Add CloudFormation methods delete_change_set, describe_change_set and list_change_sets.

IMPLEMENTATION_COVERAGE.md

@@ -477,12 +477,12 @@
 - [X] create_stack
 - [ ] create_stack_instances
 - [ ] create_stack_set
-- [ ] delete_change_set
+- [X] delete_change_set
 - [X] delete_stack
 - [ ] delete_stack_instances
 - [ ] delete_stack_set
 - [ ] describe_account_limits
-- [ ] describe_change_set
+- [X] describe_change_set
 - [ ] describe_stack_events
 - [ ] describe_stack_instance
 - [ ] describe_stack_resource
@@ -495,7 +495,7 @@
 - [ ] get_stack_policy
 - [ ] get_template
 - [ ] get_template_summary
-- [ ] list_change_sets
+- [X] list_change_sets
 - [X] list_exports
 - [ ] list_imports
 - [ ] list_stack_instances

moto/cloudformation/models.py

@@ -127,6 +127,49 @@ class FakeStack(BaseModel):
         self.status = "DELETE_COMPLETE"
 
 
+class FakeChange(BaseModel):
+
+    def __init__(self, action, logical_resource_id, resource_type):
+        self.action = action
+        self.logical_resource_id = logical_resource_id
+        self.resource_type = resource_type
+
+
+class FakeChangeSet(FakeStack):
+
+    def __init__(self, stack_id, stack_name, stack_template, change_set_id, change_set_name, template, parameters, region_name, notification_arns=None, tags=None, role_arn=None, cross_stack_resources=None):
+        super(FakeChangeSet, self).__init__(
+            stack_id,
+            stack_name,
+            stack_template,
+            parameters,
+            region_name,
+            notification_arns=notification_arns,
+            tags=tags,
+            role_arn=role_arn,
+            cross_stack_resources=cross_stack_resources,
+            create_change_set=True,
+        )
+        self.stack_name = stack_name
+        self.change_set_id = change_set_id
+        self.change_set_name = change_set_name
+        self.changes = self.diff(template=template, parameters=parameters)
+
+    def diff(self, template, parameters=None):
+        self.template = template
+        self._parse_template()
+        changes = []
+        resources_by_action = self.resource_map.diff(self.template_dict, parameters)
+        for action, resources in resources_by_action.items():
+            for resource_name, resource in resources.items():
+                changes.append(FakeChange(
+                    action=action,
+                    logical_resource_id=resource_name,
+                    resource_type=resource['ResourceType'],
+                ))
+        return changes
+
+
 class FakeEvent(BaseModel):
 
     def __init__(self, stack_id, stack_name, logical_resource_id, physical_resource_id, resource_type, resource_status, resource_status_reason=None, resource_properties=None):
@@ -171,24 +214,62 @@ class CloudFormationBackend(BaseBackend):
         return new_stack
 
     def create_change_set(self, stack_name, change_set_name, template, parameters, region_name, change_set_type, notification_arns=None, tags=None, role_arn=None):
+        stack_id = None
+        stack_template = None
         if change_set_type == 'UPDATE':
             stacks = self.stacks.values()
             stack = None
             for s in stacks:
                 if s.name == stack_name:
                     stack = s
+                    stack_id = stack.stack_id
+                    stack_template = stack.template
             if stack is None:
                 raise ValidationError(stack_name)
-
         else:
-            stack = self.create_stack(stack_name, template, parameters,
+            stack_id = generate_stack_id(stack_name)
-                                      region_name, notification_arns, tags,
+            stack_template = template
-                                      role_arn, create_change_set=True)
+
         change_set_id = generate_changeset_id(change_set_name, region_name)
-        self.stacks[change_set_name] = {'Id': change_set_id,
+        new_change_set = FakeChangeSet(
-                                        'StackId': stack.stack_id}
+            stack_id=stack_id,
-        self.change_sets[change_set_id] = stack
+            stack_name=stack_name,
-        return change_set_id, stack.stack_id
+            stack_template=stack_template,
+            change_set_id=change_set_id,
+            change_set_name=change_set_name,
+            template=template,
+            parameters=parameters,
+            region_name=region_name,
+            notification_arns=notification_arns,
+            tags=tags,
+            role_arn=role_arn,
+            cross_stack_resources=self.exports
+        )
+        self.change_sets[change_set_id] = new_change_set
+        self.stacks[stack_id] = new_change_set
+        return change_set_id, stack_id
+
+    def delete_change_set(self, change_set_name, stack_name=None):
+        if change_set_name in self.change_sets:
+            # This means arn was passed in
+            del self.change_sets[change_set_name]
+        else:
+            for cs in self.change_sets:
+                if self.change_sets[cs].change_set_name == change_set_name:
+                    del self.change_sets[cs]
+
+    def describe_change_set(self, change_set_name, stack_name=None):
+        change_set = None
+        if change_set_name in self.change_sets:
+            # This means arn was passed in
+            change_set = self.change_sets[change_set_name]
+        else:
+            for cs in self.change_sets:
+                if self.change_sets[cs].change_set_name == change_set_name:
+                    change_set = self.change_sets[cs]
+        if change_set is None:
+            raise ValidationError(change_set_name)
+        return change_set
 
     def execute_change_set(self, change_set_name, stack_name=None):
         stack = None
@@ -197,7 +278,7 @@ class CloudFormationBackend(BaseBackend):
             stack = self.change_sets[change_set_name]
         else:
             for cs in self.change_sets:
-                if self.change_sets[cs].name == change_set_name:
+                if self.change_sets[cs].change_set_name == change_set_name:
                     stack = self.change_sets[cs]
         if stack is None:
             raise ValidationError(stack_name)
@@ -223,6 +304,9 @@ class CloudFormationBackend(BaseBackend):
         else:
             return list(stacks)
 
+    def list_change_sets(self):
+        return self.change_sets.values()
+
     def list_stacks(self):
         return [
             v for v in self.stacks.values()

moto/cloudformation/parsing.py

@@ -465,36 +465,70 @@ class ResourceMap(collections.Mapping):
                 ec2_models.ec2_backends[self._region_name].create_tags(
                     [self[resource].physical_resource_id], self.tags)
 
-    def update(self, template, parameters=None):
+    def diff(self, template, parameters=None):
         if parameters:
             self.input_parameters = parameters
         self.load_mapping()
         self.load_parameters()
         self.load_conditions()
 
+        old_template = self._resource_json_map
+        new_template = template['Resources']
+
+        resource_names_by_action = {
+            'Add': set(new_template) - set(old_template),
+            'Modify': set(name for name in new_template if name in old_template and new_template[
+                name] != old_template[name]),
+            'Remove': set(old_template) - set(new_template)
+        }
+        resources_by_action = {
+            'Add': {},
+            'Modify': {},
+            'Remove': {},
+        }
+
+        for resource_name in resource_names_by_action['Add']:
+            resources_by_action['Add'][resource_name] = {
+                'LogicalResourceId': resource_name,
+                'ResourceType': new_template[resource_name]['Type']
+            }
+
+        for resource_name in resource_names_by_action['Modify']:
+            resources_by_action['Modify'][resource_name] = {
+                'LogicalResourceId': resource_name,
+                'ResourceType': new_template[resource_name]['Type']
+            }
+
+        for resource_name in resource_names_by_action['Remove']:
+            resources_by_action['Remove'][resource_name] = {
+                'LogicalResourceId': resource_name,
+                'ResourceType': old_template[resource_name]['Type']
+            }
+
+        return resources_by_action
+
+    def update(self, template, parameters=None):
+        resources_by_action = self.diff(template, parameters)
+
         old_template = self._resource_json_map
         new_template = template['Resources']
         self._resource_json_map = new_template
 
-        new_resource_names = set(new_template) - set(old_template)
+        for resource_name, resource in resources_by_action['Add'].items():
-        for resource_name in new_resource_names:
             resource_json = new_template[resource_name]
             new_resource = parse_and_create_resource(
                 resource_name, resource_json, self, self._region_name)
             self._parsed_resources[resource_name] = new_resource
 
-        removed_resource_names = set(old_template) - set(new_template)
+        for resource_name, resource in resources_by_action['Remove'].items():
-        for resource_name in removed_resource_names:
             resource_json = old_template[resource_name]
             parse_and_delete_resource(
                 resource_name, resource_json, self, self._region_name)
             self._parsed_resources.pop(resource_name)
 
-        resources_to_update = set(name for name in new_template if name in old_template and new_template[
-                                  name] != old_template[name])
         tries = 1
-        while resources_to_update and tries < 5:
+        while resources_by_action['Modify'] and tries < 5:
-            for resource_name in resources_to_update.copy():
+            for resource_name, resource in resources_by_action['Modify'].copy().items():
                 resource_json = new_template[resource_name]
                 try:
                     changed_resource = parse_and_update_resource(
@@ -505,7 +539,7 @@ class ResourceMap(collections.Mapping):
                     last_exception = e
                 else:
                     self._parsed_resources[resource_name] = changed_resource
-                    resources_to_update.remove(resource_name)
+                    del resources_by_action['Modify'][resource_name]
             tries += 1
         if tries == 5:
             raise last_exception

moto/cloudformation/responses.py

@@ -120,6 +120,31 @@ class CloudFormationResponse(BaseResponse):
             template = self.response_template(CREATE_CHANGE_SET_RESPONSE_TEMPLATE)
             return template.render(stack_id=stack_id, change_set_id=change_set_id)
 
+    def delete_change_set(self):
+        stack_name = self._get_param('StackName')
+        change_set_name = self._get_param('ChangeSetName')
+
+        self.cloudformation_backend.delete_change_set(change_set_name=change_set_name, stack_name=stack_name)
+        if self.request_json:
+            return json.dumps({
+                'DeleteChangeSetResponse': {
+                    'DeleteChangeSetResult': {},
+                }
+            })
+        else:
+            template = self.response_template(DELETE_CHANGE_SET_RESPONSE_TEMPLATE)
+            return template.render()
+
+    def describe_change_set(self):
+        stack_name = self._get_param('StackName')
+        change_set_name = self._get_param('ChangeSetName')
+        change_set = self.cloudformation_backend.describe_change_set(
+            change_set_name=change_set_name,
+            stack_name=stack_name,
+        )
+        template = self.response_template(DESCRIBE_CHANGE_SET_RESPONSE_TEMPLATE)
+        return template.render(change_set=change_set)
+
     @amzn_request_id
     def execute_change_set(self):
         stack_name = self._get_param('StackName')
@@ -187,6 +212,11 @@ class CloudFormationResponse(BaseResponse):
         template = self.response_template(DESCRIBE_STACK_EVENTS_RESPONSE)
         return template.render(stack=stack)
 
+    def list_change_sets(self):
+        change_sets = self.cloudformation_backend.list_change_sets()
+        template = self.response_template(LIST_CHANGE_SETS_RESPONSE)
+        return template.render(change_sets=change_sets)
+
     def list_stacks(self):
         stacks = self.cloudformation_backend.list_stacks()
         template = self.response_template(LIST_STACKS_RESPONSE)
@@ -354,6 +384,66 @@ CREATE_CHANGE_SET_RESPONSE_TEMPLATE = """<CreateStackResponse>
 </CreateStackResponse>
 """
 
+DELETE_CHANGE_SET_RESPONSE_TEMPLATE = """<DeleteChangeSetResponse>
+  <DeleteChangeSetResult>
+  </DeleteChangeSetResult>
+  <ResponseMetadata>
+    <RequestId>3d3200a1-810e-3023-6cc3-example</RequestId>
+  </ResponseMetadata>
+</DeleteChangeSetResponse>
+"""
+
+DESCRIBE_CHANGE_SET_RESPONSE_TEMPLATE = """<DescribeChangeSetResponse>
+  <DescribeChangeSetResult>
+    <ChangeSetId>{{ change_set.change_set_id }}</ChangeSetId>
+    <ChangeSetName>{{ change_set.change_set_name }}</ChangeSetName>
+    <StackId>{{ change_set.stack_id }}</StackId>
+    <StackName>{{ change_set.stack_name }}</StackName>
+    <Description>{{ change_set.description }}</Description>
+    <Parameters>
+      {% for param_name, param_value in change_set.stack_parameters.items() %}
+       <member>
+          <ParameterKey>{{ param_name }}</ParameterKey>
+          <ParameterValue>{{ param_value }}</ParameterValue>
+        </member>
+      {% endfor %}
+    </Parameters>
+    <CreationTime>2011-05-23T15:47:44Z</CreationTime>
+    <ExecutionStatus>{{ change_set.execution_status }}</ExecutionStatus>
+    <Status>{{ change_set.status }}</Status>
+    <StatusReason>{{ change_set.status_reason }}</StatusReason>
+    {% if change_set.notification_arns %}
+    <NotificationARNs>
+      {% for notification_arn in change_set.notification_arns %}
+      <member>{{ notification_arn }}</member>
+      {% endfor %}
+    </NotificationARNs>
+    {% else %}
+    <NotificationARNs/>
+    {% endif %}
+    {% if change_set.role_arn %}
+    <RoleARN>{{ change_set.role_arn }}</RoleARN>
+    {% endif %}
+    {% if change_set.changes %}
+    <Changes>
+      {% for change in change_set.changes %}
+      <member>
+        <Type>Resource</Type>
+        <ResourceChange>
+            <Action>{{ change.action }}</Action>
+            <LogicalResourceId>{{ change.logical_resource_id }}</LogicalResourceId>
+            <ResourceType>{{ change.resource_type }}</ResourceType>
+        </ResourceChange>
+      </member>
+      {% endfor %}
+    </Changes>
+    {% endif %}
+    {% if next_token %}
+    <NextToken>{{ next_token }}</NextToken>
+    {% endif %}
+  </DescribeChangeSetResult>
+</DescribeChangeSetResponse>"""
+
 EXECUTE_CHANGE_SET_RESPONSE_TEMPLATE = """<ExecuteChangeSetResponse>
   <ExecuteChangeSetResult>
       <ExecuteChangeSetResult/>
@@ -479,6 +569,27 @@ DESCRIBE_STACK_EVENTS_RESPONSE = """<DescribeStackEventsResponse xmlns="http://c
 </DescribeStackEventsResponse>"""
 
 
+LIST_CHANGE_SETS_RESPONSE = """<ListChangeSetsResponse>
+ <ListChangeSetsResult>
+  <Summaries>
+    {% for change_set in change_sets %}
+    <member>
+        <StackId>{{ change_set.stack_id }}</StackId>
+        <StackName>{{ change_set.stack_name }}</StackName>
+        <ChangeSetId>{{ change_set.change_set_id }}</ChangeSetId>
+        <ChangeSetName>{{ change_set.change_set_name }}</ChangeSetName>
+        <ExecutionStatus>{{ change_set.execution_status }}</ExecutionStatus>
+        <Status>{{ change_set.status }}</Status>
+        <StatusReason>{{ change_set.status_reason }}</StatusReason>
+        <CreationTime>2011-05-23T15:47:44Z</CreationTime>
+        <Description>{{ change_set.description }}</Description>
+    </member>
+    {% endfor %}
+  </Summaries>
+ </ListChangeSetsResult>
+</ListChangeSetsResponse>"""
+
+
 LIST_STACKS_RESPONSE = """<ListStacksResponse>
  <ListStacksResult>
   <StackSummaries>

tests/test_cloudformation/test_cloudformation_stack_crud_boto3.py

@@ -399,6 +399,32 @@ def test_create_change_set_from_s3_url():
     assert 'arn:aws:cloudformation:us-east-1:123456789:stack/NewStack' in response['StackId']
 
 
+@mock_cloudformation
+def test_describe_change_set():
+    cf_conn = boto3.client('cloudformation', region_name='us-east-1')
+    cf_conn.create_change_set(
+        StackName='NewStack',
+        TemplateBody=dummy_template_json,
+        ChangeSetName='NewChangeSet',
+        ChangeSetType='CREATE',
+    )
+
+    stack = cf_conn.describe_change_set(ChangeSetName="NewChangeSet")
+    stack['ChangeSetName'].should.equal('NewChangeSet')
+    stack['StackName'].should.equal('NewStack')
+
+    cf_conn.create_change_set(
+        StackName='NewStack',
+        TemplateBody=dummy_update_template_json,
+        ChangeSetName='NewChangeSet2',
+        ChangeSetType='UPDATE',
+    )
+    stack = cf_conn.describe_change_set(ChangeSetName="NewChangeSet2")
+    stack['ChangeSetName'].should.equal('NewChangeSet2')
+    stack['StackName'].should.equal('NewStack')
+    stack['Changes'].should.have.length_of(2)
+
+
 @mock_cloudformation
 def test_execute_change_set_w_arn():
     cf_conn = boto3.client('cloudformation', region_name='us-east-1')
@@ -420,7 +446,7 @@ def test_execute_change_set_w_name():
         ChangeSetName='NewChangeSet',
         ChangeSetType='CREATE',
     )
-    cf_conn.execute_change_set(ChangeSetName='NewStack', StackName='NewStack')
+    cf_conn.execute_change_set(ChangeSetName='NewChangeSet', StackName='NewStack')
 
 
 @mock_cloudformation
@@ -489,6 +515,20 @@ def test_describe_stack_by_stack_id():
     stack_by_id['StackName'].should.equal("test_stack")
 
 
+@mock_cloudformation
+def test_list_change_sets():
+    cf_conn = boto3.client('cloudformation', region_name='us-east-1')
+    cf_conn.create_change_set(
+        StackName='NewStack2',
+        TemplateBody=dummy_template_json,
+        ChangeSetName='NewChangeSet2',
+        ChangeSetType='CREATE',
+    )
+    change_set = cf_conn.list_change_sets(StackName='NewStack2')['Summaries'][0]
+    change_set['StackName'].should.equal('NewStack2')
+    change_set['ChangeSetName'].should.equal('NewChangeSet2')
+
+
 @mock_cloudformation
 def test_list_stacks():
     cf = boto3.resource('cloudformation', region_name='us-east-1')
@@ -521,6 +561,22 @@ def test_delete_stack_from_resource():
     list(cf.stacks.all()).should.have.length_of(0)
 
 
+@mock_cloudformation
+@mock_ec2
+def test_delete_change_set():
+    cf_conn = boto3.client('cloudformation', region_name='us-east-1')
+    cf_conn.create_change_set(
+        StackName='NewStack',
+        TemplateBody=dummy_template_json,
+        ChangeSetName='NewChangeSet',
+        ChangeSetType='CREATE',
+    )
+
+    cf_conn.list_change_sets(StackName='NewStack')['Summaries'].should.have.length_of(1)
+    cf_conn.delete_change_set(ChangeSetName='NewChangeSet', StackName='NewStack')
+    cf_conn.list_change_sets(StackName='NewStack')['Summaries'].should.have.length_of(0)
+
+
 @mock_cloudformation
 @mock_ec2
 def test_delete_stack_by_name():