Tag Archives: Jenkins

Terminate a stuck Jenkins job

Sometimes (especially after an un-graceful process restart), Jenkins jobs will be stuck in a running state, and cancelling through the UI just doesn’t work.

Fortunately, jobs can be stopped via the Jenkins script console with this command (courtesy of https://stackoverflow.com/a/26306081/11125318):

Jenkins.instance.getItemByFullName("JobName")
                .getBuildByNumber(JobNumber)
                .finish(
                        hudson.model.Result.ABORTED,
                        new java.io.IOException("Aborting build")
                );

Obtaining Git Repo URL from Jenkins Changeset: Unsolved

I’m attempting to obtain a Git Repo URL from a Jenkins Change set in a Groovy Scripted Pipeline, but I keep running into the same issue: the browser property (obtained via .getBrowser()) on my hudson.plugins.git.GitChangeSetList object is undefined.

I’m running the below code (with inline “status comments”) from the Jenkins groovy script console in an attempt to extract the RepoUrl from Chagesets in a Jenkins Multi branch groovy scripted pipeline:

def job = Jenkins.instance.getItem("MyJenkinsJob") 
def branch = job.getItems().findAll({ 
            item -> item.getDisplayName().contains("Project/CreateChangeLogs")
        })

printAllMethods(branch[0].getFirstBuild()) //this works, and is a org.jenkinsci.plugins.workflow.job.WorkflowRun

def builds = branch[0].getBuilds()
def currentBuild = builds[0]

currentBuild.changeSets.collect { 
  printAllMethods(it) // this works too, and is a hudson.plugins.git.GitChangeSetList.
  // enumerated methods are equals(); getClass(); hashCode(); notify(); notifyAll(); toString(); wait(); createEmpty(); getBrowser(); getItems(); getKind(); getRun(); isEmptySet(); getLogs(); iterator(); 

  it.getBrowser().repoUrl // this fails
  // the error is java.lang.NullPointerException: Cannot get property 'repoUrl' on null object
}

I found the utility class for PrintAllMethods here (https://bateru.com/news/2011/11/code-of-the-day-groovy-print-all-methods-of-an-object/):

  void printAllMethods( obj ){
    if( !obj ){
        println( "Object is null\r\n" );
        return;
    }
    if( !obj.metaClass && obj.getClass() ){
        printAllMethods( obj.getClass() );
        return;
    }
    def str = "class ${obj.getClass().name} functions:\r\n";
    obj.metaClass.methods.name.unique().each{ 
        str += it+"(); "; 
    }
    println "${str}\r\n";
}

The API spec for GitChangeSetList indicates that in extends hudson.scm.ChangeLogSet which implements getBrowser(), so the call should be valid.

Additionally, the source for GitChangeSetList invokes the super() constructor with the passed browser object.

At this point, I’m probably going to continue diving through the source code until I figure it out.

It looks like this is a documented issue with Jenkins: https://issues.jenkins-ci.org/browse/JENKINS-52747

And a (somewhat) related StackOverflow post: https://devops.stackexchange.com/questions/3798/determine-the-url-for-a-scm-trigger-from-inside-the-build

TIL: Java code in Jenkins pipelines run on the Master

I was trying to read a file with Java.io.File in a Jenkins Groovy Scripted Pipeline on a non-master node. I kept getting an exception that the file was not found (java.io.FileNotFoundException)

Turns out that Java code written in scripted pipelines (Groovy) runs on the master node: https://issues.jenkins-ci.org/browse/JENKINS-37577. This is as-designed behavior, and accessing files in the workspace on a non-master node should use the readFile function in the Pipeline Basic Steps DSL https://jenkins.io/doc/pipeline/steps/workflow-basic-steps/#pwd-determine-current-directory

I’m thoroughly embarrassed at how many failed Jenkins jobs and alerts I’ve triggered while discovering this.