do input validation before creating CRD

moved the snapshotnameprefix validation
before creating the CRD. this will help
us to catch the invalid CLI args ASAP.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

cmd/csi-snapshotter/main.go

@@ -97,6 +97,10 @@ func main() {
 		klog.Warning("--snapshotter is deprecated and will have no effect")
 	}
 
+	if len(*snapshotNamePrefix) == 0 {
+		klog.Error("Snapshot name prefix cannot be of length 0")
+		os.Exit(1)
+	}
 	// Create the client config. Use kubeconfig if given, otherwise assume in-cluster.
 	config, err := buildConfig(*kubeconfig)
 	if err != nil {
@@ -173,11 +177,6 @@ func main() {
 		os.Exit(1)
 	}
 
-	if len(*snapshotNamePrefix) == 0 {
-		klog.Error("Snapshot name prefix cannot be of length 0")
-		os.Exit(1)
-	}
-
 	klog.V(2).Infof("Start NewCSISnapshotController with snapshotter [%s] kubeconfig [%s] csiTimeout [%+v] csiAddress [%s] createSnapshotContentRetryCount [%d] createSnapshotContentInterval [%+v] resyncPeriod [%+v] snapshotNamePrefix [%s] snapshotNameUUIDLength [%d]", *snapshotterName, *kubeconfig, *csiTimeout, *csiAddress, createSnapshotContentRetryCount, *createSnapshotContentInterval, *resyncPeriod, *snapshotNamePrefix, snapshotNameUUIDLength)
 
 	snapShotter := snapshotter.NewSnapshotter(csiConn)