Hard delete backup stack after successful update.

After successful update of a stack, the backup stack and it's associated
template, resources and events should be permanently deleted.

Closes-Bug: #1332300

Change-Id: I3a462690b5f6bfadfbcf16eeb6bdec7c5ece2e83

heat/db/api.py

@@ -154,6 +154,10 @@ def stack_delete(context, stack_id):
     return IMPL.stack_delete(context, stack_id)
 
 
+def stack_delete_hard(context, stack_id):
+    return IMPL.stack_delete_hard(context, stack_id)
+
+
 def stack_lock_create(stack_id, engine_id):
     return IMPL.stack_lock_create(stack_id, engine_id)
 

heat/db/sqlalchemy/api.py

@@ -430,6 +430,27 @@ def stack_delete(context, stack_id):
     session.flush()
 
 
+def stack_delete_hard(context, stack_id):
+    s = stack_get(context, stack_id)
+    if not s:
+        raise exception.NotFound(_('Attempt to hard-delete a stack with id: '
+                                 '%(id)s %(msg)s') % {
+                                     'id': stack_id,
+                                     'msg': 'that does not exist'})
+
+    session = Session.object_session(s)
+
+    for r in s.resources:
+        session.delete(r)
+
+    for e in s.events:
+        session.delete(e)
+
+    session.delete(s)
+
+    session.flush()
+
+
 def stack_lock_create(stack_id, engine_id):
     session = get_session()
     with session.begin():

heat/db/sqlalchemy/models.py

@@ -120,7 +120,8 @@ class Stack(BASE, HeatBase, SoftDelete, StateAware):
         sqlalchemy.Integer,
         sqlalchemy.ForeignKey('raw_template.id'),
         nullable=False)
-    raw_template = relationship(RawTemplate, backref=backref('stack'))
+    raw_template = relationship(RawTemplate, cascade="all,delete",
+                                backref=backref('stack'))
     username = sqlalchemy.Column(sqlalchemy.String(256))
     tenant = sqlalchemy.Column(sqlalchemy.String(256))
     parameters = sqlalchemy.Column('parameters', Json)

heat/engine/stack.py

@@ -775,7 +775,9 @@ class Stack(collections.Mapping):
             LOG.debug('Deleting backup stack')
             backup_stack.delete(backup=True)
 
-            # flip the template to the newstack values
+            # Flip the template to the newstack values, but keep
+            # reference to old stack id to overwrite DB entry
+            newstack.t.id = self.t.id
             self.t = newstack.t
             template_outputs = self.t[self.t.OUTPUTS]
             self.outputs = self.resolve_static_data(template_outputs)
@@ -958,7 +960,10 @@ class Stack(collections.Mapping):
         if stack_status != self.FAILED:
             # delete the stack
             try:
-                db_api.stack_delete(self.context, self.id)
+                if backup:
+                    db_api.stack_delete_hard(self.context, self.id)
+                else:
+                    db_api.stack_delete(self.context, self.id)
             except exception.NotFound:
                 LOG.info(_("Tried to delete stack that does not exist "
                            "%s ") % self.id)

heat/tests/test_sqlalchemy_api.py

@@ -1329,6 +1329,44 @@ class DBAPIStackTest(HeatTestCase):
         self.assertRaises(exception.NotFound, db_api.resource_get,
                           self.ctx, resource.id)
 
+    def test_stack_delete_hard(self):
+        stack = create_stack(self.ctx, self.template, self.user_creds)
+        stack_id = stack.id
+        resource = create_resource(self.ctx, stack)
+        template_id = stack.raw_template.id
+        db_api.stack_delete_hard(self.ctx, stack_id)
+
+        self.assertIsNone(db_api.stack_get(self.ctx, stack_id,
+                                           show_deleted=False))
+
+        self.assertRaises(exception.NotFound, db_api.stack_delete,
+                          self.ctx, stack_id)
+
+        # Even soft-delete aware should not find it
+        self.assertIsNone(db_api.stack_get(self.ctx, stack_id,
+                                           show_deleted=True))
+
+        # Testing child resources deletion
+        self.assertRaises(exception.NotFound, db_api.resource_get,
+                          self.ctx, resource.id)
+
+        # Testing raw_template deletion
+        self.assertRaises(exception.NotFound, db_api.raw_template_get,
+                          self.ctx, template_id)
+
+    def test_stack_delete_hard_deletes_events(self):
+        stack = create_stack(self.ctx, self.template, self.user_creds)
+        stack_id = stack.id
+        values = [
+            {'stack_id': stack_id, 'resource_name': 'res1'},
+            {'stack_id': stack_id, 'resource_name': 'res2'},
+        ]
+        [create_event(self.ctx, **val) for val in values]
+
+        db_api.stack_delete_hard(self.ctx, stack_id)
+        events = db_api.event_get_all_by_stack(self.ctx, stack_id)
+        self.assertEqual(0, len(events))
+
     def test_stack_update(self):
         stack = create_stack(self.ctx, self.template, self.user_creds)
         values = {