async stdout & stderr for process in python

async_process.py

#!/usr/bin/python3
# encoding: utf-8

import platform
import asyncio

@asyncio.coroutine
def _read_stream(stream, cb):
    while True:
        line = yield from stream.readline()
        if line:
            cb(line)
        else:
            break

@asyncio.coroutine
def _stream_subprocess(cmd, stdout_cb, stderr_cb):
    process = yield from asyncio.create_subprocess_exec(*cmd,
            stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE)
    yield from asyncio.wait([
        _read_stream(process.stdout, stdout_cb),
        _read_stream(process.stderr, stderr_cb)
    ])
    yield from process.wait()
    return process.returncode


def execute(cmd, stdout_cb, stderr_cb):
    loop = None
    if platform.system() == "Windows":
        loop = asyncio.ProactorEventLoop()
        asyncio.set_event_loop(loop)
    else:
        loop = asyncio.SelectorEventLoop()
        asyncio.set_event_loop(loop)
    rc = loop.run_until_complete(_stream_subprocess(cmd,stdout_cb,stderr_cb))
    loop.close()
    return rc


if __name__ == '__main__':
    if platform.system() == "Windows":
        cmd = ['ping', '192.168.1.210', '-n', '10']
    else:
        cmd = ['ping', '192.168.1.210', '-c', '10']
    print(execute(
        cmd,
        lambda x: print("STDOUT: %s" % x),
        lambda x: print("STDERR: %s" % x),
    ))
    print('--------------------------------------------\n')