修复一次行监听为取消问题

middleware/etcd/lease.go

@@ -24,13 +24,18 @@ func LeaseOnce(ctx context.Context, key string, val string, ttl int64) error {
 	if ttl <= 0 {
 		return errors.New("lease time must be more than 0")
 	}
+
 	if nil == ctx {
-		ctx = context.TODO()
+		ctx = context.Background()
 	}
+
 	var (
-		resp *clientv3.LeaseGrantResponse
-		err  error
+		resp       *clientv3.LeaseGrantResponse
+		err        error
+		cancelFunc context.CancelFunc
 	)
+	ctx, cancelFunc = context.WithCancel(ctx)
+	defer cancelFunc()
 	// 创建一个5秒的租约
 	if resp, err = Client.Grant(ctx, ttl); err != nil {
 		return errors.New("lease grant error : " + err.Error())