findbooks.py

#! /usr/bin/env python

from gevent import monkey
# comment out the following line to make it work
monkey.patch_all()

import os, signal
from gevent import socket, core, event, Timeout, hub

pid2status = {}

def got_signal():
    while 1:
        try:
            pid, st = os.waitpid(-1, os.WNOHANG)
            if pid == 0:
                return
            pid2status[pid].set(st)
        except OSError:
            return

hub.get_hub().reactor.signal(signal.SIGCHLD, got_signal)

def run_cmd(args, timeout=None):
    sp = socket.socketpair()
    pid = os.fork()
    if pid == 0:
        # client
        try:
            os.dup2(sp[1].fileno(), 1)
            os.dup2(sp[1].fileno(), 2)
            sp[0].close()
            sp[1].close()
            os.execvp(args[0], args)
        finally:
            os._exit(10)

    pid2status[pid] = event.AsyncResult()
    sp[1].close()

    chunks = []

    timeout = Timeout(timeout)
    timeout.start()
    try:
        while 1:
            chunk = sp[0].recv(4096)
            if not chunk:
                break
            chunks.append(chunk)

        st = pid2status[pid].get()
        del pid2status[pid]

        return st, "".join(chunks)
    except Timeout, t:
        if t is not timeout:
            raise
    finally:
        timeout.cancel()

    os.kill(pid, 9)

    with Timeout(1):
        st = pid2status[pid].get()
        del pid2status[pid]
        return st, "".join(chunks)

if __name__=="__main__":
    print run_cmd(["ls", "-la"])