Deprecate SelfLink + featuregate for setting it

Author: wojtek-t

staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/types.go

@@ -61,6 +61,10 @@ type ListMeta struct {
 	// selfLink is a URL representing this object.
 	// Populated by the system.
 	// Read-only.
+	//
+	// DEPRECATED
+	// Kubernetes will stop propagating this field in 1.20 release and the field is planned
+	// to be removed in 1.21 release.
 	// +optional
 	SelfLink string `json:"selfLink,omitempty" protobuf:"bytes,1,opt,name=selfLink"`
 
@@ -148,6 +152,10 @@ type ObjectMeta struct {
 	// SelfLink is a URL representing this object.
 	// Populated by the system.
 	// Read-only.
+	//
+	// DEPRECATED
+	// Kubernetes will stop propagating this field in 1.20 release and the field is planned
+	// to be removed in 1.21 release.
 	// +optional
 	SelfLink string `json:"selfLink,omitempty" protobuf:"bytes,4,opt,name=selfLink"`
 

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/patch.go

@@ -224,12 +224,7 @@ func PatchResource(r rest.Patcher, scope *RequestScope, admit admission.Interfac
 		}
 		trace.Step("Object stored in database")
 
-		requestInfo, ok := request.RequestInfoFrom(ctx)
-		if !ok {
-			scope.err(fmt.Errorf("missing requestInfo"), w, req)
-			return
-		}
-		if err := setSelfLink(result, requestInfo, scope.Namer); err != nil {
+		if err := setObjectSelfLink(ctx, result, req, scope.Namer); err != nil {
 			scope.err(err, w, req)
 			return
 		}

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/rest.go

@@ -39,7 +39,9 @@ import (
 	"k8s.io/apiserver/pkg/endpoints/handlers/responsewriters"
 	"k8s.io/apiserver/pkg/endpoints/metrics"
 	"k8s.io/apiserver/pkg/endpoints/request"
+	"k8s.io/apiserver/pkg/features"
 	"k8s.io/apiserver/pkg/registry/rest"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/klog"
 )
 
@@ -318,6 +320,10 @@ func checkName(obj runtime.Object, name, namespace string, namer ScopeNamer) err
 // TODO: remove the need for the namer LinkSetters by requiring objects implement either Object or List
 //   interfaces
 func setObjectSelfLink(ctx context.Context, obj runtime.Object, req *http.Request, namer ScopeNamer) error {
+	if utilfeature.DefaultFeatureGate.Enabled(features.RemoveSelfLink) {
+		return nil
+	}
+
 	// We only generate list links on objects that implement ListInterface - historically we duck typed this
 	// check via reflection, but as we move away from reflection we require that you not only carry Items but
 	// ListMeta into order to be identified as a list.

staging/src/k8s.io/apiserver/pkg/features/kube_features.go

@@ -132,6 +132,12 @@ const (
 	//
 	// Enables managing request concurrency with prioritization and fairness at each server
 	RequestManagement featuregate.Feature = "RequestManagement"
+
+	// owner: @wojtek-t
+	// alpha: v1.16
+	//
+	// Deprecates and removes SelfLink from ObjectMeta and ListMeta.
+	RemoveSelfLink featuregate.Feature = "RemoveSelfLink"
 )
 
 func init() {
@@ -156,4 +162,5 @@ var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureS
 	WinDSR:                  {Default: false, PreRelease: featuregate.Alpha},
 	WatchBookmark:           {Default: true, PreRelease: featuregate.Beta},
 	RequestManagement:       {Default: false, PreRelease: featuregate.Alpha},
+	RemoveSelfLink:          {Default: false, PreRelease: featuregate.Alpha},
 }