Fn::Size intrinsic template function

[josb]

Scope of request

AWS CloudFormation templates.

Expected behavior

Fn::Size should return the number of elements in a list (the result of Fn::Split, or a CommaDelimitedList parameter).

Test case recommendation

If you combine this with the Fn::Split function it will allow you to see how many items were entered when someone has a CommaDelimitedList parameter, which is helpful when it comes to Conditionals:
{ "Fn::Size" : { "Fn::Split" : [ "delimiter", "source string" ] } }

Links to existing API doc

https://www.kencochrane.net/2017/03/25/my-cloudformation-wishlist/

Category

11. Other (IoT, Migration, Budgets...)

[lejiati]

@josb Thank you very much for your feedback! Since this repository is focused on resource coverage, I'm transferring this issue over to a new GitHub repository dedicated to CloudFormation template language issues.

[muneebar]

@josb Thanks for bringing this to our attention. Stay tuned for updates!

[MalikAtalla-AWS]

Hi all, we have opened an RFC (here) to address this use case. Any feedback is welcome.

[josb]

Thanks to all helping to submit this RFC!

[lejiati]

Hey @josb, really appreciate your feedback and feature proposal. I'm happy to share that Fn::Length, a new intrinsic function which returns length of a list is now available (more details can be found here).

Please feel free to try it out and leave your feedback!