#!/usr/bin/env python
import tornado.httpserver
import tornado.ioloop
import tornado.web

class MainHandler(tornado.web.RequestHandler):
    @tornado.web.asynchronous #说明1
    def get(self):
        some_async_func(callback=self.wait)

    def wait(self, result):
        if result:
            self.write(result)
            self.finish() #说明2
        else:
            tornado.ioloop.IOLoop.instance().add_timeout(time.time() + 0.5, lambda: some_async_func(callback=self.wait))
            #说明3
application = tornado.web.Application([
    (r"/", MainHandler),
])

if __name__ == "__main__":
    http_server = tornado.httpserver.HTTPServer(application)
    http_server.listen(8999)
    tornado.ioloop.IOLoop.instance().start()

upstream frontends {
    server 127.0.0.1:8999;
}
server {
    listen 8888;
    location / {
        proxy_read_timeout 1800;
        proxy_pass_header Server;
        proxy_set_header Host $http_host;
        proxy_redirect off;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Scheme $scheme;
        proxy_pass http://frontends;
    }
}