fetch several resources simultaniously in Tornado

tornado_http_fetch.py

from __future__ import print_function
import tornado.httpclient
import tornado.ioloop
import tornado.web
import tornado.gen


@tornado.gen.coroutine
def get():
    urls = [
        "http://google.com/",
        "http://BROKEN_URL.google.com",
        "http://google.com/"
    ]
    http_client = tornado.httpclient.AsyncHTTPClient()

    keys = []

    for i, url in enumerate(urls):
        key = "key-%s" % str(i)
        keys.append(key)
        http_client.fetch(
            tornado.httpclient.HTTPRequest(url, method='GET'),
            callback=(yield tornado.gen.Callback(key))
        )

    responses = yield tornado.gen.WaitAll(keys)

    print(responses)
    print(len(responses))

    tornado.ioloop.IOLoop.instance().stop()


tornado.ioloop.IOLoop.instance().add_callback(get)
tornado.ioloop.IOLoop.instance().start()