首次尝试

Question

我正在使用asyncio客户端进行连接，然后与服务器断开连接。

如果我在同一台计算机上连接到服务器程序，则~~连接正常。~~ 添加：当我开始向连接写入数据时，此连接也开始给出警告有时。请参阅下面的第二个代码版本。
如果我连接到本地网络上的设备，我会获得ResourceWarning未公开的传输。

如何正确关闭连接？

我在Windows 7（64位）上使用Python 3.6.0（32位）。

首次尝试

相关代码：

import asyncio
import logging
import warnings

class ClientConnection(asyncio.Protocol):
    def connection_made(self, transport):
        self.transport = transport
        transport.write_eof()  # Send EOF to close connection

    def connection_lost(self, exception):
        self.transport.close()
        super().connection_lost(exception)

def main():
    logging.basicConfig(level=logging.DEBUG)
    eventLoop = asyncio.get_event_loop()
    eventLoop.set_debug(True)
    warnings.simplefilter('always', ResourceWarning)  # enables ResourceWarning
    #co = eventLoop.create_connection(ClientConnection, '127.0.0.1', 7001)     # Works without warning
    co = eventLoop.create_connection(ClientConnection, '192.168.10.66', 7001)  # Gives warning
    try:
        eventLoop.run_until_complete(co)
    finally:
        eventLoop.close()

if __name__ == "__main__":
    main()

控制台输出：

DEBUG:asyncio:Using selector: SelectSelector
DEBUG:asyncio:connect <socket.socket fd=240, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=6> to ('19
2.168.10.66', 7001)
DEBUG:asyncio:poll took 0.000 ms: 1 events
DEBUG:asyncio:<socket.socket fd=240, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto=6, laddr=('192.168
.10.62', 64587), raddr=('192.168.10.66', 7001)> connected to 192.168.10.66:7001: (<_SelectorSocketTransport fd=240 read=
polling write=<idle, bufsize=0>>, <__main__.ClientConnection object at 0x005EBD90>)
DEBUG:asyncio:Close <_WindowsSelectorEventLoop running=False closed=False debug=True>
sys:1: ResourceWarning: unclosed <socket.socket fd=240, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto
=6, laddr=('192.168.10.62', 64587), raddr=('192.168.10.66', 7001)>
C:\Program Files (x86)\Python36-32\lib\asyncio\selector_events.py:631: ResourceWarning: unclosed transport <_SelectorSoc
ketTransport fd=240>
  source=self)

第二次尝试

我对代码进行了以下更改：

从transport.close()

connection_lost

将一些数据写入连接
添加了data_received和eof_received回调
添加了更多调试日志

观察：

我尝试将transport.close()添加到connection_made，但它始终会生成OSError: [WinError 10038]。 注意：这可能是另一个问题，所以现在暂时忽略它，并假设我不会这样做。
当将一些数据写入套接字时，localhost连接也开始发出警告，但并非总是如此。
当它发出警告时，不会调用connection_lost。为什么？

修改后的代码：

import asyncio
import logging
import warnings

class ClientConnection(asyncio.Protocol):
    def connection_made(self, transport):
        logging.debug('connection_made')
        self.transport = transport
        transport.write(b'1234\r')
        transport.write_eof()  # Send EOF to close connection
        #transport.close()  # Cannot close here either, gives 'OSError: [WinError 10038]'

    def connection_lost(self, exception):
        logging.debug('connection_lost')
        super().connection_lost(exception)

    def data_received(self, data):
        logging.debug('received {} bytes'.format(len(data)))

    def eof_received(self):
        logging.debug('EOF received')
        self.transport.close()

def main():
    logging.basicConfig(level=logging.DEBUG)
    eventLoop = asyncio.get_event_loop()
    eventLoop.set_debug(True)
    warnings.simplefilter('always', ResourceWarning)  # enables ResourceWarning
    #co = eventLoop.create_connection(ClientConnection, '127.0.0.1', 7001)     # Works without warning
    co = eventLoop.create_connection(ClientConnection, '192.168.10.66', 7001)  # Gives warning
    try:
        eventLoop.run_until_complete(co)
        logging.debug('done')
    finally:
        eventLoop.close()

if __name__ == "__main__":
    main()

成功时的输出：

...
DEBUG:root:EOF received
DEBUG:root:connection_lost
DEBUG:root:done
DEBUG:asyncio:Close <_WindowsSelectorEventLoop running=False closed=False debug=True>

失败时输出（注意缺少connection_lost）：

...
DEBUG:root:EOF received
DEBUG:root:done
DEBUG:asyncio:Close <_WindowsSelectorEventLoop running=False closed=False debug=True>
sys:1: ResourceWarning: unclosed <socket.socket fd=240, family=AddressFamily.AF_INET, type=SocketKind.SOCK_STREAM, proto
=6, laddr=('127.0.0.1', 63858), raddr=('127.0.0.1', 7001)>
C:\Program Files (x86)\Python36-32\lib\asyncio\selector_events.py:631: ResourceWarning: unclosed transport <_SelectorSoc
ketTransport closing fd=240>
  source=self)

Answer 1

等待服务器关闭连接，或使用transport.close()关闭传输。这也会触发connection_lost（不要从transport.close()拨打connection_lost！）：

class ClientConnection(asyncio.Protocol):
    def connection_made(self, transport):
        logging.debug("connection made, calling write eof")
        transport.write_eof()
        logging.debug("after calling write eof, calling close")
        transport.close()
        logging.debug("after calling close")

    def connection_lost(self, exception):
        logging.debug("connection lost")
        super().connection_lost(exception)

如果您尝试多一点，您也可能会为本地计算机获得一些ResourceWarning。例如，尝试在transport.write(b'hello world!')之前添加write_eof()或使本地服务器响应更慢。

Answer 2

尝试再运行一次循环。以下是使用loop.run_forever()和loop.stop()的示例，假设本地和远程计算机上有echo server：

import asyncio
import logging

import warnings


class ClientConnection(asyncio.Protocol):
    def connection_made(self, transport):
        logging.debug("connection made, sending and calling write eof")
        transport.write(b'hello')
        transport.write_eof()
        logging.debug("after calling write eof")

    def data_received(self, data):
        logging.debug("Got: {}".format(data))
        super().data_received(data)

    def connection_lost(self, exception):
        logging.debug("connection lost")
        super().connection_lost(exception)
        loop.stop()


def test_echo(ip, port):
    logging.debug("Creating connection: {}:{}".format(ip, port))
    co = loop.create_connection(ClientConnection, ip, port)
    logging.debug("Starting loop...")
    print(loop.run_until_complete(co))
    logging.debug("...create_connection done, running loop forever...")
    loop.run_forever()
    logging.debug("Loop stopped")

    logging.debug('----------------')


if __name__ == "__main__":
    logging.basicConfig(level=logging.DEBUG)
    warnings.simplefilter('always')  # enables ResourceWarning

    loop = asyncio.get_event_loop()
    loop.set_debug(True)

    test_echo('127.0.0.1', 7001)
    test_echo('54.175.103.105', 30000)

    logging.debug("done")
    loop.close()

async client：`connection_lost`未调用，导致ResourceWarning

首次尝试

第二次尝试

2 个答案: