Remove redundant session transactions

Author: lealre

docs/index.md

@@ -107,20 +107,19 @@ from sqlalchemy.ext.asyncio import (
 
 DATABASE_URL = 'sqlite+aiosqlite:///db.sqlite3'
 
-engine = create_async_engine(DATABASE_URL, future=True, echo=True)
+engine = create_async_engine(DATABASE_URL, echo=True)
 
 AsyncSessionLocal = async_sessionmaker(
-    autocommit=False,
-    expire_on_commit=False,
-    autoflush=True,
     bind=engine,
+    expire_on_commit=False,
     class_=AsyncSession,
 )
 
 
 async def get_session() -> typing.AsyncGenerator[AsyncSession, None]:
     async with AsyncSessionLocal() as session:
         yield session
+
 ```
 
 The last file before creating the routes is the `schemas.py`, which will contain all the [Pydantic](https://docs.pydantic.dev/latest/){:target="\_blank"} models.
@@ -197,8 +196,7 @@ SessionDep = Annotated[AsyncSession, Depends(get_session)]
 async def get_all_tickets(session: SessionDep):
     async with session.begin():
         tickets = await session.scalars(select(Ticket))
-
-    all_tickets = tickets.all()
+        all_tickets = tickets.all()
 
     return {'tickets': all_tickets}
 
@@ -213,10 +211,6 @@ async def create_ticket(session: SessionDep, ticket_in: TicketRequestCreate):
 
     async with session.begin():
         session.add(new_ticket)
-        await session.commit()
-
-    async with session.begin():
-        await session.refresh(new_ticket)
 
     return new_ticket
 
@@ -253,11 +247,6 @@ async def get_ticket_by_id(session: SessionDep, ticket_in: TicketRequestBuy):
                 detail='Ticket has already been sold',
             )
 
-        await session.commit()
-
-    async with session.begin():
-        await session.refresh(ticket_db)
-
     return ticket_db
 
 ```
@@ -425,7 +414,6 @@ async def test_get_all_tickets_success(
 
     async with async_session.begin():
         async_session.add_all(tickets)
-        await async_session.commit()
 
     response = await async_client.get('/tickets/all')
 
@@ -438,6 +426,7 @@ async def test_get_all_tickets_when_empty(async_client: AsyncClient):
 
     assert response.status_code == HTTPStatus.OK
     assert response.json()['tickets'] == []
+
 ```
 
 In total there are 6 test, and the rest of them has the same logic. Their full implementations can be checked in the repository.

src/app.py

@@ -33,8 +33,7 @@ async def lifespan(app: FastAPI):
 async def get_all_tickets(session: SessionDep):
     async with session.begin():
         tickets = await session.scalars(select(Ticket))
-
-    all_tickets = tickets.all()
+        all_tickets = tickets.all()
 
     return {'tickets': all_tickets}
 
@@ -49,10 +48,6 @@ async def create_ticket(session: SessionDep, ticket_in: TicketRequestCreate):
 
     async with session.begin():
         session.add(new_ticket)
-        await session.commit()
-
-    async with session.begin():
-        await session.refresh(new_ticket)
 
     return new_ticket
 
@@ -89,9 +84,4 @@ async def get_ticket_by_id(session: SessionDep, ticket_in: TicketRequestBuy):
                 detail='Ticket has already been sold',
             )
 
-        await session.commit()
-
-    async with session.begin():
-        await session.refresh(ticket_db)
-
     return ticket_db

src/database.py

@@ -8,13 +8,11 @@
 
 DATABASE_URL = 'sqlite+aiosqlite:///db.sqlite3'
 
-engine = create_async_engine(DATABASE_URL, future=True, echo=True)
+engine = create_async_engine(DATABASE_URL, echo=True)
 
 AsyncSessionLocal = async_sessionmaker(
-    autocommit=False,
-    expire_on_commit=False,
-    autoflush=True,
     bind=engine,
+    expire_on_commit=False,
     class_=AsyncSession,
 )
 

tests/conftest.py

@@ -21,15 +21,15 @@ def anyio_backend() -> str:
 
 @pytest.fixture(scope='session')
 def postgres_container(
-    anyio_backend: typing.Literal['asyncio']
+    anyio_backend: typing.Literal['asyncio'],
 ) -> typing.Generator[PostgresContainer, None, None]:
     with PostgresContainer('postgres:16', driver='asyncpg') as postgres:
         yield postgres
 
 
 @pytest.fixture
 async def async_session(
-    postgres_container: PostgresContainer
+    postgres_container: PostgresContainer,
 ) -> typing.AsyncGenerator[AsyncSession, None]:
     async_db_url = postgres_container.get_connection_url()
     async_engine = create_async_engine(async_db_url, pool_pre_ping=True)
@@ -39,10 +39,9 @@ async def async_session(
         await conn.run_sync(table_register.metadata.create_all)
 
     async_session = async_sessionmaker(
-        autoflush=False,
         bind=async_engine,
-        class_=AsyncSession,
         expire_on_commit=False,
+        class_=AsyncSession,
     )
 
     async with async_session() as session:
@@ -53,7 +52,7 @@ async def async_session(
 
 @pytest.fixture
 async def async_client(
-    async_session: AsyncSession
+    async_session: AsyncSession,
 ) -> typing.AsyncGenerator[AsyncClient, None]:
     app.dependency_overrides[get_session] = lambda: async_session
     _transport = ASGITransport(app=app)

tests/test_routes.py

@@ -21,7 +21,6 @@ async def test_get_all_tickets_success(
 
     async with async_session.begin():
         async_session.add_all(tickets)
-        await async_session.commit()
 
     response = await async_client.get('/tickets/all')
 
@@ -60,7 +59,6 @@ async def test_buy_ticket_success(
 
     async with async_session.begin():
         async_session.add(new_ticket)
-        await async_session.commit()
 
     response = await async_client.post(
         '/tickets/buy',
@@ -83,7 +81,6 @@ async def test_buy_ticket_when_ticket_not_found(
 
     async with async_session.begin():
         async_session.add(new_ticket)
-        await async_session.commit()
 
     response = await async_client.post(
         '/tickets/buy',
@@ -101,7 +98,6 @@ async def test_buy_ticket_when_already_sold(
 
     async with async_session.begin():
         async_session.add(new_ticket)
-        await async_session.commit()
 
     response = await async_client.post(
         '/tickets/buy', json={'ticket_id': new_ticket.id, 'user': 'other user'}