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Python websockets 错误处理：越来越多的线程

[英]Python websockets error handling: growing number of threads

 原文  2020-01-20 23:39:39  0   1    python/ python-3.x/ websocket/ python-asyncio

问题描述

我有一个非常简单的 MWE - 两个 WS 连接，其中一个会抛出错误。 两者都作为任务执行，并且应该各自恢复。 不幸的是，我的实现导致线程数量增加（每个错误一个）。 我在这里做错了什么？

import websockets
import asyncio
import json
uri = "wss://echo.websocket.org"
async def ws(error):
    while True:
        try:
            async with websockets.connect(uri=uri) as websocket:
                await websocket.send("foo")
                async for message in websocket:
                    if error:
                        raise ValueError
                    print(message)
        except:
            print('caught a WS exception - going to sleep for 30 seconds')
            websocket.close()
            await asyncio.sleep(30)


async def main():
    # try:
    ws_task_error = loop.create_task(ws(error=True))
    ws_task_fine = loop.create_task(ws(False))
    await asyncio.wait([ws_task_error, ws_task_fine], return_when=asyncio.FIRST_EXCEPTION)

if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.run_until_complete(main())

据我了解，一旦我离开 websockets.connect() 的上下文管理器，负责的线程就应该被删除。 我显然没有在这里正确实施它。 想法？

- - - 编辑 - - -

我感觉上面那个是WE，但不是真的M。这个例子在连接后立即强制异常。 在日志中，连接正确关闭。 尽管如此，我最终还是在每次连接时都创建了一个新线程。

import websockets
import asyncio
import logging
uri = "wss://echo.websocket.org"

logging.basicConfig(format='%(asctime)s %(levelname)s %(name)s: %(message)s')
logger = logging.getLogger('websockets')
logger.setLevel(logging.DEBUG)

async def ws():
    while True:
        async with websockets.connect(uri=uri) as websocket:
            try:
                raise ValueError
            except:
                print('Exception thrown')
            print('Exiting...')

async def main():
    ws_task_error = loop.create_task(ws())
    await asyncio.wait([ws_task_error], return_when=asyncio.FIRST_EXCEPTION)

if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.run_until_complete(main())

输出：

2020-01-21 10:44:04,710 DEBUG websockets.protocol: client - state = CONNECTING
2020-01-21 10:44:04,908 DEBUG websockets.protocol: client - event = connection_made(<asyncio.sslproto._SSLProtocolTransport object at 0x00000210389E6828>)
2020-01-21 10:44:05,001 DEBUG websockets.protocol: client - state = OPEN
Exception thrown
Exiting...
2020-01-21 10:44:05,003 DEBUG websockets.protocol: client - state = CLOSING
2020-01-21 10:44:05,003 DEBUG websockets.protocol: client > Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:05,098 DEBUG websockets.protocol: client < Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:05,099 DEBUG websockets.protocol: client - event = connection_lost(None)
2020-01-21 10:44:05,100 DEBUG websockets.protocol: client - state = CLOSED
2020-01-21 10:44:05,100 DEBUG websockets.protocol: client x code = 1000, reason = [no reason]
2020-01-21 10:44:05,100 DEBUG websockets.protocol: client x closing TCP connection
2020-01-21 10:44:05,193 DEBUG websockets.protocol: client - state = CONNECTING
2020-01-21 10:44:05,393 DEBUG websockets.protocol: client - event = connection_made(<asyncio.sslproto._SSLProtocolTransport object at 0x0000021038AB2908>)
2020-01-21 10:44:05,482 DEBUG websockets.protocol: client - state = OPEN
Exception thrown
Exiting...
2020-01-21 10:44:05,489 DEBUG websockets.protocol: client - state = CLOSING
2020-01-21 10:44:05,489 DEBUG websockets.protocol: client > Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:05,580 DEBUG websockets.protocol: client < Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:05,581 DEBUG websockets.protocol: client - event = connection_lost(None)
2020-01-21 10:44:05,582 DEBUG websockets.protocol: client - state = CLOSED
2020-01-21 10:44:05,582 DEBUG websockets.protocol: client x code = 1000, reason = [no reason]
2020-01-21 10:44:05,583 DEBUG websockets.protocol: client x closing TCP connection
2020-01-21 10:44:05,670 DEBUG websockets.protocol: client - state = CONNECTING
2020-01-21 10:44:05,863 DEBUG websockets.protocol: client - event = connection_made(<asyncio.sslproto._SSLProtocolTransport object at 0x0000021038AB2B70>)
2020-01-21 10:44:05,950 DEBUG websockets.protocol: client - state = OPEN
Exception thrown
Exiting...
2020-01-21 10:44:05,953 DEBUG websockets.protocol: client - state = CLOSING
2020-01-21 10:44:05,953 DEBUG websockets.protocol: client > Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:06,036 DEBUG websockets.protocol: client < Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:06,037 DEBUG websockets.protocol: client - event = connection_lost(None)
2020-01-21 10:44:06,037 DEBUG websockets.protocol: client - state = CLOSED
2020-01-21 10:44:06,038 DEBUG websockets.protocol: client x code = 1000, reason = [no reason]
2020-01-21 10:44:06,039 DEBUG websockets.protocol: client x closing TCP connection
2020-01-21 10:44:06,124 DEBUG websockets.protocol: client - state = CONNECTING
2020-01-21 10:44:06,308 DEBUG websockets.protocol: client - event = connection_made(<asyncio.sslproto._SSLProtocolTransport object at 0x0000021038AC6C50>)
2020-01-21 10:44:06,400 DEBUG websockets.protocol: client - state = OPEN
Exception thrown
Exiting...
2020-01-21 10:44:06,402 DEBUG websockets.protocol: client - state = CLOSING
2020-01-21 10:44:06,402 DEBUG websockets.protocol: client > Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:06,495 DEBUG websockets.protocol: client < Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:06,496 DEBUG websockets.protocol: client - event = connection_lost(None)
2020-01-21 10:44:06,496 DEBUG websockets.protocol: client - state = CLOSED
2020-01-21 10:44:06,496 DEBUG websockets.protocol: client x code = 1000, reason = [no reason]
2020-01-21 10:44:06,497 DEBUG websockets.protocol: client x closing TCP connection
2020-01-21 10:44:06,600 DEBUG websockets.protocol: client - state = CONNECTING
2020-01-21 10:44:06,827 DEBUG websockets.protocol: client - event = connection_made(<asyncio.sslproto._SSLProtocolTransport object at 0x0000021038AC6B70>)
2020-01-21 10:44:06,934 DEBUG websockets.protocol: client - state = OPEN
Exception thrown
Exiting...
2020-01-21 10:44:06,936 DEBUG websockets.protocol: client - state = CLOSING
2020-01-21 10:44:06,936 DEBUG websockets.protocol: client > Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:07,042 DEBUG websockets.protocol: client < Frame(fin=True, opcode=8, data=b'\x03\xe8', rsv1=False, rsv2=False, rsv3=False)
2020-01-21 10:44:07,043 DEBUG websockets.protocol: client - event = connection_lost(None)
2020-01-21 10:44:07,044 DEBUG websockets.protocol: client - state = CLOSED
2020-01-21 10:44:07,044 DEBUG websockets.protocol: client x code = 1000, reason = [no reason]
2020-01-21 10:44:07,045 DEBUG websockets.protocol: client x closing TCP connection

1 个解决方案

解决方案1
 1  2020-01-21 04:59:50

while True:应该async with websockets.connect(uri=uri) as websocket:

实际上，在您的示例中， ws_task_fine任务async for message in websocket:在第一条消息之后。 ws_task_error任务循环，增加线程。

这是一个如何实现它的粗略示例：

import websockets
import asyncio

uri = "wss://echo.websocket.org"


async def ws(error):
    async with websockets.connect(uri=uri) as websocket:
        while True:
            print('Starting...' + str(error))
            try:
                await websocket.send("foo")
                message = await websocket.recv()
                print(message)
                if error:
                    raise ValueError('Exception')
            except Exception as e:
                print(e)
            print('Finishing...' + str(error))
            await asyncio.sleep(2)


async def main():
    # try:
    ws_task_error = loop.create_task(ws(error=True))
    # ws_task_fine = loop.create_task(ws(False))
    await asyncio.wait([ws_task_error])

if __name__ == '__main__':
    loop = asyncio.get_event_loop()
    loop.run_until_complete(main())
    loop.run_forever()

loop.run_forever()允许我们在每次完成时重新启动main()协程

输出：

Starting...True
foo
Exception
Finishing...True
Starting...True
foo
Exception
Finishing...True
Starting...True
foo
Exception
Finishing...True

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