Conform stack resource error so it gives a 4xx

This exception was added and landed while the change to use
RequestLimitExceeded was still in progress. Giving a 5xx error when the
user has caused the problem directly is not what we want.

We leave the exception in place to allow the shared error message. I
also have hopes that we will be o-k with extra exceptions and just
extend RequestLimitExceeded when we have a similar situation.

Change-Id: Ic9b176625e6ad2b8c42c420dab79984d134304e5
Partial-Bug: #1230191

heat/engine/service.py

@@ -259,7 +259,8 @@ def _stack_create(stack):
         tmpl = parser.Template(template, files=files)
 
         if len(tmpl[tpl.RESOURCES]) > cfg.CONF.max_resources_per_stack:
-            raise exception.StackResourceLimitExceeded()
+            raise exception.RequestLimitExceeded(
+                message=exception.StackResourceLimitExceeded.message)
 
         # Extract the common query parameters
         common_params = api.extract_args(args)
@@ -307,7 +308,8 @@ def update_stack(self, cnxt, stack_identity, template, params,
         # stack definition.
         tmpl = parser.Template(template, files=files)
         if len(tmpl[tpl.RESOURCES]) > cfg.CONF.max_resources_per_stack:
-            raise exception.StackResourceLimitExceeded()
+            raise exception.RequestLimitExceeded(
+                message=exception.StackResourceLimitExceeded.message)
         stack_name = current_stack.name
         common_params = api.extract_args(args)
         env = environment.Environment(params)

heat/engine/stack_resource.py

@@ -84,7 +84,8 @@ def create_with_template(self, child_template, user_params,
         if ((len(template[tmpl.RESOURCES]) +
              self.stack.root_stack.total_resources() >
              cfg.CONF.max_resources_per_stack)):
-            raise exception.StackResourceLimitExceeded()
+            raise exception.RequestLimitExceeded(
+                message=exception.StackResourceLimitExceeded.message)
         self._outputs_to_attribs(child_template)
 
         # Note we disable rollback for nested stacks, since they
@@ -131,7 +132,8 @@ def update_with_template(self, child_template, user_params,
                 len(template[tmpl.RESOURCES]) - len(nested_stack.resources))
             new_size = nested_stack.root_stack.total_resources() + res_diff
             if new_size > cfg.CONF.max_resources_per_stack:
-                raise exception.StackResourceLimitExceeded()
+                raise exception.RequestLimitExceeded(
+                    message=exception.StackResourceLimitExceeded.message)
 
         # Note we disable rollback for nested stacks, since they
         # should be rolled back by the parent stack on failure

heat/tests/test_engine_service.py

@@ -486,9 +486,11 @@ def test_stack_create_total_resources_exceeds_max(self):
                'C': {'Type': 'GenericResourceType'}}}
         template = parser.Template(tpl)
         cfg.CONF.set_override('max_resources_per_stack', 2)
-        self.assertRaises(exception.StackResourceLimitExceeded,
-                          self.man.create_stack, self.ctx, stack_name,
-                          template, params, None, {})
+        ex = self.assertRaises(exception.RequestLimitExceeded,
+                               self.man.create_stack, self.ctx, stack_name,
+                               template, params, None, {})
+        self.assertIn(exception.StackResourceLimitExceeded.message,
+                      str(ex))
 
     def test_stack_validate(self):
         stack_name = 'service_create_test_validate'
@@ -661,9 +663,12 @@ def test_stack_update_exceeds_resource_limit(self):
 
         cfg.CONF.set_override('max_resources_per_stack', 2)
 
-        self.assertRaises(exception.StackResourceLimitExceeded,
-                          self.man.update_stack, self.ctx,
-                          old_stack.identifier(), template, params, None, {})
+        ex = self.assertRaises(exception.RequestLimitExceeded,
+                               self.man.update_stack, self.ctx,
+                               old_stack.identifier(), template, params, None,
+                               {})
+        self.assertIn(exception.StackResourceLimitExceeded.message,
+                      str(ex))
 
     def test_stack_update_verify_err(self):
         stack_name = 'service_update_verify_err_test_stack'

heat/tests/test_nested_stack.py

@@ -280,8 +280,10 @@ def test_nested_stack_update_exceeds_limit(self):
         new_res['Properties']['TemplateURL'] = (
             'https://server.test/new.template')
         prop_diff = {'TemplateURL': 'https://server.test/new.template'}
-        self.assertRaises(exception.StackResourceLimitExceeded,
-                          rsrc.handle_update, new_res, {}, prop_diff)
+        ex = self.assertRaises(exception.RequestLimitExceeded,
+                               rsrc.handle_update, new_res, {}, prop_diff)
+        self.assertIn(exception.StackResourceLimitExceeded.message,
+                      str(ex))
         rsrc.delete()
 
         self.m.VerifyAll()