title: Getting an Environment Variable in Terraform configuration?
body: <p>I have two environment variables. One is <code>TF_VAR_UN</code> and another is <code>TF_VAR_PW</code>. Then I have a terraform file that looks like this.</p>
  
  <pre><code>resource "google_container_cluster" "primary" {
      name = "marcellus-wallace"
      zone = "us-central1-a"
      initial_node_count = 3
  
      master_auth {
          username = ${env.TF_VAR_UN}
          password = ${env.TF_VAR_PW}
      }
  
      node_config {
          oauth_scopes = [
              "https://www.googleapis.com/auth/compute",
              "https://www.googleapis.com/auth/devstorage.read_only",
              "https://www.googleapis.com/auth/logging.write",
              "https://www.googleapis.com/auth/monitoring"
          ]
      }
  }
  </code></pre>
  
  <p>The two values I'd like to replace with the environment variables <code>TF_VAR_UN</code> and <code>TF_VAR_PW</code> are the values username and password. I tried what is shown above, with no success, and I've toyed around with a few other things but always get syntax issues.</p>