Occurred error 503 when testing my Tornado app implementing the Coroutine feature

Question

I'm building a Tornado web application applying the Coroutine feature. To test the performance of the app, I used the Siege. However, It occurred many 503 errors when using Siege to call the URL. By the way, my app was running on an Raspberry Pi.

The snippet of my app:

import os
import tornado.web
import tornado.gen
import tornado.ioloop
import tornado.options
import tornado.httpclient

tornado.options.define("port", default=8888, help="message...", type=int)

url='http://..../'

class Async(tornado.web.RequestHandler):
    @tornado.gen.coroutine
    def get(self):
        client = tornado.httpclient.AsyncHTTPClient()
        response = yield client.fetch(url)
        self.write('%r' % response.body)


def main():
    # Command line
    tornado.options.parse_command_line()
    app = tornado.web.Application(
            [
                (r'/async', Async)
            ],
            debug=True,
            autoreload=True
        )
    app.listen(tornado.options.options.port)
    tornado.ioloop.IOLoop.current().start()

if __name__ == "__main__":
    main()

And the command:

siege 192.168.1.x:8888/async -c 5 -r 5

And the error message:

[E 150822 18:47:15 web:1908] 500 GET /async (192.168.1.3) 2045.97ms
[I 150822 18:47:15 web:1908] 200 GET /async (192.168.1.3) 3317.43ms    
[E 150822 18:47:16 web:1496] Uncaught exception GET /async (192.168.1.3)
        HTTPServerRequest(protocol='http', host='192.168.1.x:8888', method='GET', uri='/async', version='HTTP/1.1', remote_ip='192.168.1.3', headers={'Host': '192.168.1.9:8888', 'User-Agent': 'Mozilla/5.0 (apple-x86_64-darwin14.4.0) Siege/3.1.0', 'Connection': 'close', 'Accept': '*/*', 'Accept-Encoding': 'gzip'})
        Traceback (most recent call last):
          File "/usr/lib/python2.7/site-packages/tornado/web.py", line 1415, in _execute
            result = yield result
          File "/usr/lib/python2.7/site-packages/tornado/gen.py", line 870, in run
            value = future.result()
          File "/usr/lib/python2.7/site-packages/tornado/concurrent.py", line 215, in result
            raise_exc_info(self._exc_info)
          File "/usr/lib/python2.7/site-packages/tornado/gen.py", line 876, in run
            yielded = self.gen.throw(*exc_info)
          File "server.py", line 19, in get
            response = yield client.fetch(url)
          File "/usr/lib/python2.7/site-packages/tornado/gen.py", line 870, in run
            value = future.result()
          File "/usr/lib/python2.7/site-packages/tornado/concurrent.py", line 215, in result
            raise_exc_info(self._exc_info)
          File "<string>", line 3, in raise_exc_info
        HTTPError: HTTP 503: Service Temporarily Unavailable
[E 150822 18:47:16 web:1908] 500 GET /async (192.168.1.x) 3645.07ms

So, did I omit some settings?

I would be very appreciated if you can point out what's wrong with my app. Thank you so much.

Answer 1

I changed the url to http://www.google.com, and no 503 errors occurred. I also tested my app on mac, and it worked well. Therefore, I think those errors resulted from where I fetch data.

Anyway, thank you so much, SDilmac.