爲什麼我在Windows上獲取NotImplementedError異步並等待？

我有這樣的代碼：爲什麼我在Windows上獲取NotImplementedError異步並等待？

import os 
import time 
import asyncio 


async def run_command(*args): 
    """ 
    Example from: 
     http://asyncio.readthedocs.io/en/latest/subprocess.html 
    """ 
    # Create subprocess 
    process = await asyncio.create_subprocess_exec(
     *args, 
     # stdout must a pipe to be accessible as process.stdout 
     stdout=asyncio.subprocess.PIPE) 

    # Wait for the subprocess to finish 
    stdout, stderr = await process.communicate() 

    # Result 
    result = stdout.decode().strip() 

    # Return stdout 
    return result 


def run_asyncio_commands(tasks): 
    """Run tasks using asyncio and return results""" 
    loop = asyncio.get_event_loop() 
    commands = asyncio.gather(*tasks) # Unpack list using * 
    results = loop.run_until_complete(commands) 
    loop.close() 
    return results 


if __name__ == '__main__': 

    start = time.time() 

    cmds = [ 
     ['du', '-sh', '/Users/fredrik/Desktop'], 
     ['du', '-sh', '/Users/fredrik'], 
     ['du', '-sh', '/Users/fredrik/Pictures'] 
    ] 

    tasks = [] 
    for cmd in cmds: 
     tasks.append(run_command(*cmd)) 
    results = run_asyncio_commands(tasks) 
    print(results) 

    end = time.time() 
    print('Script ran in', str(end - start), 'seconds')

當我在我的Mac上運行的Python 3.6.1的代碼，我得到這個：

['780K\t/Users/fredrik/Desktop', '46G\t/Users/fredrik', '52M\t/Users/fredrik/Pictures'] 
Script ran in 6.405519008636475 seconds

但是當我在Windows上運行相同的腳本（但隨着du命令取代到一些東西，在Windows上運行），也與Python 3.6.1，我得到這個：

Traceback (most recent call last): 
    File "C:\Users\iruser\Desktop\asynciotest.py", line 66, in <module> 
    results = run_asyncio_commands(tasks) 
    File "C:\Users\iruser\Desktop\asynciotest.py", line 41, in run_asyncio_commands 
    results = loop.run_until_complete(commands) 
    File "C:\Users\fredrik\condaenvs\dev_py36\lib\asyncio\base_events.py", line 466, in run_until_complete 
    return future.result() 
    File "C:\Users\iruser\Desktop\asynciotest.py", line 16, in run_command 
    stdout=asyncio.subprocess.PIPE) 
    File "C:\Users\fredrik\condaenvs\dev_py36\lib\asyncio\subprocess.py", line 225, in create_subprocess_exec 
    stderr=stderr, **kwds) 
    File "C:\Users\fredrik\condaenvs\dev_py36\lib\asyncio\base_events.py", line 1190, in subprocess_exec 
    bufsize, **kwargs) 
    File "C:\Users\fredrik\condaenvs\dev_py36\lib\asyncio\coroutines.py", line 210, in coro 
    res = func(*args, **kw) 
    File "C:\Users\fredrik\condaenvs\dev_py36\lib\asyncio\base_events.py", line 340, in _make_subprocess_transp 
ort 
    raise NotImplementedError 
NotImplementedError

這是我替代Unix命令在Windows上：

cmds = [['C:/Windows/system32/HOSTNAME.EXE']]

Windows版本信息：不同的方式實現

Python 3.6.1 | packaged by conda-forge | (default, May 23 2017, 14:21:39) [MSC v.1900 64 bit (AMD64)] on win32 
Windows 10 Pro, version 1703, OS build 15063.413

來源

2017-06-19 fredrik

不同的事件循環。其中一些有限制（有時與操作系統有關）。默認情況下，Windows使用SelectorEventLoop，正如你可以看到doc：

SelectorEventLoop特定的限制：使用

SelectSelector只支持插座和限制爲512座。

add_reader（）和add_writer（）只接受套接字的文件描述符

管道不支持（例如：connect_read_pipe（），connect_write_pipe（））

子過程中不支持（例如：subprocess_exec（），subprocess_shell（））

要在Windows中運行你的代碼，你可以使用默認的可用的替代事件循環 - ProactorEventLoop。

更換行：

loop = asyncio.get_event_loop()

與此：

loop = asyncio.ProactorEventLoop() 
asyncio.set_event_loop(loop)

您的代碼將工作。

來源

2017-06-19 20:48:04

爲什麼我在Windows上獲取NotImplementedError異步並等待？

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