Service Topology implementation

* Implement Service Topology for ipvs and iptables proxier
* Add test files
* API validation

pkg/proxy/config/config.go

@@ -369,3 +369,128 @@ func (c *ServiceConfig) handleDeleteService(obj interface{}) {
 		c.eventHandlers[i].OnServiceDelete(service)
 	}
 }
+
+// NodeHandler is an abstract interface of objects which receive
+// notifications about node object changes.
+type NodeHandler interface {
+	// OnNodeAdd is called whenever creation of new node object
+	// is observed.
+	OnNodeAdd(node *v1.Node)
+	// OnNodeUpdate is called whenever modification of an existing
+	// node object is observed.
+	OnNodeUpdate(oldNode, node *v1.Node)
+	// OnNodeDelete is called whever deletion of an existing node
+	// object is observed.
+	OnNodeDelete(node *v1.Node)
+	// OnNodeSynced is called once all the initial event handlers were
+	// called and the state is fully propagated to local cache.
+	OnNodeSynced()
+}
+
+// NoopNodeHandler is a noop handler for proxiers that have not yet
+// implemented a full NodeHandler.
+type NoopNodeHandler struct{}
+
+// OnNodeAdd is a noop handler for Node creates.
+func (*NoopNodeHandler) OnNodeAdd(node *v1.Node) {}
+
+// OnNodeUpdate is a noop handler for Node updates.
+func (*NoopNodeHandler) OnNodeUpdate(oldNode, node *v1.Node) {}
+
+// OnNodeDelete is a noop handler for Node deletes.
+func (*NoopNodeHandler) OnNodeDelete(node *v1.Node) {}
+
+// OnNodeSynced is a noop handler for Node syncs.
+func (*NoopNodeHandler) OnNodeSynced() {}
+
+// NodeConfig tracks a set of node configurations.
+// It accepts "set", "add" and "remove" operations of node via channels, and invokes registered handlers on change.
+type NodeConfig struct {
+	listerSynced  cache.InformerSynced
+	eventHandlers []NodeHandler
+}
+
+// NewNodeConfig creates a new NodeConfig.
+func NewNodeConfig(nodeInformer coreinformers.NodeInformer, resyncPeriod time.Duration) *NodeConfig {
+	result := &NodeConfig{
+		listerSynced: nodeInformer.Informer().HasSynced,
+	}
+
+	nodeInformer.Informer().AddEventHandlerWithResyncPeriod(
+		cache.ResourceEventHandlerFuncs{
+			AddFunc:    result.handleAddNode,
+			UpdateFunc: result.handleUpdateNode,
+			DeleteFunc: result.handleDeleteNode,
+		},
+		resyncPeriod,
+	)
+
+	return result
+}
+
+// RegisterEventHandler registers a handler which is called on every node change.
+func (c *NodeConfig) RegisterEventHandler(handler NodeHandler) {
+	c.eventHandlers = append(c.eventHandlers, handler)
+}
+
+// Run starts the goroutine responsible for calling registered handlers.
+func (c *NodeConfig) Run(stopCh <-chan struct{}) {
+	klog.Info("Starting node config controller")
+
+	if !cache.WaitForNamedCacheSync("node config", stopCh, c.listerSynced) {
+		return
+	}
+
+	for i := range c.eventHandlers {
+		klog.V(3).Infof("Calling handler.OnNodeSynced()")
+		c.eventHandlers[i].OnNodeSynced()
+	}
+}
+
+func (c *NodeConfig) handleAddNode(obj interface{}) {
+	node, ok := obj.(*v1.Node)
+	if !ok {
+		utilruntime.HandleError(fmt.Errorf("unexpected object type: %v", obj))
+		return
+	}
+	for i := range c.eventHandlers {
+		klog.V(4).Infof("Calling handler.OnNodeAdd")
+		c.eventHandlers[i].OnNodeAdd(node)
+	}
+}
+
+func (c *NodeConfig) handleUpdateNode(oldObj, newObj interface{}) {
+	oldNode, ok := oldObj.(*v1.Node)
+	if !ok {
+		utilruntime.HandleError(fmt.Errorf("unexpected object type: %v", oldObj))
+		return
+	}
+	node, ok := newObj.(*v1.Node)
+	if !ok {
+		utilruntime.HandleError(fmt.Errorf("unexpected object type: %v", newObj))
+		return
+	}
+	for i := range c.eventHandlers {
+		klog.V(5).Infof("Calling handler.OnNodeUpdate")
+		c.eventHandlers[i].OnNodeUpdate(oldNode, node)
+	}
+}
+
+func (c *NodeConfig) handleDeleteNode(obj interface{}) {
+	node, ok := obj.(*v1.Node)
+	if !ok {
+		tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
+		if !ok {
+			utilruntime.HandleError(fmt.Errorf("unexpected object type: %v", obj))
+			return
+		}
+		if node, ok = tombstone.Obj.(*v1.Node); !ok {
+			utilruntime.HandleError(fmt.Errorf("unexpected object type: %v", obj))
+			return
+		}
+	}
+	for i := range c.eventHandlers {
+		klog.V(4).Infof("Calling handler.OnNodeDelete")
+		c.eventHandlers[i].OnNodeDelete(node)
+	}
+}