Sending Notifications in Pipeline

Liam Newman's picture

Rather than sitting and watching Jenkins for job status, I want Jenkins to send notifications when events occur. There are Jenkins plugins for Slack, HipChat or even [email] among others.

Note: Something is Happening!

I think we can all agree getting notified when events occur is preferable to having to constantly monitor them just in case. I'm going to continue from where I left off in my previous post with the hermann project. I added a Jenkins Pipeline with an HTML publisher for code coverage. This week, I'd like to make Jenkins notify me when builds start and when they succeed or fail.

Setup and Configuration

First, I select targets for my notifications. For this blog post, I'll use sample targets that I control. I've created Slack and HipChat organizations called "bitwiseman", each with one member - me. And for email I'm running a Ruby SMTP server called mailcatcher, that is perfect for local testing such as this. Aside from these concessions, configuration would be much the same in a non-demo situation.

Next, I install and add server-wide configuration for the Slack, HipChat, and [Email-ext] plugins. Slack and HipChat use API tokens - both products have integration points on their side that generate tokens which I copy into my Jenkins configuration. Mailcatcher SMTP runs locally. I just point Jenkins at it.

Here's what the Jenkins configuration section for each of these looks like:

Slack Configuration

HipChat Configuration

Email Configuration

Original Pipeline

Now I can start adding notification steps. Just like in the previous post, I'll use the Jenkins Pipeline Snippet Generator to explore the step syntax for the notification plugins.

Here's the base pipeline before I start making changes:

stage 'Build'

node {
  // Checkout
  checkout scm

  // install required bundles
  sh 'bundle install'

  // build and run tests with coverage
  sh 'bundle exec rake build spec'

  // Archive the built artifacts
  archive (includes: 'pkg/*.gem')

  // publish html
  // snippet generator doesn't include "target:"
  // https://issues.jenkins-ci.org/browse/JENKINS-29711.
  publishHTML (target: [
      allowMissing: false,
      alwaysLinkToLastBuild: false,
      keepAll: true,
      reportDir: 'coverage',
      reportFiles: 'index.html',
      reportName: "RCov Report"
    ])
}

NOTE: This pipeline expects to be run from a Jenkinsfile in SCM. To copy and paste it directly into a Jenkins Pipeline job, replace the checkout scm step with git 'https://github.com/reiseburo/hermann.git'.

Job Started Notification

For the first change, I decide to add a "Job Started" notification. The snippet generator and then reformatting makes this straightforward:

node {

  notifyStarted()

  /* ... existing build steps ... */
}

def notifyStarted() {
  // send to Slack
  slackSend (color: '#FFFF00', message: "STARTED: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]' (${env.BUILD_URL})")

  // send to HipChat
  hipchatSend (color: 'YELLOW', notify: true,
      message: "STARTED: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]' (${env.BUILD_URL})"
    )

  // send to email
  emailext (
      subject: "STARTED: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]'",
      body: """

STARTED: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]':

Check console output at "${env.JOB_NAME} [${env.BUILD_NUMBER}]"

""", recipientProviders: [[$class: 'DevelopersRecipientProvider']] ) }

Since Pipeline is a Groovy-based DSL, I can use string interpolation and variables to add the exact details I want in my notification messages. When I run this I get the following notifications:

Started Notifications

Started Email Notification

Job Successful Notification

The next logical choice is to get notifications when a job succeeds. I'll copy and paste based on the notifyStarted method for now and do some refactoring later.

node {

  notifyStarted()

  /* ... existing build steps ... */

  notifySuccessful()
}

def notifyStarted() { /* .. */ }

def notifySuccessful() {
  slackSend (color: '#00FF00', message: "SUCCESSFUL: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]' (${env.BUILD_URL})")

  hipchatSend (color: 'GREEN', notify: true,
      message: "SUCCESSFUL: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]' (${env.BUILD_URL})"
    )

  emailext (
      subject: "SUCCESSFUL: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]'",
      body: """

SUCCESSFUL: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]':

Check console output at "${env.JOB_NAME} [${env.BUILD_NUMBER}]"

""", recipientProviders: [[$class: 'DevelopersRecipientProvider']] ) }

Again, I get notifications, as expected. This build is so fast that some of them are even on the screen at the same time:

Multiple Notifications

Job Failed Notification

Next I want to add failure notification. Here's where we really start to see the power and expressiveness of Jenkins Pipeline. A Pipeline is a Groovy script, so as we'd expect in any Groovy script, we can handle errors using try-catch blocks.

node {
  try {
    notifyStarted()

    /* ... existing build steps ... */

    notifySuccessful()
  } catch (e) {
    currentBuild.result = "FAILED"
    notifyFailed()
    throw e
  }
}

def notifyStarted() { /* .. */ }

def notifySuccessful() { /* .. */ }

def notifyFailed() {
  slackSend (color: '#FF0000', message: "FAILED: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]' (${env.BUILD_URL})")

  hipchatSend (color: 'RED', notify: true,
      message: "FAILED: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]' (${env.BUILD_URL})"
    )

  emailext (
      subject: "FAILED: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]'",
      body: """

FAILED: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]':

Check console output at "${env.JOB_NAME} [${env.BUILD_NUMBER}]"

""", recipientProviders: [[$class: 'DevelopersRecipientProvider']] ) }

Failed Notifications

Code Cleanup

Lastly, now that I have it all working, I'll do some refactoring. I'll unify all the notifications in one method and move the final success/failure notification into a finally block.

stage 'Build'

node {
  try {
    notifyBuild('STARTED')

    /* ... existing build steps ... */

  } catch (e) {
    // If there was an exception thrown, the build failed
    currentBuild.result = "FAILED"
    throw e
  } finally {
    // Success or failure, always send notifications
    notifyBuild(currentBuild.result)
  }
}

def notifyBuild(String buildStatus = 'STARTED') {
  // build status of null means successful
  buildStatus =  buildStatus ?: 'SUCCESSFUL'

  // Default values
  def colorName = 'RED'
  def colorCode = '#FF0000'
  def subject = "${buildStatus}: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]'"
  def summary = "${subject} (${env.BUILD_URL})"
  def details = """

STARTED: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]':

Check console output at "${env.JOB_NAME} [${env.BUILD_NUMBER}]"

""" // Override default values based on build status if (buildStatus == 'STARTED') { color = 'YELLOW' colorCode = '#FFFF00' } else if (buildStatus == 'SUCCESSFUL') { color = 'GREEN' colorCode = '#00FF00' } else { color = 'RED' colorCode = '#FF0000' } // Send notifications slackSend (color: colorCode, message: summary) hipchatSend (color: color, notify: true, message: summary) emailext ( subject: subject, body: details, recipientProviders: [[$class: 'DevelopersRecipientProvider']] ) }

You Have Been Notified!

I now get notified twice per build on three different channels. I'm not sure I need to get notified this much for such a short build. However, for a longer or complex CD pipeline, I might want exactly that. If needed, I could even improve this to handle other status strings and call it as needed throughout my pipeline.

Final View of Notifications

Links

This is the third in a series of posts showing ways to use Jenkins Pipeline. Follow along with this entire series through the links below:

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