Prevent deadlock when starting new Informers

pkg/controller/copier.go

@@ -50,6 +50,7 @@ const (
 type Controller struct {
 	Context context.Context
 
+	informerMutex  sync.Mutex
 	discovery      *discovery.Client
 	dynamicListers map[schema.GroupVersionResource][]cache.GenericLister
 	dynclient      dynamic.Interface
@@ -139,6 +140,11 @@ func (c *Controller) AddTarget(target string) error {
 }
 
 func (c *Controller) AddInformers(gvr *schema.GroupVersionResource, handler cache.ResourceEventHandler) []cache.SharedInformer {
+	c.informerMutex.Lock()
+	defer c.informerMutex.Unlock()
+	if _, ok := c.dynamicListers[*gvr]; ok {
+		return []cache.SharedInformer{}
+	}
 	c.dynamicListers[*gvr] = make([]cache.GenericLister, len(c.factories))
 	informers := make([]cache.SharedInformer, len(c.factories))
 	for i, factory := range c.factories {

pkg/controller/source.go

@@ -114,18 +114,15 @@ func (src *ResourceSource) Register(c *Controller, stopCh <-chan struct{}, rule
 				c.sources[*gvr][key] = make(map[Resource]*Rule)
 				c.sources[*gvr][key][*rule.Target] = rule
 			}
-
-			if _, ok := c.dynamicListers[*gvr]; !ok {
-				// Create new informers for the gvr we're watching.
-				informers := c.AddInformers(gvr, &QueuingEventHandler{
-					Queue: c.queue,
-					GVR:   gvr,
-				})
-				for _, informer := range informers {
-					informer.Run(stopCh)
-				}
-			}
 		}()
+		// Create new informers for the gvr we're watching.
+		informers := c.AddInformers(gvr, &QueuingEventHandler{
+			Queue: c.queue,
+			GVR:   gvr,
+		})
+		for _, informer := range informers {
+			informer.Run(stopCh)
+		}
 	}
 
 	// Try invoking the rule.