feat: allow referencing existing ES instance (#243)

* feat: allow exist es

* fix: module is a tuple

* feat: add exist rg id var

* feat: output rg id

* fix: output fix

* refactor: variable tidying

* fix: for testing

* refactor: some renaming

* fix: some variable updates

* docs: var description

* refactor: added move block

* fix: merge issue

* fix: moved block

* fix: module moved block

* fix: move block fix

* refactor: moved.tf

---------

Co-authored-by: [email protected] <[email protected]>
Co-authored-by: shemau <[email protected]>
Co-authored-by: toddgiguere <[email protected]>

Author: 3 people

solutions/standard/main.tf

@@ -10,7 +10,12 @@ locals {
   elasticsearch_key_name      = var.prefix != null ? "${var.prefix}-${var.elasticsearch_key_name}" : var.elasticsearch_key_name
   elasticsearch_key_ring_name = var.prefix != null ? "${var.prefix}-${var.elasticsearch_key_ring_name}" : var.elasticsearch_key_ring_name
 
-  kms_key_crn                      = var.existing_kms_key_crn != null ? var.existing_kms_key_crn : module.kms[0].keys[format("%s.%s", local.elasticsearch_key_ring_name, local.elasticsearch_key_name)].crn
+
+  kms_key_crn = var.existing_kms_key_crn != null ? var.existing_kms_key_crn : module.kms[0].keys[format("%s.%s", local.elasticsearch_key_ring_name, local.elasticsearch_key_name)].crn
+
+  existing_db_instance_guid = var.existing_db_instance_crn != null ? element(split(":", var.existing_db_instance_crn), length(split(":", var.existing_db_instance_crn)) - 3) : null
+  use_existing_db_instance  = var.existing_db_instance_crn != null
+
   create_cross_account_auth_policy = !var.skip_iam_authorization_policy && var.ibmcloud_kms_api_key != null
   kms_service_name = local.kms_key_crn != null ? (
     can(regex(".*kms.*", local.kms_key_crn)) ? "kms" : can(regex(".*hs-crypto.*", local.kms_key_crn)) ? "hs-crypto" : null
@@ -90,6 +95,7 @@ module "kms" {
 #######################################################################################################################
 
 module "elasticsearch" {
+  count                         = local.use_existing_db_instance ? 0 : 1
   source                        = "../../modules/fscloud"
   depends_on                    = [time_sleep.wait_for_authorization_policy]
   resource_group_id             = module.resource_group.resource_group_id
@@ -113,3 +119,26 @@ module "elasticsearch" {
   service_credential_names      = var.service_credential_names
   enable_elser_model            = var.enable_elser_model
 }
+
+# this extra block is needed when passing in an existing ES instance - the database data block
+# requires a name and resource_id to retrieve the data
+data "ibm_resource_instance" "existing_instance_resource" {
+  count      = local.use_existing_db_instance ? 1 : 0
+  identifier = local.existing_db_instance_guid
+}
+
+data "ibm_database" "existing_db_instance" {
+  count             = local.use_existing_db_instance ? 1 : 0
+  name              = data.ibm_resource_instance.existing_instance_resource[0].name
+  resource_group_id = data.ibm_resource_instance.existing_instance_resource[0].resource_group_id
+  location          = var.region
+  service           = "databases-for-elasticsearch"
+}
+
+data "ibm_database_connection" "existing_connection" {
+  count         = local.use_existing_db_instance ? 1 : 0
+  endpoint_type = "private"
+  deployment_id = data.ibm_database.existing_db_instance[0].id
+  user_id       = data.ibm_database.existing_db_instance[0].adminuser
+  user_type     = "database"
+}

solutions/standard/moved.tf

@@ -0,0 +1,4 @@
+moved {
+  from = module.elasticsearch
+  to   = module.elasticsearch[0]
+}

solutions/standard/outputs.tf

@@ -4,47 +4,47 @@
 
 output "id" {
   description = "Elasticsearch instance id"
-  value       = module.elasticsearch.id
+  value       = local.use_existing_db_instance ? data.ibm_database.existing_db_instance[0].id : module.elasticsearch[0].id
 }
 
 output "guid" {
   description = "Elasticsearch instance guid"
-  value       = module.elasticsearch.guid
+  value       = local.use_existing_db_instance ? data.ibm_database.existing_db_instance[0].guid : module.elasticsearch[0].guid
 }
 
 output "version" {
   description = "Elasticsearch instance version"
-  value       = module.elasticsearch.version
+  value       = local.use_existing_db_instance ? data.ibm_database.existing_db_instance[0].version : module.elasticsearch[0].version
 }
 
 output "crn" {
   description = "Elasticsearch instance crn"
-  value       = module.elasticsearch.crn
+  value       = local.use_existing_db_instance ? var.existing_db_instance_crn : module.elasticsearch[0].crn
 }
 
 output "cbr_rule_ids" {
   description = "CBR rule ids created to restrict Elasticsearch"
-  value       = module.elasticsearch.cbr_rule_ids
+  value       = local.use_existing_db_instance ? null : module.elasticsearch[0].cbr_rule_ids
 }
 
 output "service_credentials_json" {
   description = "Service credentials json map"
-  value       = module.elasticsearch.service_credentials_json
+  value       = local.use_existing_db_instance ? null : module.elasticsearch[0].service_credentials_json
   sensitive   = true
 }
 
 output "service_credentials_object" {
   description = "Service credentials object"
-  value       = module.elasticsearch.service_credentials_object
+  value       = local.use_existing_db_instance ? null : module.elasticsearch[0].service_credentials_object
   sensitive   = true
 }
 
 output "hostname" {
   description = "Elasticsearch instance hostname"
-  value       = module.elasticsearch.hostname
+  value       = local.use_existing_db_instance ? data.ibm_database_connection.existing_connection[0].https[0].hosts[0].hostname : module.elasticsearch[0].hostname
 }
 
 output "port" {
   description = "Elasticsearch instance port"
-  value       = module.elasticsearch.port
+  value       = local.use_existing_db_instance ? data.ibm_database_connection.existing_connection[0].https[0].hosts[0].port : module.elasticsearch[0].port
 }

solutions/standard/variables.tf

@@ -60,10 +60,17 @@ variable "plan" {
   default     = "platinum"
 }
 
+variable "existing_db_instance_crn" {
+  type        = string
+  default     = null
+  description = "The CRN of an existing Databases for Elasticsearch instance. If no value is specified, a new instance is created."
+}
+
 ##############################################################################
 # ICD hosting model properties
 ##############################################################################
 
+
 variable "members" {
   type        = number
   description = "The number of members that are allocated. [Learn more](https://cloud.ibm.com/docs/databases-for-elasticsearch?topic=databases-for-elasticsearch-resources-scaling)."