Add alpha flag for Usages

Signed-off-by: Hasan Turken <turkenh@gmail.com>
turkenh · Sep 11, 2023 · 7e4112a · 7e4112a
1 parent 0e1c4d2
commit 7e4112a
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Showing 6 changed files with 32 additions and 4 deletions.
diff --git a/cluster/webhookconfigurations/usage.yaml b/cluster/webhookconfigurations/usage.yaml
@@ -1,4 +1,7 @@
 ---
+# Note(turkenh): It is not possible to get this generated by kubebuilder at the moment due to
+# lack of support for objectSelector in controller-tools.
+# See: https://github.com/kubernetes-sigs/controller-tools/blob/master/pkg/webhook/parser.go#L202-L212
 apiVersion: admissionregistration.k8s.io/v1
 kind: ValidatingWebhookConfiguration
 metadata:

diff --git a/cmd/crossplane/core/core.go b/cmd/crossplane/core/core.go
@@ -105,6 +105,7 @@ type startCommand struct {
 	EnableExternalSecretStores               bool `group:"Alpha Features:" help:"Enable support for External Secret Stores."`
 	EnableCompositionFunctions               bool `group:"Alpha Features:" help:"Enable support for Composition Functions."`
 	EnableCompositionWebhookSchemaValidation bool `group:"Alpha Features:" help:"Enable support for Composition validation using schemas."`
+	EnableUsages                             bool `group:"Alpha Features:" help:"Enable support for deletion ordering and resource protection with Usages."`
 
 	// These are GA features that previously had alpha or beta feature flags.
 	// You can't turn off a GA feature. We maintain the flags to avoid breaking
@@ -196,6 +197,10 @@ func (c *startCommand) Run(s *runtime.Scheme, log logging.Logger) error { //noli
 		feats.Enable(features.EnableAlphaCompositionWebhookSchemaValidation)
 		log.Info("Alpha feature enabled", "flag", features.EnableAlphaCompositionWebhookSchemaValidation)
 	}
+	if c.EnableUsages {
+		feats.Enable(features.EnableAlphaUsages)
+		log.Info("Alpha feature enabled", "flag", features.EnableAlphaUsages)
+	}
 	if !c.EnableCompositionRevisions {
 		log.Info("CompositionRevisions feature is GA and cannot be disabled. The --enable-composition-revisions flag will be removed in a future release.")
 	}

diff --git a/internal/controller/apiextensions/apiextensions.go b/internal/controller/apiextensions/apiextensions.go
@@ -18,6 +18,7 @@ limitations under the License.
 package apiextensions
 
 import (
+	"github.com/crossplane/crossplane/internal/features"
 	ctrl "sigs.k8s.io/controller-runtime"
 
 	"github.com/crossplane/crossplane/internal/controller/apiextensions/composition"
@@ -37,8 +38,10 @@ func Setup(mgr ctrl.Manager, o controller.Options) error {
 		return err
 	}
 
-	if err := usage.Setup(mgr, o); err != nil {
-		return err
+	if o.Features.Enabled(features.EnableAlphaUsages) {
+		if err := usage.Setup(mgr, o); err != nil {
+			return err
+		}
 	}
 
 	return offered.Setup(mgr, o)

diff --git a/internal/features/features.go b/internal/features/features.go
@@ -40,4 +40,9 @@ const (
 	// details.
 	// https://github.com/crossplane/crossplane/blob/f32496bed53a393c8239376fd8266ddf2ef84d61/design/design-doc-composition-validating-webhook.md
 	EnableAlphaCompositionWebhookSchemaValidation feature.Flag = "EnableAlphaCompositionWebhookSchemaValidation"
+
+	// EnableAlphaUsages enables alpha support for deletion ordering and
+	// protection with Usage resource. See the below design for more details.
+	// https://github.com/crossplane/crossplane/blob/19ea23e7c1fc16b20581755540f9f45afdf89338/design/one-pager-generic-usage-type.md
+	EnableAlphaUsages feature.Flag = "EnableAlphaUsages"
 )
diff --git a/internal/initializer/webhook_configurations.go b/internal/initializer/webhook_configurations.go
@@ -111,8 +111,12 @@ func (c *WebhookConfigurations) Run(ctx context.Context, kube client.Client) err
 				conf.Webhooks[i].ClientConfig.Service.Namespace = c.ServiceReference.Namespace
 				conf.Webhooks[i].ClientConfig.Service.Port = c.ServiceReference.Port
 			}
-			// See https://github.com/kubernetes-sigs/controller-tools/issues/658
+			// Note(turkenh): We have webhook configurations other than the
+			// ones defined with kubebuilder/controller-tools, and we
+			// name them as we want. So, we need to apply workaround for the
+			// linked issue below only for the one generated by controller-tools.
 			if conf.GetName() == "validating-webhook-configuration" {
+				// See https://github.com/kubernetes-sigs/controller-tools/issues/658
 				conf.SetName("crossplane")
 			}
 		case *admv1.MutatingWebhookConfiguration:
@@ -122,8 +126,12 @@ func (c *WebhookConfigurations) Run(ctx context.Context, kube client.Client) err
 				conf.Webhooks[i].ClientConfig.Service.Namespace = c.ServiceReference.Namespace
 				conf.Webhooks[i].ClientConfig.Service.Port = c.ServiceReference.Port
 			}
-			// See https://github.com/kubernetes-sigs/controller-tools/issues/658
+			// Note(turkenh): We have webhook configurations other than the
+			// ones defined with kubebuilder/controller-tools, and we
+			// name them as we want. So, we need to apply workaround for the
+			// linked issue below only for the one generated by controller-tools.
 			if conf.GetName() == "mutating-webhook-configuration" {
+				// See https://github.com/kubernetes-sigs/controller-tools/issues/658
 				conf.SetName("crossplane")
 			}
 		default:

diff --git a/internal/usage/handler.go b/internal/usage/handler.go
@@ -21,6 +21,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"github.com/crossplane/crossplane/internal/features"
 	"net/http"
 
 	admissionv1 "k8s.io/api/admission/v1"
@@ -51,6 +52,9 @@ func IndexValueForObject(u *unstructured.Unstructured) string {
 
 // SetupWebhookWithManager sets up the webhook with the manager.
 func SetupWebhookWithManager(mgr ctrl.Manager, options controller.Options) error {
+	if !options.Features.Enabled(features.EnableAlphaUsages) {
+		return nil
+	}
 	indexer := mgr.GetFieldIndexer()
 	if err := indexer.IndexField(context.Background(), &v1alpha1.Usage{}, InUseIndexKey, func(obj client.Object) []string {
 		u := obj.(*v1alpha1.Usage)