Add a method of creating a backup stack in the DB

This is a temporary storage place for resources that are going to be
deleted once their replacements are created. They must be moved out of
the stack in order to avoid conflicting with the replacement resource.

Change-Id: I081498f4c8732f893dc0d0677cf2b3f40f56d808

diff --git a/heat/engine/parser.py b/heat/engine/parser.py
index eb796ad0bf0b7ca3bafad7b175a8b7b2d5055c1f..f0c5713477759520a81ccbfd918cd2678daf9d04 100644 (file)
--- a/heat/engine/parser.py
+++ b/heat/engine/parser.py
@@ -70,11 +70,12 @@ class Stack(object):
         stack is already in the database.
         '''
 
-        if re.match("[a-zA-Z][a-zA-Z0-9_.-]*$", stack_name) is None:
-            raise ValueError(_('Invalid stack name %s'
-                               ' must contain only alphanumeric or '
-                               '\"_-.\" characters, must start with alpha'
-                               ) % stack_name)
+        if owner_id is None:
+            if re.match("[a-zA-Z][a-zA-Z0-9_.-]*$", stack_name) is None:
+                raise ValueError(_('Invalid stack name %s'
+                                   ' must contain only alphanumeric or '
+                                   '\"_-.\" characters, must start with alpha'
+                                   ) % stack_name)
 
         self.id = stack_id
         self.owner_id = owner_id
@@ -152,7 +153,7 @@ class Stack(object):
 
         return stack
 
-    def store(self):
+    def store(self, backup=False):
         '''
         Store the stack in the database and return its ID
         If self.id is set, we update the existing stack
@@ -160,7 +161,7 @@ class Stack(object):
         new_creds = db_api.user_creds_create(self.context)
 
         s = {
-            'name': self.name,
+            'name': self._backup_name() if backup else self.name,
             'raw_template_id': self.t.store(self.context),
             'parameters': self.env.user_env_as_dict(),
             'owner_id': self.owner_id,
@@ -183,6 +184,9 @@ class Stack(object):
 
         return self.id
 
+    def _backup_name(self):
+        return '%s*' % self.name
+
     def identifier(self):
         '''
         Return an identifier for this stack.
@@ -356,6 +360,23 @@ class Stack(object):
         if callable(post_func):
             post_func()
 
+    def _backup_stack(self):
+        '''
+        Get a Stack containing any in-progress resources from the previous
+        stack state prior to an update.
+        '''
+        s = db_api.stack_get_by_name(self.context, self._backup_name(),
+                                     owner_id=self.id)
+        if s is not None:
+            logger.debug('Loaded existing backup stack')
+            return self.load(self.context, stack=s)
+        else:
+            prev = type(self)(self.context, self.name, self.t, self.env,
+                              owner_id=self.id)
+            prev.store(backup=True)
+            logger.debug('Created new backup stack')
+            return prev
+
     def update(self, newstack, action=UPDATE):
         '''
         Compare the current stack with newstack,