/
admission.go
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/
admission.go
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// Copyright (c) 2019 SAP SE or an SAP affiliate company. All rights reserved. This file is licensed under the Apache Software License, v. 2 except as noted otherwise in the LICENSE file
//
// 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 resources
import (
"context"
"errors"
"fmt"
"io"
"github.com/gardener/gardener/pkg/apis/core"
admissioninitializer "github.com/gardener/gardener/pkg/apiserver/admission/initializer"
coreclientset "github.com/gardener/gardener/pkg/client/core/clientset/internalversion"
apierrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apiserver/pkg/admission"
)
const (
// PluginName is the name of this admission plugin.
PluginName = "ControllerRegistrationResources"
)
// Register registers a plugin.
func Register(plugins *admission.Plugins) {
plugins.Register(PluginName, NewFactory)
}
// NewFactory creates a new PluginFactory.
func NewFactory(config io.Reader) (admission.Interface, error) {
return New()
}
// Resources contains an admission handler and listers.
type Resources struct {
*admission.Handler
coreClient coreclientset.Interface
readyFunc admission.ReadyFunc
}
var (
_ = admissioninitializer.WantsInternalCoreClientset(&Resources{})
readyFuncs = []admission.ReadyFunc{}
)
// New creates a new Resources admission plugin.
func New() (*Resources, error) {
return &Resources{
Handler: admission.NewHandler(admission.Create, admission.Update),
}, nil
}
// AssignReadyFunc assigns the ready function to the admission handler.
func (r *Resources) AssignReadyFunc(f admission.ReadyFunc) {
r.readyFunc = f
r.SetReadyFunc(f)
}
// SetInternalCoreClientset gets the clientset from the Kubernetes client.
func (r *Resources) SetInternalCoreClientset(c coreclientset.Interface) {
r.coreClient = c
}
// ValidateInitialization checks whether the plugin was correctly initialized.
func (r *Resources) ValidateInitialization() error {
return nil
}
var _ admission.ValidationInterface = &Resources{}
// Validate makes admissions decisions based on the resources specified in a ControllerRegistration object.
// It does reject the request if there is any other existing ControllerRegistration object in the system that
// specifies the same resource kind/type combination like the incoming object.
func (r *Resources) Validate(ctx context.Context, a admission.Attributes, o admission.ObjectInterfaces) error {
// Wait until the caches have been synced
if r.readyFunc == nil {
r.AssignReadyFunc(func() bool {
for _, readyFunc := range readyFuncs {
if !readyFunc() {
return false
}
}
return true
})
}
if !r.WaitForReady() {
return admission.NewForbidden(a, errors.New("not yet ready to handle request"))
}
// Ignore all kinds other than Shoot or Project.
if a.GetKind().GroupKind() != core.Kind("ControllerRegistration") {
return nil
}
controllerRegistration, ok := a.GetObject().(*core.ControllerRegistration)
if !ok {
return apierrors.NewBadRequest("could not convert resource into ControllerRegistration object")
}
// Live lookup to prevent missing any data
controllerRegistrationList, err := r.coreClient.Core().ControllerRegistrations().List(ctx, metav1.ListOptions{})
if err != nil {
return err
}
existingResources := map[string]string{}
for _, obj := range controllerRegistrationList.Items {
if obj.Name == controllerRegistration.Name {
continue
}
for _, resource := range obj.Spec.Resources {
if resource.Primary != nil && !*resource.Primary {
continue
}
existingResources[resource.Kind] = resource.Type
}
}
for _, resource := range controllerRegistration.Spec.Resources {
if resource.Primary != nil && !*resource.Primary {
continue
}
if t, ok := existingResources[resource.Kind]; ok && t == resource.Type {
return admission.NewForbidden(a, fmt.Errorf("another ControllerRegistration resource already exists that controls resource %s/%s primarily", resource.Kind, resource.Type))
}
}
return nil
}