Demo Slack Attachments

In this lesson, you’ll learn how to send rich, interactive Slack notifications from Jenkins pipelines using attachments and Block Kit. We will:

Explore Slack’s Block Kit Builder and message layouts
Build JSON payloads with attachments and blocks
Integrate payloads in Jenkins via a shared library
Customize messages with emojis, images, and buttons

Quick Slack Notifications Example

Out of the box, Jenkins’ Slack plugin can send basic build statuses:

jenkins  APP  20:46
ABORTED: devsecops-numeric-application #72: http://…/job/devsecops-numeric-application/72/

jenkins  APP  21:00
SUCCESS: devsecops-numeric-application #73: http://…/job/devsecops-numeric-application/73/

These simple messages work, but to stand out you can leverage Slack’s rich layouts.

Slack API: Rich Message Layouts

Slack’s Messaging Layouts guide shows how to assemble messages with attachments and blocks:

The image shows a webpage from the Slack API documentation, specifically about creating rich message layouts. It includes navigation links on the left and content about adding blocks to messages.

Use the Slack API documentation to discover block types like section, divider, and interactive elements such as buttons and overflow menus.

Block Kit Builder

Prototype your message in Slack’s Block Kit Builder before coding.

Basic Section Block

{
  "blocks": [
    {
      "type": "section",
      "text": {
        "type": "mrkdwn",
        "text": "New Paid Time Off request from <https://example.com|Fred Enriquez>\n\n<https://example.com|View request>"
      }
    }
  ]
}

Interactive Message with Button and Image

{
  "blocks": [
    {
      "type": "section",
      "text": {
        "type": "mrkdwn",
        "text": "Hello, Assistant to the Regional Manager Dwight! *Michael Scott* wants to know where you'd like to take the investors to dinner.\n*Please select a restaurant:*"
      }
    },
    { "type": "divider" },
    {
      "type": "section",
      "text": {
        "type": "mrkdwn",
        "text": "*Farmhouse Thai Cuisine*\n⭐️⭐️⭐️⭐️ 1528 reviews\nThey do have some vegan options…"
      },
      "accessory": {
        "type": "image",
        "image_url": "https://s3-media3.fl.yelpcdn.com/bphoto/c7e05s9lC12mA3arueZ7A/o.jpg",
        "alt_text": "Thai restaurant"
      }
    }
  ]
}

Constructing an Attachment Payload

Wrap blocks in an attachments array to add colors, fallbacks, or pretext:

{
  "attachments": [
    {
      "color": "#2fc744",
      "blocks": [
        {
          "type": "section",
          "text": {
            "type": "mrkdwn",
            "text": "*Hi devsecops!*"
          }
        },
        { "type": "divider" },
        {
          "type": "section",
          "text": {
            "type": "mrkdwn",
            "text": "*Farmhouse Thai Cuisine*\n⭐️⭐️⭐️⭐️⭐️…"
          },
          "accessory": {
            "type": "image",
            "image_url": "https://s3-media1.fl.yelpcdn.com/photo/c7e0s5m9lC2mA3aruue7A/o.jpg",
            "alt_text": "Restaurant image"
          }
        }
      ]
    }
  ]
}

Always validate your JSON. Slack expects arrays [] around lists and objects {} for key/value pairs.

Jenkins Slack Notification Plugin

Jenkins uses the Slack Notification Plugin to send JSON payloads. You can pass your attachment payload directly:

slackSend(color: color, attachments: attachments)

Table: Build Status Mapping

Build Status	Color	Emoji
SUCCESS	#47e05e	:tada:
UNSTABLE	#d9d26d	:warning:
FAILURE	#ec2805	:hulk:

Shared Library: sendNotifications.groovy

Use a shared library to assemble attachments dynamically:

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

    // Map status to color and emoji
    def (color, emoji) = buildStatus == 'SUCCESS' ? ['#47e05e', ':tada:']
                          : buildStatus == 'UNSTABLE'? ['#d9d26d', ':warning:']
                          : ['#ec2805', ':hulk:']

    def attachments = [
        [
            "color": color,
            "blocks": [
                [
                    "type": "header",
                    "text": [
                        "type": "plain_text",
                        "text": "K8S Deployment - ${env.JOB_NAME} ${emoji}",
                        "emoji": true
                    ]
                ],
                [
                    "type": "section",
                    "fields": [
                        ["type": "mrkdwn", "text": "*Job Name:*\n${env.JOB_NAME}"],
                        ["type": "mrkdwn", "text": "*Build Number:*\n${env.BUILD_NUMBER}"]
                    ],
                    "accessory": [
                        "type": "image",
                        "image_url": "https://raw.githubusercontent.com/sidd-harth/numeric/main/images/jenkins-slack.png",
                        "alt_text": "Slack Icon"
                    ]
                ],
                ["type": "divider"]
            ]
        ]
    ]

    slackSend(color: color, attachments: attachments)
}

Custom Emojis in Slack

Add custom emojis under Customize Slack → Add Emoji. For example, upload deadpool.png as :deadpool::

The image shows a Slack interface with a pop-up window for adding a custom emoji, where an image named "deadpool.png" is being uploaded.

Ensure your team has emojis like :tada:, :warning:, and :hulk: available.

Integrating in Jenkinsfile

Call sendNotifications in your pipeline’s post section:

pipeline {
    agent any
    stages {
        stage('Integration Tests - PROD') {
            steps {
                withKubeConfig([credentialsId: 'kubeconfig']) {
                    sh 'bash integration-test-PROD.sh'
                }
            }
        }
        stage('Testing Slack') {
            steps {
                sh 'exit 0'
            }
        }
    }
    post {
        always { /* Optional reports */ }
        success {
            script {
                env.emoji = ':white_check_mark:'
                sendNotifications(currentBuild.result)
            }
        }
        failure {
            script {
                env.emoji = ':hulk:'
                sendNotifications(currentBuild.result)
            }
        }
    }
}

Resulting Slack Message

A successful pipeline produces a detailed Slack notification:

The image shows a Slack interface with a message from the Jenkins Slack App detailing a successful Kubernetes deployment pipeline. It includes information such as job name, build number, Kubernetes deployment details, and Git commit references.

This message includes:

A header with deployment name and emoji
Job name and build number fields
Custom icons and images
Optional action buttons or links to Jenkins, Kubernetes, or GitHub

Use this approach to highlight failed stages or add actionable buttons directly in Slack.

Watch Video

Demo Slack Jenkins Custom App

Demo Slack Get Failed Stage Name

Introduction

DevSecOps Pipeline

Kubernetes Operations and Security

HashiCorp Vault + Kubernetes

Additional Topics

DevOps Pipeline

Demo Slack Attachments

Quick Slack Notifications Example

Slack API: Rich Message Layouts

Block Kit Builder

Basic Section Block

Interactive Message with Button and Image

Constructing an Attachment Payload

Jenkins Slack Notification Plugin

Shared Library: sendNotifications.groovy

Custom Emojis in Slack

Integrating in Jenkinsfile

Resulting Slack Message

Watch Video

​Quick Slack Notifications Example

​Slack API: Rich Message Layouts

​Block Kit Builder

​Basic Section Block

​Interactive Message with Button and Image

​Constructing an Attachment Payload

​Jenkins Slack Notification Plugin

​Shared Library: sendNotifications.groovy

​Custom Emojis in Slack

​Integrating in Jenkinsfile

​Resulting Slack Message

Watch Video

Quick Slack Notifications Example

Slack API: Rich Message Layouts

Block Kit Builder

Basic Section Block

Interactive Message with Button and Image

Constructing an Attachment Payload

Jenkins Slack Notification Plugin

Shared Library: sendNotifications.groovy

Custom Emojis in Slack

Integrating in Jenkinsfile

Resulting Slack Message