Define helper to run an action on many resources

This change defines do_action_on_many function as a helper to run an
action on many resources (like nova delete).

Change-Id: I1c45d11a520703c57e3ac1923d94ec5f864f266b

novaclient/tests/test_utils.py

@@ -312,3 +312,26 @@ class ResourceManagerExtraKwargsHookTestCase(test_utils.TestCase):
         except_error = ("Hook 'hook2' is attempting to redefine "
                         "attributes")
         self.assertIn(except_error, six.text_type(exc))
+
+
+class DoActionOnManyTestCase(test_utils.TestCase):
+
+    def _test_do_action_on_many(self, side_effect, fail):
+        action = mock.Mock(side_effect=side_effect)
+
+        if fail:
+            self.assertRaises(exceptions.CommandError,
+                              utils.do_action_on_many,
+                              action, [1, 2], 'success with %s', 'error')
+        else:
+            utils.do_action_on_many(action, [1, 2], 'success with %s', 'error')
+        action.assert_has_calls([mock.call(1), mock.call(2)])
+
+    def test_do_action_on_many_success(self):
+        self._test_do_action_on_many([None, None], fail=False)
+
+    def test_do_action_on_many_first_fails(self):
+        self._test_do_action_on_many([Exception(), None], fail=True)
+
+    def test_do_action_on_many_last_fails(self):
+        self._test_do_action_on_many([None, Exception()], fail=True)

novaclient/utils.py

@@ -300,6 +300,22 @@ def safe_issubclass(*args):
     return False
 
 
+def do_action_on_many(action, resources, success_msg, error_msg):
+    """Helper to run an action on many resources."""
+    failure_flag = False
+
+    for resource in resources:
+        try:
+            action(resource)
+            print(success_msg % resource)
+        except Exception as e:
+            failure_flag = True
+            print(e)
+
+    if failure_flag:
+        raise exceptions.CommandError(error_msg)
+
+
 def _load_entry_point(ep_name, name=None):
     """Try to load the entry point ep_name that matches name."""
     for ep in pkg_resources.iter_entry_points(ep_name, name=name):

novaclient/v1_1/shell.py

@@ -1677,19 +1677,11 @@ def do_show(cs, args):
            help=_('Name or ID of server(s).'))
 def do_delete(cs, args):
     """Immediately shut down and delete specified server(s)."""
-    failure_flag = False
-
-    for server in args.server:
-        try:
-            _find_server(cs, server).delete()
-            print(_("Request to delete server %s has been accepted.") % server)
-        except Exception as e:
-            failure_flag = True
-            print(e)
-
-    if failure_flag:
-        raise exceptions.CommandError(_("Unable to delete the "
-                                        "specified server(s)."))
+    utils.do_action_on_many(
+        lambda s: _find_server(cs, s).delete(),
+        args.server,
+        _("Request to delete server %s has been accepted."),
+        _("Unable to delete the specified server(s)."))
 
 
 def _find_server(cs, server):