✨Cache: Export NewInformer

Overwriting NewInformer may be useful for testing purposes and allows to
bring a custom Informer implementation.

Author: alvaroaleman

pkg/cache/cache.go

@@ -239,8 +239,9 @@ type Options struct {
 	// If unset, this will fall through to the Default* settings.
 	ByObject map[client.Object]ByObject
 
-	// newInformer allows overriding of NewSharedIndexInformer for testing.
-	newInformer *func(toolscache.ListerWatcher, runtime.Object, time.Duration, toolscache.Indexers) toolscache.SharedIndexInformer
+	// NewInformer allows overriding of NewSharedIndexInformer, for example for testing
+	// or if someone wants to write their own Informer.
+	NewInformer func(toolscache.ListerWatcher, runtime.Object, time.Duration, toolscache.Indexers) toolscache.SharedIndexInformer
 }
 
 // ByObject offers more fine-grained control over the cache's ListWatch by object.
@@ -432,7 +433,7 @@ func newCache(restConfig *rest.Config, opts Options) newCacheFunc {
 				WatchErrorHandler:     opts.DefaultWatchErrorHandler,
 				UnsafeDisableDeepCopy: ptr.Deref(config.UnsafeDisableDeepCopy, false),
 				EnableWatchBookmarks:  ptr.Deref(config.EnableWatchBookmarks, true),
-				NewInformer:           opts.newInformer,
+				NewInformer:           opts.NewInformer,
 			}),
 			readerFailOnMissingInformer: opts.ReaderFailOnMissingInformer,
 		}

pkg/cache/cache_test.go

@@ -544,14 +544,9 @@ func NonBlockingGetTest(createCacheFunc func(config *rest.Config, opts cache.Opt
 			Expect(err).NotTo(HaveOccurred())
 
 			By("creating the informer cache")
-			v := reflect.ValueOf(&opts).Elem()
-			newInformerField := v.FieldByName("newInformer")
-			newFakeInformer := func(_ kcache.ListerWatcher, _ runtime.Object, _ time.Duration, _ kcache.Indexers) kcache.SharedIndexInformer {
+			opts.NewInformer = func(_ kcache.ListerWatcher, _ runtime.Object, _ time.Duration, _ kcache.Indexers) kcache.SharedIndexInformer {
 				return &controllertest.FakeInformer{Synced: false}
 			}
-			reflect.NewAt(newInformerField.Type(), newInformerField.Addr().UnsafePointer()).
-				Elem().
-				Set(reflect.ValueOf(&newFakeInformer))
 			informerCache, err = createCacheFunc(cfg, opts)
 			Expect(err).NotTo(HaveOccurred())
 			By("running the cache and waiting for it to sync")

pkg/cache/internal/informers.go

@@ -47,7 +47,7 @@ type InformersOpts struct {
 	Mapper                meta.RESTMapper
 	ResyncPeriod          time.Duration
 	Namespace             string
-	NewInformer           *func(cache.ListerWatcher, runtime.Object, time.Duration, cache.Indexers) cache.SharedIndexInformer
+	NewInformer           func(cache.ListerWatcher, runtime.Object, time.Duration, cache.Indexers) cache.SharedIndexInformer
 	Selector              Selector
 	Transform             cache.TransformFunc
 	UnsafeDisableDeepCopy bool
@@ -59,7 +59,7 @@ type InformersOpts struct {
 func NewInformers(config *rest.Config, options *InformersOpts) *Informers {
 	newInformer := cache.NewSharedIndexInformer
 	if options.NewInformer != nil {
-		newInformer = *options.NewInformer
+		newInformer = options.NewInformer
 	}
 	return &Informers{
 		config:     config,