Avoid duplicates on controller restart when using ListerWatcher in cache.NewSharedIndexInformer

General Discussions
1

I am writing a controller to capture the events and do some stateless processing. When I am using ListWatch in cache.NewSharedIndexInformer, how can I say it not to list all the objects but start from current state (basically I need just Watch and not List)?

    	informer := cache.NewSharedIndexInformer(
    		// This lists entire cache every time we restart the controller
    		&cache.ListWatch{
    			ListFunc: func(options meta_v1.ListOptions) (runtime.Object, error) {
    				return kubeClient.CoreV1().Events(core_v1.NamespaceAll).List(options)
    			},
    			WatchFunc: func(options meta_v1.ListOptions) (watch.Interface, error) {
    				return kubeClient.CoreV1().Events(core_v1.NamespaceAll).Watch(options)
    			},
    		},
    		&core_v1.Event{},
    		0, // Skip resync
    		cache.Indexers{},
    	)

Currently whenever my controller is restarted I get a slew of old events due to the ListFunc (it lists from the beginning). Since the processing is stateless controller do not know whether it has seen the events earlier. Since ListFunc is sending everything we are seeing a lot of duplicates.

One dirty workaround is to replace core_v1.NamespaceAll in ListFunc with some namespace name that do not exist (eg, “NOT_EXISTS”).

What is the cleaner way to solve this?

2

To close the loop, looks like I cannot. Probably do a watch (Until?) with resourceVersion passed.