metrics: add version compatibility header

pkg/metrics/generator.go

@@ -34,6 +34,7 @@ import (
 	"sigs.k8s.io/controller-tools/pkg/metrics/internal/config"
 	"sigs.k8s.io/controller-tools/pkg/metrics/markers"
 	"sigs.k8s.io/controller-tools/pkg/rbac"
+	"sigs.k8s.io/controller-tools/pkg/version"
 )
 
 // Generator generates kube-state-metrics custom resource configuration files.
@@ -54,6 +55,10 @@ func (g Generator) RegisterMarkers(into *ctrlmarkers.Registry) error {
 	return nil
 }
 
+const headerText = `# Generated by controller-gen version %s
+# Compatible to kube-state-metrics %s
+`
+
 // Generate generates artifacts produced by this marker.
 // It's called after RegisterMarkers has been called.
 func (g Generator) Generate(ctx *genall.GenerationContext) error {
@@ -129,9 +134,11 @@ func (g Generator) Generate(ctx *genall.GenerationContext) error {
 		return a < b
 	})
 
+	header := fmt.Sprintf(headerText, version.Version(), config.KubeStateMetricsVersion)
+
 	// Write the rendered yaml to the context which will result in stdout.
 	virtualFilePath := "metrics.yaml"
-	if err := ctx.WriteYAML(virtualFilePath, "", []interface{}{metrics}, genall.WithTransform(addCustomResourceStateKind)); err != nil {
+	if err := ctx.WriteYAML(virtualFilePath, header, []interface{}{metrics}, genall.WithTransform(addCustomResourceStateKind)); err != nil {
 		return fmt.Errorf("WriteYAML to %s: %w", virtualFilePath, err)
 	}
 

pkg/metrics/internal/config/doc.go

@@ -15,7 +15,6 @@ limitations under the License.
 */
 
 // config contains a copy of the types from k8s.io/kube-state-metrics/pkg/customresourcestate.
-// It is currently based on kube-state-metrics v2.13.0.
 // The following modifications got applied:
 // For `config.go`:
 // * Rename the package to `config`.
@@ -38,3 +37,7 @@ limitations under the License.
 //   - `MetricGauge.LabelFromkey`
 //   - `MetricInfo.LabelFromkey`
 package config
+
+// KubeStateMetricsVersion defines which version of kube-state-metrics these types
+// are based on and the output file should be compatible to.
+const KubeStateMetricsVersion = "v2.13.0"