Feat: Config Manager API

internal/config/manager.go

@@ -1,12 +1,14 @@
 package config
 
 import (
+	"fmt"
 	"log"
 	"os"
 	"sync"
 	"time"
 
 	"github.com/fsnotify/fsnotify"
+	"gopkg.in/yaml.v3"
 )
 
 // Manager 配置管理器，支持热更新
@@ -227,6 +229,181 @@ func (m *Manager) logConfigChanges(oldConfig, newConfig *Config) {
 	}
 }
 
+// UpdateConfig 通过 API 更新配置文件
+// 返回错误如果验证失败或写入失败
+func (m *Manager) UpdateConfig(newConfig *Config) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+
+	// 1. 验证新配置
+	if err := m.validateConfig(newConfig); err != nil {
+		return err
+	}
+
+	// 2. 备份当前配置文件
+	if err := m.backupConfigFile(); err != nil {
+		log.Printf("Failed to backup config file: %v", err)
+		// 继续执行，备份失败不应阻止更新
+	}
+
+	// 3. 将新配置写入文件
+	if err := m.writeConfigFile(newConfig); err != nil {
+		return err
+	}
+
+	// 4. 更新内存中的配置
+	oldConfig := m.config
+	m.config = newConfig
+
+	// 5. 更新最后修改时间，避免文件监听重复触发
+	if fileInfo, err := os.Stat(m.configFile); err == nil {
+		m.lastModTime = fileInfo.ModTime()
+	}
+
+	log.Printf("Configuration updated successfully via API")
+
+	// 6. 触发配置变更回调（在锁外执行）
+	callbacks := make([]func(*Config), len(m.callbacks))
+	copy(callbacks, m.callbacks)
+
+	go func() {
+		for _, callback := range callbacks {
+			func() {
+				defer func() {
+					if r := recover(); r != nil {
+						log.Printf("Config change callback panic: %v", r)
+					}
+				}()
+				callback(newConfig)
+			}()
+		}
+	}()
+
+	// 7. 记录配置变更
+	m.logConfigChanges(oldConfig, newConfig)
+
+	return nil
+}
+
+// validateConfig 验证配置的有效性
+func (m *Manager) validateConfig(cfg *Config) error {
+	// 基本验证
+	if cfg.Server.Port <= 0 || cfg.Server.Port > 65535 {
+		return fmt.Errorf("invalid server port: %d", cfg.Server.Port)
+	}
+
+	if len(cfg.Buckets) == 0 {
+		return fmt.Errorf("at least one bucket is required")
+	}
+
+	// 验证存储桶配置
+	for i, bucket := range cfg.Buckets {
+		if bucket.Name == "" {
+			return fmt.Errorf("bucket[%d]: name is required", i)
+		}
+
+		// 虚拟存储桶不需要端点和凭据
+		if !bucket.Virtual {
+			if bucket.Endpoint == "" {
+				return fmt.Errorf("bucket[%d] (%s): endpoint is required for non-virtual bucket", i, bucket.Name)
+			}
+			if bucket.AccessKeyID == "" {
+				return fmt.Errorf("bucket[%d] (%s): access_key_id is required for non-virtual bucket", i, bucket.Name)
+			}
+			if bucket.SecretAccessKey == "" {
+				return fmt.Errorf("bucket[%d] (%s): secret_access_key is required for non-virtual bucket", i, bucket.Name)
+			}
+		}
+
+		// 解析并验证容量大小
+		if err := cfg.Buckets[i].ParseMaxSize(); err != nil {
+			return fmt.Errorf("bucket[%d] (%s): invalid max_size: %w", i, bucket.Name, err)
+		}
+	}
+
+	// 验证负载均衡策略
+	validStrategies := map[string]bool{
+		"round-robin": true,
+		"least-space": true,
+		"weighted":    true,
+	}
+	if !validStrategies[cfg.Balancer.Strategy] {
+		return fmt.Errorf("invalid balancer strategy: %s (must be one of: round-robin, least-space, weighted)", cfg.Balancer.Strategy)
+	}
+
+	// 验证数据库配置
+	if cfg.Database.Type == "" {
+		return fmt.Errorf("database type is required")
+	}
+	validDBTypes := map[string]bool{
+		"sqlite":   true,
+		"mysql":    true,
+		"postgres": true,
+	}
+	if !validDBTypes[cfg.Database.Type] {
+		return fmt.Errorf("invalid database type: %s (must be one of: sqlite, mysql, postgres)", cfg.Database.Type)
+	}
+
+	return nil
+}
+
+// backupConfigFile 备份当前配置文件
+func (m *Manager) backupConfigFile() error {
+	backupPath := m.configFile + ".backup." + time.Now().Format("20060102-150405")
+
+	sourceData, err := os.ReadFile(m.configFile)
+	if err != nil {
+		return fmt.Errorf("failed to read config file: %w", err)
+	}
+
+	if err := os.WriteFile(backupPath, sourceData, 0644); err != nil {
+		return fmt.Errorf("failed to write backup file: %w", err)
+	}
+
+	log.Printf("Config file backed up to: %s", backupPath)
+	return nil
+}
+
+// writeConfigFile 将配置写入 YAML 文件
+func (m *Manager) writeConfigFile(cfg *Config) error {
+	// 临时文件，确保原子性
+	tmpFile := m.configFile + ".tmp"
+
+	file, err := os.OpenFile(tmpFile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return fmt.Errorf("failed to create temp config file: %w", err)
+	}
+	defer file.Close()
+
+	encoder := yaml.NewEncoder(file)
+	encoder.SetIndent(2)
+
+	if err := encoder.Encode(cfg); err != nil {
+		file.Close()
+		os.Remove(tmpFile)
+		return fmt.Errorf("failed to encode config: %w", err)
+	}
+
+	if err := encoder.Close(); err != nil {
+		file.Close()
+		os.Remove(tmpFile)
+		return fmt.Errorf("failed to close encoder: %w", err)
+	}
+
+	if err := file.Close(); err != nil {
+		os.Remove(tmpFile)
+		return fmt.Errorf("failed to close temp file: %w", err)
+	}
+
+	// 原子性替换原文件
+	if err := os.Rename(tmpFile, m.configFile); err != nil {
+		os.Remove(tmpFile)
+		return fmt.Errorf("failed to replace config file: %w", err)
+	}
+
+	return nil
+}
+
 // Close 关闭配置管理器
 func (m *Manager) Close() error {
 	// 停止监听协程