BUILD_URL}"
    slackSend(color: color, message: msg)
}

pipeline {
    agent any
    stages {
        stage('Install Dependencies') {
            steps {
                sh 'npm install --no-audit'
            }
        }
    }
    post {
        always {
            slackNotificationMethod()
        }
    }
}

Drawbacks of Inline Methods

• Duplication across multiple Jenkinsfiles
• Harder to maintain and version
• Inconsistent behavior if modified in one pipeline only

2. Switching to the Shared Library

Replace the inline function by adding the @Library annotation at the top of your Jenkinsfile:

@Library('dasher-trusted-shared-library') _

pipeline {
    agent any

    tools {
        // ...
    }

    environment {
        MONGO_URI          = "mongodb+srv://supercluster.d83jj.mongodb.net/superData"
        MONGO_DB_CREDS     = credentials('mongo-db-credentials')
        MONGO_USERNAME     = credentials('mongo-db-username')
        MONGO_PASSWORD     = credentials('mongo-db-password')
        SONAR_SCANNER_HOME = tool 'sonarqube-scanner-6'
        GITEA_TOKEN        = credentials('gitea-api-token')
    }

    options {
        // ...
    }

    stages {
        stage('Install Dependencies') {
            steps {
                sh 'npm install --no-audit'
            }
        }
    }

    post {
        always {
            // Delegates to vars/slackNotification.groovy in the shared library
            slackNotification()
        }
    }
}

Environment Variables Reference

3. Shared Library Implementation

In your shared library repository, under vars/slackNotification.groovy, define the call method Jenkins will load:

// vars/slackNotification.groovy
def call(String buildStatus = 'STARTED') {
    buildStatus = buildStatus ?: 'SUCCESS'
    def color = (buildStatus == 'SUCCESS')  ? '#47ec05' :
                (buildStatus == 'UNSTABLE') ? '#d5ee0d' :
                                              '#ee2805'
    def msg = "${buildStatus}: '${env.JOB_NAME}' #${env.BUILD_NUMBER}\n${env.BUILD_URL}"
    slackSend(color: color, message: msg)
}

This single implementation is now reusable across any pipeline that loads the library.

4. Triggering and Verifying the Build

After committing your updated Jenkinsfile on the feature/advanced-demo branch, Jenkins will detect the change and queue a new build:

The pipeline runs successfully and posts a notification to Slack for build #6.

5. Confirming Library Loading in Console

To see how Jenkins fetches and loads your shared library, review the classic console output and filter for library:

> git ls-remote -h http://64.227.187.25:5555/dasher-org/shared-libraries # timeout=10
> git init /var/lib/jenkins/workspace/feature/advanced-demo/libs/dasher-org/shared-libraries
[Pipeline] library
Loading library dasher-trusted-shared-library @ main from http://64.227.187.25:5555/dasher-org/shared-libraries
> git fetch --no-tags --force --progress -- http://64.227.187.25:5555/dasher-org/shared-libraries +refs/heads/main:refs/remotes/dasher-org/shared-libraries/main

Later in the log, you’ll see the Slack step using values defined in the library:

Slack Send Pipeline step running, values are -
  baseUrl: <empty>,
  teamDomain: Jenkins,
  channel: dasher-notifications,
  color: #47ec05,
  botUser: true,
  tokenCredentialId: slack-bot-token,
  notifyCommitters: false

Conclusion

By centralizing common pipeline logic in Jenkins Shared Libraries, you:

• Reduce code duplication
• Simplify maintenance and updates
• Manage multiple library versions via Git branches or tags

Now you can create additional reusable steps or even combine multiple libraries for more complex workflows.

References

• Jenkins Shared Libraries
• Slack Plugin for Jenkins
• Jenkins Credentials Documentation