Demo Create a Shared Library for Slack Notification

Learn how to extract common Slack notification logic into a reusable Jenkins Shared Library for consistent alerts across multiple pipelines.

Why Use a Shared Library?

Embedding Slack notification code directly in each Jenkinsfile leads to duplicate scripts and maintenance headaches. A Shared Library lets you:

• Centralize notification logic
• Update formats or colors in one place
• Enforce consistent Slack workflows organization-wide

Example of duplicated code in a typical Jenkinsfile:

def slackNotificationMethod(String buildStatus = 'STARTED') {
    buildStatus = buildStatus ?: 'SUCCESS'
    // ... color logic ...
    slackSend(color: color, message: msg)
}

1. Create the Shared Library Repository

1. In your Git hosting platform (e.g. Gitea, GitHub), create a new repository named shared-libraries under your organization (dasher-org).

2. Initialize and push to main:

touch README.md
git init
git checkout -b main
git add README.md
git commit -m "Initialize shared library repository"
git remote add origin http://64.227.187.25:5555/dasher-org/shared-libraries.git
git push -u origin main

2. Define the Repository Layout

Jenkins Shared Libraries follow this directory structure:

(shared-libraries)
├── src
│   └── org
│       └── foo
│           └── Bar.groovy
├── vars
│   ├── foo.groovy
│   └── foo.txt
└── resources
    └── org
        └── foo
            └── bar.json

• src/org/... holds Groovy classes.
• vars/ contains global scripts (e.g., slackNotification.groovy) and help text.
• resources/ stores static assets like JSON.

Learn more in the Jenkins Shared Library Documentation.

3. Add Slack Notification Logic

Create vars/slackNotification.groovy:

// vars/slackNotification.groovy
def call(String buildStatus = 'STARTED') {
    // Default to SUCCESS if unset
    buildStatus = buildStatus ?: 'SUCCESS'

    // Map statuses to Slack colors
    def color = switch (buildStatus) {
        case 'SUCCESS' -> '#47ec05'
        case 'UNSTABLE' -> '#d5ee0d'
        default -> '#ec2805'
    }

    // Construct and send the notification
    def msg = "${buildStatus}: ${env.JOB_NAME} #${env.BUILD_NUMBER}\n${env.BUILD_URL}"
    slackSend(color: color, message: msg)
}

Build Status Color Reference

4. Use the Shared Library in Your Pipeline

1. Go to Manage Jenkins > Configure System.
2. Under Global Pipeline Libraries, add:
   • Name: shared-libraries
   • Default version: main
   • Retrieval method: Modern SCM (Git)

Then in any Jenkinsfile:

@Library('shared-libraries') _
pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                echo 'Building...'
            }
        }
        stage('Notify') {
            steps {
                // Default status SUCCESS
                slackNotification()
                // Or custom status:
                // slackNotification('FAILURE')
            }
        }
    }
}

Links and References

• Jenkins Shared Libraries
• Slack Notification Plugin
• Jenkins Pipeline Syntax
• Gitea Documentation