cloudformation variable trick

  LambdaExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
        - Effect: Allow
          Principal:
            Service: [ lambda.amazonaws.com ]
          Action: [ 'sts:AssumeRole' ]
      Policies:
      - PolicyName: lambdalogtocloudwatch
        PolicyDocument:
          Version: 2012-10-17
          Statement:
          - Effect: Allow
            Action: [ 'logs:CreateLogGroup', 'logs:CreateLogStream', 'logs:PutLogEvents' ]
            Resource: 'arn:aws:logs:*:*:*'

  DomainsLambda:
    Type: AWS::Lambda::Function
    Properties:
      Code:
        ZipFile: !Sub |
          var response = require('cfn-response');
          exports.handler = function(event, context) {
            var responseData = {
              ManagerDomain: "hoyeah-${AWS::StackName}",
              Email: "email"
            };
            response.send(event, context, response.SUCCESS, responseData);
          };
      Handler: index.handler
      Runtime: nodejs4.3
      Timeout: 30
      Role: !GetAtt LambdaExecutionRole.Arn

  DomainsDefinition:
    Type: Custom::LambdaCallout
    Properties:
      ServiceToken: !GetAtt DomainsLambda.Arn