From 2e644a3333af5c6888d537503d64120467aa80df Mon Sep 17 00:00:00 2001
From: Ludovico Magnocavallo <ludomagno@google.com>
Date: Sun, 16 Aug 2020 20:36:52 +0200
Subject: [PATCH] streamline gke module peering project id

---
 modules/gke-cluster/README.md | 2 +-
 modules/gke-cluster/main.tf   | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/modules/gke-cluster/README.md b/modules/gke-cluster/README.md
index 98d8aaff..d0293f06 100644
--- a/modules/gke-cluster/README.md
+++ b/modules/gke-cluster/README.md
@@ -58,7 +58,7 @@ module "cluster-1" {
 | *min_master_version* | Minimum version of the master, defaults to the version of the most recent official release. | <code title="">string</code> |  | <code title="">null</code> |
 | *monitoring_service* | Monitoring service (disable with an empty string). | <code title="">string</code> |  | <code title="">monitoring.googleapis.com/kubernetes</code> |
 | *node_locations* | Zones in which the cluster's nodes are located. | <code title="list&#40;string&#41;">list(string)</code> |  | <code title="">[]</code> |
-| *peering_config* | Configure peering with the master VPC for private clusters. | <code title="object&#40;&#123;&#10;export_routes &#61; bool&#10;import_routes &#61; bool&#10;project_id &#61; string&#10;&#125;&#41;">object({...})</code> |  | <code title="">null</code> |
+| *peering_config* | Configure peering with the master VPC for private clusters. | <code title="object&#40;&#123;&#10;export_routes &#61; bool&#10;import_routes &#61; bool&#10;project_id    &#61; string&#10;&#125;&#41;">object({...})</code> |  | <code title="">null</code> |
 | *pod_security_policy* | Enable the PodSecurityPolicy feature. | <code title="">bool</code> |  | <code title="">null</code> |
 | *private_cluster_config* | Enable and configure private cluster, private nodes must be true if used. | <code title="object&#40;&#123;&#10;enable_private_nodes    &#61; bool&#10;enable_private_endpoint &#61; bool&#10;master_ipv4_cidr_block  &#61; string&#10;&#125;&#41;">object({...})</code> |  | <code title="">null</code> |
 | *release_channel* | Release channel for GKE upgrades. | <code title="">string</code> |  | <code title="">null</code> |
diff --git a/modules/gke-cluster/main.tf b/modules/gke-cluster/main.tf
index 29e5a8ea..c17b1ada 100644
--- a/modules/gke-cluster/main.tf
+++ b/modules/gke-cluster/main.tf
@@ -22,7 +22,11 @@ locals {
     google_container_cluster.cluster.private_cluster_config.0.peering_name,
     null
   )
-  peering_project_id = try(var.peering_config.project_id, "") == "" ? var.project_id                    : (var.peering_config.project_id == "" ? var.project_id : var.peering_config.project_id)
+  peering_project_id = (
+    try(var.peering_config.project_id, null) == null
+    ? var.project_id
+    : var.peering_config.project_id
+  )
 }
 
 resource "google_container_cluster" "cluster" {