sdk: retry Watch() call on failure.

pkg/sdk/api.go

@@ -16,6 +16,8 @@ package sdk
 
 import (
 	"context"
+	"sync"
+	"time"
 
 	"github.com/operator-framework/operator-sdk/pkg/k8sclient"
 
@@ -24,7 +26,8 @@ import (
 
 var (
 	// informers is the set of all informers for the resources watched by the user
-	informers []Informer
+	informers    []Informer
+	informersMux sync.Mutex
 )
 
 // Watch watches for changes on the given resource.
@@ -37,16 +40,23 @@ var (
 //   - 0 means no periodic events will be sent
 // Consult the API reference for the Group, Version and Kind of a resource: https://kubernetes.io/docs/reference/
 // namespace is the Namespace to watch for the resource
+// If the resource client can not be obtained (CRD not yet deployed for example) it is retried until success.
 // TODO: support opts for specifying label selector
 func Watch(apiVersion, kind, namespace string, resyncPeriod int) {
-	resourceClient, resourcePluralName, err := k8sclient.GetResourceClient(apiVersion, kind, namespace)
-	// TODO: Better error handling, e.g retry
-	if err != nil {
-		logrus.Errorf("failed to get resource client for (apiVersion:%s, kind:%s, ns:%s): %v", apiVersion, kind, namespace, err)
-		panic(err)
-	}
-	informer := NewInformer(resourcePluralName, namespace, resourceClient, resyncPeriod)
-	informers = append(informers, informer)
+	go func() {
+		for {
+			resourceClient, resourcePluralName, err := k8sclient.GetResourceClient(apiVersion, kind, namespace)
+			if err == nil {
+				informersMux.Lock()
+				defer informersMux.Unlock()
+				informer := NewInformer(resourcePluralName, namespace, resourceClient, resyncPeriod)
+				informers = append(informers, informer)
+				break
+			}
+			logrus.Errorf("failed to get resource client for (apiVersion:%s, kind:%s, ns:%s): %v", apiVersion, kind, namespace, err)
+			time.Sleep(1 * time.Second)
+		}
+	}()
 }
 
 // Handle registers the handler for all events.