Modify batch_generator to allow create batch of increasing sizes (#7152)

lib/metasync

@@ -228,13 +228,15 @@ if args.ldap_binddn:
 def lower_keys(d):
     return dict((key.lower(), value) for key, value in d.iteritems())
 
-def batch_generator(gen, batch_size):
+def batch_generator(gen, *batch_size):
     batch = []
     for result in gen:
         batch.append(result)
-        if len(batch) == batch_size:
+        if len(batch) == batch_size[0]:
             yield batch
             batch = []
+            if len(batch_size) > 1:
+                batch_size = batch_size[1:]
     if len(batch):
         yield batch
 
@@ -361,7 +363,7 @@ def apply_action(action):
 actions.sort(key=lambda x: (x[0] == DELETE, len(x[1])))
 if args.verbose:
     print 'Actions:'
-for batch in batch_generator(actions, 100):
+for batch in batch_generator(actions, 1, 5, 10, 50, 100):
     for action in batch:
         if args.verbose:
             print_action(action)