Stupid TF Tricks

physical_from_stack_logical.tf

# how do we get credentials in here? Who knows....
data "external" "stack" {
  program = [ "xargs", "-0", 
    "aws", "cloudformation", "describe-stack-resource", "--output", "json",
    "--query", "StackResourceDetail.{id:PhysicalResourceId}" ]
  query = {
    StackName: "StackName",
    LogicalResourceId: "LogicalResourceName",
  }
}

output "physical_stack_resource":
  value = data.external.stack.result.id
}