List classes in directory (Python)

Question

I'm developing a Python 2.6 package in which I would like to fetch a list of all classes in a certain directory (within the package) in order to then perform introspection on the class objects.

Specifically, if the directory containing the currently executing module has a sub-dir called 'foobar' and 'foobar' contains .py files specifying class Foo(MyBase), class Bar(MyBase), and class Bar2, I want to obtain a list of references to the class objects that inherit from MyBase, i.e. Foo and Bar, but not Bar2.

I'm not sure if this task actually need involve any dealing with the filesystem or if the modules in the sub-dir are automatically loaded and just need to be listed via introspection somehow. Any ideas here please? Example code is much appreciated, since I'm pretty new to Python, in particular introspection.

Answer 1

Option 1: grep for "^class (\a\w+)\(Myclass" regexp with -r parameter.

Option 2: make the directory a package (create an empty __init__.py file), import it and iterate recursively over its members:

import mymodule
def itermodule(mod):
    for member in dir(mymod):
        ...

itermodule(mymodule)

Answer 2

Modules are never loaded automatically, but it should be easy to iterate over the modules in the directory and load them with the __import__ builtin function:

import os
import glob
for file in glob(os.path.join(os.path.dirname(os.path.abspath(__file__))), "*.py"):
    name = os.path.splitext(os.path.basename(file))[0]
    # add package prefix to name, if required
    module = __import__(name)
    for member in dir(module):
        # do something with the member named ``member``