AWS::Amplify::App AppId is too long to reference on AWS::Amplify::Branch and AWS::Amplify::Domain

Question

Hello,

I'm trying to create an AWS Amplify resource through CloudFormation and I'm stuck in the following situation:

When creating the AWS::Amplify::App resource it returns the AppId "arn:aws:amplify:us-east-1:000000000000:apps/xxxxxxxxxxxxx"
But when trying to create an AWS::Amplify::Branch or AWS::Amplify::Domain the character limit for the AppId is 20 characters.

Result in console:

CREATE_FAILED: LootzAppProductionBranch (AWS::Amplify::Branch)
Properties validation failed for resource LootzAppProductionBranch with message:
#/AppId: expected maxLength: 20, actual: 58

Is there any way to force a smaller AppId for AWS::Amplify::App?

How should I proceed?

Thanks!

Answer

I think there may be a problem with the Cloudformation output.
the AppId output of AWS::Amplify::App is being completed with complete Arn information..

I opened an issue on github for this case, but I haven't had a response yet.
https://github.com/aws-cloudformation/aws-cloudformation-resource-providers-amplify/issues/16

Answer

Amplify App ARN is of the form `arn:aws:amplify:us-east-1:000000000000:apps/xxxxxxxxxxxxx` however **AppID** that you are referring to is just the `xxxxxxxxxxxxx` unique string and not the complete ARN.

You may refer Amplify's service authorization [reference](https://docs.aws.amazon.com/service-authorization/latest/reference/list_awsamplify.html#awsamplify-resources-for-iam-policies) for the syntax.

AWS::Amplify::App AppId is too long to reference on AWS::Amplify::Branch and AWS::Amplify::Domain

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