Filter Git events within a Jenkinsfile

Assuming you're using Git webhooks to trigger your Jenkins builds, let's say you want to trigger a different set of pipeline stages depending on whether the Git event is a push vs. a pull request. I.e for a push you may only wish to run static analysis and unit tests, whereas for a pull request you may want to add Selenium tests.

The following Jenkinsfile snippet will achieve this

// Import JSON Slurper
import groovy.json.JsonSlurperClassic

// Get the Git payload
def payload = new JsonSlurperClassic().parseText(env.payload)


// Now define a method to filter the event type
private String getEventType ( payload ){

   if( payload.pull_request  && payload.action.toLowerCase().contains("opened") ){
      return "pull_req"
   }

   else if( payload.ref && payload.head_commit){
      if( payload.ref.split('/')[1].toLowerCase().contains('head') ){
         return "push"
      }

      else if( payload.ref.split('/')[1].toLowerCase().contains('tag') ){
         return "tag"
      }
   }
}


// Now decide what action to take 
def eventType = getEventType( payload )
switch (eventType) {
  case "push":
    ............
    do something 
    ............
    break;

  case "pull_req":
    ............
    do something else 
    ............
    break;

  default:
      println "Git event ignored";
      currentBuild.displayName = "Git event ignored"
      
      // Tidy up the Jenkins GUI by deleting the ignored build
      def buildNumber = env.BUILD_ID
      node {
            sh "curl -X POST http://:@:443/job/execute-pipeline/${buildNumber}/doDelete"
      }