Merge pull request #2838 from bblommers/feature/2388

CloudFormation - CreateChangeSet should not create resources

moto/cloudformation/models.py

@@ -239,8 +239,11 @@ class FakeStack(BaseModel):
         self.cross_stack_resources = cross_stack_resources or {}
         self.resource_map = self._create_resource_map()
         self.output_map = self._create_output_map()
-        self._add_stack_event("CREATE_COMPLETE")
-        self.status = "CREATE_COMPLETE"
+        if create_change_set:
+            self.status = "REVIEW_IN_PROGRESS"
+        else:
+            self.create_resources()
+            self._add_stack_event("CREATE_COMPLETE")
         self.creation_time = datetime.utcnow()
 
     def _create_resource_map(self):
@@ -253,7 +256,7 @@ class FakeStack(BaseModel):
             self.template_dict,
             self.cross_stack_resources,
         )
-        resource_map.create()
+        resource_map.load()
         return resource_map
 
     def _create_output_map(self):
@@ -326,6 +329,10 @@ class FakeStack(BaseModel):
     def exports(self):
         return self.output_map.exports
 
+    def create_resources(self):
+        self.resource_map.create()
+        self.status = "CREATE_COMPLETE"
+
     def update(self, template, role_arn=None, parameters=None, tags=None):
         self._add_stack_event(
             "UPDATE_IN_PROGRESS", resource_status_reason="User Initiated"
@@ -640,6 +647,7 @@ class CloudFormationBackend(BaseBackend):
         else:
             stack._add_stack_event("UPDATE_IN_PROGRESS")
             stack._add_stack_event("UPDATE_COMPLETE")
+        stack.create_resources()
         return True
 
     def describe_stacks(self, name_or_stack_id):

moto/cloudformation/parsing.py

@@ -531,14 +531,16 @@ class ResourceMap(collections_abc.Mapping):
         for condition_name in self.lazy_condition_map:
             self.lazy_condition_map[condition_name]
 
-    def create(self):
+    def load(self):
         self.load_mapping()
         self.transform_mapping()
         self.load_parameters()
         self.load_conditions()
 
+    def create(self):
         # Since this is a lazy map, to create every object we just need to
         # iterate through self.
+        # Assumes that self.load() has been called before
         self.tags.update(
             {
                 "aws:cloudformation:stack-name": self.get("AWS::StackName"),

tests/test_cloudformation/test_cloudformation_stack_crud_boto3.py

@@ -835,8 +835,10 @@ def test_describe_change_set():
     )
 
     stack = cf_conn.describe_change_set(ChangeSetName="NewChangeSet")
+
     stack["ChangeSetName"].should.equal("NewChangeSet")
     stack["StackName"].should.equal("NewStack")
+    stack["Status"].should.equal("REVIEW_IN_PROGRESS")
 
     cf_conn.create_change_set(
         StackName="NewStack",
@@ -851,15 +853,30 @@ def test_describe_change_set():
 
 
 @mock_cloudformation
+@mock_ec2
 def test_execute_change_set_w_arn():
     cf_conn = boto3.client("cloudformation", region_name="us-east-1")
+    ec2 = boto3.client("ec2", region_name="us-east-1")
+    # Verify no instances exist at the moment
+    ec2.describe_instances()["Reservations"].should.have.length_of(0)
+    # Create a Change set, and verify no resources have been created yet
     change_set = cf_conn.create_change_set(
         StackName="NewStack",
         TemplateBody=dummy_template_json,
         ChangeSetName="NewChangeSet",
         ChangeSetType="CREATE",
     )
+    ec2.describe_instances()["Reservations"].should.have.length_of(0)
+    cf_conn.describe_change_set(ChangeSetName="NewChangeSet")["Status"].should.equal(
+        "REVIEW_IN_PROGRESS"
+    )
+    # Execute change set
     cf_conn.execute_change_set(ChangeSetName=change_set["Id"])
+    # Verify that the status has changed, and the appropriate resources have been created
+    cf_conn.describe_change_set(ChangeSetName="NewChangeSet")["Status"].should.equal(
+        "CREATE_COMPLETE"
+    )
+    ec2.describe_instances()["Reservations"].should.have.length_of(1)
 
 
 @mock_cloudformation