mirror of
https://github.com/coredns/coredns.git
synced 2025-12-20 00:55:11 -05:00
Initial implementation of ForwardCRD plugin (#4512)
* Add forwardcrd plugin README.md Co-authored-by: Aidan Obley <aobley@vmware.com> Signed-off-by: Christian Ang <angc@vmware.com> * Create forwardcrd plugin - Place forwardcrd before forward plugin in plugin list. This will avoid forward from preventing the forwardcrd plugin from handling any queries in the case of having a default upstream forwarder in a server block (as is the case in the default kubernetes Corefile). Co-authored-by: Aidan Obley <aobley@vmware.com> Signed-off-by: Christian Ang <angc@vmware.com> * Add Forward CRD Signed-off-by: Christian Ang <angc@vmware.com> * Add NewWithConfig to forward plugin - allows external packages to instanciate forward plugins Co-authored-by: Aidan Obley <aobley@vmware.com> Signed-off-by: Christian Ang <angc@vmware.com> * ForwardCRD plugin handles requests for Forward CRs - add a Kubernetes controller that can read Forward CRs - instances of the forward plugin are created based on Forward CRs from the Kubernetes controller - DNS requests are handled by calling matching Forward plugin instances based on zone name - Defaults to the kube-system namespace to align with Corefile RBAC Signed-off-by: Christian Ang <angc@vmware.com> Use klog v2 in forwardcrd plugin * Refactor forward setup to use NewWithConfig Co-authored-by: Christian Ang <angc@vmware.com> Signed-off-by: Edwin Xie <exie@vmware.com> * Use ParseInt instead of Atoi - to ensure that the bitsize is 32 for later casting to uint32 Signed-off-by: Christian Ang <angc@vmware.com> * Add @christianang to CODEOWNERS for forwardcrd Signed-off-by: Christian Ang <angc@vmware.com> Co-authored-by: Edwin Xie <exie@vmware.com>
This commit is contained in:
Christian Ang
GitHub
238
plugin/forwardcrd/controller.go
Normal file
238
plugin/forwardcrd/controller.go
Normal file
@@ -0,0 +1,238 @@
|
||||
package forwardcrd
|
||||
|
||||
import (
|
||||
"context"
|
||||
"errors"
|
||||
"fmt"
|
||||
"sync"
|
||||
"time"
|
||||
|
||||
"github.com/coredns/coredns/plugin"
|
||||
"github.com/coredns/coredns/plugin/dnstap"
|
||||
"github.com/coredns/coredns/plugin/forward"
|
||||
corednsv1alpha1 "github.com/coredns/coredns/plugin/forwardcrd/apis/coredns/v1alpha1"
|
||||
|
||||
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
|
||||
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
|
||||
"k8s.io/apimachinery/pkg/runtime"
|
||||
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
|
||||
"k8s.io/apimachinery/pkg/util/wait"
|
||||
"k8s.io/apimachinery/pkg/watch"
|
||||
"k8s.io/client-go/dynamic"
|
||||
"k8s.io/client-go/tools/cache"
|
||||
"k8s.io/client-go/util/workqueue"
|
||||
)
|
||||
|
||||
const defaultResyncPeriod = 0
|
||||
|
||||
type forwardCRDController interface {
|
||||
Run(threads int)
|
||||
HasSynced() bool
|
||||
Stop() error
|
||||
}
|
||||
|
||||
type forwardCRDControl struct {
|
||||
client dynamic.Interface
|
||||
scheme *runtime.Scheme
|
||||
forwardController cache.Controller
|
||||
forwardLister cache.Store
|
||||
workqueue workqueue.RateLimitingInterface
|
||||
pluginMap *PluginInstanceMap
|
||||
instancer pluginInstancer
|
||||
tapPlugin *dnstap.Dnstap
|
||||
namespace string
|
||||
|
||||
// stopLock is used to enforce only a single call to Stop is active.
|
||||
// Needed because we allow stopping through an http endpoint and
|
||||
// allowing concurrent stoppers leads to stack traces.
|
||||
stopLock sync.Mutex
|
||||
shutdown bool
|
||||
stopCh chan struct{}
|
||||
}
|
||||
|
||||
type lifecyclePluginHandler interface {
|
||||
plugin.Handler
|
||||
OnStartup() error
|
||||
OnShutdown() error
|
||||
}
|
||||
|
||||
type pluginInstancer func(forward.ForwardConfig) (lifecyclePluginHandler, error)
|
||||
|
||||
func newForwardCRDController(ctx context.Context, client dynamic.Interface, scheme *runtime.Scheme, namespace string, pluginMap *PluginInstanceMap, instancer pluginInstancer) forwardCRDController {
|
||||
controller := forwardCRDControl{
|
||||
client: client,
|
||||
scheme: scheme,
|
||||
stopCh: make(chan struct{}),
|
||||
namespace: namespace,
|
||||
pluginMap: pluginMap,
|
||||
instancer: instancer,
|
||||
workqueue: workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "ForwardCRD"),
|
||||
}
|
||||
|
||||
controller.forwardLister, controller.forwardController = cache.NewInformer(
|
||||
&cache.ListWatch{
|
||||
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
|
||||
if namespace != "" {
|
||||
return controller.client.Resource(corednsv1alpha1.GroupVersion.WithResource("forwards")).Namespace(namespace).List(ctx, options)
|
||||
}
|
||||
return controller.client.Resource(corednsv1alpha1.GroupVersion.WithResource("forwards")).List(ctx, options)
|
||||
},
|
||||
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
|
||||
if namespace != "" {
|
||||
return controller.client.Resource(corednsv1alpha1.GroupVersion.WithResource("forwards")).Namespace(namespace).Watch(ctx, options)
|
||||
}
|
||||
return controller.client.Resource(corednsv1alpha1.GroupVersion.WithResource("forwards")).Watch(ctx, options)
|
||||
},
|
||||
},
|
||||
&unstructured.Unstructured{},
|
||||
defaultResyncPeriod,
|
||||
cache.ResourceEventHandlerFuncs{
|
||||
AddFunc: func(obj interface{}) {
|
||||
key, err := cache.MetaNamespaceKeyFunc(obj)
|
||||
if err == nil {
|
||||
controller.workqueue.Add(key)
|
||||
}
|
||||
},
|
||||
UpdateFunc: func(oldObj, newObj interface{}) {
|
||||
key, err := cache.MetaNamespaceKeyFunc(newObj)
|
||||
if err == nil {
|
||||
controller.workqueue.Add(key)
|
||||
}
|
||||
},
|
||||
DeleteFunc: func(obj interface{}) {
|
||||
key, err := cache.DeletionHandlingMetaNamespaceKeyFunc(obj)
|
||||
if err == nil {
|
||||
controller.workqueue.Add(key)
|
||||
}
|
||||
},
|
||||
},
|
||||
)
|
||||
|
||||
return &controller
|
||||
}
|
||||
|
||||
// Run starts the controller. Threads is the number of workers that can process
|
||||
// work on the workqueue in parallel.
|
||||
func (d *forwardCRDControl) Run(threads int) {
|
||||
defer utilruntime.HandleCrash()
|
||||
defer d.workqueue.ShutDown()
|
||||
|
||||
go d.forwardController.Run(d.stopCh)
|
||||
|
||||
if !cache.WaitForCacheSync(d.stopCh, d.forwardController.HasSynced) {
|
||||
utilruntime.HandleError(errors.New("Timed out waiting for caches to sync"))
|
||||
return
|
||||
}
|
||||
|
||||
for i := 0; i < threads; i++ {
|
||||
go wait.Until(d.runWorker, time.Second, d.stopCh)
|
||||
}
|
||||
|
||||
<-d.stopCh
|
||||
|
||||
// Shutdown all plugins
|
||||
for _, plugin := range d.pluginMap.List() {
|
||||
plugin.OnShutdown()
|
||||
}
|
||||
}
|
||||
|
||||
// HasSynced returns true once the controller has completed an initial resource
|
||||
// listing.
|
||||
func (d *forwardCRDControl) HasSynced() bool {
|
||||
return d.forwardController.HasSynced()
|
||||
}
|
||||
|
||||
// Stop stops the controller.
|
||||
func (d *forwardCRDControl) Stop() error {
|
||||
d.stopLock.Lock()
|
||||
defer d.stopLock.Unlock()
|
||||
|
||||
// Only try draining the workqueue if we haven't already.
|
||||
if !d.shutdown {
|
||||
close(d.stopCh)
|
||||
d.shutdown = true
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
return fmt.Errorf("shutdown already in progress")
|
||||
}
|
||||
|
||||
func (d *forwardCRDControl) runWorker() {
|
||||
for d.processNextItem() {
|
||||
}
|
||||
}
|
||||
|
||||
func (d *forwardCRDControl) processNextItem() bool {
|
||||
key, quit := d.workqueue.Get()
|
||||
if quit {
|
||||
return false
|
||||
}
|
||||
|
||||
defer d.workqueue.Done(key)
|
||||
|
||||
err := d.sync(key.(string))
|
||||
if err != nil {
|
||||
log.Errorf("Error syncing Forward %v: %v", key, err)
|
||||
d.workqueue.AddRateLimited(key)
|
||||
return true
|
||||
}
|
||||
|
||||
d.workqueue.Forget(key)
|
||||
|
||||
return true
|
||||
}
|
||||
|
||||
func (d *forwardCRDControl) sync(key string) error {
|
||||
obj, exists, err := d.forwardLister.GetByKey(key)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if !exists {
|
||||
plugin := d.pluginMap.Delete(key)
|
||||
if plugin != nil {
|
||||
plugin.OnShutdown()
|
||||
}
|
||||
} else {
|
||||
f, err := d.convertToForward(obj.(runtime.Object))
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
forwardConfig := forward.ForwardConfig{
|
||||
From: f.Spec.From,
|
||||
To: f.Spec.To,
|
||||
TapPlugin: d.tapPlugin,
|
||||
}
|
||||
plugin, err := d.instancer(forwardConfig)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
err = plugin.OnStartup()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
oldPlugin, updated := d.pluginMap.Upsert(key, f.Spec.From, plugin)
|
||||
if updated {
|
||||
oldPlugin.OnShutdown()
|
||||
}
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (d *forwardCRDControl) convertToForward(obj runtime.Object) (*corednsv1alpha1.Forward, error) {
|
||||
unstructured, ok := obj.(*unstructured.Unstructured)
|
||||
if !ok {
|
||||
return nil, fmt.Errorf("object was not Unstructured")
|
||||
}
|
||||
|
||||
switch unstructured.GetKind() {
|
||||
case "Forward":
|
||||
forward := &corednsv1alpha1.Forward{}
|
||||
err := d.scheme.Convert(unstructured, forward, nil)
|
||||
return forward, err
|
||||
default:
|
||||
return nil, fmt.Errorf("unsupported object type: %T", unstructured)
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user