feat(anthropic_adapter.py): support streaming requests for /v1/messages endpoint

Fixes https://github.com/BerriAI/litellm/issues/5011

litellm/adapters/anthropic_adapter.py

@@ -4,7 +4,7 @@ import json
 import os
 import traceback
 import uuid
-from typing import Literal, Optional
+from typing import Any, Literal, Optional
 
 import dotenv
 import httpx
@@ -13,7 +13,12 @@ from pydantic import BaseModel
 import litellm
 from litellm import ChatCompletionRequest, verbose_logger
 from litellm.integrations.custom_logger import CustomLogger
-from litellm.types.llms.anthropic import AnthropicMessagesRequest, AnthropicResponse
+from litellm.types.llms.anthropic import (
+    AnthropicMessagesRequest,
+    AnthropicResponse,
+    ContentBlockDelta,
+)
+from litellm.types.utils import AdapterCompletionStreamWrapper
 
 
 class AnthropicAdapter(CustomLogger):
@@ -43,8 +48,147 @@ class AnthropicAdapter(CustomLogger):
             response=response
         )
 
-    def translate_completion_output_params_streaming(self) -> Optional[BaseModel]:
-        return super().translate_completion_output_params_streaming()
+    def translate_completion_output_params_streaming(
+        self, completion_stream: Any
+    ) -> AdapterCompletionStreamWrapper | None:
+        return AnthropicStreamWrapper(completion_stream=completion_stream)
 
 
 anthropic_adapter = AnthropicAdapter()
+
+
+class AnthropicStreamWrapper(AdapterCompletionStreamWrapper):
+    """
+    - first chunk return 'message_start'
+    - content block must be started and stopped
+    - finish_reason must map exactly to anthropic reason, else anthropic client won't be able to parse it.
+    """
+
+    sent_first_chunk: bool = False
+    sent_content_block_start: bool = False
+    sent_content_block_finish: bool = False
+    sent_last_message: bool = False
+    holding_chunk: Optional[Any] = None
+
+    def __next__(self):
+        try:
+            if self.sent_first_chunk is False:
+                self.sent_first_chunk = True
+                return {
+                    "type": "message_start",
+                    "message": {
+                        "id": "msg_1nZdL29xx5MUA1yADyHTEsnR8uuvGzszyY",
+                        "type": "message",
+                        "role": "assistant",
+                        "content": [],
+                        "model": "claude-3-5-sonnet-20240620",
+                        "stop_reason": None,
+                        "stop_sequence": None,
+                        "usage": {"input_tokens": 25, "output_tokens": 1},
+                    },
+                }
+            if self.sent_content_block_start is False:
+                self.sent_content_block_start = True
+                return {
+                    "type": "content_block_start",
+                    "index": 0,
+                    "content_block": {"type": "text", "text": ""},
+                }
+
+            for chunk in self.completion_stream:
+                if chunk == "None" or chunk is None:
+                    raise Exception
+
+                processed_chunk = litellm.AnthropicConfig().translate_streaming_openai_response_to_anthropic(
+                    response=chunk
+                )
+                if (
+                    processed_chunk["type"] == "message_delta"
+                    and self.sent_content_block_finish is False
+                ):
+                    self.holding_chunk = processed_chunk
+                    self.sent_content_block_finish = True
+                    return {
+                        "type": "content_block_stop",
+                        "index": 0,
+                    }
+                elif self.holding_chunk is not None:
+                    return_chunk = self.holding_chunk
+                    self.holding_chunk = processed_chunk
+                    return return_chunk
+                else:
+                    return processed_chunk
+
+            if self.sent_last_message is False:
+                self.sent_last_message = True
+                return {"type": "message_stop"}
+            raise StopIteration
+        except StopIteration:
+            if self.sent_last_message is False:
+                self.sent_last_message = True
+                return {"type": "message_stop"}
+            raise StopIteration
+        except Exception as e:
+            verbose_logger.error(
+                "Anthropic Adapter - {}\n{}".format(e, traceback.format_exc())
+            )
+
+    async def __anext__(self):
+        try:
+            if self.sent_first_chunk is False:
+                self.sent_first_chunk = True
+                return {
+                    "type": "message_start",
+                    "message": {
+                        "id": "msg_1nZdL29xx5MUA1yADyHTEsnR8uuvGzszyY",
+                        "type": "message",
+                        "role": "assistant",
+                        "content": [],
+                        "model": "claude-3-5-sonnet-20240620",
+                        "stop_reason": None,
+                        "stop_sequence": None,
+                        "usage": {"input_tokens": 25, "output_tokens": 1},
+                    },
+                }
+            if self.sent_content_block_start is False:
+                self.sent_content_block_start = True
+                return {
+                    "type": "content_block_start",
+                    "index": 0,
+                    "content_block": {"type": "text", "text": ""},
+                }
+            async for chunk in self.completion_stream:
+                if chunk == "None" or chunk is None:
+                    raise Exception
+                processed_chunk = litellm.AnthropicConfig().translate_streaming_openai_response_to_anthropic(
+                    response=chunk
+                )
+                if (
+                    processed_chunk["type"] == "message_delta"
+                    and self.sent_content_block_finish is False
+                ):
+                    self.holding_chunk = processed_chunk
+                    self.sent_content_block_finish = True
+                    return {
+                        "type": "content_block_stop",
+                        "index": 0,
+                    }
+                elif self.holding_chunk is not None:
+                    return_chunk = self.holding_chunk
+                    self.holding_chunk = processed_chunk
+                    return return_chunk
+                else:
+                    return processed_chunk
+            if self.holding_chunk is not None:
+                return_chunk = self.holding_chunk
+                self.holding_chunk = None
+                return return_chunk
+            if self.sent_last_message is False:
+                self.sent_last_message = True
+                return {"type": "message_stop"}
+            raise StopIteration
+        except StopIteration:
+            if self.sent_last_message is False:
+                self.sent_last_message = True
+                return {"type": "message_stop"}
+            raise StopAsyncIteration

litellm/integrations/custom_logger.py

@@ -10,7 +10,7 @@ from pydantic import BaseModel
 from litellm.caching import DualCache
 from litellm.proxy._types import UserAPIKeyAuth
 from litellm.types.llms.openai import ChatCompletionRequest
-from litellm.types.utils import ModelResponse
+from litellm.types.utils import AdapterCompletionStreamWrapper, ModelResponse
 
 
 class CustomLogger:  # https://docs.litellm.ai/docs/observability/custom_callback#callback-class
@@ -76,7 +76,9 @@ class CustomLogger:  # https://docs.litellm.ai/docs/observability/custom_callbac
         """
         pass
 
-    def translate_completion_output_params_streaming(self) -> Optional[BaseModel]:
+    def translate_completion_output_params_streaming(
+        self, completion_stream: Any
+    ) -> Optional[AdapterCompletionStreamWrapper]:
         """
         Translates the streaming chunk, from the OpenAI format to the custom format.
         """

litellm/llms/anthropic.py

@@ -5,13 +5,16 @@ import time
 import types
 from enum import Enum
 from functools import partial
-from typing import Callable, List, Optional, Union
+from typing import Callable, List, Literal, Optional, Tuple, Union
 
 import httpx  # type: ignore
 import requests  # type: ignore
+from openai.types.chat.chat_completion_chunk import Choice as OpenAIStreamingChoice
 
 import litellm
 import litellm.litellm_core_utils
+import litellm.types
+import litellm.types.utils
 from litellm import verbose_logger
 from litellm.litellm_core_utils.core_helpers import map_finish_reason
 from litellm.llms.custom_httpx.http_handler import (
@@ -33,8 +36,12 @@ from litellm.types.llms.anthropic import (
     AnthropicResponseUsageBlock,
     ContentBlockDelta,
     ContentBlockStart,
+    ContentJsonBlockDelta,
+    ContentTextBlockDelta,
     MessageBlockDelta,
+    MessageDelta,
     MessageStartBlock,
+    UsageDelta,
 )
 from litellm.types.llms.openai import (
     AllMessageValues,
@@ -480,6 +487,74 @@ class AnthropicConfig:
 
         return translated_obj
 
+    def _translate_streaming_openai_chunk_to_anthropic(
+        self, choices: List[OpenAIStreamingChoice]
+    ) -> Tuple[
+        Literal["text_delta", "input_json_delta"],
+        Union[ContentTextBlockDelta, ContentJsonBlockDelta],
+    ]:
+        text: str = ""
+        partial_json: Optional[str] = None
+        for choice in choices:
+            if choice.delta.content is not None:
+                text += choice.delta.content
+            elif choice.delta.tool_calls is not None:
+                partial_json = ""
+                for tool in choice.delta.tool_calls:
+                    if (
+                        tool.function is not None
+                        and tool.function.arguments is not None
+                    ):
+                        partial_json += tool.function.arguments
+
+        if partial_json is not None:
+            return "input_json_delta", ContentJsonBlockDelta(
+                type="input_json_delta", partial_json=partial_json
+            )
+        else:
+            return "text_delta", ContentTextBlockDelta(type="text_delta", text=text)
+
+    def translate_streaming_openai_response_to_anthropic(
+        self, response: litellm.ModelResponse
+    ) -> Union[ContentBlockDelta, MessageBlockDelta]:
+        ## base case - final chunk w/ finish reason
+        if response.choices[0].finish_reason is not None:
+            delta = MessageDelta(
+                stop_reason=self._translate_openai_finish_reason_to_anthropic(
+                    response.choices[0].finish_reason
+                ),
+            )
+            if getattr(response, "usage", None) is not None:
+                litellm_usage_chunk: Optional[litellm.Usage] = response.usage  # type: ignore
+            elif (
+                hasattr(response, "_hidden_params")
+                and "usage" in response._hidden_params
+            ):
+                litellm_usage_chunk = response._hidden_params["usage"]
+            else:
+                litellm_usage_chunk = None
+            if litellm_usage_chunk is not None:
+                usage_delta = UsageDelta(
+                    input_tokens=litellm_usage_chunk.prompt_tokens or 0,
+                    output_tokens=litellm_usage_chunk.completion_tokens or 0,
+                )
+            else:
+                usage_delta = UsageDelta(input_tokens=0, output_tokens=0)
+            return MessageBlockDelta(
+                type="message_delta", delta=delta, usage=usage_delta
+            )
+        (
+            type_of_content,
+            content_block_delta,
+        ) = self._translate_streaming_openai_chunk_to_anthropic(
+            choices=response.choices  # type: ignore
+        )
+        return ContentBlockDelta(
+            type="content_block_delta",
+            index=response.choices[0].index,
+            delta=content_block_delta,
+        )
+
 
 # makes headers for API call
 def validate_environment(api_key, user_headers, model):

litellm/main.py

@@ -125,7 +125,7 @@ from .llms.vertex_ai_partner import VertexAIPartnerModels
 from .llms.vertex_httpx import VertexLLM
 from .llms.watsonx import IBMWatsonXAI
 from .types.llms.openai import HttpxBinaryResponseContent
-from .types.utils import ChatCompletionMessageToolCall
+from .types.utils import AdapterCompletionStreamWrapper, ChatCompletionMessageToolCall
 
 encoding = tiktoken.get_encoding("cl100k_base")
 from litellm.utils import (
@@ -515,7 +515,7 @@ def mock_completion(
         model_response = ModelResponse(stream=stream)
         if stream is True:
             # don't try to access stream object,
-            if kwargs.get("acompletion", False) == True:
+            if kwargs.get("acompletion", False) is True:
                 return CustomStreamWrapper(
                     completion_stream=async_mock_completion_streaming_obj(
                         model_response, mock_response=mock_response, model=model, n=n
@@ -524,13 +524,14 @@ def mock_completion(
                     custom_llm_provider="openai",
                     logging_obj=logging,
                 )
-            response = mock_completion_streaming_obj(
-                model_response,
-                mock_response=mock_response,
+            return CustomStreamWrapper(
+                completion_stream=mock_completion_streaming_obj(
+                    model_response, mock_response=mock_response, model=model, n=n
+                ),
                 model=model,
-                n=n,
+                custom_llm_provider="openai",
+                logging_obj=logging,
             )
-            return response
         if n is None:
             model_response.choices[0].message.content = mock_response  # type: ignore
         else:
@@ -4037,7 +4038,9 @@ def text_completion(
 ###### Adapter Completion ################
 
 
-async def aadapter_completion(*, adapter_id: str, **kwargs) -> Optional[BaseModel]:
+async def aadapter_completion(
+    *, adapter_id: str, **kwargs
+) -> Optional[Union[BaseModel, AdapterCompletionStreamWrapper]]:
     """
     Implemented to handle async calls for adapter_completion()
     """
@@ -4056,18 +4059,29 @@ async def aadapter_completion(*, adapter_id: str, **kwargs) -> Optional[BaseMode
 
         new_kwargs = translation_obj.translate_completion_input_params(kwargs=kwargs)
 
-        response: ModelResponse = await acompletion(**new_kwargs)  # type: ignore
-
+        response: Union[ModelResponse, CustomStreamWrapper] = await acompletion(**new_kwargs)  # type: ignore
+        translated_response: Optional[
+            Union[BaseModel, AdapterCompletionStreamWrapper]
+        ] = None
+        if isinstance(response, ModelResponse):
             translated_response = translation_obj.translate_completion_output_params(
                 response=response
             )
+        if isinstance(response, CustomStreamWrapper):
+            translated_response = (
+                translation_obj.translate_completion_output_params_streaming(
+                    completion_stream=response
+                )
+            )
 
         return translated_response
     except Exception as e:
         raise e
 
 
-def adapter_completion(*, adapter_id: str, **kwargs) -> Optional[BaseModel]:
+def adapter_completion(
+    *, adapter_id: str, **kwargs
+) -> Optional[Union[BaseModel, AdapterCompletionStreamWrapper]]:
     translation_obj: Optional[CustomLogger] = None
     for item in litellm.adapters:
         if item["id"] == adapter_id:
@@ -4082,11 +4096,20 @@ def adapter_completion(*, adapter_id: str, **kwargs) -> Optional[BaseModel]:
 
     new_kwargs = translation_obj.translate_completion_input_params(kwargs=kwargs)
 
-    response: ModelResponse = completion(**new_kwargs)  # type: ignore
-
+    response: Union[ModelResponse, CustomStreamWrapper] = completion(**new_kwargs)  # type: ignore
+    translated_response: Optional[Union[BaseModel, AdapterCompletionStreamWrapper]] = (
+        None
+    )
+    if isinstance(response, ModelResponse):
         translated_response = translation_obj.translate_completion_output_params(
             response=response
         )
+    elif isinstance(response, CustomStreamWrapper) or inspect.isgenerator(response):
+        translated_response = (
+            translation_obj.translate_completion_output_params_streaming(
+                completion_stream=response
+            )
+        )
 
     return translated_response
 

litellm/proxy/_new_secret_config.yaml

@@ -1,7 +1,7 @@
 model_list:
-  - model_name: "*"
+  - model_name: "claude-3-5-sonnet-20240620"
     litellm_params:
-      model: "*"
+      model: "claude-3-5-sonnet-20240620"
 
 # litellm_settings:
 #   failure_callback: ["langfuse"]

litellm/proxy/proxy_server.py

@@ -2396,7 +2396,9 @@ async def async_data_generator(
                 user_api_key_dict=user_api_key_dict, response=chunk
             )
 
+            if isinstance(chunk, BaseModel):
                 chunk = chunk.model_dump_json(exclude_none=True, exclude_unset=True)
+
             try:
                 yield f"data: {chunk}\n\n"
             except Exception as e:
@@ -2437,6 +2439,59 @@ async def async_data_generator(
         yield f"data: {error_returned}\n\n"
 
 
+async def async_data_generator_anthropic(
+    response, user_api_key_dict: UserAPIKeyAuth, request_data: dict
+):
+    verbose_proxy_logger.debug("inside generator")
+    try:
+        start_time = time.time()
+        async for chunk in response:
+            verbose_proxy_logger.debug(
+                "async_data_generator: received streaming chunk - {}".format(chunk)
+            )
+            ### CALL HOOKS ### - modify outgoing data
+            chunk = await proxy_logging_obj.async_post_call_streaming_hook(
+                user_api_key_dict=user_api_key_dict, response=chunk
+            )
+
+            event_type = chunk.get("type")
+
+            try:
+                yield f"event: {event_type}\ndata:{json.dumps(chunk)}\n\n"
+            except Exception as e:
+                yield f"event: {event_type}\ndata:{str(e)}\n\n"
+    except Exception as e:
+        verbose_proxy_logger.error(
+            "litellm.proxy.proxy_server.async_data_generator(): Exception occured - {}\n{}".format(
+                str(e), traceback.format_exc()
+            )
+        )
+        await proxy_logging_obj.post_call_failure_hook(
+            user_api_key_dict=user_api_key_dict,
+            original_exception=e,
+            request_data=request_data,
+        )
+        verbose_proxy_logger.debug(
+            f"\033[1;31mAn error occurred: {e}\n\n Debug this by setting `--debug`, e.g. `litellm --model gpt-3.5-turbo --debug`"
+        )
+        router_model_names = llm_router.model_names if llm_router is not None else []
+
+        if isinstance(e, HTTPException):
+            raise e
+        else:
+            error_traceback = traceback.format_exc()
+            error_msg = f"{str(e)}\n\n{error_traceback}"
+
+        proxy_exception = ProxyException(
+            message=getattr(e, "message", error_msg),
+            type=getattr(e, "type", "None"),
+            param=getattr(e, "param", "None"),
+            code=getattr(e, "status_code", 500),
+        )
+        error_returned = json.dumps({"error": proxy_exception.to_dict()})
+        yield f"data: {error_returned}\n\n"
+
+
 def select_data_generator(
     response, user_api_key_dict: UserAPIKeyAuth, request_data: dict
 ):
@@ -5379,6 +5434,19 @@ async def anthropic_response(
             )
         )
 
+        if (
+            "stream" in data and data["stream"] is True
+        ):  # use generate_responses to stream responses
+            selected_data_generator = async_data_generator_anthropic(
+                response=response,
+                user_api_key_dict=user_api_key_dict,
+                request_data=data,
+            )
+            return StreamingResponse(
+                selected_data_generator,
+                media_type="text/event-stream",
+            )
+
         verbose_proxy_logger.info("\nResponse from Litellm:\n{}".format(response))
         return response
     except RejectedRequestError as e:
@@ -5425,11 +5493,10 @@ async def anthropic_response(
             user_api_key_dict=user_api_key_dict, original_exception=e, request_data=data
         )
         verbose_proxy_logger.error(
-            "litellm.proxy.proxy_server.completion(): Exception occured - {}".format(
-                str(e)
+            "litellm.proxy.proxy_server.anthropic_response(): Exception occured - {}\n{}".format(
+                str(e), traceback.format_exc()
             )
         )
-        verbose_proxy_logger.debug(traceback.format_exc())
         error_msg = f"{str(e)}"
         raise ProxyException(
             message=getattr(e, "message", error_msg),

litellm/tests/test_anthropic_completion.py

@@ -8,6 +8,9 @@ import traceback
 
 from dotenv import load_dotenv
 
+import litellm.types
+import litellm.types.utils
+
 load_dotenv()
 import io
 import os
@@ -15,6 +18,7 @@ import os
 sys.path.insert(
     0, os.path.abspath("../..")
 )  # Adds the parent directory to the system path
+from typing import Optional
 from unittest.mock import MagicMock, patch
 
 import pytest
@@ -84,7 +88,22 @@ def test_anthropic_completion_input_translation_with_metadata():
     assert translated_input["metadata"] == data["litellm_metadata"]
 
 
-def test_anthropic_completion_e2e():
+def streaming_format_tests(chunk: dict, idx: int):
+    """
+    1st chunk -  chunk.get("type") == "message_start"
+    2nd chunk - chunk.get("type") == "content_block_start"
+    3rd chunk - chunk.get("type") == "content_block_delta"
+    """
+    if idx == 0:
+        assert chunk.get("type") == "message_start"
+    elif idx == 1:
+        assert chunk.get("type") == "content_block_start"
+    elif idx == 2:
+        assert chunk.get("type") == "content_block_delta"
+
+
+@pytest.mark.parametrize("stream", [True])  # False
+def test_anthropic_completion_e2e(stream):
     litellm.set_verbose = True
 
     litellm.adapters = [{"id": "anthropic", "adapter": anthropic_adapter}]
@@ -95,13 +114,40 @@ def test_anthropic_completion_e2e():
         messages=messages,
         adapter_id="anthropic",
         mock_response="This is a fake call",
+        stream=stream,
     )
 
     print("Response: {}".format(response))
 
     assert response is not None
 
+    if stream is False:
         assert isinstance(response, AnthropicResponse)
+    else:
+        """
+        - ensure finish reason is returned
+        - assert content block is started and stopped
+        - ensure last chunk is 'message_stop'
+        """
+        assert isinstance(response, litellm.types.utils.AdapterCompletionStreamWrapper)
+        finish_reason: Optional[str] = None
+        message_stop_received = False
+        content_block_started = False
+        content_block_finished = False
+        for idx, chunk in enumerate(response):
+            print(chunk)
+            streaming_format_tests(chunk=chunk, idx=idx)
+            if chunk.get("delta", {}).get("stop_reason") is not None:
+                finish_reason = chunk.get("delta", {}).get("stop_reason")
+            if chunk.get("type") == "message_stop":
+                message_stop_received = True
+            if chunk.get("type") == "content_block_stop":
+                content_block_finished = True
+            if chunk.get("type") == "content_block_start":
+                content_block_started = True
+        assert content_block_started and content_block_finished
+        assert finish_reason is not None
+        assert message_stop_received is True
 
 
 @pytest.mark.asyncio

litellm/types/llms/anthropic.py

@@ -136,7 +136,7 @@ class ContentJsonBlockDelta(TypedDict):
 
 
 class ContentBlockDelta(TypedDict):
-    type: str
+    type: Literal["content_block_delta"]
     index: int
     delta: Union[ContentTextBlockDelta, ContentJsonBlockDelta]
 

litellm/types/utils.py

@@ -6,7 +6,7 @@ from typing import Dict, List, Literal, Optional, Tuple, Union
 
 from openai._models import BaseModel as OpenAIObject
 from pydantic import ConfigDict, Field, PrivateAttr
-from typing_extensions import Dict, Required, TypedDict, override
+from typing_extensions import Callable, Dict, Required, TypedDict, override
 
 from ..litellm_core_utils.core_helpers import map_finish_reason
 from .llms.openai import ChatCompletionToolCallChunk, ChatCompletionUsageBlock
@@ -1069,3 +1069,36 @@ class LoggedLiteLLMParams(TypedDict, total=False):
     output_cost_per_token: Optional[float]
     output_cost_per_second: Optional[float]
     cooldown_time: Optional[float]
+
+
+class AdapterCompletionStreamWrapper:
+    def __init__(self, completion_stream):
+        self.completion_stream = completion_stream
+
+    def __iter__(self):
+        return self
+
+    def __aiter__(self):
+        return self
+
+    def __next__(self):
+        try:
+            for chunk in self.completion_stream:
+                if chunk == "None" or chunk is None:
+                    raise Exception
+                return chunk
+            raise StopIteration
+        except StopIteration:
+            raise StopIteration
+        except Exception as e:
+            print(f"AdapterCompletionStreamWrapper - {e}")  # noqa
+
+    async def __anext__(self):
+        try:
+            async for chunk in self.completion_stream:
+                if chunk == "None" or chunk is None:
+                    raise Exception
+                return chunk
+            raise StopIteration
+        except StopIteration:
+            raise StopAsyncIteration