How to get python caller object information?

Question

How can I fetch the caller object from within a function, and inspect information about that caller?

class A(object):
 def class_A_fun(self):
 print 'caller from class' # → B
 print 'caller from method' # → class_B_fun
 print 'caller module' # → foomodule
 print 'caller instance' # → obj
 print 'caller object file name or path' # → 'foomodule.py'
class B(object):
 def class_B_fun(self): 
 obj = A()
 obj.class_A_fun() 
if __name__ == "__main__":
 obj = B()
 obj.class_B_fun()

• BrtH: Maybe this is helpful. Google 'python get caller' turns up some nice results.
• phant0m: What are you trying to do? It's usually not a good idea to do this.
• user1559873: @phant0m i am trying to develop customized logger Framework,which fetch the object information as shown above.

Answer 1

from inspect import currentframe, getframeinfo, getmodulename
from pathlib import Path
class A(object):
 def class_A_fun(self):
 cuurent_frame = currentframe()
 caller_frame = cuurent_frame.f_back
 filename, lineno, function, code_context, index = getframeinfo(caller_frame)
 # first_arg_name in this case is 'self', but could be sth else
 first_arg_name = caller_frame.f_code.co_varnames[0]
 # f_locals is the local namespace seen by the frame
 caller_instance = caller_frame.f_locals[first_arg_name]
 assert caller_instance is caller_frame.f_back.f_locals['b'] is b
 assert type(caller_instance).__name__ == 'B'
 assert function == caller_frame.f_code.co_name == 'class_B_fun'
 assert filename == caller_frame.f_code.co_filename == __file__
 assert getmodulename(filename) == Path(__file__).stem
class B(object):
 def class_B_fun(self):
 a = A()
 a.class_A_fun()
if __name__ == "__main__":
 b = B()
 b.class_B_fun()

• David Jones: there is nothing that says your caller must have a local called self. that's pure convention (for methods not functions)
• AXO: @DavidJones I changed my answer, however there are more complicated situations, e.g. for a static method. In the end one may need to analyze the whole source code to properly identify the calling object.

Answer 2

Not all of those are possible, but most are available by inspecting the call stack:

import sys
import inspect
__metaclass__ = type
class Lorem:
 def ipsum(self):
 caller_frame = sys._getframe(1)
 caller_frameinfo = inspect.getframeinfo(caller_frame)
 print("Caller is in module {module!r}".format(
 module=inspect.getmodule(caller_frame)))
 print("Caller is defined in {path!r}, line {lineno}".format(
 path=inspect.getsourcefile(caller_frame),
 lineno=caller_frameinfo.lineno))
class Dolor:
 def sit_amet(self):
 lorem = Lorem()
 lorem.ipsum()

For more information, see the documentation for the inspect module.

• Géry Ogam: What about the caller class?