16337
8156f54004
架构变更：
- 新增 app/services/agent/ 模块（state/prompts/graph/tools）
- 7 个工具从 _tool_xxx 方法提取为 @tool 装饰器函数
- 构建 assistant + ToolNode 的 ReAct 图
- agent_dispatcher.py 改为薄壳入口，支持 USE_LANGGRAPH 开关
- MemorySaver checkpoint 持久化对话（thread_id=wechat-{user_id}）
- 新增依赖：langchain-core, langchain-openai, langgraph
向后兼容：
- USE_LANGGRAPH=false 可切回旧版 FC 循环
- LangGraph 初始化失败自动降级到 Legacy 模式
- 企微图片处理/VLM分析逻辑不变
71 lines
2.1 KiB
Python
71 lines
2.1 KiB
Python
"""
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LangGraph StateGraph 构建
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构建 assistant + ToolNode 的 ReAct 图，接入 Dashscope Qwen。
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"""
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from typing import Optional
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from langgraph.graph import StateGraph, START, END
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from langgraph.prebuilt import ToolNode, tools_condition
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from langgraph.checkpoint.memory import MemorySaver
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from langchain_openai import ChatOpenAI
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from app.config import settings
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from app.utils.logger import logger
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from .state import AgentState
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from .tools import all_tools
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from .prompts import SYSTEM_PROMPT
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def _create_llm():
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"""创建 LLM 客户端（通过 Dashscope OpenAI 兼容接口对接 Qwen）"""
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return ChatOpenAI(
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model=settings.agent.model,
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base_url=settings.agent.vlm_base_url,
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api_key=settings.agent.vlm_api_key,
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timeout=settings.agent.timeout,
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)
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def build_agent_graph(checkpointer=None):
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"""构建并编译 Agent 图
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Args:
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checkpointer: LangGraph checkpointer 实例（None=不持久化）
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Returns:
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编译后的 CompiledGraph
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"""
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llm = _create_llm()
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llm_with_tools = llm.bind_tools(all_tools)
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def assistant(state: AgentState):
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"""LLM 推理节点：接收消息 + 系统提示，返回回复或工具调用"""
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system_msg = {"role": "system", "content": SYSTEM_PROMPT}
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response = llm_with_tools.invoke([system_msg] + state["messages"])
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return {"messages": [response]}
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# 构建图
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builder = StateGraph(AgentState)
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# 两个核心节点
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builder.add_node("assistant", assistant)
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builder.add_node("tools", ToolNode(all_tools))
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# 边：START → assistant → (条件) → tools 或 END
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builder.add_edge(START, "assistant")
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builder.add_conditional_edges("assistant", tools_condition)
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builder.add_edge("tools", "assistant")
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# 编译
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graph = builder.compile(checkpointer=checkpointer)
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logger.info("LangGraph Agent 图已编译")
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return graph
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def create_default_graph():
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"""创建带内存 checkpoint 的默认图（开发用）"""
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checkpointer = MemorySaver()
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return build_agent_graph(checkpointer=checkpointer)
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