InfluxDB/Flux: support timeseries with a renamed time field (#25910)

pkg/tsdb/influxdb/flux/builder.go

@@ -2,6 +2,7 @@ package flux
 
 import (
 	"fmt"
+	"time"
 
 	"github.com/grafana/grafana-plugin-sdk-go/data"
 	"github.com/influxdata/influxdb-client-go/api/query"
@@ -38,6 +39,8 @@ type FrameBuilder struct {
 	maxSeries    int // max number of series
 	totalSeries  int
 	isTimeSeries bool
+	timeColumn   string // sometimes it is not `_time`
+	timeDisplay  string
 }
 
 func isTag(schk string) bool {
@@ -79,6 +82,7 @@ func (fb *FrameBuilder) Init(metadata *query.FluxTableMetadata) error {
 	fb.value = nil
 	fb.columns = make([]columnInfo, 0)
 	fb.isTimeSeries = false
+	fb.timeColumn = ""
 
 	for _, col := range columns {
 		switch {
@@ -97,7 +101,17 @@ func (fb *FrameBuilder) Init(metadata *query.FluxTableMetadata) error {
 		}
 	}
 
-	if !fb.isTimeSeries {
+	if fb.isTimeSeries {
+		col := getTimeSeriesTimeColumn(columns)
+		if col == nil {
+			return fmt.Errorf("no time column in timeSeries")
+		}
+		fb.timeColumn = col.Name()
+		fb.timeDisplay = "Time"
+		if "_time" != fb.timeColumn {
+			fb.timeDisplay = col.Name()
+		}
+	} else {
 		fb.labels = make([]string, 0)
 		for _, col := range columns {
 			converter, err := getConverter(col.DataType())
@@ -114,6 +128,23 @@ func (fb *FrameBuilder) Init(metadata *query.FluxTableMetadata) error {
 	return nil
 }
 
+func getTimeSeriesTimeColumn(columns []*query.FluxColumn) *query.FluxColumn {
+	// First look for '_time' column
+	for _, col := range columns {
+		if col.Name() == "_time" && col.DataType() == timeDatatypeRFC || col.DataType() == timeDatatypeRFCNano {
+			return col
+		}
+	}
+
+	// Then any time column
+	for _, col := range columns {
+		if col.DataType() == timeDatatypeRFC || col.DataType() == timeDatatypeRFCNano {
+			return col
+		}
+	}
+	return nil
+}
+
 // Append appends a single entry from an influxdb2 record to a data frame
 // Values are appended to _value
 // Tags are appended as labels
@@ -139,7 +170,7 @@ func (fb *FrameBuilder) Append(record *query.FluxRecord) error {
 				data.NewFieldFromFieldType(fb.value.OutputFieldType, 0),
 			)
 
-			fb.active.Fields[0].Name = "Time"
+			fb.active.Fields[0].Name = fb.timeDisplay
 			name, ok := record.ValueByKey("_field").(string)
 			if ok {
 				fb.active.Fields[1].Name = name
@@ -168,11 +199,16 @@ func (fb *FrameBuilder) Append(record *query.FluxRecord) error {
 	}
 
 	if fb.isTimeSeries {
+		time, ok := record.ValueByKey(fb.timeColumn).(time.Time)
+		if !ok {
+			return fmt.Errorf("unable to get time colum: %s", fb.timeColumn)
+		}
+
 		val, err := fb.value.Converter(record.Value())
 		if err != nil {
 			return err
 		}
-		fb.active.Fields[0].Append(record.Time())
+		fb.active.Fields[0].Append(time)
 		fb.active.Fields[1].Append(val)
 	} else {
 		// Table view

pkg/tsdb/influxdb/flux/executor_test.go

@@ -209,6 +209,51 @@ func TestAggregateGrouping(t *testing.T) {
 	})
 }
 
+func TestNonStandardTimeColumn(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("Time Column", func(t *testing.T) {
+		runner := &MockRunner{
+			testDataPath: "non_standard_time_column.csv",
+		}
+
+		dr := ExecuteQuery(ctx, QueryModel{MaxDataPoints: 100}, runner, 50)
+		if dr.Error != nil {
+			t.Fatal(dr.Error)
+		}
+
+		if len(dr.Frames) != 1 {
+			t.Fatal("Expected one frame")
+		}
+
+		str, _ := dr.Frames[0].StringTable(-1, -1)
+		fmt.Println(str)
+
+		// Dimensions: 2 Fields by 1 Rows
+		// +-----------------------------------------+------------------+
+		// | Name: _start_water                      | Name:            |
+		// | Labels:                                 | Labels: st=1     |
+		// | Type: []time.Time                       | Type: []*float64 |
+		// +-----------------------------------------+------------------+
+		// | 2020-06-28 17:50:13.012584046 +0000 UTC | 156.304          |
+		// +-----------------------------------------+------------------+
+
+		expectedFrame := data.NewFrame("",
+			data.NewField("_start_water", nil, []time.Time{
+				time.Date(2020, 6, 28, 17, 50, 13, 12584046, time.UTC),
+			}),
+			data.NewField("", map[string]string{"st": "1"}, []*float64{
+				pointer.Float64(156.304),
+			}),
+		)
+		expectedFrame.Meta = &data.FrameMeta{}
+
+		if diff := cmp.Diff(expectedFrame, dr.Frames[0], data.FrameTestCompareOptions()...); diff != "" {
+			t.Errorf("Result mismatch (-want +got):\n%s", diff)
+		}
+	})
+}
+
 func TestBuckets(t *testing.T) {
 	ctx := context.Background()
 

pkg/tsdb/influxdb/flux/testdata/non_standard_time_column.csv

+#group,false,false,true,true,false,true
+#datatype,string,long,dateTime:RFC3339,dateTime:RFC3339,double,string
+#default,_result,,,,,
+,result,table,_start_water,_stop_water,_value,st
+,,0,2020-06-28T17:50:13.012584046Z,2020-06-29T17:50:13.012584046Z,156.304,1