Add override_value to mdatagen (#15112)

Fixes #15109 

Workflow:
- Implement `Validate` method to verify the override value in the
startup of otel collector.
- Use parsed value in `Emit` method.

Author: XSAM

.chloggen/mdatagen-override-value.yaml

@@ -0,0 +1,24 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, e.g. pkg/confighttp, receiver/otlp, exporter/debug
+component: cmd/mdatagen
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add opt-in override_value support for resource_attributes config via `override_value_enabled` flag
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [15109]
+
+# (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: |
+  Components can opt in by setting `override_value_enabled: true` in their metadata.yaml.
+  When enabled, per-attribute config types are generated with typed `override_value` fields
+  that let users override resource attribute values in the collector configuration.
+  Components without the flag continue to use the shared `ResourceAttributeConfig` type.
+
+change_logs: [api]

cmd/mdatagen/go.mod

@@ -12,6 +12,7 @@ require (
 	go.opentelemetry.io/collector/config/configoptional v1.56.0
 	go.opentelemetry.io/collector/confmap v1.56.0
 	go.opentelemetry.io/collector/confmap/provider/fileprovider v1.56.0
+	go.opentelemetry.io/collector/confmap/xconfmap v0.150.0
 	go.opentelemetry.io/collector/connector v0.150.0
 	go.opentelemetry.io/collector/connector/connectortest v0.150.0
 	go.opentelemetry.io/collector/connector/xconnector v0.150.0
@@ -86,7 +87,6 @@ require (
 	go.opentelemetry.io/collector/config/confignet v1.56.0 // indirect
 	go.opentelemetry.io/collector/config/configopaque v1.56.0 // indirect
 	go.opentelemetry.io/collector/config/configtls v1.56.0 // indirect
-	go.opentelemetry.io/collector/confmap/xconfmap v0.150.0 // indirect
 	go.opentelemetry.io/collector/consumer/consumererror v0.150.0 // indirect
 	go.opentelemetry.io/collector/extension/extensionauth v1.56.0 // indirect
 	go.opentelemetry.io/collector/extension/extensionmiddleware v0.150.0 // indirect

cmd/mdatagen/internal/loader_test.go

@@ -53,6 +53,7 @@ func TestLoadMetadata(t *testing.T) {
 				SemConvVersion:       "1.40.0",
 				PackageName:          "go.opentelemetry.io/collector/cmd/mdatagen/internal/samplereceiver",
 				ReaggregationEnabled: true,
+				OverrideValueEnabled: true,
 				Status: &Status{
 					DisableCodeCov: true,
 					Class:          "receiver",

cmd/mdatagen/internal/metadata.go

@@ -35,6 +35,8 @@ type Metadata struct {
 	Status *Status `mapstructure:"status"`
 	// Spatial Re-aggregation featuregate.
 	ReaggregationEnabled bool `mapstructure:"reaggregation_enabled"`
+	// Override value featuregate for resource attributes.
+	OverrideValueEnabled bool `mapstructure:"override_value_enabled"`
 	// The name of the package that will be generated.
 	GeneratedPackageName string `mapstructure:"generated_package_name"`
 	// Telemetry information for the component.