tornado-async.py

import tornado
from tornado import gen
from tornado.ioloop import IOLoop
from tornado.httpclient import AsyncHTTPClient
from tornado.queues import Queue

q = Queue(maxsize=0)

@gen.coroutine
def producer():
    for x in range(10):
        print("Populating the queue with %s" % x)
        yield q.put("item %s" % x)

@gen.coroutine
def consumer():
    while True:
        x = yield q.get()
        print("Got %s from queue" % x)

        # wait ~3 secs for response
        url = 'http://shop.byte.nl/sleep.php'
        client = tornado.httpclient.AsyncHTTPClient()
        resp = yield client.fetch(url)

        q.task_done()


@gen.coroutine
def main():
    # Start consumer without waiting (since it never finishes).
    IOLoop.current().spawn_callback(consumer)
    yield producer()     # Wait for producer to put all tasks.
    yield q.join()       # Wait for consumer to finish all tasks.
    print('Done')


if __name__ == '__main__':
    IOLoop.current().run_sync(main)