hyf-backend/th_agenter/services/llm_service.py

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2026-01-21 13:45:39 +08:00
"""LLM service for workflow execution."""
import asyncio
from typing import List, Dict, Any, Optional, AsyncGenerator
from langchain_openai import ChatOpenAI
from langchain_core.messages import HumanMessage, AIMessage, SystemMessage
from ..models.llm_config import LLMConfig
from loguru import logger
class LLMService:
"""LLM服务用于工作流中的大模型调用"""
def __init__(self):
pass
async def chat_completion(
self,
model_config: LLMConfig,
messages: List[Dict[str, str]],
temperature: Optional[float] = None,
max_tokens: Optional[int] = None
) -> str:
"""调用大模型进行对话完成"""
try:
# 创建LangChain ChatOpenAI实例
llm = ChatOpenAI(
model=model_config.model_name,
api_key=model_config.api_key,
base_url=model_config.base_url,
temperature=temperature or model_config.temperature,
max_tokens=max_tokens or model_config.max_tokens,
streaming=False
)
# 转换消息格式
langchain_messages = []
for msg in messages:
role = msg.get("role", "user")
content = msg.get("content", "")
if role == "system":
langchain_messages.append(SystemMessage(content=content))
elif role == "user":
langchain_messages.append(HumanMessage(content=content))
elif role == "assistant":
langchain_messages.append(AIMessage(content=content))
# 调用LLM
response = await llm.ainvoke(langchain_messages)
# 返回响应内容
return response.content
except Exception as e:
logger.error(f"LLM调用失败: {str(e)}")
raise Exception(f"LLM调用失败: {str(e)}")
async def chat_completion_stream(
self,
model_config: LLMConfig,
messages: List[Dict[str, str]],
temperature: Optional[float] = None,
max_tokens: Optional[int] = None
) -> AsyncGenerator[str, None]:
"""调用大模型进行流式对话完成"""
try:
# 创建LangChain ChatOpenAI实例流式
llm = ChatOpenAI(
model=model_config.model_name,
api_key=model_config.api_key,
base_url=model_config.base_url,
temperature=temperature or model_config.temperature,
max_tokens=max_tokens or model_config.max_tokens,
streaming=True
)
# 转换消息格式
langchain_messages = []
for msg in messages:
role = msg.get("role", "user")
content = msg.get("content", "")
if role == "system":
langchain_messages.append(SystemMessage(content=content))
elif role == "user":
langchain_messages.append(HumanMessage(content=content))
elif role == "assistant":
langchain_messages.append(AIMessage(content=content))
# 流式调用LLM
async for chunk in llm.astream(langchain_messages):
if hasattr(chunk, 'content') and chunk.content:
yield chunk.content
except Exception as e:
logger.error(f"LLM流式调用失败: {str(e)}")
raise Exception(f"LLM流式调用失败: {str(e)}")
def get_model_info(self, model_config: LLMConfig) -> Dict[str, Any]:
"""获取模型信息"""
return {
"id": model_config.id,
"name": model_config.model_name,
"provider": model_config.provider,
"base_url": model_config.base_url,
"temperature": model_config.temperature,
"max_tokens": model_config.max_tokens,
"is_active": model_config.is_active
}