tornado forking

demo.py

#
# https://groups.google.com/d/msg/python-tornado/1LsOhqwOOTI/2Sp7RSM7sfcJ
#
#

import os
import time
from tornado import gen, ioloop, httpserver, web

def fork_processes(num_processes):
    children = {}

    def start_child(_i):
        pid = os.fork()
        if pid == 0:
            return None
        else:
            children[pid] = _i
            return pid

    for i in range(num_processes):
        _id = start_child(i)
        if _id is None:
            return None

    return children


class MainPageHandler(web.RequestHandler):
    @gen.coroutine
    def get(self, *args, **kwargs):
        self.finish(dict(key=1))


if __name__ == "__main__":
    http_server = httpserver.HTTPServer(None)
    http_server.bind(port=8320)
    child_processes = fork_processes(2)
    if isinstance(child_processes, dict):
        print u"Master process: child data={}".format(child_processes)
        time.sleep(5)
    else:
        child_pid = os.getpid()
        print u"Child process [{}] started".format(child_pid)

        _ioLoop = ioloop.IOLoop.instance()
        _ioLoop.make_current()

        application = web.Application([
            (r"/", MainPageHandler),
        ])

        http_server.request_callback = application
        http_server.io_loop = _ioLoop
        http_server.add_sockets(http_server._pending_sockets)
        _ioLoop.start()