Fix: Prevents "Invalid index" when creating private cluster (#422)

* fix Invalid index error when creating a private cluster

As google_container_cluster.primary.private_cluster_config may be empty,
we check its length before trying to access it.

When creating a new private cluster, a "Invalid index" error was showing
up during the planning.

By checking for variable length before trying to access it the plan (and
apply) works as expected.

Issue: [#419]

Co-authored-by: Morgante Pell <morgantep@google.com>

* perform generation

Co-authored-by: Morgante Pell <morgante.pell@morgante.net>

autogen/main/main.tf.tmpl

@@ -106,7 +106,7 @@ locals {
   cluster_output_zones          = local.cluster_output_regional_zones
 
 {% if private_cluster %}
-  cluster_endpoint = var.enable_private_nodes ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
+  cluster_endpoint = (var.enable_private_nodes && length(google_container_cluster.primary.private_cluster_config) > 0) ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
 {% else %}
   cluster_endpoint = google_container_cluster.primary.endpoint
 {% endif %}

modules/beta-private-cluster-update-variant/main.tf

@@ -97,7 +97,7 @@ locals {
   cluster_output_zonal_zones    = local.zone_count > 1 ? slice(var.zones, 1, local.zone_count) : []
   cluster_output_zones          = local.cluster_output_regional_zones
 
-  cluster_endpoint = var.enable_private_nodes ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
+  cluster_endpoint = (var.enable_private_nodes && length(google_container_cluster.primary.private_cluster_config) > 0) ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
 
   cluster_output_master_auth                        = concat(google_container_cluster.primary.*.master_auth, [])
   cluster_output_master_version                     = google_container_cluster.primary.master_version

modules/beta-private-cluster/main.tf

@@ -97,7 +97,7 @@ locals {
   cluster_output_zonal_zones    = local.zone_count > 1 ? slice(var.zones, 1, local.zone_count) : []
   cluster_output_zones          = local.cluster_output_regional_zones
 
-  cluster_endpoint = var.enable_private_nodes ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
+  cluster_endpoint = (var.enable_private_nodes && length(google_container_cluster.primary.private_cluster_config) > 0) ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
 
   cluster_output_master_auth                        = concat(google_container_cluster.primary.*.master_auth, [])
   cluster_output_master_version                     = google_container_cluster.primary.master_version

modules/private-cluster-update-variant/main.tf

@@ -73,7 +73,7 @@ locals {
   cluster_output_zonal_zones    = local.zone_count > 1 ? slice(var.zones, 1, local.zone_count) : []
   cluster_output_zones          = local.cluster_output_regional_zones
 
-  cluster_endpoint = var.enable_private_nodes ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
+  cluster_endpoint = (var.enable_private_nodes && length(google_container_cluster.primary.private_cluster_config) > 0) ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
 
   cluster_output_master_auth                        = concat(google_container_cluster.primary.*.master_auth, [])
   cluster_output_master_version                     = google_container_cluster.primary.master_version

modules/private-cluster/main.tf

@@ -73,7 +73,7 @@ locals {
   cluster_output_zonal_zones    = local.zone_count > 1 ? slice(var.zones, 1, local.zone_count) : []
   cluster_output_zones          = local.cluster_output_regional_zones
 
-  cluster_endpoint = var.enable_private_nodes ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
+  cluster_endpoint = (var.enable_private_nodes && length(google_container_cluster.primary.private_cluster_config) > 0) ? (var.deploy_using_private_endpoint ? google_container_cluster.primary.private_cluster_config.0.private_endpoint : google_container_cluster.primary.private_cluster_config.0.public_endpoint) : google_container_cluster.primary.endpoint
 
   cluster_output_master_auth                        = concat(google_container_cluster.primary.*.master_auth, [])
   cluster_output_master_version                     = google_container_cluster.primary.master_version