Count all nested stack resources with DB operations

The count is performed in 2 parts
- A function which builds a list of all nested stacks
  by recursively calling stack_get_all_by_owner_id
- A query which counts resources which belong to the list
  of stacks

Considering this will be the basis for fixing bug #1455589 then this
approach is appropriate for backporting to stable/kilo, but master would
ideally replace this soon with a new Stack attribute that stores the
calculated resource count.

Partial-Bug: #1455589

Change-Id: Ifa2e5609fd9a6853e20037e94a5e16696bb378ee

heat/db/api.py

@@ -202,6 +202,10 @@ def stack_get_root_id(context, stack_id):
     return IMPL.stack_get_root_id(context, stack_id)
 
 
+def stack_count_total_resources(context, stack_id):
+    return IMPL.stack_count_total_resources(context, stack_id)
+
+
 def user_creds_create(context):
     return IMPL.user_creds_create(context)
 

heat/db/sqlalchemy/api.py

@@ -583,6 +583,29 @@ def stack_get_root_id(context, stack_id):
     return s.id
 
 
+def stack_count_total_resources(context, stack_id):
+
+    # start with a stack_get to confirm the context can access the stack
+    if stack_id is None or stack_get(context, stack_id) is None:
+        return 0
+
+    def nested_stack_ids(sid):
+        yield sid
+        for child in stack_get_all_by_owner_id(context, sid):
+            for stack in nested_stack_ids(child.id):
+                yield stack
+
+    stack_ids = list(nested_stack_ids(stack_id))
+
+    # count all resources which belong to the stacks
+    results = model_query(
+        context, models.Resource
+    ).filter(
+        models.Resource.stack_id.in_(stack_ids)
+    ).count()
+    return results
+
+
 def user_creds_create(context):
     values = context.to_dict()
     user_creds_ref = models.UserCreds()

heat/objects/stack.py

@@ -138,6 +138,10 @@ class Stack(
     def count_all(cls, context, **kwargs):
         return db_api.stack_count_all(context, **kwargs)
 
+    @classmethod
+    def count_total_resources(cls, context, stack_id):
+        return db_api.stack_count_total_resources(context, stack_id)
+
     @classmethod
     def create(cls, context, values):
         return db_api.stack_create(context, values)

heat/tests/db/test_sqlalchemy_api.py

@@ -1820,6 +1820,80 @@ class DBAPIStackTest(common.HeatTestCase):
         self.assertEqual(root.id, db_api.stack_get_root_id(
             self.ctx, child_1.id))
 
+    def test_stack_count_total_resources(self):
+
+        def add_resources(stack, count):
+            for i in range(count):
+                create_resource(
+                    self.ctx, stack, name='%s-%s' % (stack.name, i))
+
+        root = create_stack(self.ctx, self.template, self.user_creds,
+                            name='root stack')
+
+        # stack with 3 children
+        s_1 = create_stack(self.ctx, self.template, self.user_creds,
+                           name='s_1', owner_id=root.id)
+        s_1_1 = create_stack(self.ctx, self.template, self.user_creds,
+                             name='s_1_1', owner_id=s_1.id)
+        s_1_2 = create_stack(self.ctx, self.template, self.user_creds,
+                             name='s_1_2', owner_id=s_1.id)
+        s_1_3 = create_stack(self.ctx, self.template, self.user_creds,
+                             name='s_1_3', owner_id=s_1.id)
+
+        # stacks 4 ancestors deep
+        s_2 = create_stack(self.ctx, self.template, self.user_creds,
+                           name='s_2', owner_id=root.id)
+        s_2_1 = create_stack(self.ctx, self.template, self.user_creds,
+                             name='s_2_1', owner_id=s_2.id)
+        s_2_1_1 = create_stack(self.ctx, self.template, self.user_creds,
+                               name='s_2_1_1', owner_id=s_2_1.id)
+        s_2_1_1_1 = create_stack(self.ctx, self.template, self.user_creds,
+                                 name='s_2_1_1_1', owner_id=s_2_1_1.id)
+
+        s_3 = create_stack(self.ctx, self.template, self.user_creds,
+                           name='s_3', owner_id=root.id)
+        s_4 = create_stack(self.ctx, self.template, self.user_creds,
+                           name='s_4', owner_id=root.id)
+
+        add_resources(root, 3)
+        add_resources(s_1, 2)
+        add_resources(s_1_1, 4)
+        add_resources(s_1_2, 5)
+        add_resources(s_1_3, 6)
+
+        add_resources(s_2, 1)
+        add_resources(s_2_1_1_1, 1)
+        add_resources(s_3, 4)
+
+        self.assertEqual(26, db_api.stack_count_total_resources(
+            self.ctx, root.id))
+
+        self.assertEqual(17, db_api.stack_count_total_resources(
+            self.ctx, s_1.id))
+        self.assertEqual(4, db_api.stack_count_total_resources(
+            self.ctx, s_1_1.id))
+        self.assertEqual(5, db_api.stack_count_total_resources(
+            self.ctx, s_1_2.id))
+        self.assertEqual(6, db_api.stack_count_total_resources(
+            self.ctx, s_1_3.id))
+
+        self.assertEqual(2, db_api.stack_count_total_resources(
+            self.ctx, s_2.id))
+        self.assertEqual(1, db_api.stack_count_total_resources(
+            self.ctx, s_2_1.id))
+        self.assertEqual(1, db_api.stack_count_total_resources(
+            self.ctx, s_2_1_1.id))
+        self.assertEqual(1, db_api.stack_count_total_resources(
+            self.ctx, s_2_1_1_1.id))
+        self.assertEqual(4, db_api.stack_count_total_resources(
+            self.ctx, s_3.id))
+        self.assertEqual(0, db_api.stack_count_total_resources(
+            self.ctx, s_4.id))
+        self.assertEqual(0, db_api.stack_count_total_resources(
+            self.ctx, 'asdf'))
+        self.assertEqual(0, db_api.stack_count_total_resources(
+            self.ctx, None))
+
 
 class DBAPIResourceTest(common.HeatTestCase):
     def setUp(self):