Concurrency backends vs AnyIO

Follow-up for @sethmlarson’s comment here: https://github.com/encode/httpx/pull/276#issuecomment-526350945

Just wondering since I just found the project, would anyio work for us?

For context: we have an internal ConcurrencyBackend interface whose job is to provide async-related operations that aren’t tied to a particular implementation, e.g. asyncio or trio.

AnyIO (docs, code, cc @agronholm) is an existing project that takes the exact similar approach to provide an async API that somewhat resembles that of trio.

Sample code taken from here:

import anyio


async def sometask(num):
    print('Task', num, 'running')
    await anyio.sleep(1)
    print('Task', num, 'finished')


async def main():
    async with anyio.create_task_group() as group:
        for num in range(5):
            await group.spawn(sometask, num)

    print('All tasks finished!')


anyio.run(main)

I think @sethmlarson’s question was really: should we consider replacing our ConcurrencyBackend API with AnyIO?

[tomchristie]

Counter-intuitively, the low-impact way of exploring this would be to implement an alternate concurrency backend, that uses AnyIO.

[tomchristie]

From a glance over the docs it looks like it’s got everything we’d need, yup. (But that’s about as much depth as I’d gone into)