Chore: Reduce TSDB Go code complexity (#26401)

* tsdb: Make code less complex

pkg/tsdb/cloudmonitoring/cloudmonitoring.go

@@ -502,11 +502,43 @@ func (e *CloudMonitoringExecutor) unmarshalResponse(res *http.Response) (cloudMo
 	return data, nil
 }
 
+func handleDistributionSeries(series timeSeries, defaultMetricName string, seriesLabels map[string]string,
+	query *cloudMonitoringQuery, queryRes *tsdb.QueryResult) {
+	points := make([]tsdb.TimePoint, 0)
+	for i := len(series.Points) - 1; i >= 0; i-- {
+		point := series.Points[i]
+		value := point.Value.DoubleValue
+
+		if series.ValueType == "INT64" {
+			parsedValue, err := strconv.ParseFloat(point.Value.IntValue, 64)
+			if err == nil {
+				value = parsedValue
+			}
+		}
+
+		if series.ValueType == "BOOL" {
+			if point.Value.BoolValue {
+				value = 1
+			} else {
+				value = 0
+			}
+		}
+
+		points = append(points, tsdb.NewTimePoint(null.FloatFrom(value), float64((point.Interval.EndTime).Unix())*1000))
+	}
+
+	metricName := formatLegendKeys(series.Metric.Type, defaultMetricName, seriesLabels, nil, query)
+
+	queryRes.Series = append(queryRes.Series, &tsdb.TimeSeries{
+		Name:   metricName,
+		Points: points,
+	})
+}
+
 func (e *CloudMonitoringExecutor) parseResponse(queryRes *tsdb.QueryResult, data cloudMonitoringResponse, query *cloudMonitoringQuery) error {
 	labels := make(map[string]map[string]bool)
 
 	for _, series := range data.TimeSeries {
-		points := make([]tsdb.TimePoint, 0)
 		seriesLabels := make(map[string]string)
 		defaultMetricName := series.Metric.Type
 		labels["resource.type"] = map[string]bool{series.Resource.Type: true}
@@ -566,34 +598,7 @@ func (e *CloudMonitoringExecutor) parseResponse(queryRes *tsdb.QueryResult, data
 
 		// reverse the order to be ascending
 		if series.ValueType != "DISTRIBUTION" {
-			for i := len(series.Points) - 1; i >= 0; i-- {
-				point := series.Points[i]
-				value := point.Value.DoubleValue
-
-				if series.ValueType == "INT64" {
-					parsedValue, err := strconv.ParseFloat(point.Value.IntValue, 64)
-					if err == nil {
-						value = parsedValue
-					}
-				}
-
-				if series.ValueType == "BOOL" {
-					if point.Value.BoolValue {
-						value = 1
-					} else {
-						value = 0
-					}
-				}
-
-				points = append(points, tsdb.NewTimePoint(null.FloatFrom(value), float64((point.Interval.EndTime).Unix())*1000))
-			}
-
-			metricName := formatLegendKeys(series.Metric.Type, defaultMetricName, seriesLabels, nil, query)
-
-			queryRes.Series = append(queryRes.Series, &tsdb.TimeSeries{
-				Name:   metricName,
-				Points: points,
-			})
+			handleDistributionSeries(series, defaultMetricName, seriesLabels, query, queryRes)
 		} else {
 			buckets := make(map[int]*tsdb.TimeSeries)
 

pkg/tsdb/cloudmonitoring/types.go

@@ -65,7 +65,11 @@ type (
 	}
 
 	cloudMonitoringResponse struct {
-		TimeSeries []struct {
+		TimeSeries []timeSeries `json:"timeSeries"`
+	}
+)
+
+type timeSeries struct {
 	Metric struct {
 		Labels map[string]string `json:"labels"`
 		Type   string            `json:"type"`
@@ -105,6 +109,4 @@ type (
 			} `json:"distributionValue"`
 		} `json:"value"`
 	} `json:"points"`
-		} `json:"timeSeries"`
-	}
-)
+}

pkg/tsdb/elasticsearch/time_series_query.go

@@ -24,9 +24,6 @@ var newTimeSeriesQuery = func(client es.Client, tsdbQuery *tsdb.TsdbQuery, inter
 }
 
 func (e *timeSeriesQuery) execute() (*tsdb.Response, error) {
-	result := &tsdb.Response{}
-	result.Results = make(map[string]*tsdb.QueryResult)
-
 	tsQueryParser := newTimeSeriesQueryParser()
 	queries, err := tsQueryParser.parse(e.tsdbQuery)
 	if err != nil {
@@ -37,12 +34,35 @@ func (e *timeSeriesQuery) execute() (*tsdb.Response, error) {
 
 	from := fmt.Sprintf("%d", e.tsdbQuery.TimeRange.GetFromAsMsEpoch())
 	to := fmt.Sprintf("%d", e.tsdbQuery.TimeRange.GetToAsMsEpoch())
-
+	result := &tsdb.Response{
+		Results: make(map[string]*tsdb.QueryResult),
+	}
 	for _, q := range queries {
-		minInterval, err := e.client.GetMinInterval(q.Interval)
+		if err := e.processQuery(q, ms, from, to, result); err != nil {
+			return nil, err
+		}
+	}
+
+	req, err := ms.Build()
 	if err != nil {
 		return nil, err
 	}
+
+	res, err := e.client.ExecuteMultisearch(req)
+	if err != nil {
+		return nil, err
+	}
+
+	rp := newResponseParser(res.Responses, queries, res.DebugInfo)
+	return rp.getTimeSeries()
+}
+
+func (e *timeSeriesQuery) processQuery(q *Query, ms *es.MultiSearchRequestBuilder, from, to string,
+	result *tsdb.Response) error {
+	minInterval, err := e.client.GetMinInterval(q.Interval)
+	if err != nil {
+		return err
+	}
 	interval := e.intervalCalculator.Calculate(e.tsdbQuery.TimeRange, minInterval)
 
 	b := ms.Search(interval)
@@ -61,13 +81,13 @@ func (e *timeSeriesQuery) execute() (*tsdb.Response, error) {
 				Error:       fmt.Errorf("invalid query, missing metrics and aggregations"),
 				ErrorString: "invalid query, missing metrics and aggregations",
 			}
-				continue
+			return nil
 		}
 		metric := q.Metrics[0]
 		b.Size(metric.Settings.Get("size").MustInt(500))
 		b.SortDesc("@timestamp", "boolean")
 		b.AddDocValueField("@timestamp")
-			continue
+		return nil
 	}
 
 	aggBuilder := b.Agg()
@@ -152,20 +172,8 @@ func (e *timeSeriesQuery) execute() (*tsdb.Response, error) {
 			})
 		}
 	}
-	}
-
-	req, err := ms.Build()
-	if err != nil {
-		return nil, err
-	}
-
-	res, err := e.client.ExecuteMultisearch(req)
-	if err != nil {
-		return nil, err
-	}
 
-	rp := newResponseParser(res.Responses, queries, res.DebugInfo)
-	return rp.getTimeSeries()
+	return nil
 }
 
 func addDateHistogramAgg(aggBuilder es.AggBuilder, bucketAgg *BucketAgg, timeFrom, timeTo string) es.AggBuilder {

pkg/tsdb/sqleng/sql_engine.go

@@ -276,45 +276,60 @@ func (e *sqlQueryEndpoint) transformToTable(query *tsdb.Query, rows *core.Rows,
 	return nil
 }
 
-func (e *sqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.Rows, result *tsdb.QueryResult, tsdbQuery *tsdb.TsdbQuery) error {
-	pointsBySeries := make(map[string]*tsdb.TimeSeries)
-	seriesByQueryOrder := list.New()
-
+func newProcessCfg(query *tsdb.Query, tsdbQuery *tsdb.TsdbQuery, rows *core.Rows) (*processCfg, error) {
 	columnNames, err := rows.Columns()
 	if err != nil {
-		return err
+		return nil, err
 	}
-
 	columnTypes, err := rows.ColumnTypes()
 	if err != nil {
-		return err
+		return nil, err
 	}
 
-	rowCount := 0
-	timeIndex := -1
-	metricIndex := -1
-	metricPrefix := false
-	var metricPrefixValue string
+	fillMissing := query.Model.Get("fill").MustBool(false)
+
+	cfg := &processCfg{
+		rowCount:           0,
+		columnTypes:        columnTypes,
+		columnNames:        columnNames,
+		rows:               rows,
+		timeIndex:          -1,
+		metricIndex:        -1,
+		metricPrefix:       false,
+		fillMissing:        fillMissing,
+		seriesByQueryOrder: list.New(),
+		pointsBySeries:     make(map[string]*tsdb.TimeSeries),
+		tsdbQuery:          tsdbQuery,
+	}
+	return cfg, nil
+}
+
+func (e *sqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.Rows, result *tsdb.QueryResult,
+	tsdbQuery *tsdb.TsdbQuery) error {
+	cfg, err := newProcessCfg(query, tsdbQuery, rows)
+	if err != nil {
+		return err
+	}
 
 	// check columns of resultset: a column named time is mandatory
 	// the first text column is treated as metric name unless a column named metric is present
-	for i, col := range columnNames {
+	for i, col := range cfg.columnNames {
 		for _, tc := range e.timeColumnNames {
 			if col == tc {
-				timeIndex = i
+				cfg.timeIndex = i
 				continue
 			}
 		}
 		switch col {
 		case "metric":
-			metricIndex = i
+			cfg.metricIndex = i
 		default:
-			if metricIndex == -1 {
-				columnType := columnTypes[i].DatabaseTypeName()
+			if cfg.metricIndex == -1 {
+				columnType := cfg.columnTypes[i].DatabaseTypeName()
 
 				for _, mct := range e.metricColumnTypes {
 					if columnType == mct {
-						metricIndex = i
+						cfg.metricIndex = i
 						continue
 					}
 				}
@@ -323,41 +338,92 @@ func (e *sqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.R
 	}
 
 	// use metric column as prefix with multiple value columns
-	if metricIndex != -1 && len(columnNames) > 3 {
-		metricPrefix = true
+	if cfg.metricIndex != -1 && len(cfg.columnNames) > 3 {
+		cfg.metricPrefix = true
 	}
 
-	if timeIndex == -1 {
+	if cfg.timeIndex == -1 {
 		return fmt.Errorf("Found no column named %s", strings.Join(e.timeColumnNames, " or "))
 	}
 
-	fillMissing := query.Model.Get("fill").MustBool(false)
-	var fillInterval float64
-	fillValue := null.Float{}
-	fillPrevious := false
-
-	if fillMissing {
-		fillInterval = query.Model.Get("fillInterval").MustFloat64() * 1000
+	if cfg.fillMissing {
+		cfg.fillInterval = query.Model.Get("fillInterval").MustFloat64() * 1000
 		switch query.Model.Get("fillMode").MustString() {
 		case "null":
 		case "previous":
-			fillPrevious = true
+			cfg.fillPrevious = true
 		case "value":
-			fillValue.Float64 = query.Model.Get("fillValue").MustFloat64()
-			fillValue.Valid = true
+			cfg.fillValue.Float64 = query.Model.Get("fillValue").MustFloat64()
+			cfg.fillValue.Valid = true
 		}
 	}
 
 	for rows.Next() {
+		if err := e.processRow(cfg); err != nil {
+			return err
+		}
+	}
+
+	for elem := cfg.seriesByQueryOrder.Front(); elem != nil; elem = elem.Next() {
+		key := elem.Value.(string)
+		result.Series = append(result.Series, cfg.pointsBySeries[key])
+		if !cfg.fillMissing {
+			continue
+		}
+
+		series := cfg.pointsBySeries[key]
+		// fill in values from last fetched value till interval end
+		intervalStart := series.Points[len(series.Points)-1][1].Float64
+		intervalEnd := float64(tsdbQuery.TimeRange.MustGetTo().UnixNano() / 1e6)
+
+		if cfg.fillPrevious {
+			if len(series.Points) > 0 {
+				cfg.fillValue = series.Points[len(series.Points)-1][0]
+			} else {
+				cfg.fillValue.Valid = false
+			}
+		}
+
+		// align interval start
+		intervalStart = math.Floor(intervalStart/cfg.fillInterval) * cfg.fillInterval
+		for i := intervalStart + cfg.fillInterval; i < intervalEnd; i += cfg.fillInterval {
+			series.Points = append(series.Points, tsdb.TimePoint{cfg.fillValue, null.FloatFrom(i)})
+			cfg.rowCount++
+		}
+	}
+
+	result.Meta.Set("rowCount", cfg.rowCount)
+	return nil
+}
+
+type processCfg struct {
+	rowCount           int
+	columnTypes        []*sql.ColumnType
+	columnNames        []string
+	rows               *core.Rows
+	timeIndex          int
+	metricIndex        int
+	metricPrefix       bool
+	metricPrefixValue  string
+	fillMissing        bool
+	pointsBySeries     map[string]*tsdb.TimeSeries
+	seriesByQueryOrder *list.List
+	fillValue          null.Float
+	tsdbQuery          *tsdb.TsdbQuery
+	fillInterval       float64
+	fillPrevious       bool
+}
+
+func (e *sqlQueryEndpoint) processRow(cfg *processCfg) error {
 	var timestamp float64
 	var value null.Float
 	var metric string
 
-		if rowCount > rowLimit {
+	if cfg.rowCount > rowLimit {
 		return fmt.Errorf("query row limit exceeded, limit %d", rowLimit)
 	}
 
-		values, err := e.queryResultTransformer.TransformQueryResult(columnTypes, rows)
+	values, err := e.queryResultTransformer.TransformQueryResult(cfg.columnTypes, cfg.rows)
 	if err != nil {
 		return err
 	}
@@ -365,31 +431,34 @@ func (e *sqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.R
 	// converts column named time to unix timestamp in milliseconds to make
 	// native mysql datetime types and epoch dates work in
 	// annotation and table queries.
-		ConvertSqlTimeColumnToEpochMs(values, timeIndex)
+	ConvertSqlTimeColumnToEpochMs(values, cfg.timeIndex)
 
-		switch columnValue := values[timeIndex].(type) {
+	switch columnValue := values[cfg.timeIndex].(type) {
 	case int64:
 		timestamp = float64(columnValue)
 	case float64:
 		timestamp = columnValue
 	default:
-			return fmt.Errorf("Invalid type for column time, must be of type timestamp or unix timestamp, got: %T %v", columnValue, columnValue)
+		return fmt.Errorf("invalid type for column time, must be of type timestamp or unix timestamp, got: %T %v",
+			columnValue, columnValue)
 	}
 
-		if metricIndex >= 0 {
-			if columnValue, ok := values[metricIndex].(string); ok {
-				if metricPrefix {
-					metricPrefixValue = columnValue
+	if cfg.metricIndex >= 0 {
+		if columnValue, ok := values[cfg.metricIndex].(string); ok {
+			if cfg.metricPrefix {
+				cfg.metricPrefixValue = columnValue
 			} else {
 				metric = columnValue
 			}
 		} else {
-				return fmt.Errorf("Column metric must be of type %s. metric column name: %s type: %s but datatype is %T", strings.Join(e.metricColumnTypes, ", "), columnNames[metricIndex], columnTypes[metricIndex].DatabaseTypeName(), values[metricIndex])
+			return fmt.Errorf("column metric must be of type %s. metric column name: %s type: %s but datatype is %T",
+				strings.Join(e.metricColumnTypes, ", "), cfg.columnNames[cfg.metricIndex],
+				cfg.columnTypes[cfg.metricIndex].DatabaseTypeName(), values[cfg.metricIndex])
 		}
 	}
 
-		for i, col := range columnNames {
-			if i == timeIndex || i == metricIndex {
+	for i, col := range cfg.columnNames {
+		if i == cfg.timeIndex || i == cfg.metricIndex {
 			continue
 		}
 
@@ -397,41 +466,41 @@ func (e *sqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.R
 			return err
 		}
 
-			if metricIndex == -1 {
+		if cfg.metricIndex == -1 {
 			metric = col
-			} else if metricPrefix {
-				metric = metricPrefixValue + " " + col
+		} else if cfg.metricPrefix {
+			metric = cfg.metricPrefixValue + " " + col
 		}
 
-			series, exist := pointsBySeries[metric]
+		series, exist := cfg.pointsBySeries[metric]
 		if !exist {
 			series = &tsdb.TimeSeries{Name: metric}
-				pointsBySeries[metric] = series
-				seriesByQueryOrder.PushBack(metric)
+			cfg.pointsBySeries[metric] = series
+			cfg.seriesByQueryOrder.PushBack(metric)
 		}
 
-			if fillMissing {
+		if cfg.fillMissing {
 			var intervalStart float64
 			if !exist {
-					intervalStart = float64(tsdbQuery.TimeRange.MustGetFrom().UnixNano() / 1e6)
+				intervalStart = float64(cfg.tsdbQuery.TimeRange.MustGetFrom().UnixNano() / 1e6)
 			} else {
-					intervalStart = series.Points[len(series.Points)-1][1].Float64 + fillInterval
+				intervalStart = series.Points[len(series.Points)-1][1].Float64 + cfg.fillInterval
 			}
 
-				if fillPrevious {
+			if cfg.fillPrevious {
 				if len(series.Points) > 0 {
-						fillValue = series.Points[len(series.Points)-1][0]
+					cfg.fillValue = series.Points[len(series.Points)-1][0]
 				} else {
-						fillValue.Valid = false
+					cfg.fillValue.Valid = false
 				}
 			}
 
 			// align interval start
-				intervalStart = math.Floor(intervalStart/fillInterval) * fillInterval
+			intervalStart = math.Floor(intervalStart/cfg.fillInterval) * cfg.fillInterval
 
-				for i := intervalStart; i < timestamp; i += fillInterval {
-					series.Points = append(series.Points, tsdb.TimePoint{fillValue, null.FloatFrom(i)})
-					rowCount++
+			for i := intervalStart; i < timestamp; i += cfg.fillInterval {
+				series.Points = append(series.Points, tsdb.TimePoint{cfg.fillValue, null.FloatFrom(i)})
+				cfg.rowCount++
 			}
 		}
 
@@ -441,36 +510,7 @@ func (e *sqlQueryEndpoint) transformToTimeSeries(query *tsdb.Query, rows *core.R
 			e.log.Debug("Rows", "metric", metric, "time", timestamp, "value", value)
 		}
 	}
-	}
-
-	for elem := seriesByQueryOrder.Front(); elem != nil; elem = elem.Next() {
-		key := elem.Value.(string)
-		result.Series = append(result.Series, pointsBySeries[key])
-
-		if fillMissing {
-			series := pointsBySeries[key]
-			// fill in values from last fetched value till interval end
-			intervalStart := series.Points[len(series.Points)-1][1].Float64
-			intervalEnd := float64(tsdbQuery.TimeRange.MustGetTo().UnixNano() / 1e6)
-
-			if fillPrevious {
-				if len(series.Points) > 0 {
-					fillValue = series.Points[len(series.Points)-1][0]
-				} else {
-					fillValue.Valid = false
-				}
-			}
-
-			// align interval start
-			intervalStart = math.Floor(intervalStart/fillInterval) * fillInterval
-			for i := intervalStart + fillInterval; i < intervalEnd; i += fillInterval {
-				series.Points = append(series.Points, tsdb.TimePoint{fillValue, null.FloatFrom(i)})
-				rowCount++
-			}
-		}
-	}
 
-	result.Meta.Set("rowCount", rowCount)
 	return nil
 }
 
@@ -526,6 +566,7 @@ func ConvertSqlTimeColumnToEpochMs(values tsdb.RowValues, timeIndex int) {
 }
 
 // ConvertSqlValueColumnToFloat converts timeseries value column to float.
+//nolint: gocyclo
 func ConvertSqlValueColumnToFloat(columnName string, columnValue interface{}) (null.Float, error) {
 	var value null.Float