cli.py 文件源码

def get_transformation(location: str) -> Transformation:
    # TODO allow use of contributed transformations
    if ':' in location:
        module_path, transformation_name = location.split(':')
    else:
        module_path, transformation_name = location, None

    if not module_path.endswith('.py'):
        module_path += '.py'
    module_path = (Path.cwd() / module_path).resolve()
    dbg(f'Transformation module path: {module_path}')

    dbg('Loading module.')
    module_spec = importlib.util.spec_from_file_location('transformation_file', module_path)
    _module = importlib.util.module_from_spec(module_spec)
    module_spec.loader.exec_module(_module)

    dbg('Inspecting module.')
    transformation_objects = {k: v for k, v in vars(_module).items()
                              if isinstance(v, Transformation)}

    if transformation_name is None:
        if 'main' in transformation_objects:
            dbg("Selected symbol 'main' from module as transformation.")
            return transformation_objects['main']
        else:
            name, instance = next((k, v) for k, v in transformation_objects.items())
            dbg(f"Selected symbol '{name}' from module as transformation.")
            return instance

    for instance in transformation_objects.values():
        if instance.name == transformation_name:
            dbg(f"Selected transformation named '{transformation_name}' from module "
                f"as transformation.")
            return instance

    dbg(f"Selected symbol '{transformation_name}' from module as transformation.")
    return transformation_objects[transformation_name]