等到几个小菜之一完成 [英] Wait until one of several greenlets finished

问题描述

我有两个从两个不同的连接接收数据的函数，在从其中一个连接获得结果后，我应该关闭两个连接.

I have two functions that receives data from two different connections, and i should close both connections after getting result from one of them.

def first():
    gevent.sleep(randint(1, 100))  # i don't know how much time it will work
    return 'foo'

def second():
    gevent.sleep(randint(1, 100))  # i don't know how much time it will work
    return 'bar'

然后我生成每个函数:

lst = [gevent.spawn(first), gevent.spawn(second)]

gevent.joinall 阻止当前的greenlet，直到来自 lst 的两个greenlet都准备就绪.

gevent.joinall blocks current greenlet until both two greenlets from lst are ready.

gevent.joinall(lst)  # wait much time
print lst[0].get(block=False)   # -> 'foo'
print lst[1].get(block=False)   # -> 'bar'

我要等到第一或第二个小菜准备就绪:

I want to wait until eiter first or second greenlet become ready:

i_want_such_function(lst)  # returns after few seconds
print lst[0].get(block=False)  # -> 'foo' because this greenlet is ready
print lst[1].get(block=False)  # -> raised Timeout because this greenlet is not ready

我该怎么办?

推荐答案

您可以使用gevent.event.Event(或AsyncResult)和Greenlet的link()方法，如下所示:

You could use gevent.event.Event (or AsyncResult) and Greenlet's link() method, like this:

...
ready = gevent.event.Event()
ready.clear()

def callback():
    ready.set()

lst = [gevent.spawn(first), gevent.spawn(second)]
for g in lst:
    g.link(callback)

ready.wait()
...

这篇关于等到几个小菜之一完成的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！