[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.
+- `delete_keys`: the list of dimensions which will be removed from 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

@@ -35,6 +35,10 @@ var defaultHistogramBucketsMs = []float64{
 }
 
 // Dimension defines the dimension name and optional default value if the Dimension is missing from a span attribute.
+
+type Keys struct {
+	Name string `mapstructure:"name"`
+}
 type Dimension struct {
 	Name    string  `mapstructure:"name"`
 	Default *string `mapstructure:"default"`
@@ -50,6 +54,7 @@ type Config struct {
 	// 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"`
+	DeleteKeys []Keys      `mapstructure:"delete_keys"`
 
 	// 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 +91,7 @@ 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.DeleteKeys)
 	if err != nil {
 		return err
 	}
@@ -114,10 +119,19 @@ func (c Config) GetAggregationTemporality() pmetric.AggregationTemporality {
 }
 
 // validateDimensions checks duplicates for reserved dimensions and additional dimensions.
-func validateDimensions(dimensions []Dimension) error {
+func validateDimensions(dimensions []Dimension, deleteKeys []Keys) error {
 	labelNames := make(map[string]struct{})
+
+	// Making map of elements for o(1) complexity
+	set := make(map[string]struct{})
+	for _, item := range deleteKeys {
+		set[item.Name] = struct{}{}
+	}
+
 	for _, key := range []string{serviceNameKey, spanKindKey, statusCodeKey, spanNameKey} {
-		labelNames[key] = struct{}{}
+		if _, exists := set[key]; !exists {
+			labelNames[key] = struct{}{}
+		}
 	}
 
 	for _, key := range dimensions {

connector/spanmetricsconnector/config_test.go

@@ -130,6 +130,7 @@ func TestValidateDimensions(t *testing.T) {
 	for _, tc := range []struct {
 		name        string
 		dimensions  []Dimension
+		deleteKeys  []Keys
 		expectedErr string
 	}{
 		{
@@ -158,9 +159,27 @@ func TestValidateDimensions(t *testing.T) {
 			},
 			expectedErr: "duplicate dimension name service_name",
 		},
+		{
+			name: "Wrong key name to delete",
+			dimensions: []Dimension{
+				{Name: "service_name"},
+			},
+			deleteKeys: []Keys{
+				{Name: "http.service"},
+			},
+		},
+		{
+			name: "Correct key to delete",
+			dimensions: []Dimension{
+				{Name: "service_name"},
+			},
+			deleteKeys: []Keys{
+				{Name: "service_name"},
+			},
+		},
 	} {
 		t.Run(tc.name, func(t *testing.T) {
-			err := validateDimensions(tc.dimensions)
+			err := validateDimensions(tc.dimensions, tc.deleteKeys)
 			if tc.expectedErr != "" {
 				assert.EqualError(t, err, tc.expectedErr)
 			} else {