@@ -369,3 +369,128 @@ func (c *ServiceConfig) handleDeleteService(obj interface{}) {
369369 c .eventHandlers [i ].OnServiceDelete (service )
370370 }
371371}
372+
373+ // NodeHandler is an abstract interface of objects which receive
374+ // notifications about node object changes.
375+ type NodeHandler interface {
376+ // OnNodeAdd is called whenever creation of new node object
377+ // is observed.
378+ OnNodeAdd (node * v1.Node )
379+ // OnNodeUpdate is called whenever modification of an existing
380+ // node object is observed.
381+ OnNodeUpdate (oldNode , node * v1.Node )
382+ // OnNodeDelete is called whever deletion of an existing node
383+ // object is observed.
384+ OnNodeDelete (node * v1.Node )
385+ // OnNodeSynced is called once all the initial event handlers were
386+ // called and the state is fully propagated to local cache.
387+ OnNodeSynced ()
388+ }
389+
390+ // NoopNodeHandler is a noop handler for proxiers that have not yet
391+ // implemented a full NodeHandler.
392+ type NoopNodeHandler struct {}
393+
394+ // OnNodeAdd is a noop handler for Node creates.
395+ func (* NoopNodeHandler ) OnNodeAdd (node * v1.Node ) {}
396+
397+ // OnNodeUpdate is a noop handler for Node updates.
398+ func (* NoopNodeHandler ) OnNodeUpdate (oldNode , node * v1.Node ) {}
399+
400+ // OnNodeDelete is a noop handler for Node deletes.
401+ func (* NoopNodeHandler ) OnNodeDelete (node * v1.Node ) {}
402+
403+ // OnNodeSynced is a noop handler for Node syncs.
404+ func (* NoopNodeHandler ) OnNodeSynced () {}
405+
406+ // NodeConfig tracks a set of node configurations.
407+ // It accepts "set", "add" and "remove" operations of node via channels, and invokes registered handlers on change.
408+ type NodeConfig struct {
409+ listerSynced cache.InformerSynced
410+ eventHandlers []NodeHandler
411+ }
412+
413+ // NewNodeConfig creates a new NodeConfig.
414+ func NewNodeConfig (nodeInformer coreinformers.NodeInformer , resyncPeriod time.Duration ) * NodeConfig {
415+ result := & NodeConfig {
416+ listerSynced : nodeInformer .Informer ().HasSynced ,
417+ }
418+
419+ nodeInformer .Informer ().AddEventHandlerWithResyncPeriod (
420+ cache.ResourceEventHandlerFuncs {
421+ AddFunc : result .handleAddNode ,
422+ UpdateFunc : result .handleUpdateNode ,
423+ DeleteFunc : result .handleDeleteNode ,
424+ },
425+ resyncPeriod ,
426+ )
427+
428+ return result
429+ }
430+
431+ // RegisterEventHandler registers a handler which is called on every node change.
432+ func (c * NodeConfig ) RegisterEventHandler (handler NodeHandler ) {
433+ c .eventHandlers = append (c .eventHandlers , handler )
434+ }
435+
436+ // Run starts the goroutine responsible for calling registered handlers.
437+ func (c * NodeConfig ) Run (stopCh <- chan struct {}) {
438+ klog .Info ("Starting node config controller" )
439+
440+ if ! cache .WaitForNamedCacheSync ("node config" , stopCh , c .listerSynced ) {
441+ return
442+ }
443+
444+ for i := range c .eventHandlers {
445+ klog .V (3 ).Infof ("Calling handler.OnNodeSynced()" )
446+ c .eventHandlers [i ].OnNodeSynced ()
447+ }
448+ }
449+
450+ func (c * NodeConfig ) handleAddNode (obj interface {}) {
451+ node , ok := obj .(* v1.Node )
452+ if ! ok {
453+ utilruntime .HandleError (fmt .Errorf ("unexpected object type: %v" , obj ))
454+ return
455+ }
456+ for i := range c .eventHandlers {
457+ klog .V (4 ).Infof ("Calling handler.OnNodeAdd" )
458+ c .eventHandlers [i ].OnNodeAdd (node )
459+ }
460+ }
461+
462+ func (c * NodeConfig ) handleUpdateNode (oldObj , newObj interface {}) {
463+ oldNode , ok := oldObj .(* v1.Node )
464+ if ! ok {
465+ utilruntime .HandleError (fmt .Errorf ("unexpected object type: %v" , oldObj ))
466+ return
467+ }
468+ node , ok := newObj .(* v1.Node )
469+ if ! ok {
470+ utilruntime .HandleError (fmt .Errorf ("unexpected object type: %v" , newObj ))
471+ return
472+ }
473+ for i := range c .eventHandlers {
474+ klog .V (5 ).Infof ("Calling handler.OnNodeUpdate" )
475+ c .eventHandlers [i ].OnNodeUpdate (oldNode , node )
476+ }
477+ }
478+
479+ func (c * NodeConfig ) handleDeleteNode (obj interface {}) {
480+ node , ok := obj .(* v1.Node )
481+ if ! ok {
482+ tombstone , ok := obj .(cache.DeletedFinalStateUnknown )
483+ if ! ok {
484+ utilruntime .HandleError (fmt .Errorf ("unexpected object type: %v" , obj ))
485+ return
486+ }
487+ if node , ok = tombstone .Obj .(* v1.Node ); ! ok {
488+ utilruntime .HandleError (fmt .Errorf ("unexpected object type: %v" , obj ))
489+ return
490+ }
491+ }
492+ for i := range c .eventHandlers {
493+ klog .V (4 ).Infof ("Calling handler.OnNodeDelete" )
494+ c .eventHandlers [i ].OnNodeDelete (node )
495+ }
496+ }
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