perf: check token revocation without BEGIN and COMMIT round trips

app/database/resources.py

@@ -1,6 +1,7 @@
 import asyncio
 import typing
 
+from db_retry import Transaction
 from sqlalchemy.ext import asyncio as sa
 
 from app.settings import settings
@@ -34,3 +35,10 @@ def create_session(engine: sa.AsyncEngine | sa.AsyncConnection) -> sa.AsyncSessi
 async def close_session(session: sa.AsyncSession) -> None:
     task: typing.Final = asyncio.create_task(session.close())
     await asyncio.shield(task)
+
+
+def create_autocommit_transaction(session: sa.AsyncSession) -> Transaction:
+    # Isolation level can only be set before the session holds a connection; test sessions are bound to one.
+    if isinstance(session.bind, sa.AsyncEngine) and not session.in_transaction():
+        return Transaction(session=session, isolation_level="AUTOCOMMIT")
+    return Transaction(session=session)

app/ioc.py

@@ -39,6 +39,12 @@ class Database(Group):
         creator=Transaction,
         kwargs={"session": database_session},
     )
+    autocommit_transaction = providers.Factory(
+        scope=Scope.REQUEST,
+        creator=database_resources.create_autocommit_transaction,
+        bound_type=None,
+        kwargs={"session": database_session},
+    )
 
 
 class Repositories(Group, scope=Scope.REQUEST):
@@ -77,7 +83,9 @@ class UseCases(Group, scope=Scope.REQUEST):
     fetch_user_use_case = providers.Factory(creator=FetchUserUseCase)
     mark_read_use_case = providers.Factory(creator=MarkReadUseCase)
     revoke_token_use_case = providers.Factory(creator=RevokeTokenUseCase)
-    check_token_revoked_use_case = providers.Factory(creator=CheckTokenRevokedUseCase)
+    check_token_revoked_use_case = providers.Factory(
+        creator=CheckTokenRevokedUseCase, kwargs={"transaction": Database.autocommit_transaction}
+    )
 
 
 ALL_GROUPS: typing.Final[list[type[Group]]] = [Database, Repositories, UseCases]

tests/use_cases/test_check_token_revoked.py

@@ -0,0 +1,30 @@
+import asyncio
+import typing
+
+import asyncpg
+import modern_di
+
+from app import ioc
+from app.database.resources import create_database_engine
+
+
+async def test_revocation_check_sends_no_transaction_statements(di_container: modern_di.Container) -> None:
+    engine: typing.Final = create_database_engine()
+    di_container.override(ioc.Database.database_engine, engine)
+    queries: typing.Final[list[asyncpg.connection.LoggedQuery]] = []
+
+    try:
+        async with engine.connect() as connection:
+            driver_connection = (await connection.get_raw_connection()).driver_connection
+            assert isinstance(driver_connection, asyncpg.Connection)
+        driver_connection.add_query_logger(queries.append)
+
+        async with di_container.build_child_container(scope=modern_di.Scope.REQUEST) as container:
+            check_token_revoked = container.resolve_provider(ioc.UseCases.check_token_revoked_use_case)
+            assert await check_token_revoked(jti="unknown") is False
+        await asyncio.sleep(0)
+    finally:
+        di_container.reset_override(ioc.Database.database_engine)
+        await engine.dispose()
+
+    assert not {"BEGIN;", "COMMIT;", "ROLLBACK;"} & {logged.query for logged in queries}, queries