fix(complexity_router): tolerate task pin deletion failures

litellm/router_strategy/complexity_router/complexity_router.py

@@ -4183,7 +4183,7 @@ class ComplexityRouter(CustomLogger):
     async def async_pre_routing_hook(
         self,
         model: str,
-        request_kwargs: dict,
+        request_kwargs: dict[str, object],
         messages: list[dict[str, Any]] | None = None,
         input: str | list | None = None,
         specific_deployment: bool | None = False,
@@ -4395,7 +4395,10 @@ class ComplexityRouter(CustomLogger):
             and not pin_replay_allowed
             and self._matched_plan_mode_signal(request_kwargs, resolved_messages) is None
         ):
-            await self.litellm_router_instance.cache.async_delete_cache(key=cache_key)
+            try:
+                await self.litellm_router_instance.cache.async_delete_cache(key=cache_key)
+            except Exception:  # noqa: BLE001  # optional cache failures must not prevent routing
+                verbose_router_logger.debug("ComplexityRouter: task pin invalidation failed; continuing classification")
 
         routed_response: Final = await self._classify_and_route(
             model=model,

tests/unit/router_strategy/test_complexity_router.py

@@ -10,7 +10,7 @@ import logging
 import math
 import sys
 import time
-from collections.abc import AsyncIterator, Mapping, Sequence
+from collections.abc import AsyncIterator, Iterator, Mapping, Sequence
 from copy import deepcopy
 from functools import partial
 from types import MappingProxyType
@@ -34,6 +34,7 @@ from litellm.router_utils.auto_router_model_naming import (
 from litellm._logging import verbose_router_logger
 from litellm.caching.dual_cache import DualCache
 from litellm.caching.in_memory_cache import InMemoryCache
+from litellm.caching.redis_cache import RedisCache
 from litellm.constants import (
     OUTPUT_TOKEN_CEILING_PARAMS,
     RETURN_RAW_MODEL_NAME_METADATA_KEY,
@@ -16963,9 +16964,37 @@ class TestNonReasoningTier:
         )
 
 
+@pytest.fixture
+def unavailable_task_pin_redis() -> Iterator[RedisCache]:
+    import redis
+    import redis.asyncio
+    from litellm import in_memory_llm_clients_cache
+
+    class UnavailableSyncConnection(redis.Connection):
+        def connect(self) -> None:
+            raise redis.ConnectionError("scripted Redis outage")
+
+    class UnavailableAsyncConnection(redis.asyncio.Connection):
+        async def connect(self) -> None:
+            raise redis.ConnectionError("scripted Redis outage")
+
+    sync_pool: Final = redis.ConnectionPool(connection_class=UnavailableSyncConnection)
+    async_pool: Final = redis.asyncio.BlockingConnectionPool(connection_class=UnavailableAsyncConnection)
+    client: Final = redis.asyncio.Redis(connection_pool=async_pool)
+    cache: Final = RedisCache(host="synthetic.invalid", connection_pool=sync_pool)
+    client_key: Final = cache._get_async_client_cache_key()
+    cache.redis_async_client = client
+    yield cache
+    in_memory_llm_clients_cache.delete_cache(client_key)
+    sync_pool.disconnect()
+
+
 @pytest.mark.asyncio
 @pytest.mark.parametrize("circuit_breaker_enabled", [True, False])
-async def test_new_user_ask_classifier_failure_clears_previous_turn_pin(circuit_breaker_enabled: bool) -> None:
+@pytest.mark.parametrize("redis_unavailable", [False, True])
+async def test_new_user_ask_classifier_failure_clears_previous_turn_pin(
+    circuit_breaker_enabled: bool, redis_unavailable: bool, unavailable_task_pin_redis: RedisCache
+) -> None:
     from openai import AsyncOpenAI
 
     outcomes: Final = iter(("SIMPLE", None, "COMPLEX"))
@@ -17002,6 +17031,8 @@ async def test_new_user_ask_classifier_failure_clears_previous_turn_pin(circuit_
                     {"model_name": "default", "litellm_params": {"model": "openai/default"}},
                 ],
             )
+            if redis_unavailable:
+                underlying.cache.redis_cache = unavailable_task_pin_redis
             router: Final = ComplexityRouter(
                 "auto",
                 underlying,
@@ -17019,6 +17050,11 @@ async def test_new_user_ask_classifier_failure_clears_previous_turn_pin(circuit_
                     "tiers": {"SIMPLE": "cheap", "MEDIUM": "default", "COMPLEX": "default", "REASONING": "default"},
                 },
             )
+            if redis_unavailable:
+                litellm.in_memory_llm_clients_cache.set_cache(
+                    unavailable_task_pin_redis._get_async_client_cache_key(),
+                    unavailable_task_pin_redis.redis_async_client,
+                )
             kwargs: Final = {"metadata": {"session_id": "stale-pin-regression"}}
             first: Final = [{"role": "user", "content": "Hello"}]
             second: Final = [