199 lines
6.7 KiB
Python
199 lines
6.7 KiB
Python
"""
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AI Agent 服务类 - 完全简化版本！
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按照指南实现，不用 stream_mode="messages" 避免重复 token！
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"""
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import json
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import asyncio
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from typing import AsyncGenerator, Dict, Any, Optional, Tuple
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# LangGraph 序列化器（修复 checkpoint 反序列化警告）
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from langgraph.checkpoint.serde.jsonplus import JsonPlusSerializer
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# 本地模块
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from backend.app.model_services import get_cached_chat_services
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from backend.app.main_graph.main_graph_builder import build_agent_graph
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from backend.app.logger import debug, info, warning, error
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from backend.app.main_graph.state import AgentState
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from .stream_context import set_stream_queue
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class AIAgentService:
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def __init__(self, checkpointer):
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self.checkpointer = checkpointer
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self.graph = None
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self.chat_services = None
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# Mem0 客户端
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self.mem0_client = None
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async def initialize(self):
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# 0. 初始化 Mem0 客户端
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from ..memory.mem0_client import Mem0Client
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self.mem0_client = Mem0Client()
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# 1. 获取缓存的模型字典
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self.chat_services = get_cached_chat_services()
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info(f"✅ 加载了 {len(self.chat_services)} 个可用模型: {list(self.chat_services.keys())}")
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# 2. 构建图
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info(f"🔄 构建 Agent 图...")
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graph_builder = build_agent_graph(
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chat_services=self.chat_services,
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mem0_client=self.mem0_client
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)
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# 编译图
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self.graph = graph_builder.compile(checkpointer=self.checkpointer)
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info(f"✅ Agent 图初始化完成")
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return self
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def _resolve_model(self, model: str) -> str:
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"""
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解析并验证模型名称，不可用时回退到第一个可用模型
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Args:
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model: 目标模型名称
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Returns:
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实际使用的模型名称
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"""
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if not model or model not in self.chat_services:
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fallback = next(iter(self.chat_services.keys()))
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warning(f"模型 '{model}' 不可用，回退到 '{fallback}'")
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return fallback
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return model
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def _build_invocation(
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self, message: str, thread_id: str, model: str, user_id: str
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) -> Tuple[Dict[str, Any], Dict[str, Any]]:
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"""
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构建图调用所需的 config 和 input_state
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Args:
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message: 用户消息
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thread_id: 会话 ID
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model: 模型名称
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user_id: 用户 ID
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Returns:
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(config, input_state) 元组
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"""
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from langchain_core.messages import HumanMessage
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config = {
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"configurable": {
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"thread_id": thread_id,
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},
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"metadata": {"user_id": user_id}
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}
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input_state = {
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"messages": [HumanMessage(content=message)],
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"user_id": user_id,
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}
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return config, input_state
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async def process_message(
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self, message: str, thread_id: str, model: str = "", user_id: str = "default_user"
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) -> dict:
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"""处理用户消息，返回包含回复、token统计和耗时的字典"""
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# 解析模型名称
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resolved_model = self._resolve_model(model)
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# 构建调用参数
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config, input_state = self._build_invocation(message, thread_id, resolved_model, user_id)
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result = await self.graph.ainvoke(input_state, config=config)
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# 优先使用 final_reply（finalize 节点返回）
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reply = result.get("final_reply", "")
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if not reply and result.get("messages"):
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reply = result["messages"][-1].content
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token_usage = result.get("last_token_usage", {})
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elapsed_time = result.get("last_elapsed_time", 0.0)
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# 获取元数据
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metadata = result.get("metadata", {})
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return {
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"reply": reply,
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"token_usage": token_usage,
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"elapsed_time": elapsed_time,
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"model_used": resolved_model,
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"metadata": metadata
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}
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async def process_message_stream(
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self, message: str, thread_id: str, model: str = "", user_id: str = "default_user"
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) -> AsyncGenerator[Dict[str, Any], None]:
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"""流式处理消息 - 完全简化！"""
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# 解析模型名称
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resolved_model = self._resolve_model(model)
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# 构建调用参数
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config, input_state = self._build_invocation(message, thread_id, resolved_model, user_id)
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info(f"🚀 开始执行 Agent 图，指定模型: {resolved_model}")
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actual_model_used = resolved_model
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# 创建 token 队列
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queue = asyncio.Queue()
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set_stream_queue(queue) # 设置上下文变量
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async def run_graph():
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"""后台任务：运行 graph，流式事件都从 agent 节点内部发送！"""
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try:
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info(f"📡 开始调用 graph.astream()...")
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# 注意：只用 stream_mode=["updates"]，不要 "messages"！避免重复 token！
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async for _ in self.graph.astream(
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input_state,
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config=config,
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stream_mode=["updates"],
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version="v2",
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subgraphs=True
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):
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# 流式事件都从 agent.py 节点内部通过队列发送了
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# 这里不需要再发送任何事件
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pass
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except Exception as e:
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error(f"❌ 执行图时出错: {e}")
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import traceback
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error(f"📋 堆栈: {traceback.format_exc()}")
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await queue.put({"type": "error", "message": str(e)})
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finally:
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await queue.put(None) # 结束哨兵
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# 启动后台任务
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bg_task = asyncio.create_task(run_graph())
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try:
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while True:
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event = await queue.get()
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if event is None:
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break
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yield event
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except GeneratorExit:
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# 客户端断开连接，取消后台任务
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info("⚠️ GeneratorExit，取消后台任务")
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bg_task.cancel()
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raise
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finally:
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# 保证任务被清理
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if not bg_task.done():
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info("⏹️ 清理后台任务")
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bg_task.cancel()
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try:
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await bg_task
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except asyncio.CancelledError:
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info("✅ 后台任务已取消")
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# 发送结束事件，保证前端平稳关闭
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yield {
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"type": "done",
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"model_used": actual_model_used
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}
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