Accessing Terraform variables within user_data provider template file

Question

I am launching a aws_launch_configuration instance using terraform.

I\'m using a shell script for the user_data variable, like so:

Answer 1

For people coming here since Terraform 0.12 and later, the templatefile function should be used instead of using template_file resource, so for the example in the question, it would be something like

locals {
  vars = {
    some_address = aws_instance.some.private_ip
  }
}

user-data = templatefile("router-init.sh", vars)

Answer 2

You can do this using a template_file data source:

data "template_file" "init" {
  template = "${file("router-init.sh.tpl")}"

  vars = {
    some_address = "${aws_instance.some.private_ip}"
  }
}

Then reference it inside the template like:

#!/bin/bash

echo "SOME_ADDRESS = ${some_address}" > /tmp/

Then use that for the user_data:

 user_data = ${data.template_file.init.rendered}