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119 lines
3.9 KiB
Go
119 lines
3.9 KiB
Go
/*
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Copyright 2014 The Kubernetes Authors.
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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 exists
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import (
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"context"
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"fmt"
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"io"
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"k8s.io/apimachinery/pkg/api/errors"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apiserver/pkg/admission"
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genericadmissioninitializer "k8s.io/apiserver/pkg/admission/initializer"
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informers "k8s.io/client-go/informers"
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"k8s.io/client-go/kubernetes"
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corev1listers "k8s.io/client-go/listers/core/v1"
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api "k8s.io/kubernetes/pkg/apis/core"
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)
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// PluginName indicates name of admission plugin.
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const PluginName = "NamespaceExists"
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// Register registers a plugin
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func Register(plugins *admission.Plugins) {
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plugins.Register(PluginName, func(config io.Reader) (admission.Interface, error) {
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return NewExists(), nil
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})
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}
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// Exists is an implementation of admission.Interface.
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// It rejects all incoming requests in a namespace context if the namespace does not exist.
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// It is useful in deployments that want to enforce pre-declaration of a Namespace resource.
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type Exists struct {
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*admission.Handler
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client kubernetes.Interface
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namespaceLister corev1listers.NamespaceLister
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}
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var _ admission.ValidationInterface = &Exists{}
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var _ = genericadmissioninitializer.WantsExternalKubeInformerFactory(&Exists{})
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var _ = genericadmissioninitializer.WantsExternalKubeClientSet(&Exists{})
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// Validate makes an admission decision based on the request attributes
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func (e *Exists) Validate(ctx context.Context, a admission.Attributes, o admission.ObjectInterfaces) error {
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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().GroupKind() == api.Kind("Namespace") {
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return nil
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}
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// we need to wait for our caches to warm
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if !e.WaitForReady() {
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return admission.NewForbidden(a, fmt.Errorf("not yet ready to handle request"))
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}
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_, err := e.namespaceLister.Get(a.GetNamespace())
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if err == nil {
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return nil
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}
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if !errors.IsNotFound(err) {
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return errors.NewInternalError(err)
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}
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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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_, err = e.client.CoreV1().Namespaces().Get(context.TODO(), a.GetNamespace(), metav1.GetOptions{})
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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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return nil
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}
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// NewExists creates a new namespace exists admission control handler
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func NewExists() *Exists {
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return &Exists{
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Handler: admission.NewHandler(admission.Create, admission.Update, admission.Delete),
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}
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}
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// SetExternalKubeClientSet implements the WantsExternalKubeClientSet interface.
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func (e *Exists) SetExternalKubeClientSet(client kubernetes.Interface) {
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e.client = client
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}
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// SetExternalKubeInformerFactory implements the WantsExternalKubeInformerFactory interface.
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func (e *Exists) SetExternalKubeInformerFactory(f informers.SharedInformerFactory) {
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namespaceInformer := f.Core().V1().Namespaces()
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e.namespaceLister = namespaceInformer.Lister()
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e.SetReadyFunc(namespaceInformer.Informer().HasSynced)
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}
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// ValidateInitialization implements the InitializationValidator interface.
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func (e *Exists) ValidateInitialization() error {
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if e.namespaceLister == nil {
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return fmt.Errorf("missing namespaceLister")
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}
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if e.client == nil {
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return fmt.Errorf("missing client")
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}
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return nil
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}
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