diff --git a/litellm/router.py b/litellm/router.py index 02027c9bd48..facb4978ae5 100644 --- a/litellm/router.py +++ b/litellm/router.py @@ -421,6 +421,36 @@ def _anthropic_stream_should_decline_fallback(has_generated_content: bool, error return has_generated_content or not error.is_pre_first_chunk +def _anthropic_stream_raised_error_status(error: Exception) -> int | None: + raw_status: Final = getattr(error, "status_code", None) + if isinstance(raw_status, int): + return raw_status + if isinstance(raw_status, str) and raw_status.isdigit(): + return int(raw_status) + response_status: Final = getattr(getattr(error, "response", None), "status_code", None) + return response_status if isinstance(response_status, int) else None + + +def _anthropic_stream_fallback_error_for_raised( + error: Exception, model: str, has_generated_content: bool +) -> "MidStreamFallbackError | None": + """Same gate as a detected SSE error event; None means the raise propagates unchanged.""" + from litellm.exceptions import MidStreamFallbackError + + if has_generated_content: + return None + status_code: Final = _anthropic_stream_raised_error_status(error) + if status_code is not None and not _is_retriable_anthropic_status(status_code): + return None + return MidStreamFallbackError( + message=str(error), + model=model, + llm_provider="anthropic", + original_exception=error, + is_pre_first_chunk=True, + ) + + def _anthropic_stream_commits_now(chunk: object, has_generated_content: bool, buffered_chunk_count: int) -> bool: """ Whether `chunk` should make Router._aanthropic_messages_streaming_iterator @@ -5065,14 +5095,15 @@ class Router: yield chunk for buffered_chunk in buffered_lifecycle_chunks: yield buffered_chunk - except MidStreamFallbackError as e: - if _anthropic_stream_should_decline_fallback(has_generated_content, e): - for buffered_chunk in buffered_lifecycle_chunks: - yield buffered_chunk - if e.original_exception is not None: - raise e.original_exception from e - raise - async for item in self._aanthropic_messages_fallback_attempt(e, initial_kwargs, wrapper): + except Exception as stream_error: # noqa: BLE001 # any raised provider error must reach the fallback gate + async for item in self._aanthropic_messages_recover_stream_error( + stream_error, + has_generated_content, + buffered_lifecycle_chunks, + model, + initial_kwargs, + wrapper, + ): yield item finally: with anyio.CancelScope(shield=True), contextlib.suppress(BaseException): @@ -5084,6 +5115,36 @@ class Router: wrapper: Final = FallbackAwareAnthropicMessagesStream(stream_with_fallbacks(), source_iterator) return wrapper + async def _aanthropic_messages_recover_stream_error( + self, + stream_error: Exception, + has_generated_content: bool, + buffered_lifecycle_chunks: tuple[bytes, ...], + model: str, + initial_kwargs: dict[str, Any], # mutable-ok: handed to _aanthropic_messages_fallback_attempt, which mutates it + wrapper: "FallbackAwareAnthropicMessagesStream", + ) -> AsyncGenerator[bytes, None]: + """Turns a source-iterator failure into a fallback attempt or the error reaching the caller.""" + from litellm.exceptions import MidStreamFallbackError + + if isinstance(stream_error, MidStreamFallbackError) and _anthropic_stream_should_decline_fallback( + has_generated_content, stream_error + ): + for buffered_chunk in buffered_lifecycle_chunks: + yield buffered_chunk + if stream_error.original_exception is not None: + raise stream_error.original_exception from stream_error + raise stream_error + fallback_error: Final = ( + stream_error + if isinstance(stream_error, MidStreamFallbackError) + else _anthropic_stream_fallback_error_for_raised(stream_error, model, has_generated_content) + ) + if fallback_error is None: + raise stream_error + async for item in self._aanthropic_messages_fallback_attempt(fallback_error, initial_kwargs, wrapper): + yield item + async def _aanthropic_messages_fallback_attempt( self, e: "MidStreamFallbackError", diff --git a/tests/test_litellm/test_router.py b/tests/test_litellm/test_router.py index 779f0bd8e56..2948568198f 100644 --- a/tests/test_litellm/test_router.py +++ b/tests/test_litellm/test_router.py @@ -5,6 +5,7 @@ import json import logging import os import threading +from types import SimpleNamespace from unittest.mock import AsyncMock, MagicMock, patch import httpx @@ -17,6 +18,7 @@ import litellm from litellm import Router from litellm.exceptions import MidStreamFallbackError from litellm.integrations.custom_logger import CustomLogger +from litellm.llms.bedrock.common_utils import BedrockError from litellm.llms.anthropic.experimental_pass_through.messages.agentic_streaming_iterator import ( SERVER_FULFILLED_TOOL_LEAK_ERROR_SSE_BYTES, ) @@ -24,6 +26,8 @@ from litellm.router import ( MAX_BUFFERED_PRE_CONTENT_ANTHROPIC_CHUNKS, FallbackAwareAnthropicMessagesStream, _anthropic_stream_commits_now, + _anthropic_stream_fallback_error_for_raised, + _anthropic_stream_raised_error_status, _anthropic_stream_should_decline_fallback, _anthropic_stream_error_is_gateway_verdict, _anthropic_stream_forwards_ping_live, @@ -10224,6 +10228,214 @@ async def test_anthropic_messages_fallback_also_catches_raised_midstream_error() assert mock_fallback.await_args.kwargs["e"] is raised_error +@pytest.mark.asyncio +@pytest.mark.parametrize( + "raised_error", + [ + BedrockError(status_code=503, message='serviceUnavailableException {"message": "Service unavailable"}'), + BedrockError(status_code=500, message='internalServerException {"message": "Internal error"}'), + BedrockError(status_code=429, message='throttlingException {"message": "Too many requests"}'), + httpx.ReadError("connection reset by upstream"), + ], + ids=["503", "500", "429", "transport-drop"], +) +async def test_anthropic_messages_raised_provider_error_before_content_triggers_fallback(raised_error): + """A retriable raise before content falls over exactly like a detected SSE error event.""" + router = _anthropic_messages_make_router() + source = _AnthropicMessagesRaisingByteStream([_anthropic_messages_message_start_chunk()], raised_error) + fallback_stream = _AnthropicMessagesFallbackByteStream([_anthropic_messages_content_chunk("fallback answer")]) + + with patch.object( + router, + "async_function_with_fallbacks_common_utils", + new=AsyncMock(return_value=fallback_stream), + ) as mock_fallback: + wrapped = await router._aanthropic_messages_streaming_iterator( + response=source, + initial_kwargs={"model": "primary"}, + ) + collected = [chunk async for chunk in wrapped] + + assert collected == [_anthropic_messages_content_chunk("fallback answer")] + mock_fallback.assert_awaited_once() + converted = mock_fallback.await_args.kwargs["e"] + assert isinstance(converted, MidStreamFallbackError) + assert converted.original_exception is raised_error + assert converted.is_pre_first_chunk is True + assert source.closed is True + + +class _AnthropicMessagesStringStatusError(Exception): + def __init__(self): + super().__init__("bad request") + self.status_code = "400" + + +class _AnthropicMessagesResponseOnlyStatusError(Exception): + def __init__(self): + super().__init__("bad request") + self.response = SimpleNamespace(status_code=400) + + +@pytest.mark.asyncio +@pytest.mark.parametrize( + "raised_error", + [ + BedrockError(status_code=400, message='validationException {"message": "Malformed input"}'), + BedrockError(status_code=424, message='modelStreamErrorException {"message": "Model stream error"}'), + _AnthropicMessagesStringStatusError(), + _AnthropicMessagesResponseOnlyStatusError(), + ], + ids=["400", "424", "str-400", "response-only-400"], +) +async def test_anthropic_messages_raised_non_retriable_provider_error_propagates_unchanged(raised_error): + """A raised client error reaches the caller as the same exception, nothing flushed, no fallback.""" + router = _anthropic_messages_make_router() + source = _AnthropicMessagesRaisingByteStream([_anthropic_messages_message_start_chunk()], raised_error) + + with patch.object( + router, + "async_function_with_fallbacks_common_utils", + new=AsyncMock(), + ) as mock_fallback: + wrapped = await router._aanthropic_messages_streaming_iterator( + response=source, + initial_kwargs={"model": "primary"}, + ) + collected = [] + + async def _consume(): + async for chunk in wrapped: + collected.append(chunk) + + with pytest.raises(type(raised_error)) as exc_info: + await _consume() + + assert collected == [] + assert exc_info.value is raised_error + mock_fallback.assert_not_awaited() + + +@pytest.mark.asyncio +async def test_anthropic_messages_raised_provider_error_after_content_propagates_unchanged(): + """A raise after content propagates unchanged even when its status is retriable.""" + router = _anthropic_messages_make_router() + content = _anthropic_messages_content_chunk("partial answer") + raised_error = BedrockError( + status_code=503, message='serviceUnavailableException {"message": "Service unavailable"}' + ) + source = _AnthropicMessagesRaisingByteStream([content], raised_error) + + with patch.object( + router, + "async_function_with_fallbacks_common_utils", + new=AsyncMock(), + ) as mock_fallback: + wrapped = await router._aanthropic_messages_streaming_iterator( + response=source, + initial_kwargs={"model": "primary"}, + ) + collected = [] + + async def _consume(): + async for chunk in wrapped: + collected.append(chunk) + + with pytest.raises(BedrockError) as exc_info: + await _consume() + + assert collected == [content] + assert exc_info.value is raised_error + mock_fallback.assert_not_awaited() + + +@pytest.mark.parametrize( + "error, expected_status", + [ + (BedrockError(status_code=503, message="unavailable"), 503), + (_AnthropicMessagesStringStatusError(), 400), + (_AnthropicMessagesResponseOnlyStatusError(), 400), + (httpx.ReadError("connection reset by upstream"), None), + ], + ids=["int", "digit-str", "response-only", "none"], +) +def test_anthropic_stream_raised_error_status_reads_every_status_shape(error, expected_status): + assert _anthropic_stream_raised_error_status(error) == expected_status + + +@pytest.mark.parametrize( + "error, has_generated_content, converts", + [ + (BedrockError(status_code=503, message="unavailable"), False, True), + (httpx.ReadError("connection reset by upstream"), False, True), + (BedrockError(status_code=400, message="malformed"), False, False), + (BedrockError(status_code=503, message="unavailable"), True, False), + ], + ids=["retriable", "no-status", "client-error", "after-content"], +) +def test_anthropic_stream_fallback_error_for_raised_gates_like_a_detected_error_event( + error, has_generated_content, converts +): + converted = _anthropic_stream_fallback_error_for_raised(error, "primary", has_generated_content) + if not converts: + assert converted is None + return + assert isinstance(converted, MidStreamFallbackError) + assert converted.original_exception is error + assert converted.is_pre_first_chunk is True + assert converted.llm_provider == "anthropic" + + +@pytest.mark.asyncio +async def test_aanthropic_messages_recover_stream_error_flushes_buffered_frames_before_declining(): + router = _anthropic_messages_make_router() + original = BedrockError(status_code=503, message="unavailable") + declined = MidStreamFallbackError( + message="unavailable", + model="primary", + llm_provider="anthropic", + original_exception=original, + is_pre_first_chunk=False, + ) + buffered = (_anthropic_messages_message_start_chunk(),) + flushed = [] + + async def drain(recovery) -> None: + async for chunk in recovery: + flushed.append(chunk) + + with patch.object(router, "_aanthropic_messages_fallback_attempt") as mock_attempt: + recovery = router._aanthropic_messages_recover_stream_error( + declined, True, buffered, "primary", {"model": "primary"}, _anthropic_messages_make_wrapper() + ) + with pytest.raises(BedrockError) as exc_info: + await drain(recovery) + assert flushed == list(buffered) + assert exc_info.value is original + mock_attempt.assert_not_called() + + +@pytest.mark.asyncio +async def test_aanthropic_messages_recover_stream_error_hands_converted_raise_to_fallback_attempt(): + router = _anthropic_messages_make_router() + raised = BedrockError(status_code=503, message="unavailable") + handed_over = [] + + async def fake_attempt(fallback_error, initial_kwargs, wrapper): + handed_over.append(fallback_error) + yield b"fallback" + + with patch.object(router, "_aanthropic_messages_fallback_attempt", new=fake_attempt): + recovery = router._aanthropic_messages_recover_stream_error( + raised, False, (), "primary", {"model": "primary"}, _anthropic_messages_make_wrapper() + ) + collected = [chunk async for chunk in recovery] + assert collected == [b"fallback"] + assert len(handed_over) == 1 + assert isinstance(handed_over[0], MidStreamFallbackError) + assert handed_over[0].original_exception is raised + + @pytest.mark.asyncio async def test_anthropic_messages_non_retriable_client_error_skips_fallback(): """A 4xx (non-429) error type (e.g. invalid_request_error) is a client