Create a utility for merging templates.

merge.py

@@ -0,0 +1,98 @@
+import sys
+import yaml
+
+templates = list(sys.argv[1:])
+
+errors = []
+end_template={'HeatTemplateFormatVersion': '2012-12-12',
+              'Description': []}
+resource_changes=[]
+for template_path in templates:
+    template = yaml.safe_load(open(template_path))
+    end_template['Description'].append(template.get('Description',
+                                                    template_path))
+    new_parameters = template.get('Parameters', {})
+    for p, pbody in iter(new_parameters.items()):
+        if p in end_template.get('Parameters', {}):
+            if pbody != end_template['Parameters'][p]:
+                errors.append('Parameter %s from %s conflicts.' % (p,
+                                                                   template_path))
+            continue
+        if 'Parameters' not in end_template:
+            end_template['Parameters'] = {}
+        end_template['Parameters'][p] = pbody
+
+    new_outputs = template.get('Outputs', {})
+    for o, obody in iter(new_outputs.items()):
+        if o in end_template.get('Outputs', {}):
+            if pbody != end_template['Outputs'][p]:
+                errors.append('Output %s from %s conflicts.' % (o,
+                                                                   template_path))
+            continue
+        if 'Outputs' not in end_template:
+            end_template['Outputs'] = {}
+        end_template['Outputs'][o] = obody
+
+    new_resources = template.get('Resources', {})
+    for r, rbody in iter(new_resources.items()):
+        if rbody['Type'] == 'AWS::EC2::Instance':
+            # XXX Assuming ImageId is always a Ref
+            del end_template['Parameters'][rbody['Properties']['ImageId']['Ref']]
+            role = rbody.get('Metadata', {}).get('OpenStack::Role', r)
+            if role != r:
+                resource_changes.append((r, role))
+            if role in end_template.get('Resources', {}):
+                new_metadata = rbody.get('Metadata', {})
+                for m, mbody in iter(new_metadata.items()):
+                    if m in end_template['Resources'][role].get('Metadata', {}):
+                        if m == 'OpenStack::ImageBuilder::Elements':
+                            end_template['Resources'][role]['Metadata'][m].extend(mbody)
+                            continue
+                        if mbody != end_template['Resources'][role]['Metadata'][m]:
+                            errors.append('Role %s metadata key %s conflicts.' %
+                                          (role, m))
+                        continue
+                    end_template['Resources'][role]['Metadata'][m] = mbody
+                continue
+            if 'Resources' not in end_template:
+                end_template['Resources'] = {}
+            end_template['Resources'][role] = rbody
+            ikey = '%sImage' % (role)
+            end_template['Resources'][role]['Properties']['ImageId'] = {'Ref': ikey}
+            end_template['Parameters'][ikey] = {'Type': 'String'}
+        else:
+            if r in end_template.get('Resources', {}):
+                if rbody != end_template['Resources'][r]:
+                    errors.append('Resource %s from %s conflicts' % (r,
+                                                                     template_path))
+                continue
+            if 'Resources' not in end_template:
+                end_template['Resources'] = {}
+            end_template['Resources'][r] = rbody
+
+def fix_ref(item, old, new):
+    if isinstance(item, dict):
+        copy_item = dict(item)
+        for k, v in iter(copy_item.items()):
+            if k == 'Ref' and v == old:
+                item[k] = new
+                continue
+            if k == 'Fn::GetAtt' and isinstance(v, list) and v[0] == old:
+                new_list = list(v)
+                new_list[0] = new
+                item[k] = new_list
+                continue
+            fix_ref(v, old, new)
+    elif isinstance(item, list):
+        copy_item = list(item)
+        for v in item:
+            fix_ref(v, old, new)
+
+for change in resource_changes:
+    fix_ref(end_template, change[0], change[1])
+            
+if errors:
+    for e in errors:
+        sys.stderr.write("ERROR: %s\n" % e)
+end_template['Description'] = ','.join(end_template['Description'])
+sys.stdout.write(yaml.safe_dump(end_template, default_flow_style=False))

mysql.yaml

@@ -60,6 +60,7 @@ Resources:
   MySQL:
     Type: AWS::EC2::Instance
     Metadata:
+      OpenStack::Role: stateful
       OpenStack::ImageBuilder::Elements: [ mysql-migration ]
       mysql:
         create-users:

nova-api.yaml

@@ -54,6 +54,7 @@ Resources:
       InstanceType: {Ref: InstanceType}
       KeyName: {Ref: KeyName}
     Metadata:
+      OpenStack::Role: stateless
       OpenStack::ImageBuilder::Elements: [ nova-api ]
       heat: 
         access_key_id:

rabbitmq.yaml

@@ -15,6 +15,7 @@ Resources:
   RabbitMQ:
     Type: AWS::EC2::Instance
     Metadata:
+      OpenStack::Role: stateful
       OpenStack::ImageBuilder::Elements: [ rabbitmq-server ]
       rabbitmq:
         password_handle: {Ref: RabbitMQPasswordHandle}