Use Jenkins 'Mailer' inside pipeline workflow - jenkins

Question

I'd like to leverage the existing Mailer plugin from Jenkins within a Jenkinsfile that defines a pipeline build job. Given the following simple failure script I would expect an email on every build.
stage 'Test'
node {
try {
sh 'exit 1'
} finally {
step([$class: 'Mailer', notifyEveryUnstableBuild: true, recipients: 'me#me.com', sendToIndividuals: true])
}
}
The output from the build is:
Started by user xxxxx
[Pipeline] stage (Test)
Entering stage Test
Proceeding
[Pipeline] node
Running on master in /var/lib/jenkins/jobs/rpk-test/workspace
[Pipeline] {
[Pipeline] sh
[workspace] Running shell script
+ exit 1
[Pipeline] step
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
ERROR: script returned exit code 1
Finished: FAILURE
As you can see, it does record that it performs the pipeline step immediately after the failure, but no emails get generated.
Emails in other free-style jobs that leverage the mailer work fine, its just invoking via pipeline jobs.
This is running with Jenkins 2.2 and mailer 1.17.
Is there a different mechanism by which I should be invoking failed build emails? I don't need all the overhead of the mail step, just need notifications on failures and recoveries.

Answer 1

In Pipeline failed sh doesn't immediately set the currentBuild.result to FAILURE whereas its initial value is null. Hence, build steps that rely on the build status like Mailer might work seemingly incorrect.
You can check it by adding a debug print:
stage 'Test'
node {
try {
sh 'exit 1'
} finally {
println currentBuild.result // this prints null
step([$class: 'Mailer', notifyEveryUnstableBuild: true, recipients: 'me#me.com', sendToIndividuals: true])
}
}
This whole pipeline is wrapped with exception handler provided by Jenkins that's why Jenkins marks the build as failed in the the end.
So if you want to utilize Mailer you need to maintain the build status properly. For instance:
stage 'Test'
node {
try {
sh 'exit 1'
currentBuild.result = 'SUCCESS'
} catch (any) {
currentBuild.result = 'FAILURE'
throw any //rethrow exception to prevent the build from proceeding
} finally {
step([$class: 'Mailer', notifyEveryUnstableBuild: true, recipients: 'me#me.com', sendToIndividuals: true])
}
}
If you don't need to re-throw the exception, you can use catchError. It is a Pipeline built-in which catches any exception within its scope, prints it into console and sets the build status. For instance:
stage 'Test'
node {
catchError {
sh 'exit 1'
}
step([$class: 'Mailer', notifyEveryUnstableBuild: true, recipients: 'me#me.com', sendToIndividuals: true])
}

Answer 2

In addition to izzekil's excellent answer, you may wish to choose email recipients based on the commit authors. You can use email-ext to do this (based on their pipeline examples):
step([$class: 'Mailer',
notifyEveryUnstableBuild: true,
recipients: emailextrecipients([[$class: 'CulpritsRecipientProvider'],
[$class: 'RequesterRecipientProvider']])])
If you're using a recent email-ext (2.50+), you can use that in your pipeline:
emailext(body: '${DEFAULT_CONTENT}', mimeType: 'text/html',
replyTo: '$DEFAULT_REPLYTO', subject: '${DEFAULT_SUBJECT}',
to: emailextrecipients([[$class: 'CulpritsRecipientProvider'],
[$class: 'RequesterRecipientProvider']]))
If you're not using a declarative Jenkinsfile, you will need to put checkout scm so Jenkins can find the committers. See JENKINS-46431.
If you're still on an older version of email-ext, you'll hit JENKINS-25267. You could roll your own HTML email:
def emailNotification() {
def to = emailextrecipients([[$class: 'CulpritsRecipientProvider'],
[$class: 'DevelopersRecipientProvider'],
[$class: 'RequesterRecipientProvider']])
String currentResult = currentBuild.result
String previousResult = currentBuild.getPreviousBuild().result
def causes = currentBuild.rawBuild.getCauses()
// E.g. 'started by user', 'triggered by scm change'
def cause = null
if (!causes.isEmpty()) {
cause = causes[0].getShortDescription()
}
// Ensure we don't keep a list of causes, or we get
// "java.io.NotSerializableException: hudson.model.Cause$UserIdCause"
// see http://stackoverflow.com/a/37897833/509706
causes = null
String subject = "$env.JOB_NAME $env.BUILD_NUMBER: $currentResult"
String body = """
<p>Build $env.BUILD_NUMBER ran on $env.NODE_NAME and terminated with $currentResult.
</p>
<p>Build trigger: $cause</p>
<p>See: $env.BUILD_URL</p>
"""
String log = currentBuild.rawBuild.getLog(40).join('\n')
if (currentBuild != 'SUCCESS') {
body = body + """
<h2>Last lines of output</h2>
<pre>$log</pre>
"""
}
if (to != null && !to.isEmpty()) {
// Email on any failures, and on first success.
if (currentResult != 'SUCCESS' || currentResult != previousResult) {
mail to: to, subject: subject, body: body, mimeType: "text/html"
}
echo 'Sent email notification'
}
}

Answer 3

I think a better way to send mail notifications in jenkins pipelines is to use the post section of a pipeline as described in the jenkins docs instead of using try catch:
pipeline {
agent any
stages {
stage('whatever') {
steps {
...
}
}
}
post {
always {
step([$class: 'Mailer',
notifyEveryUnstableBuild: true,
recipients: "example#example.com",
sendToIndividuals: true])
}
}
}
}
}