feat(server): 添加配置文件支持和示例配置生成

- 新增 GenerateSampleConfig 函数用于生成示例配置文件
- 在 main 函数中添加配置文件路径和生成示例配置的命令行参数
- 实现配置文件加载逻辑，替代命令行参数
- 优化命令行参数默认值，如 NATS 服务器地址

cmd/server/config.go

@@ -32,3 +32,22 @@ func LoadConfig(path string) (*Config, error) {
 
 	return &config, nil
 }
+
+func GenerateSampleConfig(path string) error {
+	config := Config{
+		MetricsAddr:     ":8082",
+		NATSURL:         "nats://localhost:4222",
+		PersistenceDir:  "./data",
+		PersistenceType: "memory",
+		RestAddr:        ":8080",
+		SyncEvery:       1000,
+		WsAddr:          ":8081",
+	}
+	// 序列化yaml到path
+	file, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	return yaml.NewEncoder(file).Encode(config)
+}

cmd/server/main.go

@@ -21,14 +21,38 @@ var (
 	restAddr        = flag.String("rest-addr", ":8080", "REST API服务地址")
 	wsAddr          = flag.String("ws-addr", ":8081", "WebSocket服务地址")
 	metricsAddr     = flag.String("metrics-addr", ":8082", "指标服务地址")
-	natsURL         = flag.String("nats-url", "nats://localhost:4222", "NATS服务器地址")
+	natsURL         = flag.String("nats-url", "", "NATS服务器地址")
 	persistenceType = flag.String("persistence", "none", "持久化类型 (none, wal)")
 	persistenceDir  = flag.String("persistence-dir", "./data", "持久化目录")
 	syncEvery       = flag.Int("sync-every", 100, "每写入多少条数据同步一次")
+	configPath      = flag.String("config", "config.yaml", "配置文件路径")
+	genSampleConfig = flag.Bool("gen-sample-config", false, "生成示例配置文件")
 )
 
 func main() {
+	if *genSampleConfig {
+		err := GenerateSampleConfig("./config.yaml.sample")
+		if err != nil {
+			log.Fatalf("生成示例配置文件失败: %v", err)
+		}
+		log.Println("示例配置文件已生成")
+		return
+	}
 	flag.Parse()
+	if *configPath != "" {
+
+		config, err := LoadConfig(*configPath)
+		if err != nil {
+			log.Fatalf("Failed to load config: %v", err)
+		}
+		restAddr = &config.RestAddr
+		wsAddr = &config.WsAddr
+		metricsAddr = &config.MetricsAddr
+		natsURL = &config.NATSURL
+		persistenceType = &config.PersistenceType
+		persistenceDir = &config.PersistenceDir
+		syncEvery = &config.SyncEvery
+	}
 
 	// 创建存储引擎
 	engine := storage.NewMemoryEngine()