[AWS::CloudWatch::Alarm] - [Enhancement] - Dynamically calculate timeout value for the alarm’s Threshold property.

[Waqiah]

Name of the resource

AWS::CloudWatch::Alarm

Resource name

No response

Description

Looking for a native way using CFN to be able to dynamically calculate timeout value for the alarm’s Threshold property.

Use case:
When using AWS::Lambda::Function resources, the timeout value is defined using the following:
Timeout: !Ref Timeout

A duration alarm using the AWS::CloudWatch::Alarm resource is created for the Lambda resources and for the alarm's Threshold property, currently 90% of the timeout value is calculated manually and passed like this:
Threshold: !Ref ThresholdTimeOut

However, since the timeout value may vary, want to avoid manual calculations of the 90% threshold. Instead, would like a CloudFormation solution that dynamically calculates 90% of the timeout value for the alarm's Threshold property.

Additionally it is understood that a Custom Resource can be used to calculate the 90% of the Timeout value and pass it to AWS::CloudWatch::Alarm, however, looking to avoid using a custom resource because introducing another Lambda function along with its associated maintenance overhead is not ideal for our use case.

Other Details

No response