CloudWatch: Handle permissions error and update docs (#88524)

pkg/tsdb/cloudwatch/models/query_row_response.go

@@ -1,6 +1,8 @@
 package models
 
-import "github.com/aws/aws-sdk-go/service/cloudwatch"
+import (
+	"github.com/aws/aws-sdk-go/service/cloudwatch"
+)
 
 // queryRowResponse represents the GetMetricData response for a query row in the query editor.
 type QueryRowResponse struct {
@@ -8,6 +10,8 @@ type QueryRowResponse struct {
 	ErrorCodes             map[string]bool
 	HasArithmeticError     bool
 	ArithmeticErrorMessage string
+	HasPermissionError     bool
+	PermissionErrorMessage string
 	Metrics                []*cloudwatch.MetricDataResult
 	StatusCode             string
 }
@@ -23,6 +27,10 @@ func NewQueryRowResponse(errors map[string]bool) QueryRowResponse {
 }
 
 func (q *QueryRowResponse) AddMetricDataResult(mdr *cloudwatch.MetricDataResult) {
+	if mdr.Label == nil {
+		return
+	}
+
 	if partialData, ok := q.partialDataSet[*mdr.Label]; ok {
 		partialData.Timestamps = append(partialData.Timestamps, mdr.Timestamps...)
 		partialData.Values = append(partialData.Values, mdr.Values...)
@@ -44,3 +52,8 @@ func (q *QueryRowResponse) AddArithmeticError(message *string) {
 	q.HasArithmeticError = true
 	q.ArithmeticErrorMessage = *message
 }
+
+func (q *QueryRowResponse) AddPermissionError(message *string) {
+	q.HasPermissionError = true
+	q.PermissionErrorMessage = *message
+}