I have the following python script myscript.py:

#!/usr/bin/python
def main():
    return "hello"

if __name__ == '__main__':
    main()

And I run that script from the Jenkins groovy:

returnValue = sh(returnStdout: true, script: "python3.9 -u scripts/myscript.py")
log.info("returnValue: ${returnValue}")

I expect to see returnValue: hello in the logs but I see returnValue:

I understand that returnStdout: true returns standard output from the python script, and since there is no standard output the returnValue is null resulting in returnValue:

To prove my point, I modify my python script to print “hello” instead of returning it as following:

#!/usr/bin/python
def main():
    print("hello")

if __name__ == '__main__':
    main()

And now I get returnValue: hello from Jenkins log.

Even though the implementation with the print instead of return works it just doesn’t feel right and very confusing.
Is this behavior correct?
Or is there a way to actually use return keyword in the python script and store the returned value in the variable inside the Jenkins groovy file?