feat: Add new property to explicitly return GKE private_endpoint for auth module (terraform-google-modules#841)

* Add new property to explicitly return GKE private_endpoint * Return private_endpoint if explicitly requested, otherwise return default endpoint Co-authored-by: Bharath KKB <bharathkrishnakb@gmail.com>

Author: fstr

modules/auth/README.md

@@ -9,15 +9,18 @@ This module retrieves a token for the account configured with the `google`
 provider as the Terraform runner using the provider's `credentials`,
 `access_token`, or other means of authentication.
 
+If you run a [private cluster](https://cloud.google.com/kubernetes-engine/docs/concepts/private-cluster-concept), you can set the `use_private_endpoint` property to return the GKE private_endpoint IP address.
+
 ## Usage
 
 ```tf
 module "gke_auth" {
- source = "terraform-google-modules/kubernetes-engine/google//modules/auth"
+ source  = "terraform-google-modules/kubernetes-engine/google//modules/auth"
 
- project_id = "my-project-id"
- cluster_name = "my-cluster-name"
- location = module.gke.location
+ project_id = "my-project-id"
+ cluster_name = "my-cluster-name"
+ location = module.gke.location
+ use_private_endpoint = true
 }
 ```
 

modules/auth/main.tf

@@ -16,8 +16,10 @@
 
 locals {
  cluster_ca_certificate = data.google_container_cluster.gke_cluster.master_auth != null ? data.google_container_cluster.gke_cluster.master_auth[0].cluster_ca_certificate : ""
- endpoint = data.google_container_cluster.gke_cluster.endpoint != null ? data.google_container_cluster.gke_cluster.endpoint : ""
- host = data.google_container_cluster.gke_cluster.endpoint != null ? "https://${data.google_container_cluster.gke_cluster.endpoint}" : ""
+ private_endpoint = try(data.google_container_cluster.gke_cluster.private_cluster_config[0].private_endpoint, "")
+ default_endpoint = data.google_container_cluster.gke_cluster.endpoint != null ? data.google_container_cluster.gke_cluster.endpoint : ""
+ endpoint = var.use_private_endpoint == true ? local.private_endpoint : local.default_endpoint
+ host = local.endpoint != "" ? "https://${local.endpoint}" : ""
  context = data.google_container_cluster.gke_cluster.name != null ? data.google_container_cluster.gke_cluster.name : ""
 }
 

modules/auth/variables.tf

@@ -28,3 +28,9 @@ variable "cluster_name" {
  description = "The name of the GKE cluster."
  type = string
 }
+
+variable "use_private_endpoint" {
+ description = "Connect on the private GKE cluster endpoint"
+ type = bool
+ default = false
+}