title: Getting IAM username in terraform
body: <p>We have many IAM users, all creating self-serve infrastructure on EC2 using Terraform. Users don't necessarily set the key for their instances, so it's hard to tie an instance to a particular user. I realize we could dig through CloudTrail to find out which users are creating instances, but it seems like it would be simpler to tag the instances with the current IAM username.</p>
  
  <p>The problem is Terraform doesn't appear to expose this - I can use <code>aws_caller_identity</code> or <code>aws_canonical_user_id</code>, but they both appear to return the organization account, not the specific IAM username. Is there a data source in Terraform that will return the IAM user creating the instances?</p>