fix(proxy): log the open-breaker TTL preservation fallback at debug instead of per request warning

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/proxy/hooks/parallel_request_limiter_v3.py

@@ -26,6 +26,7 @@ from typing_extensions import NotRequired, ReadOnly
 
 from litellm import DualCache
 from litellm._logging import verbose_proxy_logger
+from litellm.caching.redis_cache import RedisCircuitBreakerOpenError
 from litellm.constants import DYNAMIC_RATE_LIMIT_ERROR_THRESHOLD_PER_MINUTE, INTERNAL_CALL_ORIGIN_METADATA_KEY
 from litellm.integrations.custom_logger import CustomLogger
 from litellm.litellm_core_utils.prompt_templates.common_utils import (
@@ -3856,8 +3857,12 @@ class _PROXY_MaxParallelRequestsHandler_v3(CustomLogger):
             )
 
         except Exception as e:
-            verbose_proxy_logger.warning("TTL preservation failed, falling back to regular pipeline: %s", e)
-            # Fallback to regular pipeline on error
+            log: Final = (
+                verbose_proxy_logger.debug
+                if isinstance(e, RedisCircuitBreakerOpenError)
+                else verbose_proxy_logger.warning
+            )
+            log("TTL preservation failed, falling back to regular pipeline: %s", e)
             await self.internal_usage_cache.dual_cache.async_increment_cache_pipeline(
                 increment_list=pipeline_operations,
                 litellm_parent_otel_span=parent_otel_span,

tests/test_litellm/proxy/hooks/test_parallel_request_limiter_v3.py

@@ -1795,6 +1795,30 @@ async def test_async_increment_tokens_fallback_behavior():
     ), "Fallback method should be called when Lua script is not available"
 
 
+@pytest.mark.asyncio
+async def test_async_increment_tokens_open_breaker_falls_back_without_warning(caplog):
+    """An open Redis breaker fast-fails the Lua script on every request, so it must fall
+    back to the regular pipeline quietly instead of emitting a WARNING per request."""
+    from unittest.mock import AsyncMock
+
+    from litellm.caching.redis_cache import RedisCircuitBreakerOpenError
+
+    handler = _PROXY_MaxParallelRequestsHandler(internal_usage_cache=InternalUsageCache(DualCache()))
+    handler.token_increment_script = object()
+    handler._execute_token_increment_script = AsyncMock(
+        side_effect=RedisCircuitBreakerOpenError("Redis circuit breaker is open, skipping run_script")
+    )
+    fallback = AsyncMock()
+    handler.internal_usage_cache.dual_cache.async_increment_cache_pipeline = fallback
+    pipeline_operations = [RedisPipelineIncrementOperation(key="test_breaker_key", increment_value=10.0, ttl=60)]
+
+    with caplog.at_level(logging.DEBUG, logger="LiteLLM Proxy"):
+        await handler.async_increment_tokens_with_ttl_preservation(pipeline_operations=pipeline_operations)
+
+    assert fallback.await_count == 1
+    assert [r.levelno for r in caplog.records if "TTL preservation failed" in r.getMessage()] == [logging.DEBUG]
+
+
 # Redis Cluster Compatibility Tests
 def test_group_keys_by_hash_tag_regular_redis():
     """