refactor: 将 RAG 节点拆分为独立模块

- 新增 rag_nodes.py: 独立的 RAG 检索节点
- 从 react_nodes.py 移除 RAG 相关代码
- 更新导入和导出
- rag_nodes.py 包含 rag_retrieve_node 和 rag_re_retrieve_node
- 添加 inject_rag_tool_to_state 工具函数

backend/app/graph/react_nodes.py

@@ -2,50 +2,30 @@
 React 模式节点模块 - 带超时和重试功能
 包含：
 - react_reason_node: 使用 intent.py 进行推理
-- rag_retrieve_node: RAG 检索节点（带重试）
 - error_handling_node: 错误处理节点
 - final_response_node: 最终回答节点
+- init_state_node: 初始化节点
 """
 
 import sys
-import time
 from typing import Dict, Any, Optional
 from datetime import datetime
-from functools import wraps
 
 # 导入我们的 intent.py
 from ..agent_subgraphs.common.intent import (
     react_reason,
     get_route_by_reasoning,
     ReasoningAction,
-    RetrievalConfig,
     ReasoningResult
 )
 from ..agent_subgraphs.common.state_base import StateUtils
 from .state import MainGraphState, ErrorRecord, ErrorSeverity
 from .retry_utils import (
     RetryConfig,
-    RetryResult,
-    with_retry,
-    create_retry_wrapper_for_node,
-    RAG_RETRY_CONFIG,
     SUBGRAPH_RETRY_CONFIG
 )
 
 
-def get_rag_tool():
-    """
-    获取 RAG 工具（延迟导入，避免循环依赖）
-    """
-    try:
-        # 尝试导入现有的 RAG 工具
-        from ..rag.tools import create_rag_tool_sync
-        # 注意：这里简化处理，实际使用时应该从全局获取初始化好的工具
-        return None  # 先返回 None，后面通过注入方式
-    except Exception:
-        return None
-
-
 # ========== 1. React 推理节点 ==========
 def react_reason_node(state: MainGraphState) -> MainGraphState:
     """
@@ -94,7 +74,7 @@ def react_reason_node(state: MainGraphState) -> MainGraphState:
         "reasoning": result.reasoning
     }
     
-    # 保存推理结果到状态（供条件路由使用）
+    # 保存推理结果到状态
     state.debug_info["reasoning_result"] = result
     
     # 确定下一步动作
@@ -103,97 +83,7 @@ def react_reason_node(state: MainGraphState) -> MainGraphState:
     return state
 
 
-# ========== 2. RAG 检索节点（带超时和重试） ==========
-def _rag_retrieve_core(state: MainGraphState) -> MainGraphState:
-    """
-    RAG 检索核心逻辑（不带重试）
-    """
-    # 获取推理结果中的检索配置
-    reasoning_result: Optional[ReasoningResult] = state.debug_info.get("reasoning_result")
-    retrieval_query = state.user_query
-    
-    if reasoning_result and reasoning_result.retrieval_config:
-        cfg: RetrievalConfig = reasoning_result.retrieval_config
-        if cfg.retrieval_query:
-            retrieval_query = cfg.retrieval_query
-    
-    # 尝试获取 RAG 工具并调用
-    # 这里演示如何调用，实际使用时需要确保 RAG 已初始化
-    # 暂时用模拟数据
-    state.rag_context = (
-        f"[模拟RAG检索结果]\n"
-        f"查询: {retrieval_query}\n"
-        f"这是一个来自知识库的示例回答。"
-    )
-    state.rag_docs = [
-        {"source": "doc1.txt", "content": "示例内容1"},
-        {"source": "doc2.txt", "content": "示例内容2"}
-    ]
-    state.rag_retrieved = True
-    state.success = True
-    
-    return state
-
-
-def rag_retrieve_node(state: MainGraphState) -> MainGraphState:
-    """
-    RAG 检索节点：带超时和重试
-    
-    Returns: 更新后的状态
-    """
-    state.current_phase = "rag_retrieving"
-    
-    # 使用重试包装器
-    start_time = time.time()
-    last_error = None
-    
-    for attempt in range(RAG_RETRY_CONFIG.max_retries + 1):
-        try:
-            # 执行核心逻辑
-            result = _rag_retrieve_core(state)
-            
-            # 成功
-            state.debug_info["rag_retrieval"] = {
-                "attempt": attempt + 1,
-                "success": True,
-                "time": time.time() - start_time
-            }
-            return result
-            
-        except Exception as e:
-            last_error = e
-            
-            if attempt >= RAG_RETRY_CONFIG.max_retries:
-                break
-            
-            # 等待后重试（指数退避）
-            delay = RAG_RETRY_CONFIG.base_delay * (2 ** attempt)
-            time.sleep(min(delay, RAG_RETRY_CONFIG.max_delay))
-    
-    # 所有重试都失败，记录结构化错误
-    error_record = ErrorRecord(
-        error_type="RAGRetrievalError",
-        error_message=str(last_error) if last_error else "RAG 检索超时",
-        severity=ErrorSeverity.WARNING,
-        source="rag_retrieve_node",
-        timestamp=datetime.now().isoformat(),
-        retry_count=RAG_RETRY_CONFIG.max_retries,
-        max_retries=RAG_RETRY_CONFIG.max_retries,
-        context={
-            "query": state.user_query,
-            "total_time": time.time() - start_time,
-            "timeout": RAG_RETRY_CONFIG.timeout
-        }
-    )
-    
-    state.errors.append(error_record)
-    state.current_error = error_record
-    state.current_phase = "error_handling"
-    
-    return state
-
-
-# ========== 3. 错误处理节点 ==========
+# ========== 2. 错误处理节点 ==========
 def error_handling_node(state: MainGraphState) -> MainGraphState:
     """
     错误处理节点：处理子图/工具调用错误
@@ -210,7 +100,6 @@ def error_handling_node(state: MainGraphState) -> MainGraphState:
     state.current_phase = "error_handling"
     
     if not state.current_error:
-        # 没有错误，直接返回
         state.current_phase = "react_reasoning"
         return state
     
@@ -219,7 +108,7 @@ def error_handling_node(state: MainGraphState) -> MainGraphState:
     # 更新错误状态
     state.error_message = f"{error.error_type}: {error.error_message}"
     
-    # 记录结构化错误信息（用于 LLM 决策）
+    # 记录结构化错误信息
     structured_error = {
         "tool": error.source,
         "status": "failed",
@@ -231,11 +120,11 @@ def error_handling_node(state: MainGraphState) -> MainGraphState:
     
     # 根据错误类型添加建议
     if "RAG" in error.error_type:
-        structured_error["suggestion"] = "尝试重新表述问题或直接询问，我会用现有知识回答"
+        structured_error["suggestion"] = "尝试重新表述问题或直接询问"
     elif "subgraph" in error.source or "contact" in error.source:
-        structured_error["suggestion"] = "子图执行失败，请尝试简化查询或使用其他功能"
+        structured_error["suggestion"] = "子图执行失败，请尝试简化查询"
     elif "timeout" in error.error_message.lower():
-        structured_error["suggestion"] = "请求超时，请稍后再试或简化查询"
+        structured_error["suggestion"] = "请求超时，请稍后再试"
     else:
         structured_error["suggestion"] = "请尝试其他方式提问"
     
@@ -248,7 +137,6 @@ def error_handling_node(state: MainGraphState) -> MainGraphState:
     )
     
     if can_retry:
-        # 重试策略
         error.retry_count += 1
         state.retry_action = error.source
         state.debug_info["retry_count"] = error.retry_count
@@ -265,7 +153,6 @@ def error_handling_node(state: MainGraphState) -> MainGraphState:
     
     # 策略2: 无法重试，尝试降级方案
     if error.severity != ErrorSeverity.FATAL:
-        # 降级到直接回答模式
         state.final_result = (
             f"⚠️  遇到一些问题：\n"
             f"```json\n{structured_error}\n```\n"
@@ -275,7 +162,7 @@ def error_handling_node(state: MainGraphState) -> MainGraphState:
         state.current_phase = "finalizing"
         return state
     
-    # 策略3: 致命错误，无法继续
+    # 策略3: 致命错误
     state.final_result = (
         f"❌ 服务暂时不可用，请稍后再试。\n"
         f"```json\n{structured_error}\n```"
@@ -286,7 +173,7 @@ def error_handling_node(state: MainGraphState) -> MainGraphState:
     return state
 
 
-# ========== 4. 最终回答节点 ==========
+# ========== 3. 最终回答节点 ==========
 def final_response_node(state: MainGraphState) -> MainGraphState:
     """
     最终回答节点：整理并生成最终回答
@@ -307,12 +194,15 @@ def final_response_node(state: MainGraphState) -> MainGraphState:
         parts.append("---")
     
     # 添加子图结果（如果有）
-    if state.contact_result and state.contact_result.get("final_result"):
-        parts.append(state.contact_result["final_result"])
-    if state.dictionary_result and state.dictionary_result.get("final_result"):
-        parts.append(state.dictionary_result["final_result"])
-    if state.news_result and state.news_result.get("final_result"):
-        parts.append(state.news_result["final_result"])
+    if state.contact_result and hasattr(state.contact_result, "get"):
+        if state.contact_result.get("final_result"):
+            parts.append(state.contact_result["final_result"])
+    if state.dictionary_result and hasattr(state.dictionary_result, "get"):
+        if state.dictionary_result.get("final_result"):
+            parts.append(state.dictionary_result["final_result"])
+    if state.news_result and hasattr(state.news_result, "get"):
+        if state.news_result.get("final_result"):
+            parts.append(state.news_result["final_result"])
     
     # 如果都没有，用默认回答
     if not parts:
@@ -326,7 +216,7 @@ def final_response_node(state: MainGraphState) -> MainGraphState:
     return state
 
 
-# ========== 5. 初始化状态节点 ==========
+# ========== 4. 初始化状态节点 ==========
 def init_state_node(state: MainGraphState) -> MainGraphState:
     """
     初始化状态节点：在流程开始时设置初始值
@@ -335,7 +225,7 @@ def init_state_node(state: MainGraphState) -> MainGraphState:
     state.reasoning_step = 0
     state.start_time = datetime.now().isoformat()
     
-    # 从 messages 中提取用户查询（如果 user_query 为空）
+    # 从 messages 中提取用户查询
     if not state.user_query and state.messages:
         last_msg = state.messages[-1]
         state.user_query = getattr(last_msg, "content", str(last_msg))
@@ -343,7 +233,7 @@ def init_state_node(state: MainGraphState) -> MainGraphState:
     return state
 
 
-# ========== 6. 条件路由函数 ==========
+# ========== 5. 条件路由函数 ==========
 def route_by_reasoning(state: MainGraphState) -> str:
     """
     根据推理结果决定下一步路由
@@ -358,7 +248,6 @@ def route_by_reasoning(state: MainGraphState) -> str:
     if state.current_phase == "finalizing" or state.current_phase == "done":
         return "final_response"
     if state.current_phase == "retrying":
-        # 重试路由
         if state.retry_action and "rag" in state.retry_action.lower():
             return "rag_retrieve"
         return "react_reason"
@@ -367,7 +256,6 @@ def route_by_reasoning(state: MainGraphState) -> str:
     reasoning_result: Optional[ReasoningResult] = state.debug_info.get("reasoning_result")
     
     if not reasoning_result:
-        # 没有推理结果，直接结束
         return "final_response"
     
     # 使用 intent.py 提供的路由函数
@@ -378,11 +266,21 @@ def route_by_reasoning(state: MainGraphState) -> str:
         "direct_response": "final_response",
         "retrieve_rag": "rag_retrieve",
         "re_retrieve_rag": "rag_retrieve",
-        "clarify": "final_response",  # 简化：澄清直接回答让用户补充
-        "call_tool": "final_response",  # 简化：工具调用暂未实现
+        "clarify": "final_response",
+        "call_tool": "final_response",
         "contact": "contact_subgraph",
         "dictionary": "dictionary_subgraph",
         "news_analysis": "news_analysis_subgraph",
     }
     
     return route_mapping.get(route, "final_response")
+
+
+# ========== 导出 ==========
+__all__ = [
+    "init_state_node",
+    "react_reason_node",
+    "error_handling_node",
+    "final_response_node",
+    "route_by_reasoning"
+]