Fixed CF creation to trap imports of non-existent values

moto/cloudformation/exceptions.py

@@ -33,6 +33,18 @@ class MissingParameterError(BadRequest):
         )
 
 
+class ExportNotFound(BadRequest):
+    """Exception to raise if a template tries to import a non-existent export"""
+
+    def __init__(self, export_name):
+        template = Template(ERROR_RESPONSE)
+        super(ExportNotFound, self).__init__()
+        self.description = template.render(
+            code='ExportNotFound',
+            message="No export named {0} found.".format(export_name)
+        )
+
+
 ERROR_RESPONSE = """<ErrorResponse xmlns="http://cloudformation.amazonaws.com/doc/2010-05-15/">
   <Error>
     <Type>Sender</Type>

moto/cloudformation/models.py

@@ -38,7 +38,7 @@ class FakeStack(BaseModel):
                                   resource_status_reason="User Initiated")
 
         self.description = self.template_dict.get('Description')
-        self.cross_stack_resources = cross_stack_resources or []
+        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")

moto/cloudformation/parsing.py

@@ -28,7 +28,7 @@ from moto.s3 import models as s3_models
 from moto.sns import models as sns_models
 from moto.sqs import models as sqs_models
 from .utils import random_suffix
-from .exceptions import MissingParameterError, UnformattedGetAttTemplateException, ValidationError
+from .exceptions import ExportNotFound, MissingParameterError, UnformattedGetAttTemplateException, ValidationError
 from boto.cloudformation.stack import Output
 
 MODEL_MAP = {
@@ -206,6 +206,8 @@ def clean_json(resource_json, resources_map):
             values = [x.value for x in resources_map.cross_stack_resources.values() if x.name == cleaned_val]
             if any(values):
                 return values[0]
+            else:
+                raise ExportNotFound(cleaned_val)
 
         if 'Fn::GetAZs' in resource_json:
             region = resource_json.get('Fn::GetAZs') or DEFAULT_REGION

tests/test_cloudformation/test_import_value.py

@@ -0,0 +1,85 @@
+# -*- coding: utf-8 -*-
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+# Standard library modules
+import unittest
+
+# Third-party modules
+import boto3
+from botocore.exceptions import ClientError
+
+# Package modules
+from moto import mock_cloudformation
+
+SG_STACK_NAME = 'simple-sg-stack'
+SG_TEMPLATE = """
+AWSTemplateFormatVersion: 2010-09-09
+Description: Simple test CF template for moto_cloudformation
+
+
+Resources:
+  SimpleSecurityGroup:
+    Type: AWS::EC2::SecurityGroup
+    Description: "A simple security group"
+    Properties:
+      GroupName: simple-security-group
+      GroupDescription: "A simple security group"
+      SecurityGroupEgress:
+        -
+          Description: "Egress to remote HTTPS servers"
+          CidrIp: 0.0.0.0/0
+          IpProtocol: tcp
+          FromPort: 443
+          ToPort: 443
+
+Outputs:
+    SimpleSecurityGroupName:
+        Value: !GetAtt SimpleSecurityGroup.GroupId
+        Export:
+            Name: "SimpleSecurityGroup"
+
+"""
+
+EC2_STACK_NAME = 'simple-ec2-stack'
+EC2_TEMPLATE = """
+---
+# The latest template format version is "2010-09-09" and as of 2018-04-09
+# is currently the only valid value.
+AWSTemplateFormatVersion: 2010-09-09
+Description: Simple test CF template for moto_cloudformation
+
+
+Resources:
+  SimpleInstance:
+    Type: AWS::EC2::Instance
+    Properties:
+        ImageId: ami-03cf127a
+        InstanceType: t2.micro
+        SecurityGroups: !Split [',', !ImportValue SimpleSecurityGroup]
+"""
+
+
+class TestSimpleInstance(unittest.TestCase):
+    def test_simple_instance(self):
+        """Test that we can create a simple CloudFormation stack that imports values from an existing CloudFormation stack"""
+        with mock_cloudformation():
+            client = boto3.client('cloudformation')
+            client.create_stack(StackName=SG_STACK_NAME, TemplateBody=SG_TEMPLATE)
+            response = client.create_stack(StackName=EC2_STACK_NAME, TemplateBody=EC2_TEMPLATE)
+            self.assertIn('StackId', response)
+            response = client.describe_stacks(StackName=response['StackId'])
+            self.assertIn('Stacks', response)
+            stack_info = response['Stacks']
+            self.assertEqual(1, len(stack_info))
+            self.assertIn('StackName', stack_info[0])
+            self.assertEqual(EC2_STACK_NAME, stack_info[0]['StackName'])
+
+    def test_simple_instance_missing_export(self):
+        """Test that we get an exception if a CloudFormation stack tries to imports a non-existent export value"""
+        with mock_cloudformation():
+            client = boto3.client('cloudformation')
+            with self.assertRaises(ClientError) as e:
+                client.create_stack(StackName=EC2_STACK_NAME, TemplateBody=EC2_TEMPLATE)
+            self.assertIn('Error', e.exception.response)
+            self.assertIn('Code', e.exception.response['Error'])
+            self.assertEqual('ExportNotFound', e.exception.response['Error']['Code'])