✨ SetErrorWatchHandler on SharedIndexInformer (kubernetes-sigs#2494)

* add SetErrorWatchHandler to informers

Signed-off-by: Troy Connor <[email protected]>

* pass watchErrorHandler through Options struct

Signed-off-by: Troy Connor <[email protected]>

---------

Signed-off-by: Troy Connor <[email protected]>

Author: troy0820

pkg/cache/cache.go

@@ -188,6 +188,12 @@ type Options struct {
 	// unless there is already one set in ByObject or DefaultNamespaces.
 	DefaultTransform toolscache.TransformFunc
 
+	// DefaultWatchErrorHandler will be used to the WatchErrorHandler which is called
+	// whenever ListAndWatch drops the connection with an error.
+	//
+	// After calling this handler, the informer will backoff and retry.
+	DefaultWatchErrorHandler toolscache.WatchErrorHandler
+
 	// DefaultUnsafeDisableDeepCopy is the default for UnsafeDisableDeepCopy
 	// for everything that doesn't specify this.
 	//
@@ -353,6 +359,7 @@ func newCache(restConfig *rest.Config, opts Options) newCacheFunc {
 					Field: config.FieldSelector,
 				},
 				Transform:             config.Transform,
+				WatchErrorHandler:     opts.DefaultWatchErrorHandler,
 				UnsafeDisableDeepCopy: pointer.BoolDeref(config.UnsafeDisableDeepCopy, false),
 				NewInformer:           opts.newInformer,
 			}),

pkg/cache/internal/informers.go

@@ -49,6 +49,7 @@ type InformersOpts struct {
 	Selector              Selector
 	Transform             cache.TransformFunc
 	UnsafeDisableDeepCopy bool
+	WatchErrorHandler     cache.WatchErrorHandler
 }
 
 // NewInformers creates a new InformersMap that can create informers under the hood.
@@ -76,6 +77,7 @@ func NewInformers(config *rest.Config, options *InformersOpts) *Informers {
 		transform:             options.Transform,
 		unsafeDisableDeepCopy: options.UnsafeDisableDeepCopy,
 		newInformer:           newInformer,
+		watchErrorHandler:     options.WatchErrorHandler,
 	}
 }
 
@@ -159,6 +161,11 @@ type Informers struct {
 
 	// NewInformer allows overriding of the shared index informer constructor for testing.
 	newInformer func(cache.ListerWatcher, runtime.Object, time.Duration, cache.Indexers) cache.SharedIndexInformer
+
+	// WatchErrorHandler allows the shared index informer's
+	// watchErrorHandler to be set by overriding the options
+	// or to use the default watchErrorHandler
+	watchErrorHandler cache.WatchErrorHandler
 }
 
 // Start calls Run on each of the informers and sets started to true. Blocks on the context.
@@ -323,6 +330,13 @@ func (ip *Informers) addInformerToMap(gvk schema.GroupVersionKind, obj runtime.O
 		cache.NamespaceIndex: cache.MetaNamespaceIndexFunc,
 	})
 
+	// Set WatchErrorHandler on SharedIndexInformer if set
+	if ip.watchErrorHandler != nil {
+		if err := sharedIndexInformer.SetWatchErrorHandler(ip.watchErrorHandler); err != nil {
+			return nil, false, err
+		}
+	}
+
 	// Check to see if there is a transformer for this gvk
 	if err := sharedIndexInformer.SetTransform(ip.transform); err != nil {
 		return nil, false, err