From 39b772844dcad70ab45a12db042db4a5ee4208a6 Mon Sep 17 00:00:00 2001
From: Thomas Herve <therve@redhat.com>
Date: Mon, 15 Feb 2016 05:53:17 +0100
Subject: [PATCH] Don't query stack tags twice

Retrieving the field from the db object triggers the query to
stack_tags, so we don't need to do it a second time to retrieve the list
of tags. Instead, use the data directly.

Change-Id: Ibe6ac45d54afca6588b1b71ffa7278977d2f4d8a
---
 heat/objects/stack.py     | 7 ++-----
 heat/objects/stack_tag.py | 5 +++++
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/heat/objects/stack.py b/heat/objects/stack.py
index 8420bec00a..8e8f001ea3 100644
--- a/heat/objects/stack.py
+++ b/heat/objects/stack.py
@@ -71,11 +71,8 @@ class Stack(
                     raw_template.RawTemplate.get_by_id(
                         context, db_stack['raw_template_id']))
             elif field == 'tags':
-                if db_stack.get(field) is not None:
-                    stack['tags'] = stack_tag.StackTagList.get(
-                        context, db_stack['id'])
-                else:
-                    stack['tags'] = None
+                stack['tags'] = stack_tag.StackTagList.from_db_object(
+                    context, db_stack.get(field))
             else:
                 stack[field] = db_stack.__dict__.get(field)
         stack._context = context
diff --git a/heat/objects/stack_tag.py b/heat/objects/stack_tag.py
index 7a5bb312a3..50d86deda7 100644
--- a/heat/objects/stack_tag.py
+++ b/heat/objects/stack_tag.py
@@ -80,3 +80,8 @@ class StackTagList(
     @classmethod
     def delete(cls, context, stack_id):
         db_api.stack_tags_delete(context, stack_id)
+
+    @classmethod
+    def from_db_object(cls, context, db_tags):
+        if db_tags is not None:
+            return base.obj_make_list(context, cls(), StackTag, db_tags)