137 lines
4.4 KiB
Go
137 lines
4.4 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package lifecycle
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import (
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"fmt"
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"io"
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"time"
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clientset "k8s.io/kubernetes/pkg/client/clientset_generated/internalclientset"
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"k8s.io/kubernetes/pkg/admission"
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"k8s.io/kubernetes/pkg/api"
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"k8s.io/kubernetes/pkg/api/errors"
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"k8s.io/kubernetes/pkg/client/cache"
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"k8s.io/kubernetes/pkg/runtime"
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"k8s.io/kubernetes/pkg/util/sets"
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"k8s.io/kubernetes/pkg/watch"
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)
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const PluginName = "NamespaceLifecycle"
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func init() {
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admission.RegisterPlugin(PluginName, func(client clientset.Interface, config io.Reader) (admission.Interface, error) {
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return NewLifecycle(client, sets.NewString(api.NamespaceDefault)), nil
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})
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}
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// lifecycle is an implementation of admission.Interface.
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// It enforces life-cycle constraints around a Namespace depending on its Phase
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type lifecycle struct {
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*admission.Handler
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client clientset.Interface
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store cache.Store
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immortalNamespaces sets.String
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}
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func (l *lifecycle) Admit(a admission.Attributes) (err error) {
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// prevent deletion of immortal namespaces
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if a.GetOperation() == admission.Delete && a.GetKind() == api.Kind("Namespace") && l.immortalNamespaces.Has(a.GetName()) {
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return errors.NewForbidden(a.GetResource(), a.GetName(), fmt.Errorf("this namespace may not be deleted"))
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}
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// if we're here, then we've already passed authentication, so we're allowed to do what we're trying to do
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// if we're here, then the API server has found a route, which means that if we have a non-empty namespace
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// its a namespaced resource.
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if len(a.GetNamespace()) == 0 || a.GetKind() == api.Kind("Namespace") {
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// if a namespace is deleted, we want to prevent all further creates into it
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// while it is undergoing termination. to reduce incidences where the cache
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// is slow to update, we forcefully remove the namespace from our local cache.
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// this will cause a live lookup of the namespace to get its latest state even
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// before the watch notification is received.
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if a.GetOperation() == admission.Delete {
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l.store.Delete(&api.Namespace{
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ObjectMeta: api.ObjectMeta{
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Name: a.GetName(),
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},
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})
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}
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return nil
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}
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namespaceObj, exists, err := l.store.Get(&api.Namespace{
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ObjectMeta: api.ObjectMeta{
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Name: a.GetNamespace(),
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Namespace: "",
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},
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})
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if err != nil {
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return errors.NewInternalError(err)
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}
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// refuse to operate on non-existent namespaces
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if !exists {
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// in case of latency in our caches, make a call direct to storage to verify that it truly exists or not
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namespaceObj, err = l.client.Core().Namespaces().Get(a.GetNamespace())
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if err != nil {
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if errors.IsNotFound(err) {
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return err
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}
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return errors.NewInternalError(err)
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}
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}
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// ensure that we're not trying to create objects in terminating namespaces
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if a.GetOperation() == admission.Create {
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namespace := namespaceObj.(*api.Namespace)
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if namespace.Status.Phase != api.NamespaceTerminating {
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return nil
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}
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// TODO: This should probably not be a 403
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return admission.NewForbidden(a, fmt.Errorf("Unable to create new content in namespace %s because it is being terminated.", a.GetNamespace()))
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}
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return nil
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}
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// NewLifecycle creates a new namespace lifecycle admission control handler
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func NewLifecycle(c clientset.Interface, immortalNamespaces sets.String) admission.Interface {
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store := cache.NewStore(cache.MetaNamespaceKeyFunc)
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reflector := cache.NewReflector(
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&cache.ListWatch{
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ListFunc: func(options api.ListOptions) (runtime.Object, error) {
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return c.Core().Namespaces().List(options)
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},
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WatchFunc: func(options api.ListOptions) (watch.Interface, error) {
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return c.Core().Namespaces().Watch(options)
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},
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},
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&api.Namespace{},
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store,
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5*time.Minute,
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)
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reflector.Run()
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return &lifecycle{
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Handler: admission.NewHandler(admission.Create, admission.Update, admission.Delete),
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client: c,
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store: store,
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immortalNamespaces: immortalNamespaces,
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}
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}
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