Python调试器没有进入协程？

Question

在下面的示例中:

import asyncio
import ipdb

class EchoServerProtocol:
    def connection_made(self, transport):
        self.transport = transport

    def datagram_received(self, data, addr):
        message = data.decode()
        print('Received %r from %s' % (message, addr))
        print('Send %r to %s' % (message, addr))
        self.transport.sendto(data, addr)

loop = asyncio.get_event_loop()
ipdb.set_trace(context=21)
print("Starting UDP server")
# One protocol instance will be created to serve all client requests
listen = loop.create_datagram_endpoint(    EchoServerProtocol, local_addr=('127.0.0.1', 9999))
transport, protocol = loop.run_until_complete(listen)

try:
    loop.run_forever()
except KeyboardInterrupt:
    pass

transport.close()
loop.close()

我正试图进入

loop.create_datagram_endpoint( EchoServerProtocol, local_addr=('127.0.0.1', 9999))

了解它在内部的表现.然而,当我尝试进入协程时,调试器只是跳过它,好像n已按下而不是s.

> ../async_test.py(18)<module>()
     17 # One protocol instance will be created to serve all client requests
---> 18 listen = loop.create_datagram_endpoint(    EchoServerProtocol, local_addr=('127.0.0.1', 9999))
     19 transport, protocol = loop.run_until_complete(listen)

ipdb> s
> ../async_test.py(19)<module>()
     18 listen = loop.create_datagram_endpoint(    EchoServerProtocol, local_addr=('127.0.0.1', 9999))
---> 19 transport, protocol = loop.run_until_complete(listen)
     20 

ipdb> 

使用PyCharm(2016 2.3社区)IDE可以体验到这种行为.

我希望在这里结束,并能够通过代码进一步.

Answer 1

如果你调用await或者yield from你的协程，它会起作用

listen = await loop.create_datagram_endpoint(EchoServerProtocol, 
                                             local_addr=('127.0.0.1', 9999))

在您的示例中listen，不是协程执行的结果，而是协程实例本身。实际执行由下一行执行：loop.run_until_complete()。