Define a function in a python module so that the function name equals to a string variable

Question

I have a python module which expected to expose an function with configurable name.

module.py looks like this:

def _actual_func():
    print "do the actual work"

INTERFACE_NAME = _load_interface_name_from_conf()

if INTERFACE_NAME == 'foo':
    def foo():
        _actual_func()
elif INTERFACE_NAME == 'bar':
    def bar():
        _actual_func()
elif INTERFACE_NAME == 'baz':
    def baz():
        _actual_func()

The client uses my module like this:

import module

# call the interface function
FUNCTION_NAME_TO_CALL = _load_form_client_conf() # configured to equal INTERFACE_NAME
getattr(module, FUNCTION_NAME_TO_CALL)()

The problem is the code can only work when INTERFACE_NAME equals 'foo' , 'bar' or 'baz' . How can I rewrite my code so that I can configure the INTERFACE_NAME to any string value?

Answer 1

Use setattr . You will need sys to get the module corresponding to your own module:

import sys

def _actual_func():
    print("do the actual work")

INTERFACE_NAME = _load_interface_name_from_conf()
_thismodule = sys.modules[__name__]
setattr(_thismodule, INTERFACE_NAME, _actual_func)

Answer 2

I think you can do simpler by eval() function.

def foo():
    pass
def bar():
    pass

def call_func(name):   
    eval(name + "()")

call_func("foo")
call_func("bar")