Async subprocess for Tornado.

async_subprocess_tornado.py

#!/usr/bin/env python2.7
#-*- coding=utf-8 -*-

import shlex
import subprocess
from tornado.gen import coroutine, Task, Return
from tornado.process import Subprocess
from tornado.ioloop import IOLoop

@coroutine
def call_subprocess(cmd, stdin_data=None, stdin_async=True):
    """call sub process async

        Args:
            cmd: str, commands
            stdin_data: str, data for standard in
            stdin_async: bool, whether use async for stdin
    """
    stdin = Subprocess.STREAM if stdin_async else subprocess.PIPE
    sub_process = Subprocess(shlex.split(cmd),
                             stdin=stdin,
                             stdout=Subprocess.STREAM,
                             stderr=Subprocess.STREAM,)
    if stdin_data:
        if stdin_async:
            yield Task(sub_process.stdin.write, stdin_data)
        else:
            sub_process.stdin.write(stdin_data)

    if stdin_async or stdin_data:
        sub_process.stdin.close()

    result, error = yield [Task(sub_process.stdout.read_until_close),
                           Task(sub_process.stderr.read_until_close),]

    raise Return((result, error))

@coroutine
def example_main():
    result, error = yield call_subprocess("ls")
    result, error = yield call_subprocess("wc -l",stdin_data=result)
    result, error = yield call_subprocess("ls -l |tail -2")
    print result
    IOLoop.instance().stop()


if __name__ == "__main__":
    IOLoop.instance().add_callback(example_main)
    IOLoop.instance().start()