tornado.platform.asyncio — Bridge between asyncio and Tornado

Bridges between the asyncio module and Tornado IOLoop.

New in version 3.2.

This module integrates Tornado with the asyncio module introduced in Python 3.4. This makes it possible to combine the two libraries on the same event loop.

Most applications should use AsyncIOMainLoop to run Tornado on the default asyncio event loop. Applications that need to run event loops on multiple threads may use AsyncIOLoop to create multiple loops.


Tornado requires the add_reader family of methods, so it is not compatible with the ProactorEventLoop on Windows. Use the SelectorEventLoop instead.

class tornado.platform.asyncio.AsyncIOMainLoop[source]

AsyncIOMainLoop creates an IOLoop that corresponds to the current asyncio event loop (i.e. the one returned by asyncio.get_event_loop()). Recommended usage:

from tornado.platform.asyncio import AsyncIOMainLoop
import asyncio

See also tornado.ioloop.IOLoop.install() for general notes on installing alternative IOLoops.

class tornado.platform.asyncio.AsyncIOLoop[source]

AsyncIOLoop is an IOLoop that runs on an asyncio event loop. This class follows the usual Tornado semantics for creating new IOLoops; these loops are not necessarily related to the asyncio default event loop. Recommended usage:

from tornado.ioloop import IOLoop

Each AsyncIOLoop creates a new asyncio.EventLoop; this object can be accessed with the asyncio_loop attribute.


Convert an asyncio.Future to a tornado.concurrent.Future.

New in version 4.1.


Convert a Tornado yieldable object to an asyncio.Future.

New in version 4.1.

Changed in version 4.3: Now accepts any yieldable object, not just tornado.concurrent.Future.