fix: make cache updates synchronous for budget enforcement

The budget enforcement was failing in tests because cache updates were
fire-and-forget (asyncio.create_task), causing race conditions where
subsequent requests would read stale spend data.

Changes:
1. proxy_track_cost_callback.py: await update_cache() instead of create_task
2. proxy_server.py: await async_set_cache_pipeline() instead of create_task
3. auth_checks.py: prefer valid_token.team_member_spend (from fresh cache)
   over team_membership.spend (which may be stale)

This ensures budget checks see the most recent spend values and properly
enforce budget limits when requests come in quick succession.

Fixes: test_users_in_team_budget, test_chat_completion_low_budget

litellm/proxy/auth/auth_checks.py

@@ -2295,7 +2295,13 @@ async def _check_team_member_budget(
             and team_membership.litellm_budget_table.max_budget is not None
         ):
             team_member_budget = team_membership.litellm_budget_table.max_budget
-            team_member_spend = team_membership.spend or 0.0
+            # Prefer valid_token.team_member_spend (from token cache) over team_membership.spend
+            # The token cache is updated synchronously after each request, while the team membership
+            # cache may have stale data since DB updates are batched
+            if valid_token.team_member_spend is not None:
+                team_member_spend = valid_token.team_member_spend
+            else:
+                team_member_spend = team_membership.spend or 0.0
 
             if team_member_spend >= team_member_budget:
                 raise litellm.BudgetExceededError(

litellm/proxy/hooks/proxy_track_cost_callback.py

@@ -181,17 +181,15 @@ class _ProxyDBLogger(CustomLogger):
                         org_id=org_id,
                     )
 
-                    # update cache
-                    asyncio.create_task(
-                        update_cache(
-                            token=user_api_key,
-                            user_id=user_id,
-                            end_user_id=end_user_id,
-                            response_cost=response_cost,
-                            team_id=team_id,
-                            parent_otel_span=parent_otel_span,
-                            tags=tags,
-                        )
+                    # update cache - await to ensure budget checks see updated spend
+                    await update_cache(
+                        token=user_api_key,
+                        user_id=user_id,
+                        end_user_id=end_user_id,
+                        response_cost=response_cost,
+                        team_id=team_id,
+                        parent_otel_span=parent_otel_span,
+                        tags=tags,
                     )
 
                     await proxy_logging_obj.slack_alerting_instance.customer_spend_alert(

litellm/proxy/proxy_server.py

@@ -1703,12 +1703,11 @@ async def update_cache(  # noqa: PLR0915
     if tags is not None:
         await _update_tag_cache()
 
-    asyncio.create_task(
-        user_api_key_cache.async_set_cache_pipeline(
-            cache_list=values_to_update_in_cache,
-            ttl=60,
-            litellm_parent_otel_span=parent_otel_span,
-        )
+    # Await cache update to ensure budget checks see updated spend values
+    await user_api_key_cache.async_set_cache_pipeline(
+        cache_list=values_to_update_in_cache,
+        ttl=60,
+        litellm_parent_otel_span=parent_otel_span,
     )