Keep old files in file map for rolling update

We would need old resource definitions when doing rolling update of certain
group resources like RG/ASG. Therefore update the file map with the files
from old template.

Change-Id: I8f880e5b23c25159ecab1c63b594329d8df33973
Closes-Bug: #1765454
Task: #17360
Story: #1765454

heat/common/grouputils.py

@@ -197,3 +197,21 @@ def get_member_definitions(group, include_failed=False):
     return [(name, definitions[name])
             for name in inspector.member_names(include_failed=include_failed)
             if name in definitions]
+
+
+def get_child_template_files(context, stack,
+                             is_rolling_update,
+                             old_template_id):
+    """Return a merged map of old and new template files.
+
+    For rolling update files for old and new defintions are required as the
+    nested stack is updated in batches of scaled units.
+    """
+    if not stack.convergence:
+        old_template_id = stack.t.id
+
+    if is_rolling_update and old_template_id:
+        prev_files = template.Template.load(context, old_template_id).files
+        prev_files.update(dict(stack.t.files))
+        return prev_files
+    return stack.t.files

heat/engine/resource.py

@@ -247,6 +247,7 @@ class Resource(status.ResourceStatus):
         self.replaces = None
         self.replaced_by = None
         self.current_template_id = None
+        self.old_template_id = None
         self.root_stack_id = None
         self._calling_engine_id = None
         self._atomic_key = None
@@ -1659,7 +1660,7 @@ class Resource(status.ResourceStatus):
             after_props.validate()
             self.properties = before_props
             tmpl_diff = self.update_template_diff(after.freeze(), before)
-            old_template_id = self.current_template_id
+            self.old_template_id = self.current_template_id
 
             try:
                 if tmpl_diff and self.needs_replace_with_tmpl_diff(tmpl_diff):
@@ -1676,7 +1677,8 @@ class Resource(status.ResourceStatus):
                                                      prop_diff])
             except UpdateReplace:
                 with excutils.save_and_reraise_exception():
-                    self.current_template_id = old_template_id
+                    self.current_template_id = self.old_template_id
+                    self.old_template_id = None
                     self._prepare_update_replace(action)
 
             self.t = after

heat/engine/resources/openstack/heat/autoscaling_group.py

@@ -186,6 +186,12 @@ class AutoScalingResourceGroup(aws_asg.AutoScalingGroup):
                                                           resource_def))
         return rsrc_defn.ResourceDefinition(None, **defn_data)
 
+    def child_template_files(self, child_env):
+        is_update = self.action == self.UPDATE
+        return grouputils.get_child_template_files(self.context, self.stack,
+                                                   is_update,
+                                                   self.old_template_id)
+
     def _try_rolling_update(self, prop_diff):
         if self.RESOURCE in prop_diff:
             policy = self.properties[self.ROLLING_UPDATES]

heat/engine/resources/openstack/heat/instance_group.py

@@ -478,6 +478,13 @@ class InstanceGroup(stack_resource.StackResource):
         num_instances = int(self.properties[self.SIZE])
         return self._create_template(num_instances)
 
+    def child_template_files(self, child_env):
+        is_rolling_update = (self.action == self.UPDATE and
+                             self.update_policy[self.ROLLING_UPDATE])
+        return grouputils.get_child_template_files(self.context, self.stack,
+                                                   is_rolling_update,
+                                                   self.old_template_id)
+
     def child_params(self):
         """Return the environment for the nested stack."""
         return {

heat/engine/resources/openstack/heat/resource_group.py

@@ -668,6 +668,14 @@ class ResourceGroup(stack_resource.StackResource):
         self._add_output_defns_to_template(tmpl, [k for k, d in definitions])
         return tmpl
 
+    def child_template_files(self, child_env):
+        is_rolling_update = (self.action == self.UPDATE
+                             and self.update_policy[self.ROLLING_UPDATE])
+        return grouputils.get_child_template_files(self.context,
+                                                   self.stack,
+                                                   is_rolling_update,
+                                                   self.old_template_id)
+
     def _assemble_for_rolling_update(self, total_capacity, max_updates,
                                      include_all=False,
                                      template_version=('heat_template_version',

heat/engine/resources/stack_resource.py

@@ -222,7 +222,12 @@ class StackResource(resource.Resource):
         if isinstance(parsed_child_template, template.Template):
             parsed_child_template = parsed_child_template.t
         return template.Template(parsed_child_template,
-                                 files=self.stack.t.files, env=child_env)
+                                 files=self.child_template_files(child_env),
+                                 env=child_env)
+
+    def child_template_files(self, child_env):
+        """Default implementation to get the files map for child template."""
+        return self.stack.t.files
 
     def _parse_nested_stack(self, stack_name, child_template,
                             child_params, timeout_mins=None,

heat_integrationtests/functional/test_resource_group.py

@@ -612,6 +612,36 @@ resources:
                                    created=10,
                                    deleted=10)
 
+    def test_resource_group_update_replace_template_changed(self):
+        """Test rolling update(replace)with child template path changed.
+
+        Simple rolling update replace with child template path changed.
+        """
+
+        nested_templ = '''
+heat_template_version: "2013-05-23"
+resources:
+  oops:
+    type: OS::Heat::TestResource
+'''
+
+        create_template = yaml.safe_load(copy.deepcopy(self.template))
+        grp = create_template['resources']['random_group']
+        grp['properties']['resource_def'] = {'type': '/opt/provider.yaml'}
+        files = {'/opt/provider.yaml': nested_templ}
+
+        policy = grp['update_policy']['rolling_update']
+        policy['min_in_service'] = '1'
+        policy['max_batch_size'] = '3'
+        stack_identifier = self.stack_create(template=create_template,
+                                             files=files)
+        update_template = create_template.copy()
+        grp = update_template['resources']['random_group']
+        grp['properties']['resource_def'] = {'type': '/opt1/provider.yaml'}
+        files = {'/opt1/provider.yaml': nested_templ}
+
+        self.update_stack(stack_identifier, update_template, files=files)
+
     def test_resource_group_update_scaledown(self):
         """Test rolling update with scaledown.