CloudWatch: Display partial result in graph when max DP/call limit is reached (#21533)

* Return data and warning in case dp limit is reached

* Change warning text

pkg/tsdb/cloudwatch/query_transformer.go

@@ -71,6 +71,7 @@ func (e *CloudWatchExecutor) transformQueryResponseToQueryResult(cloudwatchRespo
 		timeSeries := make(tsdb.TimeSeriesSlice, 0)
 
 		requestExceededMaxLimit := false
+		partialData := false
 		queryMeta := []struct {
 			Expression, ID string
 		}{}
@@ -78,6 +79,7 @@ func (e *CloudWatchExecutor) transformQueryResponseToQueryResult(cloudwatchRespo
 		for _, response := range responses {
 			timeSeries = append(timeSeries, *response.series...)
 			requestExceededMaxLimit = requestExceededMaxLimit || response.RequestExceededMaxLimit
+			partialData = partialData || response.PartialData
 			queryMeta = append(queryMeta, struct {
 				Expression, ID string
 			}{
@@ -93,6 +95,11 @@ func (e *CloudWatchExecutor) transformQueryResponseToQueryResult(cloudwatchRespo
 		if requestExceededMaxLimit {
 			queryResult.ErrorString = "Cloudwatch GetMetricData error: Maximum number of allowed metrics exceeded. Your search may have been limited."
 		}
+
+		if partialData {
+			queryResult.ErrorString = "Cloudwatch GetMetricData error: Too many datapoints requested - your search have been limited. Please try to reduce the time range"
+		}
+
 		queryResult.Series = append(queryResult.Series, timeSeries...)
 		queryResult.Meta.Set("gmdMeta", queryMeta)
 		results[refID] = queryResult

pkg/tsdb/cloudwatch/response_parser.go

@@ -42,7 +42,7 @@ func (e *CloudWatchExecutor) parseResponse(metricDataOutputs []*cloudwatch.GetMe
 	cloudWatchResponses := make([]*cloudwatchResponse, 0)
 	for id, lr := range mdr {
 		response := &cloudwatchResponse{}
-		series, err := parseGetMetricDataTimeSeries(lr, queries[id])
+		series, partialData, err := parseGetMetricDataTimeSeries(lr, queries[id])
 		if err != nil {
 			return cloudWatchResponses, err
 		}
@@ -52,6 +52,7 @@ func (e *CloudWatchExecutor) parseResponse(metricDataOutputs []*cloudwatch.GetMe
 		response.RefId = queries[id].RefId
 		response.Id = queries[id].Id
 		response.RequestExceededMaxLimit = queries[id].RequestExceededMaxLimit
+		response.PartialData = partialData
 
 		cloudWatchResponses = append(cloudWatchResponses, response)
 	}
@@ -59,16 +60,18 @@ func (e *CloudWatchExecutor) parseResponse(metricDataOutputs []*cloudwatch.GetMe
 	return cloudWatchResponses, nil
 }
 
-func parseGetMetricDataTimeSeries(metricDataResults map[string]*cloudwatch.MetricDataResult, query *cloudWatchQuery) (*tsdb.TimeSeriesSlice, error) {
+func parseGetMetricDataTimeSeries(metricDataResults map[string]*cloudwatch.MetricDataResult, query *cloudWatchQuery) (*tsdb.TimeSeriesSlice, bool, error) {
 	result := tsdb.TimeSeriesSlice{}
+	partialData := false
 	for label, metricDataResult := range metricDataResults {
 		if *metricDataResult.StatusCode != "Complete" {
-			return nil, fmt.Errorf("too many datapoints requested in query %s. Please try to reduce the time range", query.RefId)
+			// return nil, fmt.Errorf("too many datapoints requested in query %s. Please try to reduce the time range", query.RefId)
+			partialData = true
 		}
 
 		for _, message := range metricDataResult.Messages {
 			if *message.Code == "ArithmeticError" {
-				return nil, fmt.Errorf("ArithmeticError in query %s: %s", query.RefId, *message.Value)
+				return nil, false, fmt.Errorf("ArithmeticError in query %s: %s", query.RefId, *message.Value)
 			}
 		}
 
@@ -102,7 +105,7 @@ func parseGetMetricDataTimeSeries(metricDataResults map[string]*cloudwatch.Metri
 		}
 		result = append(result, &series)
 	}
-	return &result, nil
+	return &result, partialData, nil
 }
 
 func formatAlias(query *cloudWatchQuery, stat string, dimensions map[string]string, label string) string {

pkg/tsdb/cloudwatch/response_parser_test.go

@@ -46,7 +46,7 @@ func TestCloudWatchResponseParser(t *testing.T) {
 				Period: 60,
 				Alias:  "{{namespace}}_{{metric}}_{{stat}}",
 			}
-			series, err := parseGetMetricDataTimeSeries(resp, query)
+			series, _, err := parseGetMetricDataTimeSeries(resp, query)
 			timeSeries := (*series)[0]
 
 			So(err, ShouldBeNil)

pkg/tsdb/cloudwatch/types.go

@@ -36,6 +36,7 @@ type cloudwatchResponse struct {
 	RefId                   string
 	Expression              string
 	RequestExceededMaxLimit bool
+	PartialData             bool
 }
 
 type queryError struct {