在 python中运行monkey.patch_all()报错问题

最新推荐文章于 2022-11-09 19:35:22 发布

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本文解决Python3.6使用gevent时出现的警告问题，通过调整monkey.patch_all()位置及更新gevent版本，消除MonkeyPatchWarning，确保协程正常运行。

在最新的python3.6中使用协程，启用gevent时，可能会出现警告,代码如下：
import gevent
from gevent import monkey
monkey.patch_all()
# monkey.patch_socket()
# monkey.patch_ssl()
import urllib.request

def run_task(url):
    print("Visit --> %s" % url)
    try:
        response = urllib.request.urlopen(url)
        data = response.read()
        print("%d bytes received from %s" % (len(data), url))
    except Exception as e:

print("程序运行错误", e)

if __name__ == '__main__':
    urls = ['https://github.com/', 'https://www.python.org/', 'http://www.cnblogs.com/']
    greenlets = [gevent.spawn(run_task, url) for url in urls]
    gevent.joinall(greenlets)

运行结果如下所示：
MonkeyPatchWarning: Monkey-patching ssl after ssl has already been imported may lead to errors, including RecursionError on Python 3.6.
Please monkey-patch earlier. See https://github.com/gevent/gevent/issues/1016
monkey.patch_all()
Visit --> https://github.com/
Visit --> https://www.python.org/
Visit --> http://www.cnblogs.com/
46365 bytes received from http://www.cnblogs.com/
48801 bytes received from https://www.python.org/
59467 bytes received from https://github.com/

而访问 https://github.com/gevent/gevent/issues/1016后可知，方法是将

import gevent
import gevent.monkey
>>> gevent.monkey.patch_all()

置顶，但再次运行后发现依然出现相同的红色警告，这是因为python3.6自带的gevent版本过低所致，卸载后重新安装最新
gevent版本即可。

解决方案：

pip uninstall gevent

pip install gevent

再次运行成功，搞定。