How to create a AWS LB Listener from CloudFormation that returns a fixed response?

Question

From the Load Balancer Lister configuration page, in the AWS Console it allows you to create a listener with a Default Action as shown here:

The Fixed Response option allows you to specify an http return code and a body:

Below is sample known-valid CloudFormation. Not sure how to edit this to support non-forwarding operations.

MyServicesLoadBalancerListener:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
        LoadBalancerArn: !Ref MyServicesLoadBalancer
        Port: 80
        Protocol: HTTP
        DefaultActions:
            - Type: forward
              TargetGroupArn: !Ref MyServicesTargetGroup

How do I do this with CloudFormation? The documentation here seems to suggest only the Forward rule is supported in CloudFormation.

Thanks

Answer 1

Not possible yet. It has been requested on the forums but no ETA.

According to the Release History of AWS CloudFormation, the feature was added on Nov 19, 2018. This should replicate the fixed response you shown with the console pictures.

MyServicesLoadBalancerListener:
  Type: AWS::ElasticLoadBalancingV2::Listener
  Properties:
    LoadBalancerArn: !Ref MyServicesLoadBalancer
    Port: 80
    Protocol: HTTP
    DefaultActions:
      - Type: fixed-response
        FixedResponseConfig:
          ContentType: "text/plain"
          MessageBody: "You've reached the listener! Congrats!"
          StatusCode: "503"