Strip ".cfn" from the deployed stack name #743
Description
Today the deploy command strips the file extension from the deployed stack name like this: rain deploy mytemplate.yaml makes a stack called mytemplate.
I use the file extension .cfn.yaml for all my templates. It helps to configure tools like pre-commit to run checks such as cfn-lint only on CloudFormation files.
Unfortunately Rain doesn't fully understand my file extension: rain deploy mytemplate.cfn.yaml makes a stack called mytemplate-cfn. Here the -cfn at the end is just noise, and I want Rain to strip it.
Today I work around the problem by being verbose: rain deploy mytemplate.cfn.yaml mytemplate.
The CloudFormation Language project has an open proposal to accept .cfn.yaml and .cfn.json as standard file extensions for CloudFormation templates. See aws-cloudformation/cfn-language-discussion#45.
Rain doesn't need to wait for an approved standard. It could implement this behaviour today, and perhaps influence adoption of the standard by being a reference implementation.
Everything I've said here would apply to .cfn.yml and .cfn.json as well.