import logging
from typing import Any, Dict, Iterator, List, Mapping, Optional, cast
from urllib.parse import urlparse
from langchain_core.callbacks import CallbackManagerForLLMRun
from langchain_core.language_models import BaseChatModel
from langchain_core.language_models.base import LanguageModelInput
from langchain_core.messages import (
AIMessage,
AIMessageChunk,
BaseMessage,
BaseMessageChunk,
ChatMessage,
ChatMessageChunk,
FunctionMessage,
HumanMessage,
HumanMessageChunk,
SystemMessage,
SystemMessageChunk,
)
from langchain_core.outputs import ChatGeneration, ChatGenerationChunk, ChatResult
from langchain_core.pydantic_v1 import (
Field,
PrivateAttr,
)
from langchain_core.runnables import RunnableConfig
logger = logging.getLogger(__name__)
[docs]class ChatMlflow(BaseChatModel):
"""`MLflow` 聊天模型 API。
要使用，您应该安装 `mlflow[genai]` python 包。
更多信息，请参见 https://mlflow.org/docs/latest/llms/deployments.
示例:
.. code-block:: python
from langchain_community.chat_models import ChatMlflow
chat = ChatMlflow(
target_uri="http://localhost:5000",
endpoint="chat",
temperature-0.1,
)
"""
endpoint: str
"""要使用的端点。"""
target_uri: str
"""要使用的目标URI。"""
temperature: float = 0.0
"""采样温度。"""
n: int = 1
"""生成完成选项的数量。"""
stop: Optional[List[str]] = None
"""停止序列。"""
max_tokens: Optional[int] = None
"""生成的最大令牌数量。"""
extra_params: dict = Field(default_factory=dict)
"""传递给端点的任何额外参数。"""
_client: Any = PrivateAttr()
def __init__(self, **kwargs: Any):
super().__init__(**kwargs)
self._validate_uri()
try:
from mlflow.deployments import get_deploy_client
self._client = get_deploy_client(self.target_uri)
except ImportError as e:
raise ImportError(
"Failed to create the client. "
f"Please run `pip install mlflow{self._mlflow_extras}` to install "
"required dependencies."
) from e
@property
def _mlflow_extras(self) -> str:
return "[genai]"
def _validate_uri(self) -> None:
if self.target_uri == "databricks":
return
allowed = ["http", "https", "databricks"]
if urlparse(self.target_uri).scheme not in allowed:
raise ValueError(
f"Invalid target URI: {self.target_uri}. "
f"The scheme must be one of {allowed}."
)
@property
def _default_params(self) -> Dict[str, Any]:
params: Dict[str, Any] = {
"target_uri": self.target_uri,
"endpoint": self.endpoint,
"temperature": self.temperature,
"n": self.n,
"stop": self.stop,
"max_tokens": self.max_tokens,
"extra_params": self.extra_params,
}
return params
def _prepare_inputs(
self,
messages: List[BaseMessage],
stop: Optional[List[str]] = None,
**kwargs: Any,
) -> Dict[str, Any]:
message_dicts = [
ChatMlflow._convert_message_to_dict(message) for message in messages
]
data: Dict[str, Any] = {
"messages": message_dicts,
"temperature": self.temperature,
"n": self.n,
**self.extra_params,
**kwargs,
}
if stop := self.stop or stop:
data["stop"] = stop
if self.max_tokens is not None:
data["max_tokens"] = self.max_tokens
return data
def _generate(
self,
messages: List[BaseMessage],
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> ChatResult:
data = self._prepare_inputs(
messages,
stop,
**kwargs,
)
resp = self._client.predict(endpoint=self.endpoint, inputs=data)
return ChatMlflow._create_chat_result(resp)
[docs] def stream(
self,
input: LanguageModelInput,
config: Optional[RunnableConfig] = None,
*,
stop: Optional[List[str]] = None,
**kwargs: Any,
) -> Iterator[BaseMessageChunk]:
# We need to override `stream` to handle the case
# that `self._client` does not implement `predict_stream`
if not hasattr(self._client, "predict_stream"):
# MLflow deployment client does not implement streaming,
# so use default implementation
yield cast(
BaseMessageChunk, self.invoke(input, config=config, stop=stop, **kwargs)
)
else:
yield from super().stream(input, config, stop=stop, **kwargs)
def _stream(
self,
messages: List[BaseMessage],
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> Iterator[ChatGenerationChunk]:
data = self._prepare_inputs(
messages,
stop,
**kwargs,
)
# TODO: check if `_client.predict_stream` is available.
chunk_iter = self._client.predict_stream(endpoint=self.endpoint, inputs=data)
for chunk in chunk_iter:
choice = chunk["choices"][0]
chunk = ChatMlflow._convert_delta_to_message_chunk(choice["delta"])
generation_info = {}
if finish_reason := choice.get("finish_reason"):
generation_info["finish_reason"] = finish_reason
if logprobs := choice.get("logprobs"):
generation_info["logprobs"] = logprobs
chunk = ChatGenerationChunk(
message=chunk, generation_info=generation_info or None
)
if run_manager:
run_manager.on_llm_new_token(chunk.text, chunk=chunk, logprobs=logprobs)
yield chunk
@property
def _identifying_params(self) -> Dict[str, Any]:
return self._default_params
def _get_invocation_params(
self, stop: Optional[List[str]] = None, **kwargs: Any
) -> Dict[str, Any]:
"""获取用于调用回调函数的参数。"""
return {
**self._default_params,
**super()._get_invocation_params(stop=stop, **kwargs),
}
@property
def _llm_type(self) -> str:
"""聊天模型的返回类型。"""
return "mlflow-chat"
@staticmethod
def _convert_dict_to_message(_dict: Mapping[str, Any]) -> BaseMessage:
role = _dict["role"]
content = _dict["content"]
if role == "user":
return HumanMessage(content=content)
elif role == "assistant":
return AIMessage(content=content)
elif role == "system":
return SystemMessage(content=content)
else:
return ChatMessage(content=content, role=role)
@staticmethod
def _convert_delta_to_message_chunk(_dict: Mapping[str, Any]) -> BaseMessageChunk:
role = _dict["role"]
content = _dict["content"]
if role == "user":
return HumanMessageChunk(content=content)
elif role == "assistant":
return AIMessageChunk(content=content)
elif role == "system":
return SystemMessageChunk(content=content)
else:
return ChatMessageChunk(content=content, role=role)
@staticmethod
def _raise_functions_not_supported() -> None:
raise ValueError(
"Function messages are not supported by Databricks. Please"
" create a feature request at https://github.com/mlflow/mlflow/issues."
)
@staticmethod
def _convert_message_to_dict(message: BaseMessage) -> dict:
if isinstance(message, ChatMessage):
message_dict = {"role": message.role, "content": message.content}
elif isinstance(message, HumanMessage):
message_dict = {"role": "user", "content": message.content}
elif isinstance(message, AIMessage):
message_dict = {"role": "assistant", "content": message.content}
elif isinstance(message, SystemMessage):
message_dict = {"role": "system", "content": message.content}
elif isinstance(message, FunctionMessage):
raise ValueError(
"Function messages are not supported by Databricks. Please"
" create a feature request at https://github.com/mlflow/mlflow/issues."
)
else:
raise ValueError(f"Got unknown message type: {message}")
if "function_call" in message.additional_kwargs:
ChatMlflow._raise_functions_not_supported()
if message.additional_kwargs:
logger.warning(
"Additional message arguments are unsupported by Databricks"
" and will be ignored: %s",
message.additional_kwargs,
)
return message_dict
@staticmethod
def _create_chat_result(response: Mapping[str, Any]) -> ChatResult:
generations = []
for choice in response["choices"]:
message = ChatMlflow._convert_dict_to_message(choice["message"])
usage = choice.get("usage", {})
gen = ChatGeneration(
message=message,
generation_info=usage,
)
generations.append(gen)
usage = response.get("usage", {})
return ChatResult(generations=generations, llm_output=usage)