How to handle nightly build in Jenkins declarative pipeline - jenkins

Question

I have a multibranch pipeline with a Jenkinsfile in my repo and I am able to have my CI workflow (build & unit tests -> deploy-dev -> approval -> deploy-QA -> approval -> deploy-prod) on every commit.
What I would like to do is add SonarQube Analysis on nightly builds in the first phase build & unit tests.
Since my build is triggerd by Gitlab I have defined my pipeline triggers as follow :
pipeline {
...
triggers {
gitlab(triggerOnPush: true, triggerOnMergeRequest: true, branchFilterType: 'All')
}
...
}
To setup my nightly build I have added
triggers {
...
cron('H H * * *')
}
But now, how to execute analysis step if we are only building the job triggered by the cron expression at night ?
My simplified build stage looks as follow :
stage('Build & Tests & Analysis') {
// HERE THE BEGIN SONAR ANALYSIS (to be executed on nightly builds)
bat 'msbuild.exe ...'
bat 'mstest.exe ...'
// HERE THE END SONAR ANALYSIS (to be executed on nightly builds)
}

Answer 1

There is the way how to get build trigger information. It is described here:
https://jenkins.io/doc/pipeline/examples/#get-build-cause
It is good for you to check this as well:
how to get $CAUSE in workflow
Very good reference for your case is https://hopstorawpointers.blogspot.com/2016/10/performing-nightly-build-steps-with.html. Here is the function from that source that exactly matches your need:
// check if the job was started by a timer
#NonCPS
def isJobStartedByTimer() {
def startedByTimer = false
try {
def buildCauses = currentBuild.rawBuild.getCauses()
for ( buildCause in buildCauses ) {
if (buildCause != null) {
def causeDescription = buildCause.getShortDescription()
echo "shortDescription: ${causeDescription}"
if (causeDescription.contains("Started by timer")) {
startedByTimer = true
}
}
}
} catch(theError) {
echo "Error getting build cause"
}
return startedByTimer
}

Answer 2

This works in declarative pipeline
when {
triggeredBy 'TimerTrigger'
}

Answer 3

For me the easiest way is to define a cron in build trigger and verify the hour on the nightly stage using a when expression:
pipeline {
agent any
triggers {
pollSCM('* * * * *') //runs this pipeline on every commit
cron('30 23 * * *') //run at 23:30:00
}
stages {
stage('nightly') {
when {//runs only when the expression evaluates to true
expression {//will return true when the build runs via cron trigger (also when there is a commit at night between 23:00 and 23:59)
return Calendar.instance.get(Calendar.HOUR_OF_DAY) in 23
}
}
steps {
echo "Running the nightly stage only at night..."
}
}
}
}

Answer 4

You could check the build cause like so:
stage('Build & Tests & Analysis') {
when {
expression {
for (Object currentBuildCause : script.currentBuild.rawBuild.getCauses()) {
return currentBuildCause.class.getName().contains('TimerTriggerCause')
}
}
steps {
bat 'msbuild.exe ...'
bat 'mstest.exe ...'
}
}
}
However, this requires the following entries in script-approval.xml:
<approvedSignatures>
<string>method hudson.model.Run getCauses</string>
<string>method org.jenkinsci.plugins.workflow.support.steps.build.RunWrapper getRawBuild</string>
</approvedSignatures>
This can also be approved via https://YOURJENKINS/scriptApproval/.
Hopefully, this won't be necessary after JENKINS-41272 is fixed.
Until then, a workaround could be to check the hour of day in the when expression (keep in mind that these times refer to to the timezone of Jenkins)
when { expression { return Calendar.instance.get(Calendar.HOUR_OF_DAY) in 0..3 } }

Answer 5

I've found a way, which does not use "currentBuild.rawBuild" which is restricted. Begin your pipeline with:
startedByTimer = false
def buildCauses = "${currentBuild.buildCauses}"
if (buildCauses != null) {
if (buildCauses.contains("Started by timer")) {
startedByTimer = true
}
}
Test the boolean where you need it, for example:
stage('Clean') {
when {
anyOf {
environment name: 'clean_build', value: 'Yes'
expression { (startedByTimer == true) }
}
}
steps {
echo "Cleaning..."
...

Answer 6

Thanks to this you can now do this without needing to the the use the non-whitelisted currentBuild.getRawBuild().getCauses() function which can give you Scripts not permitted to use method org.jenkinsci.plugins.workflow.support.steps.build.RunWrapper getRawBuild depending on your setup:
#NonCPS
def isJobStartedByTimer() {
def startedByTimer = false
try {
def buildCauses = currentBuild.getBuildCauses()
for ( buildCause in buildCauses ) {
if (buildCause != null) {
def causeDescription = buildCause.shortDescription
echo "shortDescription: ${causeDescription}"
if (causeDescription.contains("Started by timer")) {
startedByTimer = true
}
}
}
} catch(theError) {
echo "Error getting build cause"
}
return startedByTimer
}