feat: add support to use existing cloud monitoring instance with new input variable existing_cloud_monitoring_crn (#91)

Author: Soaib024

ibm_catalog.json

@@ -224,6 +224,9 @@
             {
               "key": "cloud_monitoring_provision"
             },
+            {
+              "key": "existing_cloud_monitoring_crn"
+            },
             {
               "key": "cloud_monitoring_instance_name"
             },

solutions/instances/main.tf

@@ -6,6 +6,8 @@ locals {
 
   # tflint-ignore: terraform_unused_declarations
   validate_log_analysis_provision = var.enable_at_event_routing_to_log_analysis && var.log_analysis_provision == false ? tobool("log_analysis_provision can't be false if enable_at_event_routing_to_log_analysis is true") : true
+  # tflint-ignore: terraform_unused_declarations
+  validate_existing_cloud_monitoring = var.cloud_monitoring_provision && var.existing_cloud_monitoring_crn != null ? tobool("if cloud_monitoring_provision is set to true, then existing_cloud_monitoring_crn should be null and vice versa") : true
 
   archive_api_key    = var.log_archive_api_key == null ? var.ibmcloud_api_key : var.log_archive_api_key
   default_cos_region = var.cos_region != null ? var.cos_region : var.region
@@ -25,10 +27,10 @@ locals {
   cos_target_bucket_name     = var.existing_at_cos_target_bucket_name != null ? var.existing_at_cos_target_bucket_name : module.cos_bucket[0].buckets[local.at_cos_target_bucket_name].bucket_name
   cos_target_bucket_endpoint = var.existing_at_cos_target_bucket_endpoint != null ? var.existing_at_cos_target_bucket_endpoint : module.cos_bucket[0].buckets[local.at_cos_target_bucket_name].s3_endpoint_private
 
-  metrics_monitoring = var.cloud_monitoring_provision ? {
+  metrics_monitoring = var.cloud_monitoring_provision || (var.existing_cloud_monitoring_crn != null) ? {
     usage_metrics_enabled   = true
     request_metrics_enabled = true
-    metrics_monitoring_crn  = module.observability_instance.cloud_monitoring_crn
+    metrics_monitoring_crn  = var.cloud_monitoring_provision ? module.observability_instance.cloud_monitoring_crn : var.existing_cloud_monitoring_crn
   } : null
 
   bucket_config_1 = var.existing_log_archive_cos_bucket_name == null && var.log_analysis_provision == true ? {
@@ -152,7 +154,6 @@ module "observability_instance" {
 
   # Routes
   activity_tracker_routes = local.at_routes
-
 }
 
 #######################################################################################################################

solutions/instances/variables.tf

@@ -118,11 +118,17 @@ variable "enable_at_event_routing_to_log_analysis" {
 ##############################################################################
 
 variable "cloud_monitoring_provision" {
-  description = "Set it to true to provision an IBM cloud monitoring instance"
+  description = "Whether to create an IBM cloud monitoring instance. Set to `false` if a CRN is specified in `existing_cloud_monitoring_crn`."
   type        = bool
   default     = true
 }
 
+variable "existing_cloud_monitoring_crn" {
+  description = "The CRN of an IBM Cloud Monitoring instance. If specified, set the `cloud_monitoring_provision` variable to `false`."
+  type        = string
+  default     = null
+}
+
 variable "cloud_monitoring_instance_name" {
   type        = string
   description = "The name of the IBM Cloud Monitoring instance to create. If prefix input variable is passed then it will get prefixed infront of the value in the format of '<prefix>-value'"