add validation to check existing stack prefix before provisioning

Author: HarshadVilekar

terraform/main.tf

@@ -350,7 +350,7 @@ module "vcn-peering" {
 module "validators" {
   #depends_on = [module.network-validation]
   source     = "./modules/validators"
-
+  compartment_id             = var.compartment_ocid
   service_name               = var.service_name
   wls_ms_port                = var.wls_ms_extern_port
   wls_ms_ssl_port            = var.wls_ms_extern_ssl_port

terraform/modules/validators/stack_validators.tf

@@ -0,0 +1,28 @@
+# Copyright (c) 2023, Oracle and/or its affiliates.
+# Licensed under the Universal Permissive License v1.0 as shown at https://oss.oracle.com/licenses/upl.
+
+# list all stacks in all states (active, deleted etc)
+data "oci_resourcemanager_stacks" "all_stacks_in_the_compartment" {
+  compartment_id = var.compartment_id
+}
+
+locals {
+  stack_list = data.oci_resourcemanager_stacks.all_stacks_in_the_compartment.stacks
+  num_stacks = length(local.stack_list)
+  stack_ids = [for stack in local.stack_list : { id = stack.id }]
+}
+
+# get details of each stack
+data "oci_resourcemanager_stack" "all_stacks" {
+  count = local.num_stacks
+  #Required
+  stack_id = local.stack_ids[count.index].id
+}
+
+locals {
+  stack_variables = [for stack in data.oci_resourcemanager_stack.all_stacks : { variables = stack.variables }]
+  service_names_used_by_existing_stacks = [for stack_variables in local.stack_variables : lookup(stack_variables.variables, "service_name", "?service_name_attribute_not_found?")]
+  service_name_already_exists = contains(local.service_names_used_by_existing_stacks, var.service_name) ? true : false
+  service_name_already_exists_msg      = "WLSC-ERROR: The stack with the service_name [${var.service_name}] already exisits in the stack compartment. Try again with a different service name."
+  validate_service_name_is_not_already_used = local.service_name_already_exists ? local.validators_msg_map[local.service_name_already_exists_msg] : null
+}

terraform/modules/validators/variables.tf

@@ -1,6 +1,11 @@
 # Copyright (c) 2023, Oracle and/or its affiliates.
 # Licensed under the Universal Permissive License v1.0 as shown at https://oss.oracle.com/licenses/upl.
 
+variable "compartment_id" {
+  type        = string
+  description = "Compartment for stack resources"
+}
+
 variable "service_name" {
   type        = string
   description = "Prefix for stack resources"