修正資料庫未關閉問題

lib/connection-monitor.ts

@@ -0,0 +1,206 @@
+// =====================================================
+// 資料庫連線監控服務
+// =====================================================
+
+import { db } from './database';
+import { dbFailover } from './database-failover';
+
+export interface ConnectionStats {
+  totalConnections: number;
+  activeConnections: number;
+  idleConnections: number;
+  queuedRequests: number;
+  maxConnections: number;
+  usagePercentage: number;
+  isHealthy: boolean;
+  lastCheck: Date;
+}
+
+export class ConnectionMonitor {
+  private static instance: ConnectionMonitor;
+  private stats: ConnectionStats | null = null;
+  private checkInterval: NodeJS.Timeout | null = null;
+  private isMonitoring = false;
+
+  private constructor() {}
+
+  public static getInstance(): ConnectionMonitor {
+    if (!ConnectionMonitor.instance) {
+      ConnectionMonitor.instance = new ConnectionMonitor();
+    }
+    return ConnectionMonitor.instance;
+  }
+
+  // 開始監控
+  public startMonitoring(intervalMs: number = 30000): void {
+    if (this.isMonitoring) {
+      console.log('⚠️ 連線監控已在運行中');
+      return;
+    }
+
+    this.isMonitoring = true;
+    console.log(`🔍 開始連線監控，檢查間隔: ${intervalMs}ms`);
+
+    this.checkInterval = setInterval(async () => {
+      await this.checkConnectionHealth();
+    }, intervalMs);
+
+    // 立即執行一次檢查
+    this.checkConnectionHealth();
+  }
+
+  // 停止監控
+  public stopMonitoring(): void {
+    if (this.checkInterval) {
+      clearInterval(this.checkInterval);
+      this.checkInterval = null;
+    }
+    this.isMonitoring = false;
+    console.log('🛑 連線監控已停止');
+  }
+
+  // 檢查連線健康狀態
+  public async checkConnectionHealth(): Promise<ConnectionStats> {
+    try {
+      const stats = await this.getConnectionStats();
+      this.stats = stats;
+      
+      // 記錄連線狀態
+      console.log(`📊 資料庫連線狀態: ${stats.activeConnections}/${stats.maxConnections} (${stats.usagePercentage.toFixed(1)}%)`);
+      
+      // 檢查是否健康
+      if (stats.usagePercentage > 80) {
+        console.warn(`⚠️ 資料庫連線使用率過高: ${stats.usagePercentage.toFixed(1)}%`);
+      }
+      
+      if (stats.usagePercentage > 95) {
+        console.error(`🚨 資料庫連線使用率危險: ${stats.usagePercentage.toFixed(1)}%`);
+      }
+
+      return stats;
+    } catch (error) {
+      console.error('❌ 連線健康檢查失敗:', error);
+      return {
+        totalConnections: 0,
+        activeConnections: 0,
+        idleConnections: 0,
+        queuedRequests: 0,
+        maxConnections: 0,
+        usagePercentage: 0,
+        isHealthy: false,
+        lastCheck: new Date()
+      };
+    }
+  }
+
+  // 獲取連線統計
+  public async getConnectionStats(): Promise<ConnectionStats> {
+    try {
+      // 檢查備援狀態
+      const failoverStatus = db.getFailoverStatus();
+      
+      if (failoverStatus?.isEnabled) {
+        // 使用備援系統獲取統計
+        const result = await dbFailover.queryOne<{
+          current_connections: number;
+          max_connections: number;
+        }>('SHOW STATUS LIKE "Threads_connected"');
+        
+        const maxResult = await dbFailover.queryOne<{
+          Variable_name: string;
+          Value: string;
+        }>('SHOW VARIABLES LIKE "max_connections"');
+
+        const currentConnections = result?.current_connections || 0;
+        const maxConnections = parseInt(maxResult?.Value || '0');
+        const usagePercentage = maxConnections > 0 ? (currentConnections / maxConnections) * 100 : 0;
+
+        return {
+          totalConnections: currentConnections,
+          activeConnections: currentConnections,
+          idleConnections: 0, // MySQL 不直接提供空閒連線數
+          queuedRequests: 0,
+          maxConnections,
+          usagePercentage,
+          isHealthy: usagePercentage < 90,
+          lastCheck: new Date()
+        };
+      } else {
+        // 使用主資料庫獲取統計
+        const result = await db.queryOne<{
+          current_connections: number;
+          max_connections: number;
+        }>('SHOW STATUS LIKE "Threads_connected"');
+        
+        const maxResult = await db.queryOne<{
+          Variable_name: string;
+          Value: string;
+        }>('SHOW VARIABLES LIKE "max_connections"');
+
+        const currentConnections = result?.current_connections || 0;
+        const maxConnections = parseInt(maxResult?.Value || '0');
+        const usagePercentage = maxConnections > 0 ? (currentConnections / maxConnections) * 100 : 0;
+
+        return {
+          totalConnections: currentConnections,
+          activeConnections: currentConnections,
+          idleConnections: 0,
+          queuedRequests: 0,
+          maxConnections,
+          usagePercentage,
+          isHealthy: usagePercentage < 90,
+          lastCheck: new Date()
+        };
+      }
+    } catch (error) {
+      console.error('獲取連線統計失敗:', error);
+      throw error;
+    }
+  }
+
+  // 獲取當前統計
+  public getCurrentStats(): ConnectionStats | null {
+    return this.stats;
+  }
+
+  // 強制清理連線
+  public async forceCleanup(): Promise<void> {
+    try {
+      console.log('🧹 開始強制清理資料庫連線...');
+      
+      // 獲取當前連線數
+      const stats = await this.getConnectionStats();
+      console.log(`清理前連線數: ${stats.activeConnections}`);
+      
+      // 強制關閉所有空閒連線
+      try {
+        const { db } = await import('./database');
+        await db.close();
+        console.log('✅ 資料庫連線池已關閉');
+        
+        // 等待連線完全關閉
+        await new Promise(resolve => setTimeout(resolve, 1000));
+        
+        // 重新初始化
+        const { Database } = await import('./database');
+        const newDb = Database.getInstance();
+        console.log('✅ 資料庫連線池已重新初始化');
+        
+      } catch (error) {
+        console.error('❌ 強制清理連線池失敗:', error);
+      }
+      
+      console.log('✅ 連線清理完成');
+    } catch (error) {
+      console.error('❌ 連線清理失敗:', error);
+    }
+  }
+
+  // 檢查是否正在監控
+  public isCurrentlyMonitoring(): boolean {
+    return this.isMonitoring;
+  }
+}
+
+// 導出單例實例
+export const connectionMonitor = ConnectionMonitor.getInstance();