Right way to “timeout” a Request in Tornado

Question

I managed to code a rather silly bug that would make one of my request handlers run a very slow DB query.

Interesting bit is that I noticed that even long-after si

Answer 1

Another solution to this problem is to use gen.with_timeout:

import time
from tornado import gen
from tornado.util import TimeoutError


class MainHandler

    @gen.coroutine
    def get(self):
        try:
            # I'm using gen.sleep here but you can use any future in this place
            yield gen.with_timeout(time.time() + 2, gen.sleep(5))
            self.write("This will never be reached!!")
        except TimeoutError as te:
            logger.warning(te.__repr__())
            self.timed_out()

    def timed_out(self):
        self.write("Request timed out!\n")

I liked the way handled by the contextlib solution but I'm was always getting logging leftovers.

The native coroutine solution would be:

async def get(self):
    try:
        await gen.with_timeout(time.time() + 2, gen.sleep(5))
        self.write("This will never be reached!!")
    except TimeoutError as te:
        logger.warning(te.__repr__())
        self.timed_out()