355 lines
12 KiB
Python
355 lines
12 KiB
Python
"""
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生成式大模型服务模块
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本模块提供统一的生成式大模型服务获取接口，支持多种模型：
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1. Local VLLM 服务：本地 gemma-4-E4B-it 模型
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2. Zhipu AI：智谱 glm-5.1 模型
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3. DeepSeek：deepseek-v4-pro 模型
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主要功能：
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- LocalVLLMChatProvider：本地 VLLM 服务提供者
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- ZhipuChatProvider：智谱 API 服务提供者
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- DeepSeekChatProvider：DeepSeek API 服务提供者
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- get_chat_service()：获取默认服务（带自动降级）
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- get_all_chat_services()：获取所有可用模型服务（用于多模型切换）
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"""
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import logging
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from typing import Dict, Callable
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from langchain_core.language_models import BaseChatModel
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from .base import (
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BaseServiceProvider,
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FallbackServiceChain,
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SingletonServiceManager
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)
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from backend.app.config import (
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VLLM_BASE_URL,
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LLM_API_KEY,
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ZHIPUAI_API_KEY,
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DEEPSEEK_API_KEY,
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LOCAL_MODEL_NAME
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)
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logger = logging.getLogger(__name__)
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# 缓存已初始化的模型字典
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_cached_services: Dict[str, BaseChatModel] | None = None
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def _check_http_service_available(base_url: str, api_key: str = "", timeout: float = 2.0) -> bool:
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"""通过探测 /models 端点检查 HTTP API 是否可用（内部工具函数）"""
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try:
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import httpx
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client = httpx.Client(base_url=base_url.rstrip('/'), timeout=timeout)
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headers = {"Authorization": f"Bearer {api_key}"} if api_key else {}
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resp = client.get("/models", headers=headers)
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return resp.status_code == 200
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except Exception:
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return False
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class LocalVLLMChatProvider(BaseServiceProvider[BaseChatModel]):
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"""
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本地 VLLM 生成式大模型服务提供者
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"""
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def __init__(self, model: str = None):
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super().__init__("local_vllm_chat")
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self._model = model or LOCAL_MODEL_NAME
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def is_available(self) -> bool:
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"""
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检查本地 VLLM 服务是否可用
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Returns:
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bool: 服务是否可用
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"""
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if not VLLM_BASE_URL:
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logger.warning("VLLM_BASE_URL 未配置")
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return False
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# 使用统一的 HTTP 探测方法
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return _check_http_service_available(VLLM_BASE_URL, LLM_API_KEY, timeout=2.0)
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def get_service(self) -> BaseChatModel:
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"""
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获取本地 VLLM 服务
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Returns:
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BaseChatModel: LangChain 兼容的 ChatModel 实例
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"""
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if self._service_instance is None:
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from langchain_openai import ChatOpenAI
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from pydantic import SecretStr
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self._service_instance = ChatOpenAI(
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base_url=VLLM_BASE_URL,
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api_key=SecretStr(LLM_API_KEY) if LLM_API_KEY else SecretStr(""),
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model=self._model,
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timeout=60.0,
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max_retries=2,
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streaming=True,
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)
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return self._service_instance
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class ZhipuChatProvider(BaseServiceProvider[BaseChatModel]):
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"""
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智谱 AI 生成式大模型服务提供者
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"""
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def __init__(self, model: str = "glm-5.1"):
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super().__init__("zhipu_chat")
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self._model = model
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def is_available(self) -> bool:
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"""
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检查智谱 AI 服务是否可用
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Returns:
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bool: 服务是否可用
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"""
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if not ZHIPUAI_API_KEY:
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logger.warning("ZHIPUAI_API_KEY 未配置")
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return False
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try:
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logger.info(f"智谱 AI 服务配置正确，准备使用: {self._model}")
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return True
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except Exception as e:
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logger.warning(f"智谱 AI 服务不可用: {e}")
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return False
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def get_service(self) -> BaseChatModel:
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"""
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获取智谱 AI 服务
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Returns:
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BaseChatModel: LangChain 兼容的 ChatModel 实例
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"""
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if self._service_instance is None:
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from langchain_community.chat_models import ChatZhipuAI
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self._service_instance = ChatZhipuAI(
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model=self._model,
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api_key=ZHIPUAI_API_KEY,
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temperature=0.1,
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max_tokens=4096,
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timeout=120.0,
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max_retries=3,
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streaming=True,
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)
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return self._service_instance
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class DeepSeekChatProvider(BaseServiceProvider[BaseChatModel]):
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"""
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DeepSeek 生成式大模型服务提供者
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"""
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def __init__(self, model: str = "deepseek-v4-pro"):
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super().__init__("deepseek_chat")
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self._model = model
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def is_available(self) -> bool:
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"""
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检查 DeepSeek 服务是否可用
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Returns:
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bool: 服务是否可用
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"""
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if not DEEPSEEK_API_KEY:
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logger.warning("DEEPSEEK_API_KEY 未配置")
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return False
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try:
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logger.info(f"DeepSeek 服务配置正确，准备使用: {self._model}")
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return True
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except Exception as e:
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logger.warning(f"DeepSeek 服务不可用: {e}")
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return False
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def get_service(self) -> BaseChatModel:
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"""
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获取 DeepSeek 服务
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Returns:
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BaseChatModel: LangChain 兼容的 ChatModel 实例
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"""
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if self._service_instance is None:
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from langchain_openai import ChatOpenAI
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from pydantic import SecretStr
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self._service_instance = ChatOpenAI(
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base_url="https://api.deepseek.com",
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api_key=SecretStr(DEEPSEEK_API_KEY),
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model=self._model,
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temperature=0.1,
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max_tokens=4096,
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timeout=60.0,
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max_retries=2,
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streaming=True,
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)
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return self._service_instance
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# ========== 轻量级模型 Provider ==========
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class LocalSmallModelProvider(BaseServiceProvider[BaseChatModel]):
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"""
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本地轻量级模型服务提供者（用于查询改写、意图分类等简单任务）
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使用小模型独立配置
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"""
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def __init__(self, model: str = None):
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from backend.app.config import SMALL_LOCAL_MODEL_NAME, SMALL_VLLM_BASE_URL, SMALL_LLM_API_KEY
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super().__init__("local_small")
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self._model = model or SMALL_LOCAL_MODEL_NAME
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self._base_url = SMALL_VLLM_BASE_URL
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self._api_key = SMALL_LLM_API_KEY
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def is_available(self) -> bool:
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"""检查本地小模型服务是否可用"""
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if not self._base_url:
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logger.warning("SMALL_VLLM_BASE_URL 未配置，本地小模型不可用")
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return False
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# 使用统一的 HTTP 探测方法
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return _check_http_service_available(self._base_url, self._api_key, timeout=2.0)
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def get_service(self) -> BaseChatModel:
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"""获取本地小模型服务"""
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if self._service_instance is None:
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from langchain_openai import ChatOpenAI
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from pydantic import SecretStr
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self._service_instance = ChatOpenAI(
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base_url=self._base_url,
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api_key=SecretStr(self._api_key) if self._api_key else SecretStr(""),
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model=self._model,
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timeout=30.0,
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max_retries=2,
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streaming=False,
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)
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return self._service_instance
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class DeepSeekSmallModelProvider(BaseServiceProvider[BaseChatModel]):
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"""
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DeepSeek 轻量级模型服务提供者（用于查询改写、意图分类等简单任务）
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使用小模型独立配置
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"""
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def __init__(self, model: str = None):
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from backend.app.config import SMALL_DEEPSEEK_MODEL, SMALL_DEEPSEEK_API_KEY, SMALL_DEEPSEEK_API_BASE
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super().__init__("deepseek_small")
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self._model = model or SMALL_DEEPSEEK_MODEL
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self._api_key = SMALL_DEEPSEEK_API_KEY
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self._api_base = SMALL_DEEPSEEK_API_BASE
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def is_available(self) -> bool:
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if not self._api_key:
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logger.warning("SMALL_DEEPSEEK_API_KEY 未配置")
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return False
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logger.info(f"DeepSeek 轻量模型配置正确: {self._model}")
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return True
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def get_service(self) -> BaseChatModel:
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if self._service_instance is None:
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from langchain_openai import ChatOpenAI
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from pydantic import SecretStr
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self._service_instance = ChatOpenAI(
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base_url=self._api_base,
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api_key=SecretStr(self._api_key),
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model=self._model,
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temperature=0.1,
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max_tokens=2048,
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timeout=30.0,
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max_retries=2,
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streaming=False,
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)
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return self._service_instance
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# 全局服务映射表 - 名称 -> Provider
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CHAT_PROVIDERS: Dict[str, Callable[[], BaseServiceProvider[BaseChatModel]]] = {
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"local": lambda: LocalVLLMChatProvider(),
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"zhipu": lambda: ZhipuChatProvider(),
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"deepseek": lambda: DeepSeekChatProvider(),
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}
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def get_chat_service() -> BaseChatModel:
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"""
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获取默认的生成式大模型服务（带自动降级）
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优先顺序: local -> zhipu -> deepseek
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Returns:
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BaseChatModel: LangChain 兼容的 ChatModel 实例
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"""
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def _create_chain():
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primary = LocalVLLMChatProvider()
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fallbacks = [ZhipuChatProvider(), DeepSeekChatProvider()]
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return FallbackServiceChain(primary, fallbacks)
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chain = SingletonServiceManager.get_or_create("chat_service_chain", _create_chain)
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return chain.get_available_service()
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def _init_chat_services() -> Dict[str, BaseChatModel]:
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"""实际初始化所有可用模型（仅在首次调用）"""
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services = {}
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for name, provider_factory in CHAT_PROVIDERS.items():
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try:
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provider = provider_factory()
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if provider.is_available():
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services[name] = provider.get_service()
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logger.info(f"已加载模型: {name}")
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except Exception as e:
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logger.warning(f"模型 {name} 初始化失败: {e}")
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if not services:
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raise RuntimeError(f"没有可用的生成式大模型，尝试了: {list(CHAT_PROVIDERS.keys())}")
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return services
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def get_cached_chat_services() -> Dict[str, BaseChatModel]:
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"""获取缓存的可用模型字典（用于单图动态注入）"""
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global _cached_services
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if _cached_services is None:
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_cached_services = _init_chat_services()
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return _cached_services
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def get_all_chat_services() -> Dict[str, BaseChatModel]:
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"""
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获取所有可用的生成式大模型服务（用于多模型切换，保留兼容性）
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新代码请使用 get_cached_chat_services() 获取缓存版本
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Returns:
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Dict[str, BaseChatModel]: 模型名称 -> ChatModel 实例 的字典
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"""
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return get_cached_chat_services()
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def get_small_llm_service() -> BaseChatModel:
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"""
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获取轻量级大模型服务（用于查询改写、意图分类等简单任务）
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优先顺序: 本地模型 -> DeepSeek 小模型
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⚠️ 注意：小模型任务不降级到大模型，避免不必要的 token 消耗！
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Returns:
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BaseChatModel: LangChain 兼容的 ChatModel 实例
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"""
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def _create_small_chain():
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primary = LocalSmallModelProvider()
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fallbacks = [DeepSeekSmallModelProvider()]
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return FallbackServiceChain(primary, fallbacks)
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chain = SingletonServiceManager.get_or_create("small_llm_chain", _create_small_chain)
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return chain.get_available_service()
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