Add intervals for scheduled task

[so-saf]

Hi!

Following up on PR #399, which I left unfinished half a year ago:

In this PR, I want to add intervals for scheduled tasks.

List of changes:

• Added a new interval field to ScheduledTask.
• Implemented the SchedulerLoop class—an abstraction over the scheduler loop.
• Added a new loop_interval argument to SchedulerArgs.
• Moved the skip_first_run mechanism into SchedulerLoop.run().
• The teskiq.api.scheduler.run_scheduler_tasks function now uses SchedulerLoop.
• Implemented the schedule_by_interval method in the AsyncTaskiqDecoratedTask and AsyncKicker classes.
• Wrote tests for the new logic.
• Updated the documentation.

The main idea is to iterate through all tasks every loop_interval and check if they need to be executed.

Example:

@broker.task(schedule=[{"interval": 5, "args": [1]}])  
async def add_one(value: int) -> int:  
    await asyncio.sleep(0.5)  
    return value + 1  

Logs:

[2025-08-18 11:07:50,547][INFO   ][run:run_scheduler:396] Starting scheduler.
[2025-08-18 11:07:50,551][INFO   ][run:run_scheduler:398] Startup completed.
[2025-08-18 11:07:51,001][INFO   ][run:send:160] Sending task test:add_one with schedule_id 5b32c74a07d447d68f506b089616d526.
[2025-08-18 11:07:56,002][INFO   ][run:send:160] Sending task test:add_one with schedule_id 5b32c74a07d447d68f506b089616d526.
[2025-08-18 11:08:01,002][INFO   ][run:send:160] Sending task test:add_one with schedule_id 5b32c74a07d447d68f506b089616d526.
[2025-08-18 11:08:06,002][INFO   ][run:send:160] Sending task test:add_one with schedule_id 5b32c74a07d447d68f506b089616d526.
[2025-08-18 11:08:11,001][INFO   ][run:send:160] Sending task test:add_one with schedule_id 5b32c74a07d447d68f506b089616d526.
[2025-08-18 11:08:16,001][INFO   ][run:send:160] Sending task test:add_one with schedule_id 5b32c74a07d447d68f506b089616d526.
[2025-08-18 11:08:21,001][INFO   ][run:send:160] Sending task test:add_one with schedule_id 5b32c74a07d447d68f506b089616d526.

[so-saf]

I saw that several tests failed on older versions of Pydantic and Python, so I pushed fixes.

[danfimov]

I enabled anyio_mode = "auto" flag for pytest. So tests doesn't need to explicitly say that they are async with pytest.mark.anyio marker.

You can just remove it and tests should work as they were)

[so-saf]

done

[so-saf]

I have resolved the merge conflicts and fixed the failing tests.

[danfimov]

Seems like this logic should be in a separate validator for interval field. Also we can use strict=True and ge=1 arguments for pydantic.Field to check that it's really a positive integer.

I think it should look like that and work the same as your implementation:

class ScheduledTask(BaseModel):
    ....  # other field here
    interval: Union[int, timedelta, None] = Field(ge=1, strict=True)
    
    @pydantic.field_validator("interval", mode="before")
    @classmethod
    def __check_interval(cls, value: Any) -> int | None:
        if isinstance(value, timedelta):
           return value.total_seconds()
        return value

[so-saf]

Unfortunately, this approach won't work because the strict=True parameter doesn't function with Union annotations, and le=1 is not designed for timedelta classes.

However, I've reviewed the validation for the interval parameter and decided to extract it into a separate function to avoid code duplication between the v1 and v2 schemas.

[s3rius]

It looks good, however I spot only one thing that may bug in the future.

So, please consider replacing back dict to list of tuples.

[s3rius]

There was a reason why this thing is a list. And the reason is that not all schedule sources are hashable.

For example redis source has connection pool, which is impossible to hash. Please revert it to be list of tuples.

[so-saf]

I should have realized there was a reason it wasn't using a hashmap initially :)

[s3rius]

is_not_ready will always be false in that case. But we can leave it for readability.