Allow google_container_cluster.id reference for the value for the g…

…ke_cluster of a `google_gke_hub_membership` (GoogleCloudPlatform#4985)

Co-authored-by: upodroid <[email protected]>

mmv1/products/gkehub/api.yaml

@@ -103,7 +103,8 @@ objects:
                   Self-link of the GCP resource for the GKE cluster.
                   For example: `//container.googleapis.com/projects/my-project/zones/us-west1-a/clusters/my-cluster`.
                   It can be at the most 1000 characters in length. If the cluster is provisioned with Terraform,
-                  this is `"//container.googleapis.com/${google_container_cluster.my-cluster.id}"`.
+                  this can be `"//container.googleapis.com/${google_container_cluster.my-cluster.id}"` or
+                  `google_container_cluster.my-cluster.id`.
                 input: true
                 required: true
       - !ruby/object:Api::Type::NestedObject

mmv1/products/gkehub/terraform.yaml

@@ -34,6 +34,12 @@ overrides: !ruby/object:Overrides::ResourceOverrides
     skip_sweeper: true
     id_format: "{{name}}"
     import_format: ["{{%name}}"]
+    properties:
+      endpoint.gkeCluster.resourceLink: !ruby/object:Overrides::Terraform::PropertyOverride
+        diff_suppress_func: suppressGkeHubEndpointSelfLinkDiff
+        custom_expand: 'templates/terraform/custom_expand/gke_hub_membership.erb'
+    custom_code: !ruby/object:Provider::Terraform::CustomCode
+      constants: templates/terraform/constants/gke_hub_membership_diff.go
 # This is for copying files over
 files: !ruby/object:Provider::Config::Files
   # These files have templating (ERB) code that will be run.

mmv1/templates/terraform/constants/gke_hub_membership_diff.go

@@ -0,0 +1,9 @@
+func suppressGkeHubEndpointSelfLinkDiff(_, old, new string, _ *schema.ResourceData) bool {
+	// The custom expander injects //container.googleapis.com/ if a selflink is supplied.
+	selfLink := strings.TrimPrefix(old, "//container.googleapis.com/")
+	if selfLink == new {
+		return true
+	}
+
+	return false
+}

mmv1/templates/terraform/custom_expand/gke_hub_membership.erb

@@ -0,0 +1,22 @@
+<%# The license inside this block applies to this file.
+	# Copyright 2021 Google Inc.
+	# Licensed under the Apache License, Version 2.0 (the "License");
+	# you may not use this file except in compliance with the License.
+	# You may obtain a copy of the License at
+	#
+	#     http://www.apache.org/licenses/LICENSE-2.0
+	#
+	# Unless required by applicable law or agreed to in writing, software
+	# distributed under the License is distributed on an "AS IS" BASIS,
+	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+	# See the License for the specific language governing permissions and
+	# limitations under the License.
+-%>
+func expand<%= prefix -%><%= titlelize_property(property) -%>(v interface{}, d TerraformResourceData, config *Config) (interface{}, error) {
+	if strings.HasPrefix(v.(string), "//container.googleapis.com/") {
+		return v, nil
+	} else {
+		v = "//container.googleapis.com/" + v.(string)
+		return v, nil
+	}
+}

mmv1/templates/terraform/examples/gkehub_membership_issuer.tf.erb

@@ -11,7 +11,7 @@ resource "google_gke_hub_membership" "membership" {
   membership_id = "<%= ctx[:vars]['name'] %>"
   endpoint {
     gke_cluster {
-      resource_link = "//container.googleapis.com/${google_container_cluster.primary.id}"
+      resource_link = google_container_cluster.primary.id
     }
   }
   authority {