Implement removeAboveValue/removeBelowValue

pkg/datasource/functions.go

@@ -60,6 +60,8 @@ func init() {
 		"groupBy":          applyGroupBy,
 		"scale":            applyScale,
 		"offset":           applyOffset,
+		"removeAboveValue": applyRemoveAboveValue,
+		"removeBelowValue": applyRemoveBelowValue,
 		"transformNull":    applyTransformNull,
 		"percentile":       applyPercentile,
 		"timeShift":        applyTimeShiftPost,
@@ -203,6 +205,26 @@ func applyOffset(series timeseries.TimeSeries, params ...interface{}) (timeserie
 	return series.Transform(transformFunc), nil
 }
 
+func applyRemoveAboveValue(series timeseries.TimeSeries, params ...interface{}) (timeseries.TimeSeries, error) {
+	threshold, err := MustFloat64(params[0])
+	if err != nil {
+		return nil, errParsingFunctionParam(err)
+	}
+
+	transformFunc := timeseries.TransformRemoveAboveValue(threshold)
+	return series.Transform(transformFunc), nil
+}
+
+func applyRemoveBelowValue(series timeseries.TimeSeries, params ...interface{}) (timeseries.TimeSeries, error) {
+	threshold, err := MustFloat64(params[0])
+	if err != nil {
+		return nil, errParsingFunctionParam(err)
+	}
+
+	transformFunc := timeseries.TransformRemoveBelowValue(threshold)
+	return series.Transform(transformFunc), nil
+}
+
 func applyTransformNull(series timeseries.TimeSeries, params ...interface{}) (timeseries.TimeSeries, error) {
 	nullValue, err := MustFloat64(params[0])
 	if err != nil {

pkg/timeseries/transform_functions.go

@@ -4,53 +4,55 @@ import "time"
 
 func TransformScale(factor float64) TransformFunc {
 	return func(point TimePoint) TimePoint {
-		return transformScale(point, factor)
-	}
-}
-
-func TransformOffset(offset float64) TransformFunc {
-	return func(point TimePoint) TimePoint {
-		return transformOffset(point, offset)
-	}
-}
-
-func TransformNull(nullValue float64) TransformFunc {
-	return func(point TimePoint) TimePoint {
-		return transformNull(point, nullValue)
-	}
-}
-
-func TransformShiftTime(interval time.Duration) TransformFunc {
-	return func(point TimePoint) TimePoint {
-		return transformShiftTime(point, interval)
-	}
-}
-
-func transformScale(point TimePoint, factor float64) TimePoint {
 		if point.Value != nil {
 			newValue := *point.Value * factor
 			point.Value = &newValue
 		}
 		return point
+	}
 }
 
-func transformOffset(point TimePoint, offset float64) TimePoint {
+func TransformOffset(offset float64) TransformFunc {
+	return func(point TimePoint) TimePoint {
 		if point.Value != nil {
 			newValue := *point.Value + offset
 			point.Value = &newValue
 		}
 		return point
+	}
 }
 
-func transformShiftTime(point TimePoint, interval time.Duration) TimePoint {
-	shiftedTime := point.Time.Add(interval)
-	point.Time = shiftedTime
-	return point
-}
-
-func transformNull(point TimePoint, nullValue float64) TimePoint {
+func TransformNull(nullValue float64) TransformFunc {
+	return func(point TimePoint) TimePoint {
 		if point.Value == nil {
 			point.Value = &nullValue
 		}
 		return point
+	}
+}
+
+func TransformRemoveAboveValue(threshold float64) TransformFunc {
+	return func(point TimePoint) TimePoint {
+		if *point.Value > threshold {
+			point.Value = nil
+		}
+		return point
+	}
+}
+
+func TransformRemoveBelowValue(threshold float64) TransformFunc {
+	return func(point TimePoint) TimePoint {
+		if *point.Value < threshold {
+			point.Value = nil
+		}
+		return point
+	}
+}
+
+func TransformShiftTime(interval time.Duration) TransformFunc {
+	return func(point TimePoint) TimePoint {
+		shiftedTime := point.Time.Add(interval)
+		point.Time = shiftedTime
+		return point
+	}
 }