a re-implementation of the asyncio mainloop on top of Trio
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Trio-Asyncio is a re-implementation of the asyncio mainloop on top of Trio.

Trio-Asyncio requires Python 3.6 or 3.7. It should work on Python 3.5.3, but that's not tested, as the test suite requires 3.6.


Trio has native concepts of tasks and task cancellation. Asyncio is based on callbacks and chaining Futures, albeit with nicer syntax, which make handling of failures and timeouts fundamentally less reliable, esp. in larger programs. Thus, you really want to base your async project on Trio.

On the other hand, there are quite a few asyncio-enhanced libraries. You really don't want to re-invent any wheels in your project.

Thus, being able to use asyncio libraries from Trio is useful. Trio-Asyncio enables you to do that, and more.

Transparent vs. explicit translation

trio_asyncio does not try to magically allow calling await trio_code() from asyncio or vice versa. There are multiple reasons for this; the executive summary is that cross-domain calls can't be made to work correctly, and any such call is likely to result in an irrecoverable error. You need to keep your code's asyncio and trio domains rigidly separate.

Fortunately, this is not difficult.


Trio-Asyncio's documentation is too large for a README.

For further information, see the manual on readthedocs.

Hacking trio-asyncio


Like trio, trio-asyncio is licensed under both the MIT and Apache licenses. Submitting patches or pull requests imply your acceptance of these licenses.


are accepted gladly.


As in trio, testing is done with pytest.

Test coverage is close to 100%. Please keep it that way.


Matthias Urlichs <matthias@urlichs.de>