added support to null DRG ID passed as input from external modules (#9)

* fix: removed the region variable

* added support to null DRG ID passed as input from external modules

Author: snafuz

drg.tf

@@ -17,7 +17,7 @@ data "oci_core_drgs" "drg_data" {
 
   filter {
     name   = "id"
-    values = [var.drg_id]
+    values = [var.drg_id == null ? "none" : var.drg_id]
   }
 
 }

outputs.tf

@@ -27,7 +27,7 @@ output "drg_summary" {
   description = "drg information summary"
   value = {
     (length(data.oci_core_drgs.drg_data.drgs) == 0 ? oci_core_drg.drg[0].display_name : data.oci_core_drgs.drg_data.drgs[0].display_name) = {
-      drg_id          = length(data.oci_core_drgs.drg_data.drgs) == 0 ? oci_core_drg.drg[0].id : data.oci_core_drgs.drg_data.drgs[*].id
+      drg_id          = length(data.oci_core_drgs.drg_data.drgs) == 0 ? oci_core_drg.drg[0].id : data.oci_core_drgs.drg_data.drgs[0].id
       vcn_attachments = { for k, v in oci_core_drg_attachment.vcns : k => v.network_details[0].id }
 
     }

terraform.tfvars.example

@@ -1,10 +1,6 @@
 # Copyright (c) 2022 Oracle Corporation and/or affiliates.  All rights reserved.
 # Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl
 
-# Region
-
-region = "us-phoenix-1"
-
 # general oci parameters
 
 compartment_id = ""