Files
langsmith-model-server/app/custom_model.py
T

101 lines
3.9 KiB
Python

from typing import Any, Dict, Iterator, List, Optional
from langchain_core.callbacks.manager import CallbackManagerForLLMRun
from langchain_core.language_models.llms import LLM
from langchain_core.outputs import GenerationChunk
from langchain_core.runnables import ConfigurableField, Runnable
class CustomLLM(LLM):
"""A custom instruct style model.
This model returns the first n characters of the input prompt. This is intended to serve as a template for
your own instruct style model you may want to expose in the playground.
"""
n: int = 5
def _call(
self,
prompt: str,
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> str:
"""Run the LLM on the given input.
Override this method to implement the LLM logic.
Args:
prompt: The prompt to generate from.
stop: Stop words to use when generating. Model output is cut off at the
first occurrence of any of the stop substrings.
If stop tokens are not supported consider raising NotImplementedError.
run_manager: Callback manager for the run.
**kwargs: Arbitrary additional keyword arguments. These are usually passed
to the model provider API call.
Returns:
The model output as a string. Actual completions SHOULD NOT include the prompt.
"""
return prompt[: self.n]
def _stream(
self,
prompt: str,
stop: Optional[List[str]] = None,
run_manager: Optional[CallbackManagerForLLMRun] = None,
**kwargs: Any,
) -> Iterator[GenerationChunk]:
"""Stream the LLM on the given prompt.
This method should be overridden by subclasses that support streaming.
If not implemented, the default behavior of calls to stream will be to
fallback to the non-streaming version of the model and return
the output as a single chunk. Do not implement this method if the model
does not support streaming.
Args:
prompt: The prompt to generate from.
stop: Stop words to use when generating. Model output is cut off at the
first occurrence of any of these substrings.
run_manager: Callback manager for the run.
**kwargs: Arbitrary additional keyword arguments. These are usually passed
to the model provider API call.
Returns:
An iterator of GenerationChunks.
"""
for char in prompt[: self.n]:
chunk = GenerationChunk(text=char)
if run_manager:
run_manager.on_llm_new_token(chunk.text, chunk=chunk)
yield chunk
@property
def _identifying_params(self) -> Dict[str, Any]:
"""Return a dictionary of identifying parameters. """
return {
# The model name allows users to specify custom token counting
# rules in LLM monitoring applications (e.g., in LangSmith users
# can provide per token pricing for their model and monitor
# costs for the given LLM.)
"model_name": "CustomChatModel",
}
@property
def _llm_type(self) -> str:
"""Get the type of language model used by this chat model. Used for logging purposes only."""
return "custom"
def with_configurable_fields(self) -> Runnable:
"""Expose fields you want to be configurable in the playground. We will automatically expose these to the
playground. If you don't want to expose any fields, you can remove this method."""
return self.configurable_fields(n=ConfigurableField(
id="n",
name="Num Characters",
description="Number of characters to return from the input prompt.",
))