Merge "Avoid always loading nested stack on update"

heat/engine/resources/stack_resource.py

@@ -222,6 +222,7 @@ class StackResource(resource.Resource):
 
         parsed_template = self._child_parsed_template(child_template,
                                                       child_env)
+        self._validate_nested_resources(parsed_template)
 
         # Note we disable rollback for nested stacks, since they
         # should be rolled back by the parent stack on failure
@@ -248,7 +249,6 @@ class StackResource(resource.Resource):
 
     def _child_parsed_template(self, child_template, child_env):
         parsed_template = self._parse_child_template(child_template, child_env)
-        self._validate_nested_resources(parsed_template)
 
         # Don't overwrite the attributes_schema for subclasses that
         # define their own attributes_schema.
@@ -260,12 +260,16 @@ class StackResource(resource.Resource):
     def _validate_nested_resources(self, templ):
         if cfg.CONF.max_resources_per_stack == -1:
             return
+
         total_resources = (len(templ[templ.RESOURCES]) +
                            self.stack.total_resources(self.root_stack_id))
 
-        if self.nested():
-            # It's an update and these resources will be deleted
-            total_resources -= len(self.nested().resources)
+        identity = self.nested_identifier()
+        if identity is not None:
+            existing = self.rpc_client().list_stack_resources(self.context,
+                                                              identity)
+            # Don't double-count existing resources during an update
+            total_resources -= len(existing)
 
         if (total_resources > cfg.CONF.max_resources_per_stack):
             message = exception.StackResourceLimitExceeded.msg_fmt

heat/tests/test_provider_template.py

@@ -311,7 +311,6 @@ class ProviderTemplateTest(common.HeatTestCase):
         temp_res = template_resource.TemplateResource('test_t_res',
                                                       definition, stack)
         temp_res.resource_id = 'dummy_id'
-        self.assertIsNone(temp_res.validate())
         temp_res.nested_identifier = mock.Mock()
         temp_res.nested_identifier.return_value = {'foo': 'bar'}
 
@@ -319,6 +318,8 @@ class ProviderTemplateTest(common.HeatTestCase):
         output = {'outputs': [{'output_key': 'Foo', 'output_value': None,
                                'output_error': 'it is all bad'}]}
         temp_res._rpc_client.show_stack.return_value = [output]
+        temp_res._rpc_client.list_stack_resources.return_value = []
+        self.assertIsNone(temp_res.validate())
         self.assertRaises(exception.TemplateOutputError,
                           temp_res.FnGetAtt, 'Foo')