get current function name inside that function using python

Actually, Eric's answer points the way if this is about logging:

For my logging purpose i want to log all the names of functions where my code is going

You can adjust the formatter to log the function name:

import logging               

def whoami():
    logging.info("Now I'm there")

def foo():
    logging.info("I'm here")
    whoami()
    logging.info("I'm back here again")

logging.basicConfig(
    format="%(asctime)-15s [%(levelname)s] %(funcName)s: %(message)s",
    level=logging.INFO)
foo()

prints

2015-10-16 16:29:34,227 [INFO] foo: I'm here
2015-10-16 16:29:34,227 [INFO] whoami: Now I'm there
2015-10-16 16:29:34,227 [INFO] foo: I'm back here again

You probably want inspect.getframeinfo(frame).function:

import inspect

def whoami(): 
    frame = inspect.currentframe()
    return inspect.getframeinfo(frame).function

def foo():
    print(whoami())

foo()

prints

whoami