CloudWatch/Logs: Don't group dataframes for non time series queries (#37998)

* Don't split response when there is no time field

* Refactor grouping to separate function

* Add test

pkg/tsdb/cloudwatch/live.go

@@ -270,33 +270,9 @@ func (e *cloudWatchExecutor) startLiveQuery(ctx context.Context, responseChannel
 
 		dataFrame.Name = query.RefID
 		dataFrame.RefID = query.RefID
-		var dataFrames data.Frames
-
-		// When a query of the form "stats ... by ..." is made, we want to return
-		// one series per group defined in the query, but due to the format
-		// the query response is in, there does not seem to be a way to tell
-		// by the response alone if/how the results should be grouped.
-		// Because of this, if the frontend sees that a "stats ... by ..." query is being made
-		// the "statsGroups" parameter is sent along with the query to the backend so that we
-		// can correctly group the CloudWatch logs response.
-		statsGroups := model.Get("statsGroups").MustStringArray()
-		if len(statsGroups) > 0 && len(dataFrame.Fields) > 0 {
-			groupedFrames, err := groupResults(dataFrame, statsGroups)
-			if err != nil {
-				return retryer.FuncError, err
-			}
-
-			dataFrames = groupedFrames
-		} else {
-			if dataFrame.Meta != nil {
-				dataFrame.Meta.PreferredVisualization = "logs"
-			} else {
-				dataFrame.Meta = &data.FrameMeta{
-					PreferredVisualization: "logs",
-				}
-			}
-
-			dataFrames = data.Frames{dataFrame}
+		dataFrames, err := groupResponseFrame(dataFrame, model.Get("statsGroups").MustStringArray())
+		if err != nil {
+			return retryer.FuncError, fmt.Errorf("failed to group dataframe response: %v", err)
 		}
 
 		responseChannel <- &backend.QueryDataResponse{
@@ -317,6 +293,54 @@ func (e *cloudWatchExecutor) startLiveQuery(ctx context.Context, responseChannel
 	}, maxAttempts, minRetryDelay, maxRetryDelay)
 }
 
+func groupResponseFrame(frame *data.Frame, statsGroups []string) (data.Frames, error) {
+	var dataFrames data.Frames
+
+	// When a query of the form "stats ... by ..." is made, we want to return
+	// one series per group defined in the query, but due to the format
+	// the query response is in, there does not seem to be a way to tell
+	// by the response alone if/how the results should be grouped.
+	// Because of this, if the frontend sees that a "stats ... by ..." query is being made
+	// the "statsGroups" parameter is sent along with the query to the backend so that we
+	// can correctly group the CloudWatch logs response.
+	// Check if we have time field though as it makes sense to split only for time series.
+	if hasTimeField(frame) {
+		if len(statsGroups) > 0 && len(frame.Fields) > 0 {
+			groupedFrames, err := groupResults(frame, statsGroups)
+			if err != nil {
+				return nil, err
+			}
+
+			dataFrames = groupedFrames
+		} else {
+			setPreferredVisType(frame, "logs")
+			dataFrames = data.Frames{frame}
+		}
+	} else {
+		dataFrames = data.Frames{frame}
+	}
+	return dataFrames, nil
+}
+
+func hasTimeField(frame *data.Frame) bool {
+	for _, field := range frame.Fields {
+		if field.Type() == data.FieldTypeNullableTime {
+			return true
+		}
+	}
+	return false
+}
+
+func setPreferredVisType(frame *data.Frame, visType data.VisType) {
+	if frame.Meta != nil {
+		frame.Meta.PreferredVisualization = visType
+	} else {
+		frame.Meta = &data.FrameMeta{
+			PreferredVisualization: visType,
+		}
+	}
+}
+
 // Service quotas client factory.
 //
 // Stubbable by tests.

pkg/tsdb/cloudwatch/live_test.go

@@ -0,0 +1,31 @@
+package cloudwatch
+
+import (
+	"testing"
+
+	"github.com/grafana/grafana-plugin-sdk-go/data"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGroupResponseFrame(t *testing.T) {
+	t.Run("Doesn't group results without time field", func(t *testing.T) {
+		frame := data.NewFrameOfFieldTypes("test", 0, data.FieldTypeString, data.FieldTypeInt32)
+		frame.AppendRow("val1", int32(10))
+		frame.AppendRow("val2", int32(20))
+		frame.AppendRow("val3", int32(30))
+
+		groupedFrame, err := groupResponseFrame(frame, []string{"something"})
+		require.NoError(t, err)
+		require.Equal(t, 3, groupedFrame[0].Rows())
+		require.Equal(t, []interface{}{"val1", "val2", "val3"}, asArray(groupedFrame[0].Fields[0]))
+		require.Equal(t, []interface{}{int32(10), int32(20), int32(30)}, asArray(groupedFrame[0].Fields[1]))
+	})
+}
+
+func asArray(field *data.Field) []interface{} {
+	var vals []interface{}
+	for i := 0; i < field.Len(); i++ {
+		vals = append(vals, field.At(i))
+	}
+	return vals
+}