Generator injection

[insani7y]

I'm injecting into lifespan generator. And want to start some background task.
In first case i use default that-depends flow for injection and task doesn't getting called at all.
But as soon as i resolve dependency myself - then everything works great.
Could you, please, support generator injections?

Code example:

# Doesnt work
@that_depends.inject
@contextlib.asynccontextmanager
async def run_lifespan(
    my_dep: ReportsRepository = that_depends.Provide[IOCContainer.my_dep],
) -> typing.AsyncIterator[None]:
    async with asyncio.TaskGroup() as task_group:
        task_group.create_task(my_dep.my_background_task())
        yield

    await IOCContainer.tear_down()

# Works correctly
@contextlib.asynccontextmanager
async def run_lifespan() -> typing.AsyncIterator[None]:
    my_dep: typing.Final = await IOCContainer.my_dep.async_resolve()

    async with asyncio.TaskGroup() as task_group:
        task_group.create_task(my_dep.my_background_task())
        yield

    await IOCContainer.tear_down()

[alexanderlazarev0]

We can probably support it for all providers except the ContextResource provider.

[alexanderlazarev0]

@insani7y Could it be that you are simply using an incorrect order for your annotations (@inject should be below @asynccontextmanager)?

This works for me with that-depends==3.1.0:

import asyncio
from contextlib import asynccontextmanager
from typing import AsyncGenerator

from that_depends import BaseContainer, providers, inject, Provide


class Container(BaseContainer):
    factory = providers.Factory(lambda: "hello")


@inject
async def generator(v: str = Provide[Container.factory]) -> AsyncGenerator[str, None]:
    """A simple generator function."""
    yield v

ctx = asynccontextmanager(generator)


async def main() -> None:
    v = await anext(generator())
    print(v)
    async with ctx() as v:
        print(v)


if __name__ == '__main__':
    asyncio.run(main())

Or am I missing something in your example?

[insani7y]

Yeah, i should point out, that in my initial realisation, that exactly what i did.
I've placed @Inject right after the first decorator and it didn't work

[alexanderlazarev0]

Alright I seem to have found what I missed, your IOCContainer.my_dep is async, and I am assuming can only be resolved asynchronously (ie. resolve_sync() fails). So injection does not work because the generator is created with a sync call:

v = await anext(generator()) # the call to create the generator itself has no await

So right now sync dependency providers will work more or less as expected with generators. I will see what can be done in the async case.

[alexanderlazarev0]

@insani7y Resolved in that-depends==3.2.0, please see the documentation linked in the release notes. If there are any issues please let me know.