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import importlib
import inspect
import re
from typing import Any, Callable, Type, Union, get_type_hints
from pydantic import BaseModel, parse_raw_as
from pydantic.tools import parse_obj_as
def name_to_title(name: str) -> str:
"""Converts a camelCase or snake_case name to title case."""
# If camelCase -> convert to snake case
name = re.sub("(.)([A-Z][a-z]+)", r"\1_\2", name)
name = re.sub("([a-z0-9])([A-Z])", r"\1_\2", name).lower()
# Convert to title case
return name.replace("_", " ").strip().title()
def is_compatible_type(type: Type) -> bool:
"""Returns `True` if the type is opyrator-compatible."""
try:
if issubclass(type, BaseModel):
return True
except Exception:
pass
try:
# valid list type
if type.__origin__ is list and issubclass(type.__args__[0], BaseModel):
return True
except Exception:
pass
return False
def get_input_type(func: Callable) -> Type:
"""Returns the input type of a given function (callable).
Args:
func: The function for which to get the input type.
Raises:
ValueError: If the function does not have a valid input type annotation.
"""
type_hints = get_type_hints(func)
if "input" not in type_hints:
raise ValueError(
"The callable MUST have a parameter with the name `input` with typing annotation. "
"For example: `def my_opyrator(input: InputModel) -> OutputModel:`."
)
input_type = type_hints["input"]
if not is_compatible_type(input_type):
raise ValueError(
"The `input` parameter MUST be a subclass of the Pydantic BaseModel or a list of Pydantic models."
)
# TODO: return warning if more than one input parameters
return input_type
def get_output_type(func: Callable) -> Type:
"""Returns the output type of a given function (callable).
Args:
func: The function for which to get the output type.
Raises:
ValueError: If the function does not have a valid output type annotation.
"""
type_hints = get_type_hints(func)
if "return" not in type_hints:
raise ValueError(
"The return type of the callable MUST be annotated with type hints."
"For example: `def my_opyrator(input: InputModel) -> OutputModel:`."
)
output_type = type_hints["return"]
if not is_compatible_type(output_type):
raise ValueError(
"The return value MUST be a subclass of the Pydantic BaseModel or a list of Pydantic models."
)
return output_type
def get_callable(import_string: str) -> Callable:
"""Import a callable from an string."""
callable_seperator = ":"
if callable_seperator not in import_string:
# Use dot as seperator
callable_seperator = "."
if callable_seperator not in import_string:
raise ValueError("The callable path MUST specify the function. ")
mod_name, callable_name = import_string.rsplit(callable_seperator, 1)
mod = importlib.import_module(mod_name)
return getattr(mod, callable_name)
class Opyrator:
def __init__(self, func: Union[Callable, str]) -> None:
if isinstance(func, str):
# Try to load the function from a string notion
self.function = get_callable(func)
else:
self.function = func
self._action = "Execute"
self._input_type = None
self._output_type = None
if not callable(self.function):
raise ValueError("The provided function parameters is not a callable.")
if inspect.isclass(self.function):
raise ValueError(
"The provided callable is an uninitialized Class. This is not allowed."
)
if inspect.isfunction(self.function):
# The provided callable is a function
self._input_type = get_input_type(self.function)
self._output_type = get_output_type(self.function)
try:
# Get name
self._name = name_to_title(self.function.__name__)
except Exception:
pass
try:
# Get description from function
doc_string = inspect.getdoc(self.function)
if doc_string:
self._action = doc_string
except Exception:
pass
elif hasattr(self.function, "__call__"):
# The provided callable is a function
self._input_type = get_input_type(self.function.__call__) # type: ignore
self._output_type = get_output_type(self.function.__call__) # type: ignore
try:
# Get name
self._name = name_to_title(type(self.function).__name__)
except Exception:
pass
try:
# Get action from
doc_string = inspect.getdoc(self.function.__call__) # type: ignore
if doc_string:
self._action = doc_string
if (
not self._action
or self._action == "Call"
):
# Get docstring from class instead of __call__ function
doc_string = inspect.getdoc(self.function)
if doc_string:
self._action = doc_string
except Exception:
pass
else:
raise ValueError("Unknown callable type.")
@property
def name(self) -> str:
return self._name
@property
def action(self) -> str:
return self._action
@property
def input_type(self) -> Any:
return self._input_type
@property
def output_type(self) -> Any:
return self._output_type
def __call__(self, input: Any, **kwargs: Any) -> Any:
input_obj = input
if isinstance(input, str):
# Allow json input
input_obj = parse_raw_as(self.input_type, input)
if isinstance(input, dict):
# Allow dict input
input_obj = parse_obj_as(self.input_type, input)
return self.function(input_obj, **kwargs)