CloudWatch Logs: Fixes grouping of results by numeric field (#26298)

* CloudWatch Logs: Fixes grouping of results by numeric field
Closes #25721 

pkg/tsdb/cloudwatch/log_query.go

 package cloudwatch
 
 import (
+	"fmt"
 	"sort"
 	"strconv"
 	"time"
 
+	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/service/cloudwatchlogs"
 	"github.com/grafana/grafana-plugin-sdk-go/data"
 )
@@ -108,9 +110,19 @@ func logsResultsToDataframes(response *cloudwatchlogs.GetQueryResultsOutput) (*d
 func groupResults(results *data.Frame, groupingFieldNames []string) ([]*data.Frame, error) {
 	groupingFields := make([]*data.Field, 0)
 
-	for _, field := range results.Fields {
+	for i, field := range results.Fields {
 		for _, groupingField := range groupingFieldNames {
 			if field.Name == groupingField {
+				// convert numeric grouping field to string field
+				if field.Type().Numeric() {
+					newField, err := numericFieldToStringField(field)
+					if err != nil {
+						return nil, err
+					}
+					results.Fields[i] = newField
+					field = newField
+				}
+
 				groupingFields = append(groupingFields, field)
 			}
 		}
@@ -153,3 +165,25 @@ func generateGroupKey(fields []*data.Field, row int) string {
 
 	return groupKey
 }
+
+func numericFieldToStringField(field *data.Field) (*data.Field, error) {
+	if !field.Type().Numeric() {
+		return nil, fmt.Errorf("field is not numeric")
+	}
+
+	strings := make([]*string, field.Len())
+	for i := 0; i < field.Len(); i++ {
+		floatVal, err := field.FloatAt(i)
+		if err != nil {
+			return nil, err
+		}
+
+		strVal := fmt.Sprintf("%g", floatVal)
+		strings[i] = aws.String(strVal)
+	}
+
+	newField := data.NewField(field.Name, field.Labels, strings)
+	newField.Config = field.Config
+
+	return newField, nil
+}

pkg/tsdb/cloudwatch/log_query_test.go

@@ -356,3 +356,124 @@ func TestGroupingResults(t *testing.T) {
 	require.NoError(t, err)
 	assert.ElementsMatch(t, expectedGroupedFrames, groupedResults)
 }
+
+func TestGroupingResultsWithNumericField(t *testing.T) {
+	timeA, err := time.Parse("2006-01-02 15:04:05.000", "2020-03-02 15:04:05.000")
+	require.NoError(t, err)
+	timeB, err := time.Parse("2006-01-02 15:04:05.000", "2020-03-02 16:04:05.000")
+	require.NoError(t, err)
+	timeC, err := time.Parse("2006-01-02 15:04:05.000", "2020-03-02 17:04:05.000")
+	require.NoError(t, err)
+	timeVals := []*time.Time{
+		&timeA, &timeA, &timeA, &timeB, &timeB, &timeB, &timeC, &timeC, &timeC,
+	}
+	timeField := data.NewField("@timestamp", data.Labels{}, timeVals)
+
+	httpResponseField := data.NewField("httpresponse", data.Labels{}, []*float64{
+		aws.Float64(400),
+		aws.Float64(404),
+		aws.Float64(500),
+		aws.Float64(400),
+		aws.Float64(404),
+		aws.Float64(500),
+		aws.Float64(400),
+		aws.Float64(404),
+		aws.Float64(500),
+	})
+
+	countField := data.NewField("count", data.Labels{}, []*string{
+		aws.String("100"),
+		aws.String("150"),
+		aws.String("20"),
+		aws.String("34"),
+		aws.String("57"),
+		aws.String("62"),
+		aws.String("105"),
+		aws.String("200"),
+		aws.String("99"),
+	})
+
+	fakeDataFrame := &data.Frame{
+		Name: "CloudWatchLogsResponse",
+		Fields: []*data.Field{
+			timeField,
+			httpResponseField,
+			countField,
+		},
+		RefID: "",
+	}
+
+	groupedTimeVals := []*time.Time{
+		&timeA, &timeB, &timeC,
+	}
+	groupedTimeField := data.NewField("@timestamp", data.Labels{}, groupedTimeVals)
+	groupedHttpResponseFieldA := data.NewField("httpresponse", data.Labels{}, []*string{
+		aws.String("400"),
+		aws.String("400"),
+		aws.String("400"),
+	})
+
+	groupedCountFieldA := data.NewField("count", data.Labels{}, []*string{
+		aws.String("100"),
+		aws.String("34"),
+		aws.String("105"),
+	})
+
+	groupedHttpResponseFieldB := data.NewField("httpresponse", data.Labels{}, []*string{
+		aws.String("404"),
+		aws.String("404"),
+		aws.String("404"),
+	})
+
+	groupedCountFieldB := data.NewField("count", data.Labels{}, []*string{
+		aws.String("150"),
+		aws.String("57"),
+		aws.String("200"),
+	})
+
+	groupedHttpResponseFieldC := data.NewField("httpresponse", data.Labels{}, []*string{
+		aws.String("500"),
+		aws.String("500"),
+		aws.String("500"),
+	})
+
+	groupedCountFieldC := data.NewField("count", data.Labels{}, []*string{
+		aws.String("20"),
+		aws.String("62"),
+		aws.String("99"),
+	})
+
+	expectedGroupedFrames := []*data.Frame{
+		{
+			Name: "400",
+			Fields: []*data.Field{
+				groupedTimeField,
+				groupedHttpResponseFieldA,
+				groupedCountFieldA,
+			},
+			RefID: "",
+		},
+		{
+			Name: "404",
+			Fields: []*data.Field{
+				groupedTimeField,
+				groupedHttpResponseFieldB,
+				groupedCountFieldB,
+			},
+			RefID: "",
+		},
+		{
+			Name: "500",
+			Fields: []*data.Field{
+				groupedTimeField,
+				groupedHttpResponseFieldC,
+				groupedCountFieldC,
+			},
+			RefID: "",
+		},
+	}
+
+	groupedResults, err := groupResults(fakeDataFrame, []string{"httpresponse"})
+	require.NoError(t, err)
+	assert.ElementsMatch(t, expectedGroupedFrames, groupedResults)
+}