Role ARN with Path does not match Gorilla Mux URL

[joshuamorris3]

Hi,

I'm trying to use the /role-arn/{role arn} option for the AWS_CONTAINER_CREDENTIALS_RELATIVE_URI. If I try using a role with a path in it e.g. arn:aws:iam::111122223333:role/division_abc/subdivision_xyz/custom_role it does not appear to work. I believe it is due to the Gorilla Mux path pattern used at https://github.com/awslabs/amazon-ecs-local-container-endpoints/blob/mainline/local-container-endpoints/config/config.go#L73, it doesn't allow expansion to multiple /.

I checked out the code and added a simple expansion RoleArnCredentialsPath = "/role-arn/{roleArn}/{roleName:.+}" and this fixed the problem. I did need to update the STS role session name to exclude any / as this is not allowed in the role session name.

Am I understanding this correctly or am I missing something? I can create a PR with a fix if needed.