I have a use case where I want to extract information from a Child job in the parent job.

This is my pipeline script:

pipeline {
  agent any
    stages {
    stage('Validate Other Job') {
        steps {
            script {
                echo "triggerring build"
                   def triggeredJob = build job: 'Pipeline1'
                   def logs = triggeredJob.rawBuild.getLog(100)
                   echo "Logs '$logs'"
                   }
                }
            }
       }
}

Output: When ‘Pipeline1’ job status is: SUCCESS
It prints the logs

Issue: When ‘Pipeline1’ job status is: FAILURE or UNSTABLE
It throws error:

Build Pipeline1 #18 completed: FAILURE
   [Pipeline] }
   [Pipeline] // script
   [Pipeline] }
   [Pipeline] // stage
   [Pipeline] }
   [Pipeline] // node
   [Pipeline] End of Pipeline
   Pipieline1 #18 completed with status FAILURE (propagate: false to ignore)
  org.jenkinsci.plugins.workflow.actions.ErrorAction$ErrorId: edf4f356-929c-4720- 
  a57f-b2bdef027f2c
  Finished: FAILURE

My use case is to get the logs when Build fails/unstable and check that weather a particular string is available in the logs. If yes, then trigger a mail.

Child job is a dummy job:

pipeline {
agent any

stages {
    stage('Hello') {
        steps1 { // step1 for marking the build fail for testing
            echo 'Hello World'
        }
      }
    }
  }