CF : Added support for get template summary (#3179)

* CF : Added support for get template summary

* Linting

Co-authored-by: Bert Blommers <info@bertblommers.nl>

moto/cloudformation/responses.py

@@ -10,6 +10,31 @@ from moto.s3 import s3_backend
 from moto.core import ACCOUNT_ID
 from .models import cloudformation_backends
 from .exceptions import ValidationError
+from .utils import yaml_tag_constructor
+
+
+def get_template_summary_response_from_template(template_body):
+    def get_resource_types(template_dict):
+        resources = {}
+        for key, value in template_dict.items():
+            if key == "Resources":
+                resources = value
+
+        resource_types = []
+        for key, value in resources.items():
+            resource_types.append(value["Type"])
+        return resource_types
+
+    yaml.add_multi_constructor("", yaml_tag_constructor)
+
+    try:
+        template_dict = yaml.load(template_body, Loader=yaml.Loader)
+    except (yaml.parser.ParserError, yaml.scanner.ScannerError):
+        template_dict = json.loads(template_body)
+
+    resources_types = get_resource_types(template_dict)
+    template_dict["resourceTypes"] = resources_types
+    return template_dict
 
 
 class CloudFormationResponse(BaseResponse):
@@ -269,6 +294,20 @@ class CloudFormationResponse(BaseResponse):
             template = self.response_template(GET_TEMPLATE_RESPONSE_TEMPLATE)
             return template.render(stack=stack)
 
+    def get_template_summary(self):
+        stack_name = self._get_param("StackName")
+        template_url = self._get_param("TemplateURL")
+        stack_body = self._get_param("TemplateBody")
+
+        if stack_name:
+            stack_body = self.cloudformation_backend.get_stack(stack_name).template
+        elif template_url:
+            stack_body = self._get_stack_from_s3_url(template_url)
+
+        template_summary = get_template_summary_response_from_template(stack_body)
+        template = self.response_template(GET_TEMPLATE_SUMMARY_TEMPLATE)
+        return template.render(template_summary=template_summary)
+
     def update_stack(self):
         stack_name = self._get_param("StackName")
         role_arn = self._get_param("RoleARN")
@@ -743,7 +782,6 @@ DESCRIBE_STACKS_TEMPLATE = """<DescribeStacksResponse>
   </DescribeStacksResult>
 </DescribeStacksResponse>"""
 
-
 DESCRIBE_STACK_RESOURCE_RESPONSE_TEMPLATE = """<DescribeStackResourceResponse>
   <DescribeStackResourceResult>
     <StackResourceDetail>
@@ -758,7 +796,6 @@ DESCRIBE_STACK_RESOURCE_RESPONSE_TEMPLATE = """<DescribeStackResourceResponse>
   </DescribeStackResourceResult>
 </DescribeStackResourceResponse>"""
 
-
 DESCRIBE_STACK_RESOURCES_RESPONSE = """<DescribeStackResourcesResponse>
     <DescribeStackResourcesResult>
       <StackResources>
@@ -777,7 +814,6 @@ DESCRIBE_STACK_RESOURCES_RESPONSE = """<DescribeStackResourcesResponse>
     </DescribeStackResourcesResult>
 </DescribeStackResourcesResponse>"""
 
-
 DESCRIBE_STACK_EVENTS_RESPONSE = """<DescribeStackEventsResponse xmlns="http://cloudformation.amazonaws.com/doc/2010-05-15/">
   <DescribeStackEventsResult>
     <StackEvents>
@@ -802,7 +838,6 @@ DESCRIBE_STACK_EVENTS_RESPONSE = """<DescribeStackEventsResponse xmlns="http://c
   </ResponseMetadata>
 </DescribeStackEventsResponse>"""
 
-
 LIST_CHANGE_SETS_RESPONSE = """<ListChangeSetsResponse>
  <ListChangeSetsResult>
   <Summaries>
@@ -823,7 +858,6 @@ LIST_CHANGE_SETS_RESPONSE = """<ListChangeSetsResponse>
  </ListChangeSetsResult>
 </ListChangeSetsResponse>"""
 
-
 LIST_STACKS_RESPONSE = """<ListStacksResponse>
  <ListStacksResult>
   <StackSummaries>
@@ -840,7 +874,6 @@ LIST_STACKS_RESPONSE = """<ListStacksResponse>
  </ListStacksResult>
 </ListStacksResponse>"""
 
-
 LIST_STACKS_RESOURCES_RESPONSE = """<ListStackResourcesResponse>
   <ListStackResourcesResult>
     <StackResourceSummaries>
@@ -860,7 +893,6 @@ LIST_STACKS_RESOURCES_RESPONSE = """<ListStackResourcesResponse>
   </ResponseMetadata>
 </ListStackResourcesResponse>"""
 
-
 GET_TEMPLATE_RESPONSE_TEMPLATE = """<GetTemplateResponse>
   <GetTemplateResult>
     <TemplateBody>{{ stack.template }}</TemplateBody>
@@ -870,7 +902,6 @@ GET_TEMPLATE_RESPONSE_TEMPLATE = """<GetTemplateResponse>
   </ResponseMetadata>
 </GetTemplateResponse>"""
 
-
 DELETE_STACK_RESPONSE_TEMPLATE = """<DeleteStackResponse>
   <ResponseMetadata>
     <RequestId>5ccc7dcd-744c-11e5-be70-example</RequestId>
@@ -878,7 +909,6 @@ DELETE_STACK_RESPONSE_TEMPLATE = """<DeleteStackResponse>
 </DeleteStackResponse>
 """
 
-
 LIST_EXPORTS_RESPONSE = """<ListExportsResponse xmlns="http://cloudformation.amazonaws.com/doc/2010-05-15/">
   <ListExportsResult>
     <Exports>
@@ -1139,3 +1169,19 @@ LIST_STACK_SET_OPERATION_RESULTS_RESPONSE_TEMPLATE = (
 </ListStackSetOperationResultsResponse>
 """
 )
+
+GET_TEMPLATE_SUMMARY_TEMPLATE = """<GetTemplateSummaryResponse xmlns="http://cloudformation.amazonaws.com/doc/2010-05-15/">
+  <GetTemplateSummaryResult>
+    <Description>{{ template_summary.Description }}</Description>
+    {% for resource in template_summary.resourceTypes %}
+      <ResourceTypes>
+        <ResourceType>{{ resource }}</ResourceType>
+      </ResourceTypes>
+    {% endfor %}
+    <Version>{{ template_summary.AWSTemplateFormatVersion }}</Version>
+  </GetTemplateSummaryResult>
+  <ResponseMetadata>
+    <RequestId>b9b4b068-3a41-11e5-94eb-example</RequestId>
+  </ResponseMetadata>
+</GetTemplateSummaryResponse>
+"""

tests/test_cloudformation/test_cloudformation_stack_crud_boto3.py

@@ -35,6 +35,14 @@ dummy_template = {
     },
 }
 
+dummy_template3 = {
+    "AWSTemplateFormatVersion": "2010-09-09",
+    "Description": "Stack 3",
+    "Resources": {
+        "VPC": {"Properties": {"CidrBlock": "192.168.0.0/16"}, "Type": "AWS::EC2::VPC"}
+    },
+}
+
 dummy_template_yaml = """---
 AWSTemplateFormatVersion: 2010-09-09
 Description: Stack1 with yaml template
@@ -668,6 +676,48 @@ def test_boto3_create_stack_with_short_form_func_yaml():
     )
 
 
+@mock_s3
+@mock_cloudformation
+def test_get_template_summary():
+    s3 = boto3.client("s3")
+    s3_conn = boto3.resource("s3", region_name="us-east-1")
+
+    conn = boto3.client("cloudformation", region_name="us-east-1")
+    result = conn.get_template_summary(TemplateBody=json.dumps(dummy_template3))
+
+    result["ResourceTypes"].should.equal(["AWS::EC2::VPC"])
+    result["Version"].should.equal("2010-09-09")
+    result["Description"].should.equal("Stack 3")
+
+    conn.create_stack(StackName="test_stack", TemplateBody=json.dumps(dummy_template3))
+
+    result = conn.get_template_summary(StackName="test_stack")
+
+    result["ResourceTypes"].should.equal(["AWS::EC2::VPC"])
+    result["Version"].should.equal("2010-09-09")
+    result["Description"].should.equal("Stack 3")
+
+    s3_conn.create_bucket(Bucket="foobar")
+    s3_conn.Object("foobar", "template-key").put(Body=json.dumps(dummy_template3))
+
+    key_url = s3.generate_presigned_url(
+        ClientMethod="get_object", Params={"Bucket": "foobar", "Key": "template-key"}
+    )
+
+    conn.create_stack(StackName="stack_from_url", TemplateURL=key_url)
+    result = conn.get_template_summary(TemplateURL=key_url)
+    result["ResourceTypes"].should.equal(["AWS::EC2::VPC"])
+    result["Version"].should.equal("2010-09-09")
+    result["Description"].should.equal("Stack 3")
+
+    conn = boto3.client("cloudformation", region_name="us-east-1")
+    result = conn.get_template_summary(TemplateBody=dummy_template_yaml)
+
+    result["ResourceTypes"].should.equal(["AWS::EC2::Instance"])
+    result["Version"].should.equal("2010-09-09")
+    result["Description"].should.equal("Stack1 with yaml template")
+
+
 @mock_cloudformation
 def test_boto3_create_stack_with_ref_yaml():
     cf_conn = boto3.client("cloudformation", region_name="us-east-1")