Hi folks! I made a little utility with trio over the weekend that I thought I’d share with you.
When I wish to use asynchronous code, it’s frequently to execute multiple io-bound operations in parallel. When I do this, I typically also want to gather and recombine the results of those operations. From what I could tell, the idiomatic way to do this in trio would be to start tasks that do the various pieces of work that I want to parallelize, and have some sort of “receiver” function to gather their results. I tried this out a couple of times and was able to get things to work, but it led to a lot of channel bookkeeping intermingled with my “application code”.
So, I decided to make a little utility to manage some of those details. I modeled it after the scala Future class, which I’ve worked with a bunch in the past. In brief, it allows you to take a trio async function, schedule it to ‘run soon’, and synchronously get back a container object. That will eventually be filled with the result of the operation, and code can
await the container being filled. Here’s a very basic example:
async def my_fn(): await trio.sleep(3) return 7 async def test_the_future(): async with trio.open_nursery() as nursery: fut = Future.run(my_fn, nursery) func_outcome = await fut.outcome() assert func_outcome == Value(7)
Value is from the
outcome util; exceptions will captured as an
outcome.Error. I’ve also implemented functionality to join results of multiple futures together, similar to
asyncio.gather. You can see more usage examples at https://github.com/danielhfrank/trio-future/blob/master/tests/test_future.py and https://github.com/danielhfrank/trio-future/blob/master/scripts/concurrent_sleep.py
Full disclosure, I only learned about trio relatively recently. I can’t say that I’ve read all the philosophy documents, and so I’m not sure if this is in the spirit of the library. I’d appreciate any feedback you might have on that, and would love to do what I can to make it useful for others. I’ll probably publish it to pypi after I work out a couple of rough edges. Thanks for looking, and for all your hard work on the project!