jenkins parallel call for external function loaded from file - jenkins

Question

I have an external function to call multiple times (with different variable values) from my jenkins pipeline and was hoping to make this call parallel.
Here's my pipeline code.
stepsForParallel = [:]
parallel_list = ['apple','banana','orange']
def groovyFile = load "${path}/runFruit.groovy"
for(value in parallel_list){
stepsForParallel.put("Run for fruit-${value}", groovyFile.runForFruit(value))
}
parallel stepsForParallel
And my groovy file called 'runFruit' is as follows.
#!/usr/bin/env groovy
def runForFruit(fruitValue){
..do something here..
}
return this
For this code the pipeline still runs sequentially.
Perhaps because in this line inside the for loop
stepsForParallel.put("Run for fruit-${value}", groovyFile.runForFruit(value)) an actual call to the external function is being made?
Any suggestions on how to achieve this parallelization?

Answer 1

Take a look at the Documentation for the parallel step, it takes a map from branch names (the name of the parallel executions) to closures which are the code that will be executed per parallel stage. In your case you are not passing a closure, but rather executing the function itself.
parallel firstBranch: {
// do something
}, secondBranch: {
// do something else
},
failFast: true|false
So you need to construct your code to fit the parallel format by passing a closure that contains your code to execute as the map value.
In your case it will look something like (using collectEntries):
parallel_list = ['apple','banana','orange']
def groovyFile = load "${path}/runFruit.groovy"
stepsForParallel = parallel_list.collectEntries{ fruit ->
["Run for fruit-${fruit}" : {
groovyFile.runForFruit(fruit)
}]
}
parallel stepsForParallel
Or if you prefer your format using the for loop:
stepsForParallel = [:]
parallel_list = ['apple','banana','orange']
def groovyFile = load "${path}/runFruit.groovy"
for(value in parallel_list){
stepsForParallel.put("Run for fruit-${value}", { groovyFile.runForFruit(value) })
}
parallel stepsForParallel

Answer 2

You can also use it in below way :
def fruit_list = ['apple','banana','orange']
def groovyFile
def stepsForParallel = [:]
pipeline {
agent any
stages {
stage('Hello') {
steps {
script{
groovyFile = load "runFruit.groovy"
stepsForParallel = fruit_list.collectEntries {
["${it}" : groovyFile.runForFruit(it)]
}
}
}
}
}
}
parallel stepsForParallel
Output: