Question

I want to get information about the callers of a specific function in python. For example:

class SomeClass():
    def __init__(self, x):
        self.x = x
    def caller(self):
        return special_func(self.x)

def special_func(x):
    print "My caller is the 'caller' function in an 'SomeClass' class."

Is it possible with python?

Answer 1

Yes, the sys._getframe() function let’s you retrieve frames from the current execution stack, which you can then inspect with the methods and documentation found in the inspect module; you’ll be looking for specific locals in the f_locals attribute, as well as for the f_code information:

import sys
def special_func(x):
    callingframe = sys._getframe(1)
    print 'My caller is the %r function in a %r class' % (
        callingframe.f_code.co_name, 
        callingframe.f_locals['self'].__class__.__name__)

Note that you’ll need to take some care to detect what kind of information you find in each frame.

sys._getframe() returns a frame object, you can chain through the whole stack by following the f_back reference on each. Or you can use the inspect.stack() function to produce a lists of frames with additional information.