from __future__ import annotations
from abc import ABCMeta, abstractmethod
from types import TracebackType
from typing import TypeVar
T = TypeVar("T")
class AsyncResource(metaclass=ABCMeta):
"""
Abstract base class for all closeable asynchronous resources.
Works as an asynchronous context manager which returns the instance itself on enter,
and calls :meth:`aclose` on exit.
"""
__slots__ = ()
async def __aenter__(self: T) -> T:
return self
async def __aexit__(
self,
exc_type: type[BaseException] | None,
exc_val: BaseException | None,
exc_tb: TracebackType | None,
) -> None:
await self.aclose()
@abstractmethod
async def aclose(self) -> None:
"""Close the resource."""