From 77220456b6c5478e3dc0addfc3838008fb1ea2a5 Mon Sep 17 00:00:00 2001
From: Mitsuhiro Tanda <mitsuhiro.tanda@gmail.com>
Date: Fri, 22 Jun 2018 16:35:17 +0900
Subject: [PATCH] improve error message

---
 pkg/tsdb/cloudwatch/cloudwatch.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkg/tsdb/cloudwatch/cloudwatch.go b/pkg/tsdb/cloudwatch/cloudwatch.go
index 54634bc0614..38fbac3aa29 100644
--- a/pkg/tsdb/cloudwatch/cloudwatch.go
+++ b/pkg/tsdb/cloudwatch/cloudwatch.go
@@ -112,6 +112,10 @@ func (e *CloudWatchExecutor) executeTimeSeriesQuery(ctx context.Context, queryCo
 			continue
 		}
 
+		if query.Id == "" && query.Expression != "" {
+			return nil, fmt.Errorf("Invalid query: id should be set if using expression")
+		}
+
 		eg.Go(func() error {
 			queryRes, err := e.executeQuery(ectx, query, queryContext)
 			if err != nil {