Jenkins variable defined inside global variable(env variable) - jenkins

Question

I have defined an environment(global) variable in jenkins via configuration as
REPORT = "Test, ${CycleNumber},${JOB_NAME}"
I have 1 parameter defined in my pipeline called Cycle which has values new & update. Based on this cycle value CycleNumber should be updated and I tried it via groovy using script block in my pipeline as below
if(Cycle == "New")
{
CycleNumber = "12345"
}
else if (Cycle == "Update")
{
CycleNumber = "7890"
}
after this update if I do echo "${env.REPORT}" I get the value as "Test,,TestJob" where in the CycleNumber variable is not updated. Could you please let me know if there is a way to update this CycleNumber field ?

Answer 1

Don't rely on Groovy's String interpolation to replace the CycleNumber. You can have your own placeholder(e.g: _CYCLE_NUMBER_) in the environment variable which you can replace later in your flow. Take a look at the following example.
pipeline {
agent any
stages {
stage("Test") {
environment {
REPORT = "Test, _CYCLE_NUMBER_,${JOB_NAME}"
}
steps {
script {
def Cycle = 'New'
def CycleNumber = 'none'
if(Cycle == "New"){
CycleNumber = "12345"
} else if (Cycle == "Update") {
CycleNumber = "7890"
}
def newReport = "$REPORT".replace('_CYCLE_NUMBER_', CycleNumber)
echo "$newReport"
}
}
}
}
}
Also once you set the newReport variable, make sure you use the same variable. if you do "${env.REPORT}" you will always get the original value assigned the tne environment variable.

Answer 2

Here is an answer with a workaround here: Updating environment global variable in Jenkins pipeline from the stage level - is it possible?
TLDR:
You can't override a global environment variable that has been declared in environment(global), however you can use the withEnv() function to wrap your script block in your pipeline to reference the updated value, eg:
withEnv(['REPORT=...']) {
// do something with updated env.REPORT
}