custom_llm.py

from typing import Any, List, Mapping, Optional
from langchain_core.language_models.llms import LLM
from langchain_core.callbacks.manager import CallbackManagerForLLMRun

from typing import Literal

import requests


class CustomLLM(LLM):
    repo_id : str
    api_token : str
    model_type: Literal["text2text-generation", "text-generation"]
    max_new_tokens: int = None
    temperature: float = 0.001
    timeout: float = None
    top_p: float = None
    top_k : int = None
    repetition_penalty : float = None
    stop : List[str] = []


    @property
    def _llm_type(self) -> str:
        return "custom"

    def _call(
        self,
        prompt: str,
        stop: Optional[List[str]] = None,
        run_manager: Optional[CallbackManagerForLLMRun] = None,
        **kwargs: Any,
    ) -> str:

        headers = {"Authorization": f"Bearer {self.api_token}"}
        API_URL = f"https://api-inference.huggingface.co/models/{self.repo_id}"

        parameters_dict = {
          'max_new_tokens': self.max_new_tokens,
          'temperature': self.temperature,
          'timeout': self.timeout,
          'top_p': self.top_p,
          'top_k': self.top_k,
          'repetition_penalty': self.repetition_penalty,
          'stop':self.stop
        }

        if self.model_type == 'text-generation':
          parameters_dict["return_full_text"]=False

        data = {"inputs": prompt, "parameters":parameters_dict, "options":{"wait_for_model":True}}
        data = requests.post(API_URL, headers=headers, json=data).json()
        try:
            return data[0]['generated_text']
        except:
            return data

    @property
    def _identifying_params(self) -> Mapping[str, Any]:
        """Get the identifying parameters."""
        return  {
          'repo_id': self.repo_id,
          'model_type':self.model_type,
          'stop_sequences':self.stop,
          'max_new_tokens': self.max_new_tokens,
          'temperature': self.temperature,
          'timeout': self.timeout,
          'top_p': self.top_p,
          'top_k': self.top_k,
          'repetition_penalty': self.repetition_penalty
      }