Istio integration (#421)

This the very first step for fission to integrate with Istio, which is an open platform to connect, manage, and secure microservices. With Istio, users are able to monitor functions usage and trace requests latency through dashboards. For more information, please visit http://fission.io/docs/

crd/crd.go

@@ -17,6 +17,9 @@ limitations under the License.
 package crd
 
 import (
+	"log"
+	"time"
+
 	apiextensionsv1beta1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
 	apiextensionsclient "k8s.io/apiextensions-apiserver/pkg/client/clientset/clientset"
 	"k8s.io/apimachinery/pkg/api/errors"
@@ -32,14 +35,28 @@ const (
 // needed. (Note that this creates the CRD type; it doesn't create any
 // _instances_ of that type.)
 func ensureCRD(clientset *apiextensionsclient.Clientset, crd *apiextensionsv1beta1.CustomResourceDefinition) error {
-	_, err := clientset.ApiextensionsV1beta1().CustomResourceDefinitions().Get(crd.ObjectMeta.Name, metav1.GetOptions{})
-	if err != nil {
-		if errors.IsNotFound(err) {
-			_, err := clientset.ApiextensionsV1beta1().CustomResourceDefinitions().Create(crd)
-			if err != nil {
-				return err
+	maxRetries := 5
+	for i := 0; i < maxRetries; i++ {
+		_, err := clientset.ApiextensionsV1beta1().CustomResourceDefinitions().Get(crd.ObjectMeta.Name, metav1.GetOptions{})
+
+		if err != nil {
+			if errors.IsNotFound(err) {
+				// crd resource not found error
+				_, err := clientset.ApiextensionsV1beta1().CustomResourceDefinitions().Create(crd)
+				if err != nil {
+					return err
+				}
+			} else {
+				// The requests fail to connect to k8s api server before
+				// istio-prxoy is ready to serve traffic. Retry again.
+				log.Printf("Error connecting to kubernetes api service (%v), retrying", err)
+				time.Sleep(500 * time.Duration(2*i) * time.Millisecond)
+				continue
 			}
 		}
+
+		// resource already exists
+		break
 	}
 	return nil
 }