Python调试器不执行协程

Question

在下面的例子中:

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))

来理解它的内部行为。然而，当我尝试进入协程时，调试器只是跳过它，好像n已被按下而不是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> 

PyCharm (2016 2.3 Community) IDE中有此行为。

我希望在这里结束，并能够进一步通过代码。

Answer 1

如果您在协程中调用await或yield from，则可以工作，如

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() .