fix(add): DNS 记录已存在时自动更新而非报错 (close #15)

cmd/add.go

@@ -73,14 +73,30 @@ var addCmd = &cobra.Command{
 			return err
 		}
 
-		// 创建 CNAME
+		// 检查 DNS 记录是否已存在
 		target := cfg.Tunnel.ID + ".cfargotunnel.com"
-		fmt.Printf("正在创建 DNS 记录 %s → %s\n", addDomain, target)
-		recordID, err := client.CreateCNAME(ctx, zone.ID, addDomain, target)
+		existingRecordID, err := client.FindDNSRecord(ctx, zone.ID, addDomain)
 		if err != nil {
 			return err
 		}
 
+		var recordID string
+		if existingRecordID != "" {
+			// 记录已存在,更新
+			fmt.Printf("DNS 记录已存在,正在更新 %s → %s\n", addDomain, target)
+			if err := client.UpdateCNAME(ctx, zone.ID, existingRecordID, addDomain, target); err != nil {
+				return err
+			}
+			recordID = existingRecordID
+		} else {
+			// 记录不存在,创建
+			fmt.Printf("正在创建 DNS 记录 %s → %s\n", addDomain, target)
+			recordID, err = client.CreateCNAME(ctx, zone.ID, addDomain, target)
+			if err != nil {
+				return err
+			}
+		}
+
 		// 构建路由配置
 		route := config.RouteConfig{
 			Name:        name,

internal/cfapi/dns.go

@@ -36,3 +36,40 @@ func (c *Client) DeleteDNSRecord(ctx context.Context, zoneID, recordID string) e
 	}
 	return nil
 }
+
+// FindDNSRecord 查找指定域名的 DNS 记录
+func (c *Client) FindDNSRecord(ctx context.Context, zoneID, name string) (string, error) {
+	records, err := c.api.DNS.Records.List(ctx, dns.RecordListParams{
+		ZoneID: cf.F(zoneID),
+		Name: cf.F(dns.RecordListParamsName{
+			Exact: cf.F(name),
+		}),
+	})
+	if err != nil {
+		return "", fmt.Errorf("查询 DNS 记录失败: %w", err)
+	}
+	for _, r := range records.Result {
+		if r.Name == name {
+			return r.ID, nil
+		}
+	}
+	return "", nil // 未找到
+}
+
+// UpdateCNAME 更新 CNAME 记录
+func (c *Client) UpdateCNAME(ctx context.Context, zoneID, recordID, name, target string) error {
+	_, err := c.api.DNS.Records.Update(ctx, recordID, dns.RecordUpdateParams{
+		ZoneID: cf.F(zoneID),
+		Body: dns.CNAMERecordParam{
+			Name:    cf.F(name),
+			Content: cf.F(target),
+			Type:    cf.F(dns.CNAMERecordTypeCNAME),
+			TTL:     cf.F(dns.TTL(1)),
+			Proxied: cf.F(true),
+		},
+	})
+	if err != nil {
+		return fmt.Errorf("更新 CNAME 记录失败: %w", err)
+	}
+	return nil
+}