Get fully qualified class name of an object in Python

Question

For logging purposes I want to retrieve the fully qualified class name of a Python object. (With fully qualified I mean the class name including the package and module name.)

I know about x.__class__.__name__, but is there a simple method to get the package and module?

Answer 1

With the following program

#! /usr/bin/env python

import foo

def fullname(o):
  # o.__module__ + "." + o.__class__.__qualname__ is an example in
  # this context of H.L. Mencken's "neat, plausible, and wrong."
  # Python makes no guarantees as to whether the __module__ special
  # attribute is defined, so we take a more circumspect approach.
  # Alas, the module name is explicitly excluded from __qualname__
  # in Python 3.

  module = o.__class__.__module__
  if module is None or module == str.__class__.__module__:
    return o.__class__.__name__  # Avoid reporting __builtin__
  else:
    return module + '.' + o.__class__.__name__

bar = foo.Bar()
print fullname(bar)

and Bar defined as

class Bar(object):
  def __init__(self, v=42):
    self.val = v

the output is

$ ./prog.py
foo.Bar