[pkg/otlp/metrics] Add WithSplatArrayAttributes

.chloggen/mx-psi_splat-tags.yaml

@@ -0,0 +1,17 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component (e.g. pkg/quantile)
+component: pkg/otlp/metrics
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add `WithSplatArrayAttributes` translator option
+
+# The PR related to this change
+issues: [329]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+   - This option destructures an array valued attribute into multiple tags with the same key and different values.

.chloggen/mx-psi_splat-tags2.yaml

@@ -0,0 +1,17 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component (e.g. pkg/quantile)
+component: pkg/otlp/metrics
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add `splat` option to `WithAttributeMap`
+
+# The PR related to this change
+issues: [329]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+   - This option destructures an array valued attribute into multiple tags with the same key and different values.

pkg/otlp/metrics/config.go

@@ -29,6 +29,7 @@ type translatorConfig struct {
 	InitialCumulMonoValueMode            InitialCumulMonoValueMode
 	InstrumentationLibraryMetadataAsTags bool
 	InstrumentationScopeMetadataAsTags   bool
+	SplatArrayAttributes                 bool
 
 	originProduct OriginProduct
 
@@ -215,3 +216,11 @@ func WithInitialCumulMonoValueMode(mode InitialCumulMonoValueMode) TranslatorOpt
 		return nil
 	}
 }
+
+// WithSplatArrayAttributes destructures an array attribute into multiple Datadog tags.
+func WithSplatArrayAttributes() TranslatorOption {
+	return func(t *translatorConfig) error {
+		t.SplatArrayAttributes = true
+		return nil
+	}
+}

pkg/otlp/metrics/dimensions.go

@@ -78,11 +78,18 @@ func (d *Dimensions) OriginProductDetail() OriginProductDetail {
 }
 
 // getTags maps an attributeMap into a slice of Datadog tags
-func getTags(labels pcommon.Map) []string {
+func getTags(labels pcommon.Map, splat bool) []string {
 	tags := make([]string, 0, labels.Len())
 	labels.Range(func(key string, value pcommon.Value) bool {
-		v := value.AsString()
-		tags = append(tags, utils.FormatKeyValueTag(key, v))
+		if splat && value.Type() == pcommon.ValueTypeSlice {
+			for i := 0; i < value.Slice().Len(); i++ {
+				v := value.Slice().At(i).AsString()
+				tags = append(tags, utils.FormatKeyValueTag(key, v))
+			}
+		} else {
+			v := value.AsString()
+			tags = append(tags, utils.FormatKeyValueTag(key, v))
+		}
 		return true
 	})
 	return tags
@@ -106,8 +113,8 @@ func (d *Dimensions) AddTags(tags ...string) *Dimensions {
 }
 
 // WithAttributeMap creates a new metricDimensions struct with additional tags from attributes.
-func (d *Dimensions) WithAttributeMap(labels pcommon.Map) *Dimensions {
-	return d.AddTags(getTags(labels)...)
+func (d *Dimensions) WithAttributeMap(labels pcommon.Map, splat bool) *Dimensions {
+	return d.AddTags(getTags(labels, splat)...)
 }
 
 // WithSuffix creates a new dimensions struct with an extra name suffix.

pkg/otlp/metrics/dimensions_test.go

@@ -27,12 +27,29 @@ func TestWithAttributeMap(t *testing.T) {
 		"key1": "val1",
 		"key2": "val2",
 		"key3": "",
+		"key4": []any{"val4a", "val4b"},
 	})
 
 	dims := Dimensions{}
 	assert.ElementsMatch(t,
-		dims.WithAttributeMap(attributes).tags,
-		[...]string{"key1:val1", "key2:val2", "key3:n/a"},
+		dims.WithAttributeMap(attributes, false).tags,
+		[...]string{"key1:val1", "key2:val2", "key3:n/a", `key4:["val4a","val4b"]`},
+	)
+}
+
+func TestWithAttributeMapSplat(t *testing.T) {
+	attributes := pcommon.NewMap()
+	attributes.FromRaw(map[string]interface{}{
+		"key1": "val1",
+		"key2": "val2",
+		"key3": "",
+		"key4": []any{"val4a", "val4b"},
+	})
+
+	dims := Dimensions{}
+	assert.ElementsMatch(t,
+		dims.WithAttributeMap(attributes, true).tags,
+		[...]string{"key1:val1", "key2:val2", "key3:n/a", "key4:val4a", "key4:val4b"},
 	)
 }
 
@@ -115,7 +132,7 @@ func TestAllFieldsAreCopied(t *testing.T) {
 	newDims := dims.
 		AddTags("tagThree:c").
 		WithSuffix("suffix").
-		WithAttributeMap(attributes)
+		WithAttributeMap(attributes, false)
 
 	assert.Equal(t, "example.name.suffix", newDims.Name())
 	assert.Equal(t, "hostname", newDims.Host())

pkg/otlp/metrics/exponential_histograms_translator.go

@@ -93,7 +93,7 @@ func (t *Translator) mapExponentialHistogramMetrics(
 		p := slice.At(i)
 		startTs := uint64(p.StartTimestamp())
 		ts := uint64(p.Timestamp())
-		pointDims := dims.WithAttributeMap(p.Attributes())
+		pointDims := dims.WithAttributeMap(p.Attributes(), t.cfg.SplatArrayAttributes)
 
 		histInfo := histogramInfo{ok: true}
 

pkg/otlp/metrics/metrics_translator.go

@@ -151,7 +151,7 @@ func (t *Translator) mapNumberMetrics(
 
 	for i := 0; i < slice.Len(); i++ {
 		p := slice.At(i)
-		pointDims := dims.WithAttributeMap(p.Attributes())
+		pointDims := dims.WithAttributeMap(p.Attributes(), t.cfg.SplatArrayAttributes)
 		var val float64
 		switch p.ValueType() {
 		case pmetric.NumberDataPointValueTypeDouble:
@@ -205,7 +205,7 @@ func (t *Translator) mapNumberMonotonicMetrics(
 		p := slice.At(i)
 		ts := uint64(p.Timestamp())
 		startTs := uint64(p.StartTimestamp())
-		pointDims := dims.WithAttributeMap(p.Attributes())
+		pointDims := dims.WithAttributeMap(p.Attributes(), t.cfg.SplatArrayAttributes)
 
 		var val float64
 		switch p.ValueType() {
@@ -452,7 +452,7 @@ func (t *Translator) mapHistogramMetrics(
 		p := slice.At(i)
 		startTs := uint64(p.StartTimestamp())
 		ts := uint64(p.Timestamp())
-		pointDims := dims.WithAttributeMap(p.Attributes())
+		pointDims := dims.WithAttributeMap(p.Attributes(), t.cfg.SplatArrayAttributes)
 
 		histInfo := histogramInfo{ok: true}
 
@@ -556,7 +556,7 @@ func (t *Translator) mapSummaryMetrics(
 		p := slice.At(i)
 		startTs := uint64(p.StartTimestamp())
 		ts := uint64(p.Timestamp())
-		pointDims := dims.WithAttributeMap(p.Attributes())
+		pointDims := dims.WithAttributeMap(p.Attributes(), t.cfg.SplatArrayAttributes)
 
 		// count and sum are increasing; we treat them as cumulative monotonic sums.
 		{