Replace "" default values with nulls

Author: jonassvalin

CHANGELOG.md

@@ -11,6 +11,13 @@ BACKWARDS INCOMPATIBILITIES / NOTES:
   `true|false`.
 * The `allowed_cidrs` variable has been renamed to `default_ingress_cidrs`.
 * The `egress_cidrs` variable has been renamed to `default_egress_cidrs`.
+* The `cluster_instance_amis` variable has been replaced with the singular
+  `cluster_instance_ami`, with default value of `null`.
+* The following variables have had their default value replaced from `""` to
+  `null`:
+  - `cluster_instance_user_data_template`
+  - `cluster_instance_iam_policy_contents`
+  - `cluster_service_iam_policy_contents`
 
 IMPROVEMENTS:
 

config/defaults.yaml

@@ -22,7 +22,6 @@ custom_ami_id: "ami-3fb6bc5b"
 cluster_name: 'test-cluster'
 cluster_instance_ssh_public_key_path: "%{hiera('project_directory')}/config/secrets/cluster/ssh.public"
 cluster_instance_type: 't2.medium'
-cluster_instance_ami: "''"
 cluster_instance_root_block_device_size: 40
 cluster_instance_root_block_device_path: '/dev/xvda'
 

variables.tf

@@ -37,7 +37,6 @@ variable "cluster_instance_ssh_public_key_path" {
   description = "The path to the public key to use for the container instances."
   type        = string
   default     = null
-  nullable    = true
 }
 
 variable "cluster_instance_root_block_device_size" {
@@ -63,29 +62,24 @@ variable "cluster_instance_root_block_device_path" {
 variable "cluster_instance_user_data_template" {
   description = "The contents of a template for container instance user data."
   type        = string
-  default     = ""
-  nullable    = false
+  default     = null
 }
 
 variable "cluster_instance_ami" {
   description = "AMI for the container instances."
   type        = string
-
-  default     = ""
-  nullable    = false
+  default     = null
 }
 
 variable "cluster_instance_iam_policy_contents" {
   description = "The contents of the cluster instance IAM policy."
   type        = string
-  default     = ""
-  nullable    = false
+  default     = null
 }
 variable "cluster_service_iam_policy_contents" {
   description = "The contents of the cluster service IAM policy."
   type        = string
-  default     = ""
-  nullable    = false
+  default     = null
 }
 
 variable "cluster_minimum_size" {