feat: add crd gen

Signed-off-by: runzexia <runzexia@yunify.com>

vendor/k8s.io/apiserver/pkg/admission/plugin/namespace/lifecycle/admission.go

@@ -0,0 +1,224 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package lifecycle
+
+import (
+	"fmt"
+	"io"
+	"time"
+
+	"k8s.io/klog"
+
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/errors"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	utilcache "k8s.io/apimachinery/pkg/util/cache"
+	"k8s.io/apimachinery/pkg/util/clock"
+	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/apiserver/pkg/admission"
+	"k8s.io/apiserver/pkg/admission/initializer"
+	"k8s.io/client-go/informers"
+	"k8s.io/client-go/kubernetes"
+	corelisters "k8s.io/client-go/listers/core/v1"
+)
+
+const (
+	// PluginName indicates the name of admission plug-in
+	PluginName = "NamespaceLifecycle"
+	// how long a namespace stays in the force live lookup cache before expiration.
+	forceLiveLookupTTL = 30 * time.Second
+	// how long to wait for a missing namespace before re-checking the cache (and then doing a live lookup)
+	// this accomplishes two things:
+	// 1. It allows a watch-fed cache time to observe a namespace creation event
+	// 2. It allows time for a namespace creation to distribute to members of a storage cluster,
+	//    so the live lookup has a better chance of succeeding even if it isn't performed against the leader.
+	missingNamespaceWait = 50 * time.Millisecond
+)
+
+// Register registers a plugin
+func Register(plugins *admission.Plugins) {
+	plugins.Register(PluginName, func(config io.Reader) (admission.Interface, error) {
+		return NewLifecycle(sets.NewString(metav1.NamespaceDefault, metav1.NamespaceSystem, metav1.NamespacePublic))
+	})
+}
+
+// Lifecycle is an implementation of admission.Interface.
+// It enforces life-cycle constraints around a Namespace depending on its Phase
+type Lifecycle struct {
+	*admission.Handler
+	client             kubernetes.Interface
+	immortalNamespaces sets.String
+	namespaceLister    corelisters.NamespaceLister
+	// forceLiveLookupCache holds a list of entries for namespaces that we have a strong reason to believe are stale in our local cache.
+	// if a namespace is in this cache, then we will ignore our local state and always fetch latest from api server.
+	forceLiveLookupCache *utilcache.LRUExpireCache
+}
+
+var _ = initializer.WantsExternalKubeInformerFactory(&Lifecycle{})
+var _ = initializer.WantsExternalKubeClientSet(&Lifecycle{})
+
+// Admit makes an admission decision based on the request attributes
+func (l *Lifecycle) Admit(a admission.Attributes) error {
+	// prevent deletion of immortal namespaces
+	if a.GetOperation() == admission.Delete && a.GetKind().GroupKind() == v1.SchemeGroupVersion.WithKind("Namespace").GroupKind() && l.immortalNamespaces.Has(a.GetName()) {
+		return errors.NewForbidden(a.GetResource().GroupResource(), a.GetName(), fmt.Errorf("this namespace may not be deleted"))
+	}
+
+	// always allow non-namespaced resources
+	if len(a.GetNamespace()) == 0 && a.GetKind().GroupKind() != v1.SchemeGroupVersion.WithKind("Namespace").GroupKind() {
+		return nil
+	}
+
+	if a.GetKind().GroupKind() == v1.SchemeGroupVersion.WithKind("Namespace").GroupKind() {
+		// if a namespace is deleted, we want to prevent all further creates into it
+		// while it is undergoing termination.  to reduce incidences where the cache
+		// is slow to update, we add the namespace into a force live lookup list to ensure
+		// we are not looking at stale state.
+		if a.GetOperation() == admission.Delete {
+			l.forceLiveLookupCache.Add(a.GetName(), true, forceLiveLookupTTL)
+		}
+		// allow all operations to namespaces
+		return nil
+	}
+
+	// always allow deletion of other resources
+	if a.GetOperation() == admission.Delete {
+		return nil
+	}
+
+	// always allow access review checks.  Returning status about the namespace would be leaking information
+	if isAccessReview(a) {
+		return nil
+	}
+
+	// we need to wait for our caches to warm
+	if !l.WaitForReady() {
+		return admission.NewForbidden(a, fmt.Errorf("not yet ready to handle request"))
+	}
+
+	var (
+		exists bool
+		err    error
+	)
+
+	namespace, err := l.namespaceLister.Get(a.GetNamespace())
+	if err != nil {
+		if !errors.IsNotFound(err) {
+			return errors.NewInternalError(err)
+		}
+	} else {
+		exists = true
+	}
+
+	if !exists && a.GetOperation() == admission.Create {
+		// give the cache time to observe the namespace before rejecting a create.
+		// this helps when creating a namespace and immediately creating objects within it.
+		time.Sleep(missingNamespaceWait)
+		namespace, err = l.namespaceLister.Get(a.GetNamespace())
+		switch {
+		case errors.IsNotFound(err):
+			// no-op
+		case err != nil:
+			return errors.NewInternalError(err)
+		default:
+			exists = true
+		}
+		if exists {
+			klog.V(4).Infof("found %s in cache after waiting", a.GetNamespace())
+		}
+	}
+
+	// forceLiveLookup if true will skip looking at local cache state and instead always make a live call to server.
+	forceLiveLookup := false
+	if _, ok := l.forceLiveLookupCache.Get(a.GetNamespace()); ok {
+		// we think the namespace was marked for deletion, but our current local cache says otherwise, we will force a live lookup.
+		forceLiveLookup = exists && namespace.Status.Phase == v1.NamespaceActive
+	}
+
+	// refuse to operate on non-existent namespaces
+	if !exists || forceLiveLookup {
+		// as a last resort, make a call directly to storage
+		namespace, err = l.client.CoreV1().Namespaces().Get(a.GetNamespace(), metav1.GetOptions{})
+		switch {
+		case errors.IsNotFound(err):
+			return err
+		case err != nil:
+			return errors.NewInternalError(err)
+		}
+		klog.V(4).Infof("found %s via storage lookup", a.GetNamespace())
+	}
+
+	// ensure that we're not trying to create objects in terminating namespaces
+	if a.GetOperation() == admission.Create {
+		if namespace.Status.Phase != v1.NamespaceTerminating {
+			return nil
+		}
+
+		// TODO: This should probably not be a 403
+		return admission.NewForbidden(a, fmt.Errorf("unable to create new content in namespace %s because it is being terminated", a.GetNamespace()))
+	}
+
+	return nil
+}
+
+// NewLifecycle creates a new namespace Lifecycle admission control handler
+func NewLifecycle(immortalNamespaces sets.String) (*Lifecycle, error) {
+	return newLifecycleWithClock(immortalNamespaces, clock.RealClock{})
+}
+
+func newLifecycleWithClock(immortalNamespaces sets.String, clock utilcache.Clock) (*Lifecycle, error) {
+	forceLiveLookupCache := utilcache.NewLRUExpireCacheWithClock(100, clock)
+	return &Lifecycle{
+		Handler:              admission.NewHandler(admission.Create, admission.Update, admission.Delete),
+		immortalNamespaces:   immortalNamespaces,
+		forceLiveLookupCache: forceLiveLookupCache,
+	}, nil
+}
+
+// SetExternalKubeInformerFactory implements the WantsExternalKubeInformerFactory interface.
+func (l *Lifecycle) SetExternalKubeInformerFactory(f informers.SharedInformerFactory) {
+	namespaceInformer := f.Core().V1().Namespaces()
+	l.namespaceLister = namespaceInformer.Lister()
+	l.SetReadyFunc(namespaceInformer.Informer().HasSynced)
+}
+
+// SetExternalKubeClientSet implements the WantsExternalKubeClientSet interface.
+func (l *Lifecycle) SetExternalKubeClientSet(client kubernetes.Interface) {
+	l.client = client
+}
+
+// ValidateInitialization implements the InitializationValidator interface.
+func (l *Lifecycle) ValidateInitialization() error {
+	if l.namespaceLister == nil {
+		return fmt.Errorf("missing namespaceLister")
+	}
+	if l.client == nil {
+		return fmt.Errorf("missing client")
+	}
+	return nil
+}
+
+// accessReviewResources are resources which give a view into permissions in a namespace.  Users must be allowed to create these
+// resources because returning "not found" errors allows someone to search for the "people I'm going to fire in 2017" namespace.
+var accessReviewResources = map[schema.GroupResource]bool{
+	{Group: "authorization.k8s.io", Resource: "localsubjectaccessreviews"}: true,
+}
+
+func isAccessReview(a admission.Attributes) bool {
+	return accessReviewResources[a.GetResource().GroupResource()]
+}