A kind of initial commit

app/db/session.py

@@ -0,0 +1,35 @@
+from __future__ import annotations
+
+from collections.abc import AsyncIterator
+from contextlib import asynccontextmanager
+
+from sqlalchemy.ext.asyncio import AsyncEngine, AsyncSession, async_sessionmaker, create_async_engine
+
+from app.config import Settings
+from app.db.base import Base
+
+
+def create_engine(settings: Settings) -> AsyncEngine:
+    return create_async_engine(settings.database_url, future=True, echo=False)
+
+
+def create_session_factory(engine: AsyncEngine) -> async_sessionmaker[AsyncSession]:
+    return async_sessionmaker(engine, expire_on_commit=False, class_=AsyncSession)
+
+
+async def init_db(engine: AsyncEngine) -> None:
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+
+
+@asynccontextmanager
+async def session_scope(factory: async_sessionmaker[AsyncSession]) -> AsyncIterator[AsyncSession]:
+    session = factory()
+    try:
+        yield session
+        await session.commit()
+    except Exception:
+        await session.rollback()
+        raise
+    finally:
+        await session.close()