使用请求和多处理时出现的奇怪问题 [英] Strange problems when using requests and multiprocessing

问题描述

请检查以下python代码:

Please check this python code:

#!/usr/bin/env python
import requests
import multiprocessing
from time import sleep, time
from requests import async

def do_req():
    r = requests.get("http://w3c.org/")

def do_sth():    
    while True:
        sleep(10)

if __name__ == '__main__':        
    do_req()
    multiprocessing.Process( target=do_sth, args=() ).start()

当我按Ctrl-C(运行后等待2秒钟-让Process运行)时，它不会停止.当我将导入顺序更改为:

When I press Ctrl-C (wait 2sec after run - let Process run), it doesn't stop. When I change the import order to:

from requests import async
from time import sleep, time

它在Ctrl-C之后停止.为什么在第一个示例中它不会停止/杀死?

it stops after Ctrl-C. Why it doesn't stop/kill in first example?

是错误还是功能?

注意:

• 是的，我知道，我没有在代码中使用异步，这只是精简的代码.在实际代码中，我使用它.我这样做是为了简化我的问题.
• 按Ctrl-C后，将运行一个新的(子)进程.为什么?
• multiprocessing.__version__ == 0.70a1，requests.__version__ == 0.11.2，gevent.__version__ == 0.13.7

• Yes I know, that I didn't use async in this code, this is just stripped down code. In real code I use it. I did it to simplify my question.
• After pressing Ctrl-C there is a new (child) process running. Why?
• multiprocessing.__version__ == 0.70a1, requests.__version__ == 0.11.2, gevent.__version__ == 0.13.7

推荐答案

请求异步模块使用gevent.如果您查看gevent的源代码，您会发现它是 monkey补丁的许多Python标准库函数，包括sleep:

Requests async module uses gevent. If you look at the source code of gevent you will see that it monkey patches many of Python's standard library functions, including sleep:

request.async模块在导入期间执行:

request.async module during import executes:

    from gevent import monkey as curious_george
    # Monkey-patch.
    curious_george.patch_all(thread=False, select=False)

查看gevent的monkey.py模块，您会看到:

Looking at the monkey.py module of gevent you can see:

https://bitbucket.org/denis/gevent/src/f838056c793d /gevent/monkey.py#cl-128

def patch_time():
    """Replace :func:`time.sleep` with :func:`gevent.sleep`."""
    from gevent.hub import sleep
    import time
    patch_item(time, 'sleep', sleep)

查看gevent存储库中的代码以了解详细信息.

Take a look at the code from the gevent's repository for details.

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