anyioutils

Utility classes and functions for AnyIO.

Task

task = anyioutils.create_task(my_async_func()) behaves the same as task = asyncio.create_task(my_async_func()) except that:

• the task still has to be launched in the background with an existing task group tg, using tg.start_soon(task.wait),
• and/or the task can be awaited with result = task.wait().

from anyioutils import CancelledError, create_task
from anyio import create_task_group, run, sleep

async def foo():
    return 1

async def bar():
    await sleep(float("inf"))

async def main():
    async with create_task_group() as tg:
        task = create_task(foo())
        assert await task.wait() == 1

    try:
        async with create_task_group() as tg:
            task = create_task(bar())
            tg.start_soon(task.wait)
            await sleep(0.1)
            task.cancel()
    except ExceptionGroup as exc_group:
        assert len(exc_group.exceptions) == 1
        assert type(exc_group.exceptions[0]) == CancelledError

run(main)

Future

anyioutils.Future behaves the same as asyncio.Future except that:

• you cannot directly await an anyioutils.Future object, but through its .wait() method (unlike an asyncio.Future, but like an asyncio.Event).
• cancelling an anyioutils.Future doesn't raise an anyio.get_cancelled_exc_class(), but an anyioutils.CancelledError.

from anyioutils import CancelledError, Future
from anyio import create_task_group, run

async def set_result(future):
    future.set_result("done")

async def cancel(future):
    future.cancel()

async def main():
    async with create_task_group() as tg:
        future0 = Future()
        tg.start_soon(set_result, future0)
        assert await future0.wait() == "done"

        future1 = Future()
        tg.start_soon(cancel, future1)
        try:
            await future1.wait()
        except CancelledError:
            assert future1.cancelled()

run(main)