diff --git a/litellm/caching/redis_cache.py b/litellm/caching/redis_cache.py index 6b93529e456..7b7d3841109 100644 --- a/litellm/caching/redis_cache.py +++ b/litellm/caching/redis_cache.py @@ -321,7 +321,15 @@ def _redis_timeout_error_types() -> tuple[type, ...]: def _is_redis_timeout_failure(exc: BaseException) -> bool: - return isinstance(exc, _redis_timeout_error_types()) + """True when ``exc`` or any exception it was explicitly raised ``from`` is a timeout. + + redis-py's blocking pool reports a pool wait timeout as ``ConnectionError`` chained from + ``asyncio.TimeoutError``, which is a busy pool rather than an unreachable Redis. + """ + if isinstance(exc, _redis_timeout_error_types()): + return True + cause: Final = exc.__cause__ + return cause is not None and _is_redis_timeout_failure(cause) class _BreakerMetrics: diff --git a/tests/test_litellm/caching/test_redis_cache.py b/tests/test_litellm/caching/test_redis_cache.py index bcaa58c9c40..2e1dfb77fd2 100644 --- a/tests/test_litellm/caching/test_redis_cache.py +++ b/tests/test_litellm/caching/test_redis_cache.py @@ -1030,3 +1030,63 @@ def test_sync_guard_counts_a_timeout_as_a_timeout(): _run_under_circuit_breaker_sync(breaker, "op", timing_out_call) assert breaker.is_open() is False + + +@pytest.mark.asyncio +async def test_pool_wait_timeout_is_a_timeout_failure_not_hard_connectivity(): + """A saturated blocking pool must not open the breaker before the timeout minimum duration. + + redis-py's async BlockingConnectionPool gives up waiting for a free connection by raising + ConnectionError("No connection available.") chained from asyncio.TimeoutError. Redis itself + is healthy in that case, so the failure has to be classed as a timeout and stay behind the + duration gate instead of being counted as a hard connectivity failure. + """ + from fakeredis import FakeServer + from fakeredis.aioredis import FakeConnection + from redis.asyncio import BlockingConnectionPool, Redis + from redis.exceptions import ConnectionError as RedisConnectionError + + from litellm.caching.redis_cache import RedisCircuitBreaker, _run_under_circuit_breaker + + pool = BlockingConnectionPool(connection_class=FakeConnection, server=FakeServer(), max_connections=1, timeout=0.01) + client = Redis(connection_pool=pool) + breaker = RedisCircuitBreaker(failure_threshold=3, recovery_timeout=60, timeout_min_duration=5.0) + + busy_connection = await pool.get_connection() + try: + for _ in range(breaker.failure_threshold * 2): + with pytest.raises(RedisConnectionError, match="No connection available"): + await _run_under_circuit_breaker(breaker, "op", lambda: client.get("k")) + finally: + await pool.release(busy_connection) + + assert breaker.is_open() is False, "a busy pool is a timeout gated on duration, not a dead Redis" + assert await _run_under_circuit_breaker(breaker, "op", lambda: client.get("k")) is None + await client.aclose() + + +def test_timeout_classification_follows_the_explicit_cause_chain_only(): + from redis.exceptions import ConnectionError as RedisConnectionError + + from litellm.caching.redis_cache import _is_redis_timeout_failure + + def raise_chained_from_timeout() -> None: + try: + raise asyncio.TimeoutError() + except asyncio.TimeoutError as err: + raise RedisConnectionError("No connection available.") from err + + def raise_while_handling_timeout() -> None: + try: + raise asyncio.TimeoutError() + except asyncio.TimeoutError: + raise RedisConnectionError("refused") + + with pytest.raises(RedisConnectionError) as chained: + raise_chained_from_timeout() + with pytest.raises(RedisConnectionError) as contextual: + raise_while_handling_timeout() + + assert _is_redis_timeout_failure(chained.value) is True + assert _is_redis_timeout_failure(contextual.value) is False + assert _is_redis_timeout_failure(RedisConnectionError("refused")) is False