在父对象销毁时关闭 aiohttp.ClientSession

Question

我正在编写一个用于访问 REST API 的 CLI。我在异步初始化方法中定义了aiohttp.ClientSession类字段_client_session。

如何正确关闭aiohttp.ClientSession？如果我这样做：

import asyncio
import aiohttp


class Profile:                                                                    
    def __init__(self, loop):                                                     
        self._loop = loop                                                         
        self._client_session = None                                               

    def __del__(self):                                                            
        self._loop.run_until_complete(self._client_session.close())              

    async def async_init(self):
        self._client_session = aiohttp.ClientSession()                           

    @classmethod
    async def create(cls, loop):
        self = cls(loop)
        await self.async_init()
        return self


loop = asyncio.get_event_loop()
profile = loop.run_until_complete(Profile.create(loop))                          
loop.close()

我明白了：

Exception ignored in: <bound method Profile.__del__ of <profile.Profile object at 0x7f8ab82e15c0>>
Traceback (most recent call last):
File "/home/rominf/projects/profile/profile/__init__.py", line 197, in __del__
File "/home/rominf/.pyenv/versions/3.6.6/lib/python3.6/asyncio/base_events.py", line 444, in run_until_complete
File "/home/rominf/.pyenv/versions/3.6.6/lib/python3.6/asyncio/base_events.py", line 358, in _check_closed
RuntimeError: Event loop is closed
sys:1: RuntimeWarning: coroutine 'ClientSession.close' was never awaited
Unclosed client session
client_session: <aiohttp.client.ClientSession object at 0x7f8ab43bf588>
Unclosed connector
connections: ['[(<aiohttp.client_proto.ResponseHandler object at 0x7f8ab28a06a8>, 11519.944147989)]']
connector: <aiohttp.connector.TCPConnector object at 0x7f8ab43bf3c8>

我知道发生这种情况是有原因的：我在垃圾收集器删除 profile 之前关闭了 loop。解决办法是用del手动删除，但我不想这样做。

有没有办法在事件循环关闭之前注册未来执行？

Answer 1

asyncio 不支持析构函数中的 IO。 构造函数和属性也是如此。

推荐的方法是添加async with Profile 或await profile.close() 支持。