Create a Shared Library for Slack Notification

In this guide, you’ll learn how to extract Slack notification logic from a Jenkinsfile into a reusable Shared Library. By the end, any pipeline in your organization can send Slack updates with a single method call.

Why Refactor Slack Notifications?

Embedding Slack logic directly in each Jenkinsfile leads to:

• Duplication across repositories
• Harder maintenance when updating message formats
• Inconsistent notification behavior

By centralizing the code in a Shared Library, you maintain one source of truth and simplify pipeline scripts.

Current Jenkinsfile Implementation

Here’s a typical approach you might find in your project (e.g., the Solar System repository):

def slackNotificationMethod(String buildStatus = 'STARTED') {
    buildStatus = buildStatus ?: 'SUCCESS'

    def color
    if (buildStatus == 'SUCCESS') {
        color = '#47ec05'
    } else if (buildStatus == 'UNSTABLE') {
        color = '#d5ee0d'
    } else {
        color = '#ec2805'
    }

    def msg = "${buildStatus}: *${env.JOB_NAME}* #${env.BUILD_NUMBER}:\n${env.BUILD_URL}"
    slackSend(color: color, message: msg)
}

pipeline {
    agent any
    // ...
}

While functional, this code is locked to a single repository and must be copied everywhere you need it.

Benefits of a Shared Library

1. Create the Git Repository

On your Git hosting platform (e.g., Gitea), create a new repository for your Shared Libraries.
For example, under the dasher-org organization name it shared-libraries.

2. Initialize the Repository

Clone and prepare the repo locally:

git init
git checkout -b main
touch README.md
git add README.md
git commit -m "Initial commit for Shared Libraries"
git remote add origin http://64.227.187.25:5555/dasher-org/shared-libraries.git
git push -u origin main

For full details on directory layout and configuration, see the Jenkins Shared Libraries documentation.

3. Define the Directory Structure

A standard Shared Library uses this layout:

shared-libraries/
├── vars/
│   └── SlackNotification.groovy    # global step for Slack notifications
├── src/
│   └── org/
│       └── foo/
│           ├── Bar.groovy          # org.foo.Bar class
│           ├── foo.groovy          # global 'foo' variable
│           └── foo.txt             # help text for 'foo'
└── resources/
    └── org/
        └── foo/
            └── Bar.json            # static helper data

4. Add the Slack Notification Script

Create vars/SlackNotification.groovy via your Git hosting UI or locally:

Paste the extracted logic, rename the entry method to call so Jenkins treats it like a native step:

// vars/SlackNotification.groovy
def call(String buildStatus = 'STARTED') {
    buildStatus = buildStatus ?: 'SUCCESS'

    def color
    if (buildStatus == 'SUCCESS') {
        color = '#47ec05'
    } else if (buildStatus == 'UNSTABLE') {
        color = '#d5ee0d'
    } else {
        color = '#ec2805'
    }

    def msg = "${buildStatus}: ${env.JOB_NAME} #${env.BUILD_NUMBER}:\n${env.BUILD_URL}"
    slackSend(color: color, message: msg)
}

5. How the call Method Works

Jenkins treats each Groovy script in vars/ with a call method as a pipeline step. For instance, vars/sayHello.groovy:

// vars/sayHello.groovy
def call(String name = 'human') {
    echo "Hello, ${name}."
}

You’d use it in a pipeline like:

pipeline {
    agent any
    stages {
        stage('Greet') {
            steps {
                sayHello('Jenkins')
            }
        }
    }
}

Likewise, after configuring your new Shared Library in Manage Jenkins → Configure System, invoke Slack notifications:

pipeline {
    agent any
    stages {
        stage('Notify') {
            steps {
                SlackNotification('SUCCESS')
            }
        }
    }
}

Next Steps

1. Commit and push all changes to shared-libraries.
2. Configure the Shared Library in Jenkins global settings:
   • Library name: shared-libraries
   • Default version: main
3. Update your pipelines to replace inline Slack logic with SlackNotification(...).

Once configured, you’ll enjoy centralized, consistent Slack alerts across every Jenkins pipeline.

References

• Jenkins Pipeline Shared Libraries
• Slack Plugin for Jenkins