AWS Custom resource example. Multiplies number by 42

custom-resource.yaml

AWSTemplateFormatVersion: 2010-09-09
Description: 'Custom resource test'

Parameters:
  Value:
    Type: Number
    Description: input a number
    Default: 1

Resources:
  FooRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
        - Action: ['sts:AssumeRole']
          Effect: Allow
          Principal:
            Service: [lambda.amazonaws.com]

  FooFunction:
    Type: AWS::Lambda::Function
    Properties:
      Code:
        ZipFile: |
          import json
          import cfnresponse
          def handler(event, context):
            responseValue = int(event['ResourceProperties']['Input']) * 42
            responseData = {}
            responseData['Data'] = responseValue
            cfnresponse.send(event, context, cfnresponse.SUCCESS, responseData, "CustomResourcePhysicalID")
      Handler: index.handler
      Role: !GetAtt FooRole.Arn
      Runtime: 'python2.7'

  Foo:
    Type: Custom::Foo
    Version: 1.0
    Properties:
      ServiceToken: !GetAtt FooFunction.Arn
      Input: !Ref Value

Outputs:
  Results:
    Value: !GetAtt Foo.Data