Refactor ScaleWorkload (#238)

* Refactore ScaleWorkload

* nit fix

pkg/function/scale_workload.go

@@ -66,25 +66,24 @@ func getArgs(tp param.TemplateParams, args map[string]interface{}) (namespace, k
 		return namespace, kind, name, replicas, err
 	}
 
-	var val int
-	switch rep.(type) {
+	switch val := rep.(type) {
 	case int:
-		val = rep.(int)
+		replicas = int32(val)
 	case int32:
-		val = int(rep.(int32))
+		replicas = val
 	case int64:
-		val = int(rep.(int64))
+		replicas = int32(val)
 	case string:
-		if val, err = strconv.Atoi(rep.(string)); err != nil {
-			err = errors.Wrapf(err, "Cannot convert %s to int ", rep.(string))
+		var v int
+		if v, err = strconv.Atoi(val); err != nil {
+			err = errors.Wrapf(err, "Cannot convert %s to int ", val)
 			return
 		}
+		replicas = int32(v)
 	default:
 		err = errors.Errorf("Invalid arg type %T for Arg %s ", rep, ScaleWorkloadReplicas)
 		return
 	}
-
-	replicas = int32(val)
 	// Populate default values for optional arguments from template parameters
 	switch {
 	case tp.StatefulSet != nil: