Python 3 asyncio：run_until_complete（）在等待ProcessPoolExecutor作业完成时阻止

Question

我试图将TCP echo client and server用于测试自动化，并将其用于使用ProcessPoolExecutor（）的单个模块，并且按预期工作。

唯一的问题是我无法完成事件循环。我可以看到执行程序目标run_client（）的最后一行的调试输出，但看起来像执行程序本身仍然阻塞。

的代码：

import asyncio 
import concurrent.futures 
from concurrent.futures import ProcessPoolExecutor 

async def server_handle_echo(reader, writer): 
    data = await reader.read(100) 
    message = data.decode() 
    addr = writer.get_extra_info('peername') 
    print("Received %r from %r" % (message, addr)) 

    print("Send: %r" % message) 
    writer.write(data) 
    await writer.drain() 

    print("Close the client socket") 
    writer.close() 


async def echo_client_handler(message, loop): 
    reader, writer = await asyncio.open_connection('127.0.0.1', 8888, 
                loop=loop) 

    print('Send: %r' % message) 
    writer.write(message.encode()) 

    data = await reader.read(100) 
    print('Received: %r' % data.decode()) 

    print('Close the socket') 
    writer.close() 



def run_client(): 
    message = 'Hello World!' 
    loop = asyncio.get_event_loop() 
    loop.run_until_complete(echo_client_handler(message, loop)) 
    loop.close() 
    print('run_client last line') 

executor = ProcessPoolExecutor(1) 
loop = asyncio.get_event_loop() 

coro = asyncio.start_server(server_handle_echo, '127.0.0.1', 8888, loop=loop) 
server = loop.run_until_complete(coro) 

# Serve requests until Ctrl+C is pressed 
print('Serving on {}'.format(server.sockets[0].getsockname())) 
try: 
    #loop.run_forever() 
    client = asyncio.ensure_future(loop.run_in_executor(executor, run_client)) 
    loop.run_until_complete(client) 

except KeyboardInterrupt: 
    pass 

# Close the server 
server.close() 
loop.run_until_complete(server.wait_closed()) 
loop.close() 

输出：

Serving on ('127.0.0.1', 8888) 
Send: 'Hello World!' 
Received 'Hello World!' from ('127.0.0.1', 51157) 
Send: 'Hello World!' 
Close the client socket 
Received: 'Hello World!' 
Close the socket 
run_client last line 

此输出递给在msg中循环等待IO后。

期待您的帮助。对不起，我是一个天asyncioist :)

Answer 1

不能使用相同的事件循环为您的客户在一个子运行，你需要一个new loop：

def run_client(): 
    loop = asyncio.new_event_loop() 
    asyncio.set_event_loop(loop) 
    [...]