Make the tornado httpserver.HTTPServer to be shutdown safely.

make_safely_shutdown.py

# vim: fileencoding=utf-8
import time, signal
from tornado import web, ioloop, options, httpserver

_SHUTDOWN_TIMEOUT = 30

def make_safely_shutdown(server):
    io_loop = server.io_loop or ioloop.IOLoop.instance()
    def stop_handler(*args, **keywords):
        def shutdown():
            server.stop() # this may still disconnection backlogs at a low probability
            deadline = time.time() + _SHUTDOWN_TIMEOUT
            def stop_loop():
                now = time.time()
                if now < deadline and (io_loop._callbacks or io_loop._timeouts):
                    io_loop.add_timeout(now + 1, stop_loop)
                else:
                    io_loop.stop()
            stop_loop()
        io_loop.add_callback(shutdown)
    signal.signal(signal.SIGQUIT, stop_handler) # SIGQUIT is send by our supervisord to stop this server.
    signal.signal(signal.SIGTERM, stop_handler) # SIGTERM is send by Ctrl+C or supervisord's default.
    signal.signal(signal.SIGINT, stop_handler)

if __name__ == '__main__':
    options.parse_command_line()
    server = httpserver.HTTPServer(web.Application([('/', web.RequestHandler)]))
    server.listen(8888)
    make_safely_shutdown(server)
    ioloop.IOLoop.instance().start()