Tornado async handler with threading

async_thread.py

import time

# For python 2.7 use:
# pip install futures
import concurrent.futures 
import tornado.ioloop
import tornado.web
import tornado.gen


thread_pool = concurrent.futures.ThreadPoolExecutor(max_workers=4)


def future_thread(func):
    def wrapper(*args, **kwargs):
        return thread_pool.submit(func, *args, **kwargs)
    return wrapper


@future_thread
def blocking():
    time.sleep(10)


class Index(tornado.web.RequestHandler):
    @tornado.gen.coroutine
    def get(self, block=False):
        if block:
            yield blocking()
        self.write('hello world')



app = tornado.web.Application([
    (r'/', Index),
    (r'/(block)', Index)
])
app.listen(8888)
tornado.ioloop.IOLoop.instance().start()