cli.py 文件源码

def import_callable(ctx, param, value):
    if value is None:
        return None

    delim = ':'
    if delim not in value:
        raise click.BadParameter(
            'string to import should have the form '
            'pkg.module:callable_attribute')

    mod, identifier = value.rsplit(delim, 1)

    try:
        func_or_cls = getattr(importlib.import_module(mod), identifier)
    except AttributeError:
        raise click.BadParameter('{} does not exist in {}'
                                 .format(identifier, mod))

    if callable(func_or_cls):
        return func_or_cls
    raise RuntimeError('{} is not callable'.format(value))