Creating Python callback via monkey-patching

Question

I'm creating an object that will represent some system info that can be changed outside of my program. Im thinking about allowing a callback function to be specified by the user of my code that will be called when a change is detected. This is what I have, which seems to work (the function doodie would be user supplied)

def doodie(cls):
    print cls.teststr

class Testarino(object):
    def __init__(self):
        self.teststr = 'Yay!'

    def callback(self):
        raise NotImplementedError

    def go(self):
         self.callback(self)

 tester = Testarino()
 tester.callback = doodie

 tester.go()

I thought about using a user supplied decorator, but I think that might be less intuitive for a user.

Is this the best way to do this? Is there a better way?

Answer 1

There is no need for monkey-patching here, it would be cleaner to add a set_callback() function to your Testarino class, like this:

def doodie(cls):
    print cls.teststr

class Testarino(object):
    def __init__(self):
        self.teststr = 'Yay!'
        self.callback = None

    def set_callback(self, callback):
        self.callback = callback

    def go(self):
         if self.callback is None:
             raise NotImplementedError
         self.callback(self)

tester = Testarino()
tester.set_callback(doodie)

tester.go()