feat: implement async scheduler with lifespan management and update README

app/services/scheduler.py

@@ -1,13 +1,16 @@
+from collections.abc import AsyncIterator
+from contextlib import asynccontextmanager
 from datetime import datetime
 
-from apscheduler import AsyncScheduler
+from apscheduler import AsyncScheduler, ConflictPolicy
+from apscheduler.datastores.sqlalchemy import SQLAlchemyDataStore
+from apscheduler.eventbrokers.redis import RedisEventBroker
 from apscheduler.triggers.interval import IntervalTrigger
-from attrs import define
 from rotoger import get_logger
 from sqlalchemy import text
-from starlette.types import ASGIApp, Receive, Scope, Send
 
-from app.database import AsyncSessionFactory
+from app.config import settings as global_settings
+from app.database import AsyncSessionFactory, engine
 
 logger = get_logger()
 
@@ -21,26 +24,19 @@ async def tick():
         return True
 
 
-@define
-class SchedulerMiddleware:
-    app: ASGIApp
-    scheduler: AsyncScheduler
+@asynccontextmanager
+async def scheduler_lifespan() -> AsyncIterator[None]:
+    scheduler = AsyncScheduler(
+        SQLAlchemyDataStore(engine, schema="scheduler"),
+        RedisEventBroker(client_or_url=global_settings.redis_url.unicode_string()),
+    )
 
-    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
-        """
-        Handles the incoming request and schedules tasks if the scope type is 'lifespan'.
-
-        Args:
-            scope (Scope): The ASGI scope dictionary containing request information.
-            receive (Receive): The ASGI receive callable.
-            send (Send): The ASGI send callable.
-        """
-        if scope["type"] == "lifespan":
-            async with self.scheduler:
-                await self.scheduler.add_schedule(
-                    tick, IntervalTrigger(seconds=25), id="tick-sql-25"
-                )
-                await self.scheduler.start_in_background()
-                await self.app(scope, receive, send)
-        else:
-            await self.app(scope, receive, send)
+    async with scheduler:
+        await scheduler.add_schedule(
+            tick,
+            IntervalTrigger(seconds=25),
+            id="tick-sql-25",
+            conflict_policy=ConflictPolicy.replace,
+        )
+        await scheduler.start_in_background()
+        yield