define db session connector

app/db/session.py

@@ -0,0 +1,29 @@
+from typing import AsyncGenerator
+from sqlalchemy.ext.asyncio import create_async_engine, async_sessionmaker, AsyncSession
+from app.core.config import settings
+
+engine = create_async_engine(
+    settings.DATABASE_URL,
+    echo=False,
+    future=True,
+    pool_size=10,
+    max_overflow=20,
+)
+
+AsyncSessionLocal = async_sessionmaker(
+    bind=engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+)
+
+
+async def get_db() -> AsyncGenerator[AsyncSession, None]:
+    async with AsyncSessionLocal() as session:
+        try:
+            yield session
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            raise
+        finally:
+            await session.close()