add 'only_transfers_as_changes' option to synchronize module

lib/ansible/modules/files/synchronize.py

@@ -178,6 +178,12 @@
     type: list
     default:
     version_added: "2.5"
+  only_transfers_as_changes:
+    description:
+      - Only files really transfered are considered as changes. Changing of permissions, ownership or times is NOT considered a change
+    type: bool
+    default: no
+    version_added: "2.10"
 notes:
    - rsync must be installed on both the local and remote host.
    - For the C(synchronize) module, the "local host" is the host `the synchronize task originates on`, and the "destination host" is the host
@@ -407,7 +413,8 @@ def main():
             partial=dict(type='bool', default=False),
             verify_host=dict(type='bool', default=False),
             mode=dict(type='str', default='push', choices=['pull', 'push']),
-            link_dest=dict(type='list')
+            link_dest=dict(type='list'),
+            only_transfers_as_changes=dict(type='bool', default=False)
         ),
         supports_check_mode=True,
     )
@@ -446,6 +453,9 @@ def main():
     ssh_args = module.params['ssh_args']
     verify_host = module.params['verify_host']
     link_dest = module.params['link_dest']
+    only_transfers_as_changes = module.params['only_transfers_as_changes']
+    if only_transfers_as_changes:
+        checksum = True
 
     if '/' not in rsync:
         rsync = module.get_bin_path(rsync, required=True)
@@ -596,6 +606,8 @@ def _write_password_to_pipe(proc):
     if link_dest:
         # a leading period indicates no change
         changed = (changed_marker + '.') not in out
+    elif only_transfers_as_changes:
+        changed = (changed_marker + '<') in out
     else:
         changed = changed_marker in out