first commit

app/database.py

@@ -0,0 +1,39 @@
+from collections.abc import AsyncIterator
+
+from sqlalchemy.ext.asyncio import (
+    AsyncSession,
+    async_sessionmaker,
+    create_async_engine,
+)
+from sqlalchemy.orm import DeclarativeBase
+from sqlalchemy.pool import NullPool
+
+from app.config import settings
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+engine_options: dict[str, object] = {
+    "pool_pre_ping": True,
+}
+if not settings.database_url.startswith("sqlite"):
+    engine_options.update(
+        pool_size=settings.database_pool_size,
+        max_overflow=settings.database_max_overflow,
+    )
+else:
+    engine_options["poolclass"] = NullPool
+
+engine = create_async_engine(settings.database_url, **engine_options)
+SessionLocal = async_sessionmaker(engine, expire_on_commit=False, class_=AsyncSession)
+
+
+async def get_db() -> AsyncIterator[AsyncSession]:
+    async with SessionLocal() as session:
+        try:
+            yield session
+        except Exception:
+            await session.rollback()
+            raise