return default region list from backend

pkg/tsdb/cloudwatch/metric_find_query.go

@@ -234,6 +234,8 @@ func parseMultiSelectValue(input string) []string {
 // Please update the region list in public/app/plugins/datasource/cloudwatch/partials/config.html
 func (e *CloudWatchExecutor) handleGetRegions(ctx context.Context, parameters *simplejson.Json, queryContext *tsdb.TsdbQuery) ([]suggestData, error) {
 	regions := []string{
+		"ap-northeast-1", "ap-northeast-2", "ap-northeast-3", "ap-south-1", "ap-southeast-1", "ap-southeast-2", "ca-central-1",
+		"eu-central-1", "eu-north-1", "eu-west-1", "eu-west-2", "eu-west-3", "me-south-1", "sa-east-1", "us-east-1", "us-east-2", "us-west-1", "us-west-2",
 		"cn-north-1", "cn-northwest-1", "us-gov-east-1", "us-gov-west-1", "us-isob-east-1", "us-iso-east-1",
 	}
 
@@ -243,10 +245,12 @@ func (e *CloudWatchExecutor) handleGetRegions(ctx context.Context, parameters *s
 	}
 	r, err := e.ec2Svc.DescribeRegions(&ec2.DescribeRegionsInput{})
 	if err != nil {
-		return nil, err
-	}
-	for _, region := range r.Regions {
-		regions = append(regions, *region.RegionName)
+		// ignore error for backward compatibility
+		plog.Error("Failed to get regions", "error", err)
+	} else {
+		for _, region := range r.Regions {
+			regions = append(regions, *region.RegionName)
+		}
 	}
 	sort.Strings(regions)
 

public/app/plugins/datasource/cloudwatch/config_ctrl.ts

@@ -41,32 +41,7 @@ export class CloudWatchConfigCtrl {
     { name: 'Yearly', value: 'Yearly', example: '[logstash-]YYYY' },
   ];
 
-  regions = [
-    'ap-northeast-1',
-    'ap-northeast-2',
-    'ap-northeast-3',
-    'ap-south-1',
-    'ap-southeast-1',
-    'ap-southeast-2',
-    'ca-central-1',
-    'cn-north-1',
-    'cn-northwest-1',
-    'eu-central-1',
-    'eu-north-1',
-    'eu-west-1',
-    'eu-west-2',
-    'eu-west-3',
-    'me-south-1',
-    'sa-east-1',
-    'us-east-1',
-    'us-east-2',
-    'us-gov-east-1',
-    'us-gov-west-1',
-    'us-iso-east-1',
-    'us-isob-east-1',
-    'us-west-1',
-    'us-west-2',
-  ];
+  regions = [];
 
   getRegions() {
     this.datasourceSrv
@@ -74,10 +49,13 @@ export class CloudWatchConfigCtrl {
       .then(ds => {
         return ds.getRegions();
       })
-      .then(regions => {
-        this.regions = _.map(regions, 'value');
-      }, err => {
-        console.error('failed to call ec2:DescribeRegions, please check iam setting');
-      });
+      .then(
+        regions => {
+          this.regions = _.map(regions, 'value');
+        },
+        err => {
+          console.error('failed to get latest regions');
+        }
+      );
   }
 }