Support Druid GroupBy queries (#52)

Author: jmichalak-fluxninja

pkg/tsdb/druid/druid.go

@@ -486,7 +486,12 @@ func (ds *Service) executeQuery(
 		}
 		resultFramer = &r
 	case "groupBy":
-		return nil, errors.New("not implemented")
+		var r result.GroupByResult
+		_, err := s.client.Query().Execute(q, &r, headers)
+		if err != nil {
+			return nil, fmt.Errorf("Query error: %w", err)
+		}
+		resultFramer = &r
 	case "scan":
 		q.(*druidquery.Scan).SetResultFormat("compactedList")
 		return nil, errors.New("not implemented")

pkg/tsdb/druid/result/groupby.go

@@ -0,0 +1,74 @@
+package result
+
+import (
+	"sort"
+	"time"
+
+	"github.com/grafana/grafana-plugin-sdk-go/data"
+)
+
+type GroupByResult []GroupByRecord
+
+// Frame returns data formatted as Grafana Frame.
+func (t *GroupByResult) Frame() *data.Frame {
+	columns := t.Columns()
+	fields := make([]*data.Field, len(columns))
+	for i, column := range columns {
+		labels := data.Labels{}
+		fields[i] = data.NewField(column, labels, t.Values(column))
+	}
+	return data.NewFrame("", fields...)
+}
+
+// Columns returns list of columns. It calls `Columns()` on first record. If
+// no records are available it returns nil.
+func (t *GroupByResult) Columns() []string {
+	for _, r := range *t {
+		return r.Columns()
+	}
+	return nil
+}
+
+// Values returns all values for given column.
+func (t *GroupByResult) Values(column string) interface{} {
+	if len(*t) == 0 {
+		return nil
+	}
+	results := make([]interface{}, len(*t))
+	for i, r := range *t {
+		results[i] = r.Value(column)
+	}
+	return toTypedResults(results)
+}
+
+type GroupByRecord struct {
+	Timestamp time.Time              `json:"timestamp"`
+	Event     map[string]interface{} `json:"event"`
+}
+
+// Columns returns list of columns for given record.
+// The first column will always be "timestamp" followed by other columns sorted
+// alphabetically.
+func (t *GroupByRecord) Columns() []string {
+	columns := make([]string, len(t.Event)+1)
+	columns[0] = timestampColumn
+	i := 1
+	for c := range t.Event {
+		columns[i] = c
+		i++
+	}
+	sort.Strings(columns[1:])
+	return columns
+}
+
+// Value returns value for given column.
+func (t *GroupByRecord) Value(column string) interface{} {
+	if column == timestampColumn {
+		return t.Timestamp
+	}
+	v, ok := t.Event[column]
+	if !ok {
+		return nil
+	}
+	return v
+}

pkg/tsdb/druid/result/groupby_test.go

@@ -0,0 +1,60 @@
+package result
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"github.com/grafana/grafana-plugin-sdk-go/data"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGroupByResultUnmarshal(t *testing.T) {
+	input := []byte(`[
+		{
+			"timestamp": "2022-10-14T08:08:10.000Z",
+			"event": {
+				"dog_count": 47,
+				"dog_rate": 2.083,
+				"dog_name": "foo"
+			}
+		},
+		{
+			"timestamp": "2022-10-14T08:08:11.000Z",
+			"event": {
+				"dog_count": 75,
+				"dog_rate": 3.846,
+				"dog_name": "bar"
+			}
+		}
+	]`)
+
+	var res GroupByResult
+	err := json.Unmarshal(input, &res)
+	assert.Nil(t, err, "Failed to unmarshal response")
+	assert.Equal(t, len(res), 2, "Wrong number of unmarshalled results")
+	frame := res.Frame()
+	assert.Equal(t, len(frame.Fields), 4, "Wrong number of framed fields")
+
+	assert.Equal(t, frame.Fields[0].Name, "timestamp")
+	assert.Equal(t, frame.Fields[0].Type(), data.FieldTypeTime)
+	assert.Equal(t, frame.Fields[0].Len(), 2)
+	assert.Equal(t, frame.Fields[0].At(0), time.Time(time.Date(2022, time.October, 14, 8, 8, 10, 0, time.UTC)))
+	assert.Equal(t, frame.Fields[0].At(1), time.Time(time.Date(2022, time.October, 14, 8, 8, 11, 0, time.UTC)))
+
+	assert.Equal(t, frame.Fields[1].Name, "dog_count")
+	assert.Equal(t, frame.Fields[1].Type(), data.FieldTypeFloat64)
+	assert.Equal(t, frame.Fields[1].At(0), float64(47))
+	assert.Equal(t, frame.Fields[1].At(1), float64(75))
+
+	assert.Equal(t, frame.Fields[2].Name, "dog_name")
+	assert.Equal(t, frame.Fields[2].Type(), data.FieldTypeString)
+	assert.Equal(t, frame.Fields[2].At(0), "foo")
+	assert.Equal(t, frame.Fields[2].At(1), "bar")
+
+	assert.Equal(t, frame.Fields[3].Name, "dog_rate")
+	assert.Equal(t, frame.Fields[3].Type(), data.FieldTypeFloat64)
+	assert.Equal(t, frame.Fields[3].At(0), float64(2.083))
+	assert.Equal(t, frame.Fields[3].At(1), float64(3.846))
+
+}

pkg/tsdb/druid/result/topn.go

@@ -46,7 +46,7 @@ type TopNRecord struct {
 // Columns returns list of columns for given record.
 // It assumes that every map from Result has the same columns, so it gets
 // the list from first item.
-// The first column will always be "timestamp" followed by other columns sorter
+// The first column will always be "timestamp" followed by other columns sorted
 // alphabetically.
 func (t *TopNRecord) Columns() []string {
 	for _, result := range t.Result {