Can an aws IAM policy dynamically refer to the logged in username?

Question

I am trying to write an IAM policy which will control access to EC2 instances. All EC2 instances will have a custom tag called username and only if the tag value matches the log

Answer 1

The IAM user can be referred to in policy documents by ${aws:username}.

There is a list of other IAM policy variables and their uses here:

http://docs.aws.amazon.com/IAM/latest/UserGuide/PolicyVariables.html