find_userdefined_classses.py

VALID_PYTHON_EXTENSIONS = ('.py', )


def get_userdefined_class(directory: str, target_baseclass: object) -> list:
    """
    Load Classes that sub-classed the given 'target_baseclass' for modules in the given directory
    :param directory: directory containing user-defined classes subclassing 'target_baseclass'
    :param target_baseclass: the ABC class that the user class subclasses
    :return: (class) [UserDefinedClass, ...]
    """
    import inspect
    import importlib

    # find classes subclassed from target_baseclass
    userdefined_classes = []
    python_module_filepaths = [os.path.join(directory, f) for f in os.listdir(directory) if f.endswith(VALID_PYTHON_EXTENSIONS)]
    for python_module_filepath in python_module_filepaths:
        module_name, module_ext = os.path.splitext(os.path.basename(python_module_filepath))
        spec = importlib.util.spec_from_file_location(module_name, python_module_filepath)
        module = importlib.util.module_from_spec(spec)
        spec.loader.exec_module(module)
        module_classes = inspect.getmembers(module, inspect.isclass)
        for identifier, klass in module_classes:
            if klass is not target_baseclass and issubclass(klass, target_baseclass):
                userdefined_classes.append(klass)

    return userdefined_classes