import argparse import inspect from enum import Enum from typing import ( Any, Callable, Dict, List, Optional, Type, get_args, get_origin, get_type_hints, ) from pydantic import BaseModel from typing_extensions import Annotated SEP = "__" class ArgparseCustomArgument(BaseModel): help: Optional[str] = None # action: Optional[Any] = None class ArgparseActionType(Enum): store = "store" store_true = "store_true" class ArgparseTranslator: def __init__(self, func: Callable, add_help: Optional[bool] = False): """ Initializes the ArgparseTranslator. Args: func (Callable): The function to translate into an argparse program. add_help (Optional[bool], optional): Whether to add the help argument. Defaults to False. """ self.func = func self.signature = inspect.signature(func) self.type_hints = get_type_hints(func) self.parser = argparse.ArgumentParser( description=func.__doc__, formatter_class=argparse.ArgumentDefaultsHelpFormatter, add_help=add_help, ) self._generate_argparse_arguments(self.signature.parameters) @staticmethod def _param_is_default(param: inspect.Parameter) -> bool: return param.default != inspect.Parameter.empty def _get_action_type(self, param: inspect.Parameter) -> str: param_type = self.type_hints[param.name] if param_type == bool: return ArgparseActionType.store_true.value return ArgparseActionType.store.value def _get_type(self, param: inspect.Parameter): param_type = self.type_hints[param.name] if get_origin(param_type) is list: # TODO: dict should also go here return get_args(param_type)[0] return param_type @staticmethod def _split_annotation( base_annotation: Type[Any], ) -> tuple[Type[Any], List[ArgparseCustomArgument]]: if get_origin(base_annotation) is not Annotated: return base_annotation, [] base_annotation, *maybe_custom_annotations = get_args(base_annotation) return base_annotation, [ annotation for annotation in maybe_custom_annotations if isinstance(annotation, ArgparseCustomArgument) ] @classmethod def _get_argument_help(cls, param: inspect.Parameter) -> Optional[str]: base_annotation = param.annotation _, custom_annotations = cls._split_annotation(base_annotation) help_annotation = custom_annotations[0].help if custom_annotations else None if not help_annotation: # try to get it from the docstring pass return help_annotation def _get_nargs(self, param: inspect.Parameter) -> Optional[str]: param_type = self.type_hints[param.name] if get_origin(param_type) is list: return "+" return None def _generate_argparse_arguments(self, parameters) -> None: for param in parameters.values(): param_type = self._get_type(param) # if the param is a custom type, we need to flatten it if inspect.isclass(param_type) and issubclass(param_type, BaseModel): # update type hints with the custom type fields type_hints = get_type_hints(param_type) # prefix the type hints keys with the param name type_hints = { f"{param.name}{SEP}{key}": value for key, value in type_hints.items() } self.type_hints.update(type_hints) # create a signature from the custom type sig = inspect.signature(param_type) # add help to the annotation annotated_parameters: List[inspect.Parameter] = [] for child_param in sig.parameters.values(): child_param = child_param.replace( name=f"{param.name}{SEP}{child_param.name}", annotation=Annotated[ child_param.annotation, ArgparseCustomArgument( help=param_type.schema()["properties"][ child_param.name ].get("help", None) ), ], kind=inspect.Parameter.KEYWORD_ONLY, ) annotated_parameters.append(child_param) # replacing with the annotated parameters new_signature = inspect.Signature( parameters=annotated_parameters, return_annotation=sig.return_annotation, ) self._generate_argparse_arguments(new_signature.parameters) # the custom type itself should not be added as an argument continue self.parser.add_argument( f"--{param.name}", type=param_type, dest=param.name, default=param.default, required=not self._param_is_default(param), action=self._get_action_type(param), help=self._get_argument_help(param), nargs=self._get_nargs(param), ) @staticmethod def _unflatten_args(args: dict) -> Dict[str, Any]: result: Dict[str, Any] = {} for key, value in args.items(): if SEP in key: parts = key.split(SEP) nested_dict = result for part in parts[:-1]: if part not in nested_dict: nested_dict[part] = {} nested_dict = nested_dict[part] nested_dict[parts[-1]] = value else: result[key] = value return result def _update_with_custom_types(self, kwargs: Dict[str, Any]) -> Dict[str, Any]: # for each argument in the signature that is a custom type, we need to # update the kwargs with the custom type kwargs for param in self.signature.parameters.values(): param_type = self._get_type(param) if inspect.isclass(param_type) and issubclass(param_type, BaseModel): custom_type_kwargs = kwargs[param.name] kwargs[param.name] = param_type(**custom_type_kwargs) return kwargs def execute_func( self, parsed_args: Optional[argparse.Namespace] = None, ) -> Any: kwargs = self._unflatten_args(vars(parsed_args)) kwargs = self._update_with_custom_types(kwargs) kwargs.pop("help", None) return self.func(**kwargs) def parse_args_and_execute(self) -> Any: """ Parses the arguments and executes the original function. Returns: Any: The return value of the original function. """ parsed_args = self.parser.parse_args() return self.execute_func(parsed_args) def translate(self) -> Callable: """ Wraps the original function with an argparse program. Returns: Callable: The original function wrapped with an argparse program. """ def wrapper_func(): return self.parse_args_and_execute() return wrapper_func # def hello_world(name: str, age: int): # print(f"Hello {name}! You are {age} years old.") # translator = ArgparseTranslator(hello_world) # parser = translator.parser # parsed_args = parser.parse_args() # print(parsed_args) # translator.execute_func(parsed_args)