Jenkins groovy plugin file not found exception

Question

I've a script to find the all idle slaves and create a text file using Jenkins system groovy. I'm able to create a empty file and find all idle slaves where as coming to append to the file "idle_slaves.list" i got java.io.FileNotFoundException exception. Can somebody help me on this?

import jenkins.*
import hudson.*
import jenkins.model.Jenkins

jenkins = jenkins.model.Jenkins

File file1 = new File(build.workspace.toString() + "/idle_slaves.list")

if(build.workspace.isRemote())
{
    channel = build.workspace.channel;
    fp = new FilePath(channel, build.workspace.toString() + "/idle_slaves.list")
} else {
    fp = new FilePath(new File(build.workspace.toString() + "/idle_slaves.list"))
}

if(fp != null)
{
    fp.write("", null); //writing to file
} 

for (node in Jenkins.instance.nodes) {
  computer = node.toComputer()
  if (computer.getChannel() == null) {
    continue
  }
if (computer.isIdle()) {
 slave = node.name.toString()
file1.append( slave )
}
}

Jenkins 2.46

groovy 2.0

Line of error? Can you share your stack trace ? Also what is your requirement, maybe there are another approaches. — JRichardsz, Jul 09 '18 at 19:33

score 2 · Answer 1 · answered Jul 10 '18 at 03:10

Actually the file itself is not created yet :)

File file1 = new File(build.workspace.toString() + "/idle_slaves.list")

just creates a pointer to the path if you want to create the file, then add the following line

file1.createNewFile()

Also ensure the file that you create has permission access, otherwise you will get permission denied.

You add the following piece of code to confirm.

// check if the file exists
        boolean exists = file.exists();
        if(exists == true)
        {
            // printing the permissions associated with the file
            println "Executable: " + file.canExecute();
            println "Readable: " + file.canRead();
            println "Writable: "+ file.canWrite();
        }
        else
        {
            println "File not found.";
        }

Hope it helps :)

score 0 · Answer 2 · answered Jul 10 '18 at 15:28

Instead of manually read, why not use jenkins/hudson libraries :

https://serverfault.com/a/889954

pipeline {
    agent {label 'slave'}
    stages {
        ...
    }
}

https://stackoverflow.com/a/43111789/3957754

def jenkins = Jenkins.instance
def computers = jenkins.computers

computers.each{ 
  println "${it.displayName} ${it.hostName}"
}

https://github.com/jenkinsci/jenkins-scripts/blob/master/scriptler/disableSlaveNodeStartsWith.groovy

https://wiki.jenkins.io/display/JENKINS/Display+Information+About+Nodes

for (aSlave in hudson.model.Hudson.instance.slaves) {

Jenkins groovy plugin file not found exception

2 Answers2