[connector/spanmetricsconnector] fix default metrics initialization

connector/spanmetricsconnector/README.md

@@ -74,6 +74,7 @@ The following settings can be optionally configured:
       buckets: `[2ms, 4ms, 6ms, 8ms, 10ms, 50ms, 100ms, 200ms, 400ms, 800ms, 1s, 1400ms, 2s, 5s, 10s, 15s]`
   - `exponential`:
     - `max_size` (default: 160) the maximum number of buckets per positive or negative number range.
+- `override_default_dimensions`: the list of dimensions which will override all default dimensions defined above.
 - `dimensions`: the list of dimensions to add together with the default dimensions defined above.
 
   Each additional dimension is defined with a `name` which is looked up in the span's collection of attributes or

connector/spanmetricsconnector/config.go

@@ -49,7 +49,8 @@ type Config struct {
 	// - status.code
 	// The dimensions will be fetched from the span's attributes. Examples of some conventionally used attributes:
 	// https://github.com/open-telemetry/opentelemetry-collector/blob/main/model/semconv/opentelemetry.go.
-	Dimensions []Dimension `mapstructure:"dimensions"`
+	Dimensions                []Dimension `mapstructure:"dimensions"`
+	OverrideDefaultDimensions []Dimension `mapstructure:"override_default_dimensions"`
 
 	// DimensionsCacheSize defines the size of cache for storing Dimensions, which helps to avoid cache memory growing
 	// indefinitely over the lifetime of the collector.
@@ -86,7 +87,7 @@ var _ component.ConfigValidator = (*Config)(nil)
 
 // Validate checks if the processor configuration is valid
 func (c Config) Validate() error {
-	err := validateDimensions(c.Dimensions)
+	err := validateDimensions(c.Dimensions, c.OverrideDefaultDimensions)
 	if err != nil {
 		return err
 	}
@@ -114,10 +115,19 @@ func (c Config) GetAggregationTemporality() pmetric.AggregationTemporality {
 }
 
 // validateDimensions checks duplicates for reserved dimensions and additional dimensions.
-func validateDimensions(dimensions []Dimension) error {
+func validateDimensions(dimensions []Dimension, overrideDefaultDimensions []Dimension) error {
 	labelNames := make(map[string]struct{})
-	for _, key := range []string{serviceNameKey, spanKindKey, statusCodeKey, spanNameKey} {
-		labelNames[key] = struct{}{}
+	if len(overrideDefaultDimensions) > 0 {
+		for _, key := range overrideDefaultDimensions {
+			if _, ok := labelNames[key.Name]; ok {
+				return fmt.Errorf("duplicate dimension name %s", key.Name)
+			}
+			labelNames[key.Name] = struct{}{}
+		}
+	} else {
+		for _, key := range []string{serviceNameKey, spanKindKey, statusCodeKey, spanNameKey} {
+			labelNames[key] = struct{}{}
+		}
 	}
 
 	for _, key := range dimensions {

connector/spanmetricsconnector/config_test.go

@@ -128,9 +128,10 @@ func TestGetAggregationTemporality(t *testing.T) {
 
 func TestValidateDimensions(t *testing.T) {
 	for _, tc := range []struct {
-		name        string
-		dimensions  []Dimension
-		expectedErr string
+		name                      string
+		dimensions                []Dimension
+		overrideDefaultDimensions []Dimension
+		expectedErr               string
 	}{
 		{
 			name:       "no additional dimensions",
@@ -158,9 +159,28 @@ func TestValidateDimensions(t *testing.T) {
 			},
 			expectedErr: "duplicate dimension name service_name",
 		},
+		{
+			name: "no duplicate dimensions in overrideDefaultDimensions and dimensions",
+			dimensions: []Dimension{
+				{Name: "service_name"},
+			},
+			overrideDefaultDimensions: []Dimension{
+				{Name: "http.service"},
+			},
+		},
+		{
+			name: "duplicate dimensions in overrideDefaultDimensions and dimensions",
+			dimensions: []Dimension{
+				{Name: "service_name"},
+			},
+			overrideDefaultDimensions: []Dimension{
+				{Name: "service_name"},
+			},
+			expectedErr: "duplicate dimension name service_name",
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			err := validateDimensions(tc.dimensions)
+			err := validateDimensions(tc.dimensions, tc.overrideDefaultDimensions)
 			if tc.expectedErr != "" {
 				assert.EqualError(t, err, tc.expectedErr)
 			} else {