adapt scale function to be an editor function

Signed-off-by: Florian Bacher <florian.bacher@dynatrace.com>

pkg/ottl/e2e/e2e_test.go

@@ -54,6 +54,7 @@ func Test_e2e_editors(t *testing.T) {
 				tCtx.GetLogRecord().Attributes().Remove("flags")
 				tCtx.GetLogRecord().Attributes().Remove("total.string")
 				tCtx.GetLogRecord().Attributes().Remove("foo")
+				tCtx.GetLogRecord().Attributes().Remove("double_value")
 			},
 		},
 		{
@@ -280,6 +281,12 @@ func Test_e2e_editors(t *testing.T) {
 				s.AppendEmpty().SetInt(6)
 			},
 		},
+		{
+			statement: `scale_metric(attributes["double_value"],0.1)`,
+			want: func(tCtx ottllog.TransformContext) {
+				tCtx.GetLogRecord().Attributes().PutDouble("double_value", 1.05)
+			},
+		},
 	}
 
 	for _, tt := range tests {
@@ -713,12 +720,6 @@ func Test_e2e_converters(t *testing.T) {
 				m.PutStr("bar", "pass")
 			},
 		},
-		{
-			statement: `set(attributes["double_value"], Scale(attributes["double_value"],0.1))`,
-			want: func(tCtx ottllog.TransformContext) {
-				tCtx.GetLogRecord().Attributes().PutDouble("double_value", 1.05)
-			},
-		},
 	}
 
 	for _, tt := range tests {

pkg/ottl/ottlfuncs/README.md

@@ -59,6 +59,7 @@ Available Editors:
 - [replace_pattern](#replace_pattern)
 - [set](#set)
 - [truncate_all](#truncate_all)
+- [scale_metric](#scale_metric)
 
 ### append
 
@@ -402,6 +403,24 @@ Examples:
 
 - `truncate_all(resource.attributes, 50)`
 
+### scale_metric
+
+`scale_metric(value, factor)`
+
+The `Scale` function multiplies the original `value` by the `factor`.
+The supported data types are:
+
+- `int`
+- `double`
+- `data_points` - Supported metric types are `Gauge`, `Sum` and `Histogram`.
+  To scale a metric of these types, the `data_points` property of the respective metric needs to be passed to the function,
+  as indicated in the examples below.
+
+Examples:
+
+- `scale_metric(10.0, 0.1)`: Trivial example
+- `scale_metric(data_points, 10.0)`: Modifies the metric's `data_points` by multiplying them with the factor `10.0`.
+
 ## Converters
 
 Converters are pure functions that take OTTL values as input and output a single value for use within a statement.
@@ -457,7 +476,6 @@ Available Converters:
 - [UnixSeconds](#unixseconds)
 - [UUID](#UUID)
 - [Year](#year)
-- [Scale](#scale)
 
 ### Base64Decode
 
@@ -1391,30 +1409,6 @@ Examples:
 
 - `Year(Now())`
 
-### Scale
-
-`Scale(value, factor)`
-
-The `Scale` function returns the original `value`, multiplied by the `factor`.
-The supported data types are:
-
-- `int`
-- `double`
-- `data_points` - Supported metric types are `Gauge`, `Sum` and `Histogram`.
-To scale a metric of these types, the `data_points` property of the respective metric needs to be passed to the function,
-as indicated in the examples below.
-
-Examples:
-
-- `Scale(10.0, 0.1)`: Trivial example
-- `Scale(data_points, 10.0)`: Returns the scaled `data_points` of a metric as a result.
-
-If the actual metric value should be modified, this can be done in combination with the `set` function:
-
-```
-set(data_points, Scale(data_points, 10.0))
-```
-
 ## Function syntax
 
 Functions should be named and formatted according to the following standards.

pkg/ottl/ottlfuncs/func_scale.go

@@ -14,12 +14,12 @@ import (
 )
 
 type ScaleArguments[K any] struct {
-	Value      ottl.Getter[K]
+	Value      ottl.GetSetter[K]
 	Multiplier float64
 }
 
 func NewScaleFactory[K any]() ottl.Factory[K] {
-	return ottl.NewFactory("Scale", &ScaleArguments[K]{}, createScaleFunction[K])
+	return ottl.NewFactory("scale_metric", &ScaleArguments[K]{}, createScaleFunction[K])
 }
 
 func createScaleFunction[K any](_ ottl.FunctionContext, oArgs ottl.Arguments) (ottl.ExprFunc[K], error) {
@@ -32,40 +32,34 @@ func createScaleFunction[K any](_ ottl.FunctionContext, oArgs ottl.Arguments) (o
 	return Scale(args.Value, args.Multiplier)
 }
 
-func Scale[K any](getter ottl.Getter[K], multiplier float64) (ottl.ExprFunc[K], error) {
+func Scale[K any](getSetter ottl.GetSetter[K], multiplier float64) (ottl.ExprFunc[K], error) {
 	return func(ctx context.Context, tCtx K) (any, error) {
-		got, err := getter.Get(ctx, tCtx)
+		got, err := getSetter.Get(ctx, tCtx)
 		if err != nil {
 			return nil, err
 		}
 
 		switch value := got.(type) {
 		case float64:
-			return value * multiplier, nil
+			value *= multiplier
+			return nil, getSetter.Set(ctx, tCtx, value)
 		case int64:
-			return float64(value) * multiplier, nil
+			value = int64(float64(value) * multiplier)
+			return nil, getSetter.Set(ctx, tCtx, value)
 		case pmetric.NumberDataPointSlice:
-			scaledMetric := pmetric.NewNumberDataPointSlice()
-			value.CopyTo(scaledMetric)
-			scaleMetric(scaledMetric, multiplier)
-			return scaledMetric, nil
+			scaleMetric(value, multiplier)
+			return nil, nil
 		case pmetric.HistogramDataPointSlice:
-			scaledMetric := pmetric.NewHistogramDataPointSlice()
-			value.CopyTo(scaledMetric)
-			scaleHistogram(scaledMetric, multiplier)
-			return scaledMetric, nil
+			scaleHistogram(value, multiplier)
+			return nil, nil
 		case pmetric.SummaryDataPointValueAtQuantileSlice:
-			scaledMetric := pmetric.NewSummaryDataPointValueAtQuantileSlice()
-			value.CopyTo(scaledMetric)
-			scaleSummaryDataPointValueAtQuantileSlice(scaledMetric, multiplier)
-			return scaledMetric, nil
+			scaleSummaryDataPointValueAtQuantileSlice(value, multiplier)
+			return nil, nil
 		case pmetric.ExemplarSlice:
-			scaledSlice := pmetric.NewExemplarSlice()
-			value.CopyTo(scaledSlice)
-			scaleExemplarSlice(scaledSlice, multiplier)
-			return scaledSlice, nil
+			scaleExemplarSlice(value, multiplier)
+			return nil, nil
 		case pmetric.ExponentialHistogramDataPointSlice:
-			return nil, errors.New("exponential histograms are not supported by the 'Scale' function")
+			return nil, errors.New("exponential histograms are not supported by the 'scale_metric' function")
 		default:
 			return nil, fmt.Errorf("unsupported data type: '%T'", value)
 		}
@@ -97,7 +91,6 @@ func scaleSummaryDataPointValueAtQuantileSlice(values pmetric.SummaryDataPointVa
 }
 
 func scaleHistogram(datapoints pmetric.HistogramDataPointSlice, multiplier float64) {
-
 	for i := 0; i < datapoints.Len(); i++ {
 		dp := datapoints.At(i)