asyncio：运行一个函数与来自websocket客户端的多个请求进行线程化

Question

我有一个websocket服务器（python 3.x）接受请求，其中每个都是url变量。它运行得很好，除了它只能串行执行每个请求，然后相互执行。 当函数运行时，它也会阻止尝试连接的客户端。非阻塞就是我想要的！

• websocket和subprocess函数的Asyncronous 多处理线程。
• 设置要使用的核心数的功能。但这不是强制性的。

这就是我所拥有的：

答案（插图和Foo g(5)已接受答案）

所以，我对这种挫败感并没有走得那么远。我恢复了原来的代码，事实证明，你需要使用asyncio.subprocess睡眠功能。现在它运行得非常好，我同时测试了多个客户端并且它异步处理它。

await asyncio.sleep(.001)

@udi 建议

更新，如果您想要一个缓慢的外部进程，那么可以采用asyncio.subprocess而不是子进程。使用阻塞调用从管道读取会停止其他线程，这就是asyncio.subprocess所处理的。

Answer 1

time.sleep()正在阻止。

尝试：

# blocking_server.py
import asyncio
import time

import websockets

x = 0


async def handler(websocket, path):
    global x
    x += 1
    client_id = x

    try:
        print("[#{}] Connected.".format(client_id))

        n = int(await websocket.recv())
        print("[#{}] Got: {}".format(client_id, n))
        for i in range(1, n + 1):
            print("[#{}] zzz...".format(client_id))
            time.sleep(1)
            print("[#{}] woke up!".format(client_id))
            await asyncio.sleep(.001)
            msg = "*" * i
            print("[#{}] sending: {}".format(client_id, msg))
            await websocket.send(msg)

        msg = "bye!"
        print("[#{}] sending: {}".format(client_id, msg))
        await websocket.send(msg)

        print("[#{}] Done.".format(client_id, msg))

    except websockets.exceptions.ConnectionClosed:
        print("[#{}] Disconnected!.".format(client_id))


if __name__ == "__main__":
    port = 8080
    server = websockets.serve(handler, '0.0.0.0', port)
    print("Started server on port {}".format(port))
    loop = asyncio.get_event_loop()
    loop.run_until_complete(server)
    loop.run_forever()

使用此测试客户端：

# test_client.py
import asyncio
import time

import websockets


async def client(client_id, n):
    t0 = time.time()
    async with websockets.connect('ws://localhost:8080') as websocket:
        print("[#{}] > {}".format(client_id, n))
        await websocket.send(str(n))
        while True:
            resp = await websocket.recv()
            print("[#{}] < {}".format(client_id, resp))
            if resp == "bye!":
                break

    print("[#{}] Done in {:.2f} seconds".format(client_id, time.time() - t0))


tasks = [client(i + 1, 3) for i in range(4)]
loop = asyncio.get_event_loop()
loop.run_until_complete(asyncio.wait(tasks))
loop.close()

现在比较time.sleep(x)替换为await asyncio.sleep(x)时的结果！

如果您需要通过asyncio运行缓慢的外部流程，请尝试asynico.subprocess：

示例外部程序：

# I am `slow_writer.py`
import sys
import time

n = int(sys.argv[1])

for i in range(1, n + 1):
    time.sleep(1)
    print("*" * i)

使用此服务器：

# nonblocking_server.py

import asyncio
import sys

import websockets

x = 0


async def handler(websocket, path):
    global x
    x += 1
    client_id = x

    try:
        print("[#{}] Connected.".format(client_id))

        n = int(await websocket.recv())

        print("[#{}] Got: {}. Running subprocess..".format(client_id, n))

        cmd = (sys.executable, 'slow_writer.py', str(n))
        proc = await asyncio.create_subprocess_exec(
            *cmd, stdout=asyncio.subprocess.PIPE)

        async for data in proc.stdout:
            print("[#{}] got from subprocess, sending: {}".format(
                client_id, data))
            await websocket.send(data.decode().strip())

        return_value = await proc.wait()
        print("[#{}] Subprocess done.".format(client_id))

        msg = "bye!"
        print("[#{}] sending: {}".format(client_id, msg))
        await websocket.send(msg)

        print("[#{}] Done.".format(client_id, msg))

    except websockets.exceptions.ConnectionClosed:
        print("[#{}] Disconnected!.".format(client_id))


if __name__ == "__main__":

    if sys.platform == 'win32':
        loop = asyncio.ProactorEventLoop()
        asyncio.set_event_loop(loop)

    port = 8080
    server = websockets.serve(handler, '0.0.0.0', port)
    print("Started server on port {}".format(port))
    loop = asyncio.get_event_loop()
    loop.run_until_complete(server)
    loop.run_forever()