python - eventlet是否为线程模块做了monkey_patch？

Question

文档位于 http://eventlet.net/doc/patching.htm说“如果没有指定参数，则所有内容都会被修补。”和“线程，用于修补线程、线程和队列”。

但是通过一个简单的测试:

#!/bin/env python

import threading

import eventlet
eventlet.monkey_patch()

if __name__ == '__main__':
    patched = eventlet.patcher.is_monkey_patched(threading)
    print('patched : %s' % patched)

结果是:

patched : False

线程似乎根本没有修补。文档有误吗？

Answer 1

我发现文档是正确的。问题在于 is_monkey_patched()，它无法检测到某些情况，例如“线程，队列”模块。看一下这个函数的 src，其行为很容易理解。

def _green_thread_modules():
    from eventlet.green import Queue
    from eventlet.green import thread
    from eventlet.green import threading
    if six.PY2:
        return [('Queue', Queue), ('thread', thread), ('threading', threading)]
    if six.PY3:
        return [('queue', Queue), ('_thread', thread), ('threading', threading)]

<小时/>

    if on['thread'] and not already_patched.get('thread'):
        modules_to_patch += _green_thread_modules()
        already_patched['thread'] = True

<小时/>

def is_monkey_patched(module):
    """Returns True if the given module is monkeypatched currently, False if
    not.  *module* can be either the module itself or its name.

    Based entirely off the name of the module, so if you import a
    module some other way than with the import keyword (including
    import_patched), this might not be correct about that particular
    module."""
    return module in already_patched or \
        getattr(module, '__name__', None) in already_patched

又因为patch操作是这样实现的:

    for name, mod in modules_to_patch:
        orig_mod = sys.modules.get(name)
        if orig_mod is None:
            orig_mod = __import__(name)
        for attr_name in mod.__patched__:
            patched_attr = getattr(mod, attr_name, None)
            if patched_attr is not None:
                setattr(orig_mod, attr_name, patched_attr)

我们可以使用以下方法检查像 threading/Queue 这样的模块是否已修补:

 >>>import threading
 >>>eventlet.monkey_patch()
 >>>threading.current_thread.__module__
 >>>'eventlet.green.threading'