package k8s import ( corev1 "k8s.io/api/core/v1" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" ) // ResourceEventHandler handles Add, Update or Delete Events for resources. type ResourceEventHandler struct { Ev chan<- interface{} } // OnAdd is called on Add Events. func (reh *ResourceEventHandler) OnAdd(obj interface{}) { eventHandlerFunc(reh.Ev, obj) } // OnUpdate is called on Update Events. // Ignores useless changes. func (reh *ResourceEventHandler) OnUpdate(oldObj, newObj interface{}) { if objChanged(oldObj, newObj) { eventHandlerFunc(reh.Ev, newObj) } } // OnDelete is called on Delete Events. func (reh *ResourceEventHandler) OnDelete(obj interface{}) { eventHandlerFunc(reh.Ev, obj) } // eventHandlerFunc will pass the obj on to the events channel or drop it. // This is so passing the events along won't block in the case of high volume. // The events are only used for signaling anyway so dropping a few is ok. func eventHandlerFunc(events chan<- interface{}, obj interface{}) { select { case events <- obj: default: } } func objChanged(oldObj, newObj interface{}) bool { if oldObj == nil || newObj == nil { return true } if oldObj.(metav1.Object).GetResourceVersion() == newObj.(metav1.Object).GetResourceVersion() { return false } if _, ok := oldObj.(*corev1.Endpoints); ok { if endpointsChanged(oldObj.(*corev1.Endpoints), newObj.(*corev1.Endpoints)) { return true } } return false } func endpointsChanged(a, b *corev1.Endpoints) bool { if len(a.Subsets) != len(b.Subsets) { return true } for i, sa := range a.Subsets { sb := b.Subsets[i] if subsetsChanged(sa, sb) { return true } } return false } func subsetsChanged(sa, sb corev1.EndpointSubset) bool { if len(sa.Addresses) != len(sb.Addresses) { return true } if len(sa.Ports) != len(sb.Ports) { return true } // in Addresses and Ports, we should be able to rely on // these being sorted and able to be compared // they are supposed to be in a canonical format for addr, aaddr := range sa.Addresses { baddr := sb.Addresses[addr] if aaddr.IP != baddr.IP { return true } if aaddr.Hostname != baddr.Hostname { return true } } for port, aport := range sa.Ports { bport := sb.Ports[port] if aport.Name != bport.Name { return true } if aport.Port != bport.Port { return true } if aport.Protocol != bport.Protocol { return true } } return false }