call_inspection.py

# -*- coding: utf-8 -*-

import inspect


def get_caller():
    """ Inspects the call stack to determine the path of a caller.
        Returns a string representing the full path to the caller.
    """

    # If we want to get the "caller" of a function, from this context we
    # must go backwards by two layers. The first frame is the current frame.
    # The second frame would be the function that calls get_caller().
    # The third frame is the frame we want to know the identity of.

    # The named tuple, Traceback, looks like this:
    #  Traceback(filename, lineno, function, code_context, index)

    frame = inspect.currentframe()
    # Get a list of frames up to two outside of the current frame1.
    callstack = inspect.getouterframes(frame, 2)
    # callstack is [Traceback(...), ...]
    # Grab the outermost frame
    caller = callstack[2][0]
    # Pull the Traceback tuple for the current frame.
    callerinfo = inspect.getframeinfo(caller)

    # Determine if the function is a bound method.
    if 'self' in caller.f_locals:
        # Since the caller is a bound method, extract the 'self' reference
        # from the locals, then pull the class name from the instance class.
        caller_class = caller.f_locals["self"].__class__.__name__
    else:
        # There is no object this method is bound to -- it is a module
        # function.
        caller_class = None

    # Get the FQN of the module that the calling frame belongs to.
    caller_module = inspect.getmodule(caller).__name__
    # callerinfo is Traceback(...)
    caller_name = callerinfo[2]

    # Check the determined caller class.
    if caller_class:
        # If there is a caller class, prepend it to the caller name.
        caller_string = f"{caller_class}.{caller_name}"
    else:
        # The caller string is just the caller name by itself.
        caller_string = caller_name

    # Check if we know the caller module.
    if caller_module:
        caller_string = f"{caller_module}.{caller_string}"

    if caller.f_lineno:
        caller_string = f"{caller_string}:{caller.f_lineno}"

    return caller_string