[Python] Why am I getting NotImplementedError with async and await on Windows?

I have this code:

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')


When I run the that code in Python 3.6.1 on my mac, I get this:

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


But when I run the same script on Windows (but with the du commands substituted to something which works on Windows), also with Python 3.6.1, I get this:

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


This is what I substitute the Unix commands with on Windows:

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


Python and Windows version info:

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

Continue reading...