Reverse order of CRD init operations (#155)

This commit reverses the order of CRD init operations. The reason for
doing CRD init operations in this new order, is so that k8s admins
can manually create the expected CRDs. By creating the CRDs by hand,
create CRD permission does not need to be granted to the nats-operator SA.
Only read permission is required.

pkg/util/kubernetes/crd.go

@@ -128,36 +128,25 @@ func WaitCRDs(extsClient extsclientset.Interface) error {
 
 // createOrUpdateCRD creates or updates the specified custom resource definition according to the provided specification.
 func createOrUpdateCRD(crd *extsv1beta1.CustomResourceDefinition, extsClient extsclientset.Interface) error {
-	// Attempt to register the CRD.
-	_, err := extsClient.ApiextensionsV1beta1().CustomResourceDefinitions().Create(crd)
-	if err == nil {
-		// Registration was successful.
-		return nil
-	}
-	if !IsKubernetesResourceAlreadyExistError(err) {
-		// The crd doesn't exist yet but we've got an unexpected error while registering it.
-		return err
-	}
-
-	// At this point the CRD already exists but its spec may differ.
-	// This can happen, for instance, if the user has tampered with the CRD.
-	// Hence, we do our best to bring in line with our expectations.
-	// Fetch the latest version of the CRD.
+	// At this point the CRD may already exist from manual creation. Attempt to get the CRD
 	d, err := extsClient.ApiextensionsV1beta1().CustomResourceDefinitions().Get(crd.Name, metav1.GetOptions{})
-	if err != nil {
-		// We've failed to fetch the latest version of the CRD, so return accordingly.
-		return err
-	}
-	if reflect.DeepEqual(d.Spec, crd.Spec) {
-		// The specs match, so there's nothing to do.
+
+	// CRD already exists, but it's what we expect.
+	if err == nil && reflect.DeepEqual(d.Spec, crd.Spec) {
 		return nil
 	}
-	// Attempt to update the CRD by setting its spec to the expected value.
-	d.Spec = crd.Spec
-	if _, err := extsClient.ApiextensionsV1beta1().CustomResourceDefinitions().Update(d); err != nil {
+
+	// CRD already exists, and is different than what is expected.
+	if err == nil {
+		// Attempt to update the CRD by setting its spec to the expected value.
+		d.Spec = crd.Spec
+		_, err = extsClient.ApiextensionsV1beta1().CustomResourceDefinitions().Update(d)
 		return err
 	}
-	return nil
+
+	// No CRD existed, attempt to register the CRD.
+	_, err = extsClient.ApiextensionsV1beta1().CustomResourceDefinitions().Create(crd)
+	return err
 }
 
 // waitCRDReady blocks until the specified custom resource definition has been established and is ready for being used.