custom-resource-demo.yml

Description: >
    Simple custom resource demo
Parameters:

    InputMessage:
      Type: String
      Description: An input to the custom resource
      Default: Hello function!    

    RoleForLambda:
        Description: ARN of the role you created
        Type: String


Resources:

  MyCustomResourceFunction:
    Type: AWS::Lambda::Function
    Properties:
      Code:
        ZipFile: |
          var response = require('cfn-response');
          var aws = require("aws-sdk");
          exports.handler = function(event, context) {
            var input = event.ResourceProperties.InputParameter;
            var responseData = {msg: "hello world!", msg2: input + " --received from caller"};
            response.send(event, context, response.SUCCESS, responseData);
          };
      Handler: index.handler
      Timeout: 30
      Runtime: nodejs14.x
      Role: !Ref RoleForLambda

  MyCustomResourceCallout:
    Type: Custom::LambdaCallout
    Properties:
      ServiceToken: !GetAtt MyCustomResourceFunction.Arn
      InputParameter: !Ref InputMessage

Outputs:
  OutputFromFunction:
    Description: Output from the custom function
    Value: !GetAtt MyCustomResourceCallout.msg

  ModifiedInputReturned:
    Description: Pipe out the input so we know we got it
    Value: !GetAtt MyCustomResourceCallout.msg2