Question

我有这段代码，当有异常时，未设置事件。如果我将超时时间增加到10，则事件已设置。

为什么事件不在异常期间？

import sys
print(sys.version)
from concurrent import futures
import urllib.request
import multiprocessing
import time

URLS = ['http://www.foxnews.com/',
        'http://www.cnn.com/',
        'http://europe.wsj.com/',
        'http://www.bbc.co.uk/',
        'http://some-made-up-domain.com/']


def load_url(url, e, timeout=0):
    print('load_url')
    time.sleep(1)

    try:
        result = urllib.request.urlopen(url, timeout=timeout).read()
    except Exception as e:
        print(e)
    e.set()
    return result


def main():
    manager = multiprocessing.Manager()
    e = manager.Event()
    with futures.ThreadPoolExecutor(max_workers=5) as executor:
        future_to_url = dict(
            (executor.submit(load_url, url, e), url)
            for url in URLS)
        print('waiting to set the event')
        e.wait()
        print('event set')
        for future in futures.as_completed(future_to_url):
            url = future_to_url[future]
            try:
                print('%r page is %d bytes' % (
                    url, len(future.result())))
            except Exception as e:
                print('%r generated an exception: %s' % (
                    url, e))


if __name__ == '__main__':
    main()

Answer 1

很好...原因实际上很简单。您的except Exception as e:会覆盖该e变量。

异常时未设置python并发期货事件

1 个答案: