Dynamic closures called in parallel

[Mirek S]

Hi!

I'm using the following Pipeline script:

testruns = [:]

for (name in ["one", "two", "three"]) {

  print("Adding ${name} to testruns")

  testruns[name] = { print("Staring phase ${name}"); sleep 10; print("Finished phase ${name}")}

}

pipeline {

  agent { label 'master' }

  stages {

    stage("Parallelism") {

      steps {

        script {

          parallel testruns

        }

      }

    }

  }

}

I'm expecting to run those three dynamically created closures in parallel. But it appears that all closures were created using only the last field ("three"). Console output:

Started by user ...

[Pipeline] echo

Adding one to testruns

[Pipeline] echo

Adding two to testruns

[Pipeline] echo

Adding three to testruns

[Pipeline] node

Running on master in ...

[Pipeline] {

[Pipeline] stage

[Pipeline] { (Parallelism)

[Pipeline] script

[Pipeline] {

[Pipeline] parallel

[Pipeline] [one] { (Branch: one)

[Pipeline] [two] { (Branch: two)

[Pipeline] [three] { (Branch: three)

[Pipeline] [one] echo

[one] Staring phase three

[Pipeline] [one] sleep

[one] Sleeping for 10 sec

[Pipeline] [two] echo

[two] Staring phase three

[Pipeline] [two] sleep

[two] Sleeping for 10 sec

[Pipeline] [three] echo

[three] Staring phase three

[Pipeline] [three] sleep

[three] Sleeping for 10 sec

[Pipeline] [one] echo

[one] Finished phase three

[Pipeline] [one] }

[Pipeline] [two] echo

[two] Finished phase three

[Pipeline] [two] }

[Pipeline] [three] echo

[three] Finished phase three

[Pipeline] [three] }

[Pipeline] // parallel

[Pipeline] }

[Pipeline] // script

[Pipeline] }

[Pipeline] // stage

[Pipeline] }

[Pipeline] // node

[Pipeline] End of Pipeline

Finished: SUCCESS

Please note that all phases are saying "three":

[two] Finished phase three

I was thinking that maybe there's a need for some kind of splat operator on argument for "parallel", but pipeline parallel example doesn't use it (and when I tried I got java.lang.UnsupportedOperationException)

What am I not seeing here? Why the closures are not created properly?

[Mirek S]

Huh... Only now I noticed that my issue is mentioned in the pipeline parallel example. You can ignore this topic :)

//the dummy parameter is for preventing mutation of the parameter before the execution of the closure.
//we have to assign it outside the closure or it will run the job multiple times with the same parameter "4"
//and jenkins will unite them into a single run of the job

[Björn Pedersen]

Hi,

your problem is  actually addressed in the example.
The closure is evalutated only during the parallel call. There $name is constant.
Put a
def xname  = name
inside your loop and use xname in the closures.
 (in the example it is  the def index=i line).

Björn