Do not raise NotFound for resource_get_all_* queries

A stack with zero resources is not an exception worthy condition (for
example, a stack being deleted, a stack which really does have zero
resources).

Also its unusual that a collection query function would raise a
NotFound when the result count is zero.

This change fixes that for resource_get_all_by_stack and
resource_get_all_active_by_stack

Change-Id: I3420d5099830f5626095b17c01e9d886b477915c
Related-Bug: #1301320
Related-Bug: #1523748

heat/db/sqlalchemy/api.py

@@ -349,10 +349,6 @@ def resource_get_all_by_stack(context, stack_id, filters=None):
     query = db_filters.exact_filter(query, models.Resource, filters)
     results = query.all()
 
-    if not results:
-        raise exception.NotFound(_("no resources for stack_id %s were found")
-                                 % stack_id)
-
     return dict((res.name, res) for res in results)
 
 
@@ -365,9 +361,6 @@ def resource_get_all_active_by_stack(context, stack_id):
         models.Resource.id.notin_(subquery.as_scalar())
     ).options(orm.joinedload("data")).all()
 
-    if not results:
-        raise exception.NotFound(_("no active resources for stack_id %s were"
-                                   " found") % stack_id)
     return dict((res.id, res) for res in results)
 
 

heat/engine/stack.py

@@ -344,22 +344,19 @@ class Stack(collections.Mapping):
                 yield nested_res
 
     def db_active_resources_get(self):
-        try:
-            return resource_objects.Resource.get_all_active_by_stack(
-                self.context, self.id)
-        except exception.NotFound:
-            return None
+        resources = resource_objects.Resource.get_all_active_by_stack(
+            self.context, self.id)
+        return resources or None
 
     def db_resource_get(self, name):
         if not self.id:
             return None
         if self._db_resources is None:
-            try:
-                _db_resources = resource_objects.Resource.get_all_by_stack(
-                    self.context, self.id)
-                self._db_resources = _db_resources
-            except exception.NotFound:
+            _db_resources = resource_objects.Resource.get_all_by_stack(
+                self.context, self.id)
+            if not _db_resources:
                 return None
+            self._db_resources = _db_resources
         return self._db_resources.get(name)
 
     @property

heat/tests/db/test_sqlalchemy_api.py

@@ -2055,9 +2055,8 @@ class DBAPIStackTest(common.HeatTestCase):
             rt_id = stacks[s].raw_template_id
             self.assertRaises(exception.NotFound,
                               db_api.raw_template_get, ctx, rt_id)
-            self.assertRaises(exception.NotFound,
-                              db_api.resource_get_all_by_stack,
-                              ctx, stacks[s].id)
+            self.assertEqual({}, db_api.resource_get_all_by_stack(
+                ctx, stacks[s].id))
             self.assertRaises(exception.NotFound,
                               db_api.raw_template_files_get,
                               ctx, tmpl_files[tmpl_idx].files_id)
@@ -2252,8 +2251,8 @@ class DBAPIResourceTest(common.HeatTestCase):
         self.assertEqual('res1', resources.get('res1').name)
         self.assertEqual('res2', resources.get('res2').name)
 
-        self.assertRaises(exception.NotFound, db_api.resource_get_all_by_stack,
-                          self.ctx, self.stack2.id)
+        self.assertEqual({}, db_api.resource_get_all_by_stack(
+            self.ctx, self.stack2.id))
 
     def test_resource_get_all_active_by_stack(self):
         values = [