how to get $CAUSE in workflow

Question

Jenkins has a $CAUSE variable available to freestyle build jobs.

How can I access this or something similar in workflow?

My team makes use of it in email out

Answer 1

It looks like Workflow builds don't have this variable injected. However you can retrieve the required info from currentBuild.rawBuild object using hudson.model.Run.getCause() or hudson.model.Run.getCauses() method.

Example:

Workflow script:

println "CAUSE ${currentBuild.rawBuild.getCause(hudson.model.Cause$UserIdCause).properties}"

results with this output:

Running: Print Message
CAUSE [userName:John Smith, userId:jsmith, class:class hudson.model.Cause$UserIdCause, shortDescription:Started by user John Smith]

Other Cause subtypes can be found in the javadoc.

There is also a good get-build-cause example which is based on this answer in the jenkins Pipeline Examples repository.

Answer 2

$BUILD_CAUSE env is not available for pipelines, and in multibranch pipeline even currentBuild.rawBuild.getCause(hudson.model.Cause$UserIdCause) would fail, if build was triggered by SCM change or timer. So, I implemented below workaround..

    def manualTrigger = false
    node('master'){
       def causes = currentBuild.rawBuild.getCauses()
       for(cause in causes) {
          if(cause.properties.shortDescription =~ 'Started by user') {
             manualTrigger = true
             break
          }
      }
  }

And rest of my workflow is in another node

   node('nodefarm') {
       if(manualTrigger) {
         // do build stuff here
       } else {
         //build not triggered by user.
       }
   } 

Answer 3

We all like one-liners, so let me share one here:

env.STARTED_BY = currentBuild.getBuildCauses().iterator().next().userId ?: "SYSTEM"

To break it down, after 2.22 pipeline plugin release there is a nice getBuildCauses method added to access build causes.

If you run your job like:

def causes = currentBuild.getBuildCauses()
causes.each {
    echo "$it"
}
echo "${causes.iterator().next().userId}"

you will see:

[Pipeline] echo
[_class:hudson.model.Cause$UserIdCause, shortDescription:Started by user User Name (user.name), userId:user.name, userName:User Name (user.name)]
[Pipeline] echo
user.name

and if it was started by cron then you will see:

[Pipeline] echo
[_class:hudson.triggers.TimerTrigger$TimerTriggerCause, shortDescription:Started by timer]
[Pipeline] echo
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