/
plugin.go
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/
plugin.go
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/*
Copyright 2022 The KCP 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 mutatingwebhook
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"sync"
kcpkubernetesinformers "github.com/kcp-dev/client-go/informers"
kcpkubernetesclientset "github.com/kcp-dev/client-go/kubernetes"
"github.com/kcp-dev/logicalcluster/v3"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apiserver/pkg/admission"
"k8s.io/apiserver/pkg/admission/configuration"
"k8s.io/apiserver/pkg/admission/plugin/webhook/generic"
"k8s.io/apiserver/pkg/admission/plugin/webhook/mutating"
genericapirequest "k8s.io/apiserver/pkg/endpoints/request"
kcpinitializers "github.com/kcp-dev/kcp/pkg/admission/initializers"
apisv1alpha1 "github.com/kcp-dev/kcp/sdk/apis/apis/v1alpha1"
kcpinformers "github.com/kcp-dev/kcp/sdk/client/informers/externalversions"
)
const (
PluginName = "apis.kcp.io/MutatingWebhook"
)
type Plugin struct {
*admission.Handler
config []byte
// Injected/set via initializers
kubeClusterClient kcpkubernetesclientset.ClusterInterface
localKubeSharedInformerFactory kcpkubernetesinformers.SharedInformerFactory
globalKubeSharedInformerFactory kcpkubernetesinformers.SharedInformerFactory
getAPIBindings func(clusterName logicalcluster.Name) ([]*apisv1alpha1.APIBinding, error)
managerLock sync.Mutex
managersCache map[logicalcluster.Name]generic.Source
}
var (
_ = admission.MutationInterface(&Plugin{})
_ = admission.InitializationValidator(&Plugin{})
_ = kcpinitializers.WantsKubeClusterClient(&Plugin{})
_ = kcpinitializers.WantsKubeInformers(&Plugin{})
_ = kcpinitializers.WantsKcpInformers(&Plugin{})
)
func NewMutatingAdmissionWebhook(configFile io.Reader) (*Plugin, error) {
p := &Plugin{
managerLock: sync.Mutex{},
managersCache: make(map[logicalcluster.Name]generic.Source),
Handler: admission.NewHandler(admission.Connect, admission.Create, admission.Delete, admission.Update),
}
if configFile != nil {
config, err := io.ReadAll(configFile)
if err != nil {
return nil, err
}
p.config = config
}
return p, nil
}
func Register(plugins *admission.Plugins) {
plugins.Register(PluginName, func(configFile io.Reader) (admission.Interface, error) {
return NewMutatingAdmissionWebhook(configFile)
})
}
func (p *Plugin) Admit(ctx context.Context, attr admission.Attributes, o admission.ObjectInterfaces) error {
cluster, err := genericapirequest.ValidClusterFrom(ctx)
if err != nil {
return err
}
clusterName := cluster.Name
var config io.Reader
if len(p.config) > 0 {
config = bytes.NewReader(p.config)
}
hookSource, err := p.getHookSource(clusterName, attr.GetResource().GroupResource())
if err != nil {
return err
}
plugin, err := mutating.NewMutatingWebhook(config)
if err != nil {
return fmt.Errorf("error creating mutating admission webhook: %w", err)
}
plugin.SetExternalKubeClientSet(p.kubeClusterClient.Cluster(clusterName.Path()))
plugin.SetNamespaceInformer(p.localKubeSharedInformerFactory.Core().V1().Namespaces().Cluster(clusterName))
plugin.SetHookSource(hookSource)
plugin.SetReadyFuncFromKCP(p.localKubeSharedInformerFactory.Core().V1().Namespaces().Cluster(clusterName))
if err := plugin.ValidateInitialization(); err != nil {
return fmt.Errorf("error validating MutatingWebhook initialization: %w", err)
}
return plugin.Admit(ctx, attr, o)
}
func (p *Plugin) getHookSource(clusterName logicalcluster.Name, groupResource schema.GroupResource) (generic.Source, error) {
clusterNameForGroupResource, err := p.getSourceClusterForGroupResource(clusterName, groupResource)
if err != nil {
return nil, err
}
p.managerLock.Lock()
defer p.managerLock.Unlock()
if _, ok := p.managersCache[clusterNameForGroupResource]; !ok {
p.managersCache[clusterNameForGroupResource] = configuration.NewMutatingWebhookConfigurationManagerForInformer(
p.globalKubeSharedInformerFactory.Admissionregistration().V1().MutatingWebhookConfigurations().Cluster(clusterNameForGroupResource),
)
}
return p.managersCache[clusterNameForGroupResource], nil
}
func (p *Plugin) getSourceClusterForGroupResource(clusterName logicalcluster.Name, groupResource schema.GroupResource) (logicalcluster.Name, error) {
objs, err := p.getAPIBindings(clusterName)
if err != nil {
return "", err
}
for _, apiBinding := range objs {
for _, br := range apiBinding.Status.BoundResources {
if br.Group == groupResource.Group && br.Resource == groupResource.Resource {
// GroupResource comes from an APIBinding/APIExport
return logicalcluster.Name(apiBinding.Status.APIExportClusterName), nil
}
}
}
// GroupResource is local to this cluster
return clusterName, nil
}
func (p *Plugin) ValidateInitialization() error {
if p.kubeClusterClient == nil {
return errors.New("missing kubeClusterClient")
}
if p.localKubeSharedInformerFactory == nil {
return errors.New("missing localKubeSharedInformerFactory")
}
if p.globalKubeSharedInformerFactory == nil {
return errors.New("missing globalKubeSharedInformerFactory")
}
return nil
}
func (p *Plugin) SetKubeClusterClient(client kcpkubernetesclientset.ClusterInterface) {
p.kubeClusterClient = client
}
func (p *Plugin) SetKubeInformers(local, global kcpkubernetesinformers.SharedInformerFactory) {
p.localKubeSharedInformerFactory = local
p.globalKubeSharedInformerFactory = global
}
func (p *Plugin) SetKcpInformers(local, global kcpinformers.SharedInformerFactory) {
p.getAPIBindings = func(clusterName logicalcluster.Name) ([]*apisv1alpha1.APIBinding, error) {
return local.Apis().V1alpha1().APIBindings().Lister().Cluster(clusterName).List(labels.Everything())
}
}