feat(log): 增强日志系统功能与追踪能力

- 新增模块级别日志控制和采样配置
- 为操作日志添加requestId字段支持全链路追踪
- 优化请求日志中间件，增强结构化记录能力
- 实现日志降级机制，数据库不可用时写入文件
- 添加相关数据库迁移脚本和模型索引

backend/utils/operationLogger.js

@@ -1,9 +1,27 @@
+/**
+ * 操作日志记录器
+ * 支持：
+ * - 关联请求追踪ID（requestId）
+ * - 数据库写入失败时降级到文件日志
+ * - 统一错误处理（使用logger替代console.error）
+ */
+
 const OperationLog = require('../models/OperationLog');
+const logger = require('./logger');
+const fs = require('fs');
+const path = require('path');
+
+const logModule = logger.module('OperationLogger');
 
 const generateRecordId = () => {
   return `OPLOG_${Date.now().toString(36)}_${Math.random().toString(36).substr(2, 9)}`;
 };
 
+/**
+ * 获取操作人信息
+ * @param {Object} req - Express请求对象
+ * @returns {Object} 操作人信息
+ */
 const getOperatorInfo = req => {
   if (!req || !req.user) {
     return {
@@ -19,9 +37,14 @@ const getOperatorInfo = req => {
   };
 };
 
+/**
+ * 获取客户端信息
+ * @param {Object} req - Express请求对象
+ * @returns {Object} 客户端信息（含requestId）
+ */
 const getClientInfo = req => {
   if (!req) {
-    return { ipAddress: null, userAgent: null };
+    return { ipAddress: null, userAgent: null, requestId: null };
   }
   const ipAddress =
     req.headers['x-forwarded-for'] ||
@@ -29,8 +52,11 @@ const getClientInfo = req => {
     req.connection?.remoteAddress ||
     req.ip ||
     null;
-  const userAgent = req.headers['user-agent'] || null;
-  return { ipAddress, userAgent };
+  return {
+    ipAddress,
+    userAgent: req.headers['user-agent'] || null,
+    requestId: req.requestId || null,
+  };
 };
 
 const DEVICE_TYPE_MAP = {
@@ -43,6 +69,13 @@ const DEVICE_TYPE_MAP = {
   other: '其他设备',
 };
 
+/**
+ * 生成设备操作描述
+ * @param {string} operation - 操作类型描述
+ * @param {Object} device - 设备信息
+ * @param {Object} options - 选项
+ * @returns {string} 操作描述
+ */
 const generateDeviceDescription = (operation, device, options = {}) => {
   const {
     includeRack = true,
@@ -82,6 +115,12 @@ const generateDeviceDescription = (operation, device, options = {}) => {
   return `${operation}${parts.join('，')}`;
 };
 
+/**
+ * 构建设备元数据
+ * @param {Object} device - 设备信息
+ * @param {Object} extra - 额外字段
+ * @returns {Object} 元数据
+ */
 const buildDeviceMetadata = (device, extra = {}) => {
   return {
     deviceId: device.deviceId || null,
@@ -99,6 +138,46 @@ const buildDeviceMetadata = (device, extra = {}) => {
   };
 };
 
+/**
+ * 降级写入文件日志
+ * 当数据库不可用时，将操作日志写入文件作为降级方案
+ * @param {Object} logData - 日志数据
+ */
+const fallbackToFile = (logData) => {
+  try {
+    const fallbackDir = path.join(process.env.LOG_DIR || './logs', 'fallback');
+    if (!fs.existsSync(fallbackDir)) {
+      fs.mkdirSync(fallbackDir, { recursive: true });
+    }
+    const fallbackPath = path.join(fallbackDir, `operation-fallback-${new Date().toISOString().slice(0, 10)}.log`);
+    const fallbackEntry = {
+      timestamp: new Date().toISOString(),
+      level: 'warn',
+      module: 'OperationLogger',
+      message: '操作日志数据库写入失败（降级记录）',
+      data: logData,
+    };
+    fs.appendFileSync(fallbackPath, JSON.stringify(fallbackEntry) + '\n');
+  } catch {
+    // 文件写入也失败时静默忽略，避免级联错误
+  }
+};
+
+/**
+ * 记录操作日志（核心方法）
+ * @param {Object} params - 参数对象
+ * @param {string} params.module - 模块名称
+ * @param {string} params.operationType - 操作类型
+ * @param {string} params.operationDescription - 操作描述
+ * @param {string} params.targetId - 目标ID
+ * @param {string} params.targetName - 目标名称
+ * @param {Object} params.beforeState - 操作前状态
+ * @param {Object} params.afterState - 操作后状态
+ * @param {string} params.result - 操作结果
+ * @param {Object} params.req - 请求对象
+ * @param {Object} params.metadata - 附加元数据
+ * @returns {Promise<Object|null>} 创建的日志记录
+ */
 async function logOperation({
   module,
   operationType,
@@ -111,32 +190,64 @@ async function logOperation({
   req,
   metadata = {},
 }) {
-  try {
-    const operatorInfo = getOperatorInfo(req);
-    const clientInfo = getClientInfo(req);
+  const operatorInfo = getOperatorInfo(req);
+  const clientInfo = getClientInfo(req);
 
-    await OperationLog.create({
+  const logData = {
+    module,
+    operationType,
+    operationDescription,
+    targetId: targetId || null,
+    targetName: targetName || null,
+    operatorId: operatorInfo.operatorId,
+    operatorName: operatorInfo.operatorName,
+    operatorRole: operatorInfo.operatorRole,
+    beforeState: beforeState || null,
+    afterState: afterState || null,
+    result,
+    ipAddress: clientInfo.ipAddress,
+    userAgent: clientInfo.userAgent,
+    requestId: clientInfo.requestId,
+    metadata,
+  };
+
+  try {
+    const operationLog = await OperationLog.create({
       recordId: generateRecordId(),
+      ...logData,
+    });
+
+    logModule.debug('操作日志记录成功', {
+      recordId: operationLog.recordId,
       module,
       operationType,
-      operationDescription,
-      targetId: targetId || null,
-      targetName: targetName || null,
-      operatorId: operatorInfo.operatorId,
-      operatorName: operatorInfo.operatorName,
-      operatorRole: operatorInfo.operatorRole,
-      beforeState: beforeState || null,
-      afterState: afterState || null,
-      result,
-      ipAddress: clientInfo.ipAddress,
-      userAgent: clientInfo.userAgent,
-      metadata,
+      targetId,
+      requestId: clientInfo.requestId,
     });
+
+    return operationLog;
   } catch (error) {
-    console.error('记录操作日志失败:', error);
+    logModule.error('记录操作日志失败', {
+      error: error.message,
+      module,
+      operationType,
+      targetId,
+      requestId: clientInfo.requestId,
+    });
+
+    fallbackToFile(logData);
+
+    return null;
   }
 }
 
+/**
+ * 记录设备操作日志
+ * @param {string} operationType - 操作类型
+ * @param {string} operationDescription - 操作描述
+ * @param {Object} params - 参数
+ * @returns {Promise<Object|null>}
+ */
 async function logDeviceOperation(
   operationType,
   operationDescription,
@@ -156,6 +267,13 @@ async function logDeviceOperation(
   });
 }
 
+/**
+ * 记录用户操作日志
+ * @param {string} operationType - 操作类型
+ * @param {string} operationDescription - 操作描述
+ * @param {Object} params - 参数
+ * @returns {Promise<Object|null>}
+ */
 async function logUserOperation(
   operationType,
   operationDescription,
@@ -175,6 +293,13 @@ async function logUserOperation(
   });
 }
 
+/**
+ * 记录角色操作日志
+ * @param {string} operationType - 操作类型
+ * @param {string} operationDescription - 操作描述
+ * @param {Object} params - 参数
+ * @returns {Promise<Object|null>}
+ */
 async function logRoleOperation(
   operationType,
   operationDescription,