traefik/pkg/provider/kubernetes/k8s/event_handler.go

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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 {
return endpointsChanged(oldObj.(*corev1.Endpoints), newObj.(*corev1.Endpoints))
}
return true
}
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
}