Make terraform module variables nullable

So we can have the option of leaving some parameters empty and they
pick the default value or we override the default other values when
we use the modules

aks/application/variables.tf

@@ -37,6 +37,7 @@ variable "cluster_configuration_map" {
 
 variable "replicas" {
   type        = number
+  nullable    = false
   default     = 1
   description = "Number of application instances"
 }
@@ -64,12 +65,14 @@ variable "docker_image" {
 
 variable "command" {
   type        = list(string)
+  nullable    = false
   default     = []
   description = "Custom command that overwrites Docker image"
 }
 
 variable "max_memory" {
   type        = string
+  nullable    = false
   default     = "1Gi"
   description = "Maximum memory of the instance"
 }
@@ -82,24 +85,28 @@ variable "is_web" {
 
 variable "web_external_hostnames" {
   type        = list(string)
+  nullable    = false
   default     = []
   description = "List of external hostnames for the web application"
 }
 
 variable "web_port" {
   type        = number
+  nullable    = false
   default     = 3000
   description = "Port of the web application"
 }
 
 variable "probe_path" {
   type        = string
+  nullable    = false
   default     = "/healthcheck"
   description = "Path for the liveness and startup probe. The probe can be disabled by setting this to null."
 }
 
 variable "probe_command" {
   type        = list(string)
+  nullable    = false
   default     = []
   description = "Command for the liveness and startup probe"
 }

aks/postgres/variables.tf

@@ -46,6 +46,7 @@ variable "cluster_configuration_map" {
 
 variable "server_docker_image" {
   type        = string
+  nullable    = false
   default     = "postgres:14-alpine"
   description = "Database image to use with kubernetes deployment, eg. postgis/postgis:14-3.4"
 }
@@ -116,6 +117,7 @@ variable "azure_enable_monitoring" {
 
 variable "alert_window_size" {
   type        = string
+  nullable    = false
   default     = "PT5M"
   description = "The period of time that is used to monitor alert activity e.g PT1M, PT5M, PT15M, PT30M, PT1H, PT6H or PT12H"
 }

aks/redis/variables.tf

@@ -46,6 +46,7 @@ variable "cluster_configuration_map" {
 
 variable "server_version" {
   type        = string
+  nullable    = false
   default     = "6"
   description = "Version of Redis server"
 }
@@ -71,13 +72,15 @@ variable "azure_sku_name" {
 }
 
 variable "azure_minimum_tls_version" {
-  type    = string
-  default = "1.2"
+  type     = string
+  nullable = false
+  default  = "1.2"
 }
 
 variable "azure_public_network_access_enabled" {
-  type    = bool
-  default = false
+  type     = bool
+  nullable = false
+  default  = false
 }
 
 variable "azure_memory_threshold" {
@@ -86,8 +89,9 @@ variable "azure_memory_threshold" {
 }
 
 variable "azure_maxmemory_policy" {
-  type    = string
-  default = "allkeys-lru"
+  type     = string
+  nullable = false
+  default  = "allkeys-lru"
 }
 
 variable "azure_enable_monitoring" {
@@ -107,6 +111,7 @@ variable "azure_patch_schedule" {
 variable "alert_window_size" {
   type        = string
   default     = "PT5M"
+  nullable    = false
   description = "The period of time that is used to monitor alert activity e.g PT1M, PT5M, PT15M, PT30M, PT1H, PT6H or PT12H"
 }
 

domains/environment_domains/variables.tf

@@ -13,6 +13,7 @@ variable "host_name" {
 }
 
 variable "null_host_header" {
+  nullable    = false
   default     = false
   description = "The origin_host_header for the azurerm_cdn_frontdoor_origin resource will be var.host_name (if false) or null (if true). If null then the host name from the incoming request will be used."
 }

monitoring/statuscake/variables.tf

@@ -12,12 +12,14 @@ variable "ssl_urls" {
 
 variable "contact_groups" {
   type        = list(string)
+  nullable    = false
   description = "Contact groups for the alerts"
   default     = []
 }
 
 variable "confirmation" {
   type        = number
+  nullable    = false
   description = "Retry the check when an error is detected to avoid false positives and micro downtimes"
   default     = 2
 }