[cmd/mdatagen]: Add feature gates support to metadata-schema.yaml

cmd/mdatagen/internal/loader.go

 	featuregate.WithRegisterToVersion("v0.70.0")) 
 var myFeatureGate = featuregate.GlobalRegistry().MustRegister( 
 	"namespaced.uniqueIdentifier", 
 	featuregate.Stable, 
     featuregate.WithRegisterFromVersion("v0.65.0") 
 	featuregate.WithRegisterDescription("A brief description of what the gate controls"), 
 	featuregate.WithRegisterReferenceURL("https://github.com/open-telemetry/opentelemetry-collector/issues/6167"), 
 	featuregate.WithRegisterToVersion("v0.70.0")) 
@@ -9,6 +9,7 @@
 	"fmt"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"strings"
 
 	"go.opentelemetry.io/collector/component"
@@ -20,6 +21,20 @@
 	"go.opentelemetry.io/collector/pdata/pcommon"
 )
 
+var (
+	// idRegexp is used to validate the ID of a Gate.
+	// IDs' characters must be alphanumeric or dots.
+	idRegexp           = regexp.MustCompile(`^[0-9a-zA-Z\.]*$`)
+	versionRegexp      = regexp.MustCompile(`^v(\d+)\.(\d+)\.(\d+)$`)
+	referenceURLRegexp = regexp.MustCompile(`^(https?:\/\/)?([a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)+)(\/[^\s]*)?$`)
+	validStages        = map[string]bool{
+		"Alpha":      true,
+		"Beta":       true,
+		"Stable":     true,
+		"Deprecated": true,
+	}
+)
+
 type MetricName string
 
 func (mn MetricName) Render() (string, error) {
@@ -40,6 +55,16 @@
 	return FormatIdentifier(string(mn), false)
 }
 
+type featureGateName string
+
+func (mn featureGateName) Render() (string, error) {
+	return FormatIdentifier(string(mn), true)
+}
+
+func (mn featureGateName) RenderUnexported() (string, error) {
+	return FormatIdentifier(string(mn), false)
+}
+
 // ValueType defines an attribute value type.
 type ValueType struct {
 	// ValueType is type of the attribute value.
@@ -159,6 +184,7 @@
 	}
 	return parser.Unmarshal(m)
 }
+
 func (m Metric) Data() MetricData {
 	if m.Sum != nil {
 		return m.Sum
@@ -296,6 +322,8 @@
 	ShortFolderName string `mapstructure:"-"`
 	// Tests is the set of tests generated with the component
 	Tests tests `mapstructure:"tests"`
+	// FeatureGates that can be used for the component.
+	FeatureGates map[featureGateName]featureGate `mapstructure:"feature_gates"`
 }
 
 func setAttributesFullName(attrs map[AttributeName]Attribute) {
@@ -373,3 +401,50 @@
 	}
 	return strings.TrimSpace(string(output)), nil
 }
+
+type featureGate struct {
+	// Required.
+	Id string `mapstructure:"id"`
+	// Description describes the purpose of the attribute.
+	Description string `mapstructure:"description"`
+	// Stage current stage at which the feature gate is in the development lifecyle
+	Stage string `mapstructure:"stage"`
+	// ReferenceURL can optionally give the url of the feature_gate
+	ReferenceURL string `mapstructure:"reference_url"`
+	// FromVersion optional field which gives the release version from which the gate has been given the current stage
+	FromVersion string `mapstructure:"from_version"`
+	// ToVersion optional field which gives the release version till which the gate the gate had the given lifecycle stage
+	ToVersion string `mapstructure:"to_version"`
+	// FeatureGateName name of the feature gate
+	FeatureGateName featureGateName `mapstructure:"-"`
+}
+
+func (f *featureGate) validate(parser *confmap.Conf) error {
+	if !parser.IsSet("id") {
+		return errors.New("missing required field: `id`")
+	}
+	var err []error
+	if !idRegexp.MatchString(fmt.Sprintf("%v", parser.Get("id"))) {
+		err = append(err, fmt.Errorf("invalid character(s) in ID"))
+	}
+	if !versionRegexp.MatchString(fmt.Sprintf("%v", parser.Get("from_version"))) {
+		err = append(err, fmt.Errorf("invalid character(s) in from_version"))
+	}
+	if !versionRegexp.MatchString(fmt.Sprintf("%v", parser.Get("to_version"))) {
+		err = append(err, fmt.Errorf("invalid character(s) in to_version"))
+	}
+	if !referenceURLRegexp.MatchString(fmt.Sprintf("%v", parser.Get("reference_url"))) {
+		err = append(err, fmt.Errorf("invalid character(s) in reference_url"))
+	}
+	if _, ok := validStages[fmt.Sprintf("%v", parser.Get("stage"))]; !ok {
+		err = append(err, fmt.Errorf("invalid stage"))
+	}
+	return errors.Join(err...)
+}
+
+func (f *featureGate) Unmarshal(parser *confmap.Conf) error {
+	if err := f.validate(parser); err != nil {
+		return err
+	}
+	return parser.Unmarshal(f)
+}

cmd/mdatagen/metadata-schema.yaml

@@ -175,3 +175,20 @@ telemetry:
       # Optional: array of attributes that were defined in the attributes section that are emitted by this metric.
       # Note: Only the following attribute types are supported: <string|int|double|bool>
       attributes: [string]
+
+#Optional: Gate is an immutable object that is owned by the Registry and represents an individual feature that
+# may be enabled or disabled based on the lifecycle state of the feature and CLI flags specified by the user.
+feature_gates:
+  <feature_gate.name>:
+    #Required: id of the feature gate
+    id:
+    #Required: description of the gate
+    description:
+    #Required: current stage at which the feature gate is in the development lifecyle
+    stage:
+    #Optional: link to the issue where the gate has been discussed
+    reference_url:
+    #Optional: the release version from which the gate has been given the current stage
+    from_version:
+    #Optional: the release version till which the gate had the given lifecycle stage
+    to_version: