CloudWatch: Clean up code (#24666)

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/tsdb/cloudwatch/time_series_query.go

@@ -10,107 +10,108 @@ import (
 )
 
 func (e *CloudWatchExecutor) executeTimeSeriesQuery(ctx context.Context, queryContext *tsdb.TsdbQuery) (*tsdb.Response, error) {
-	results := &tsdb.Response{
-		Results: make(map[string]*tsdb.QueryResult),
-	}
-
 	startTime, err := queryContext.TimeRange.ParseFrom()
 	if err != nil {
 		return nil, err
 	}
-
 	endTime, err := queryContext.TimeRange.ParseTo()
 	if err != nil {
 		return nil, err
 	}
-
 	if !startTime.Before(endTime) {
-		return nil, fmt.Errorf("Invalid time range: Start time must be before end time")
+		return nil, fmt.Errorf("invalid time range: start time must be before end time")
 	}
 
 	requestQueriesByRegion, err := e.parseQueries(queryContext, startTime, endTime)
 	if err != nil {
-		return results, err
+		return nil, err
 	}
+
+	if len(requestQueriesByRegion) == 0 {
+		return &tsdb.Response{
+			Results: make(map[string]*tsdb.QueryResult),
+		}, nil
+	}
+
 	resultChan := make(chan *tsdb.QueryResult, len(queryContext.Queries))
 	eg, ectx := errgroup.WithContext(ctx)
-
-	if len(requestQueriesByRegion) > 0 {
-		for r, q := range requestQueriesByRegion {
-			requestQueries := q
-			region := r
-			eg.Go(func() error {
-				defer func() {
-					if err := recover(); err != nil {
-						plog.Error("Execute Get Metric Data Query Panic", "error", err, "stack", log.Stack(1))
-						if theErr, ok := err.(error); ok {
-							resultChan <- &tsdb.QueryResult{
-								Error: theErr,
-							}
-						}
-					}
-				}()
-
-				client, err := e.getClient(region)
-				if err != nil {
-					return err
-				}
-
-				queries, err := e.transformRequestQueriesToCloudWatchQueries(requestQueries)
-				if err != nil {
-					for _, query := range requestQueries {
+	for r, q := range requestQueriesByRegion {
+		requestQueries := q
+		region := r
+		eg.Go(func() error {
+			defer func() {
+				if err := recover(); err != nil {
+					plog.Error("Execute Get Metric Data Query Panic", "error", err, "stack", log.Stack(1))
+					if theErr, ok := err.(error); ok {
 						resultChan <- &tsdb.QueryResult{
-							RefId: query.RefId,
-							Error: err,
+							Error: theErr,
 						}
 					}
-					return nil
 				}
+			}()
 
-				metricDataInput, err := e.buildMetricDataInput(startTime, endTime, queries)
-				if err != nil {
-					return err
-				}
+			client, err := e.getClient(region)
+			if err != nil {
+				return err
+			}
 
-				cloudwatchResponses := make([]*cloudwatchResponse, 0)
-				mdo, err := e.executeRequest(ectx, client, metricDataInput)
-				if err != nil {
-					for _, query := range requestQueries {
-						resultChan <- &tsdb.QueryResult{
-							RefId: query.RefId,
-							Error: err,
-						}
+			queries, err := e.transformRequestQueriesToCloudWatchQueries(requestQueries)
+			if err != nil {
+				for _, query := range requestQueries {
+					resultChan <- &tsdb.QueryResult{
+						RefId: query.RefId,
+						Error: err,
 					}
-					return nil
-				}
-
-				responses, err := e.parseResponse(mdo, queries)
-				if err != nil {
-					for _, query := range requestQueries {
-						resultChan <- &tsdb.QueryResult{
-							RefId: query.RefId,
-							Error: err,
-						}
-					}
-					return nil
-				}
-				cloudwatchResponses = append(cloudwatchResponses, responses...)
-				res := e.transformQueryResponseToQueryResult(cloudwatchResponses)
-				for _, queryRes := range res {
-					resultChan <- queryRes
 				}
 				return nil
-			})
-		}
-	}
+			}
 
+			metricDataInput, err := e.buildMetricDataInput(startTime, endTime, queries)
+			if err != nil {
+				return err
+			}
+
+			cloudwatchResponses := make([]*cloudwatchResponse, 0)
+			mdo, err := e.executeRequest(ectx, client, metricDataInput)
+			if err != nil {
+				for _, query := range requestQueries {
+					resultChan <- &tsdb.QueryResult{
+						RefId: query.RefId,
+						Error: err,
+					}
+				}
+				return nil
+			}
+
+			responses, err := e.parseResponse(mdo, queries)
+			if err != nil {
+				for _, query := range requestQueries {
+					resultChan <- &tsdb.QueryResult{
+						RefId: query.RefId,
+						Error: err,
+					}
+				}
+				return nil
+			}
+
+			cloudwatchResponses = append(cloudwatchResponses, responses...)
+			res := e.transformQueryResponseToQueryResult(cloudwatchResponses)
+			for _, queryRes := range res {
+				resultChan <- queryRes
+			}
+			return nil
+		})
+	}
 	if err := eg.Wait(); err != nil {
 		return nil, err
 	}
 	close(resultChan)
+
+	results := &tsdb.Response{
+		Results: make(map[string]*tsdb.QueryResult),
+	}
 	for result := range resultChan {
 		results.Results[result.RefId] = result
 	}
-
 	return results, nil
 }