improve typing (#1)

automatic failover cannot be enabled if nodes < 2 to safeguard against misconfiguration

Author: ghaddow

README.md

@@ -42,14 +42,14 @@ Module managed by [Marcin Cuber](https://github.com/marcincuber) [linkedin](http
 |------|-------------|:----:|:-----:|:-----:|
 | name\_prefix | The replication group identifier. This parameter is stored as a lowercase string. | string | n/a | yes |
 | node\_type | The compute and memory capacity of the nodes in the node group. | string | n/a | yes |
-| number\_cache\_clusters | The number of cache clusters (primary and replicas) this replication group will have. | string | n/a | yes |
+| number\_cache\_clusters | The number of cache clusters (primary and replicas) this replication group will have. | number | n/a | yes |
 | subnet\_ids | List of VPC Subnet IDs for the cache subnet group. | list(string) | n/a | yes |
 | vpc\_id | VPC Id to associate with Redis ElastiCache. | string | n/a | yes |
-| apply\_immediately | Specifies whether any modifications are applied immediately, or during the next maintenance window. | string | `"false"` | no |
-| at\_rest\_encryption\_enabled | Whether to enable encryption at rest. | string | `"true"` | no |
+| apply\_immediately | Specifies whether any modifications are applied immediately, or during the next maintenance window. | bool | `false` | no |
+| at\_rest\_encryption\_enabled | Whether to enable encryption at rest. | bool | `true` | no |
 | auth\_token | The password used to access a password protected server. Can be specified only if `transit_encryption_enabled = true`. | string | `""` | no |
 | auto\_minor\_version\_upgrade |  | string | `"true"` | no |
-| automatic\_failover\_enabled | Specifies whether a read-only replica will be automatically promoted to read/write primary if the existing primary fails. | string | `"true"` | no |
+| automatic\_failover\_enabled | Specifies whether a read-only replica will be automatically promoted to read/write primary if the existing primary fails. | bool | `true` | no |
 | description | The description of the all resources. | string | `"Managed by Terraform"` | no |
 | engine\_version | The version number of the cache engine to be used for the cache clusters in this replication group. | string | `"5.0.6"` | no |
 | family | The family of the ElastiCache parameter group. | string | `"redis5.0"` | no |
@@ -58,12 +58,12 @@ Module managed by [Marcin Cuber](https://github.com/marcincuber) [linkedin](http
 | maintenance\_window | Specifies the weekly time range for when maintenance on the cache cluster is performed. | string | `""` | no |
 | notification\_topic\_arn | An Amazon Resource Name (ARN) of an SNS topic to send ElastiCache notifications to. Example: `arn:aws:sns:us-east-1:012345678999:my_sns_topic` | string | `""` | no |
 | parameter | A list of Redis parameters to apply. Note that parameters may differ from one Redis family to another | object | `[]` | no |
-| port | The port number on which each of the cache nodes will accept connections. | string | `"6379"` | no |
+| port | The port number on which each of the cache nodes will accept connections. | number | `6379` | no |
 | security\_group\_ids | List of Security Groups. | list(string) | `[]` | no |
-| snapshot\_retention\_limit | The number of days for which ElastiCache will retain automatic cache cluster snapshots before deleting them. | string | `"30"` | no |
+| snapshot\_retention\_limit | The number of days for which ElastiCache will retain automatic cache cluster snapshots before deleting them. | number | `30` | no |
 | snapshot\_window | The daily time range (in UTC) during which ElastiCache will begin taking a daily snapshot of your cache cluster. | string | `""` | no |
 | tags | A mapping of tags to assign to all resources. | map(string) | `{}` | no |
-| transit\_encryption\_enabled | Whether to enable encryption in transit. | string | `"true"` | no |
+| transit\_encryption\_enabled | Whether to enable encryption in transit. | bool | `true` | no |
 
 ## Outputs
 

main.tf

@@ -15,7 +15,7 @@ resource "aws_elasticache_replication_group" "redis" {
   maintenance_window         = var.maintenance_window
   snapshot_window            = var.snapshot_window
   snapshot_retention_limit   = var.snapshot_retention_limit
-  automatic_failover_enabled = var.automatic_failover_enabled
+  automatic_failover_enabled = var.automatic_failover_enabled && var.number_cache_clusters > 1 ? true : false
   auto_minor_version_upgrade = var.auto_minor_version_upgrade
 
   at_rest_encryption_enabled = var.at_rest_encryption_enabled

outputs.tf

@@ -58,3 +58,7 @@ output "security_group_egress" {
   description = "The egress rules of the Redis ElastiCache security group."
 }
 
+output "elasticache_auth_token" {
+  description = "The Redis Auth Token"
+  value       = aws_elasticache_replication_group.redis.auth_token
+}

variables.tf

@@ -4,7 +4,7 @@ variable "name_prefix" {
 }
 
 variable "number_cache_clusters" {
-  type        = string
+  type        = number
   description = "The number of cache clusters (primary and replicas) this replication group will have."
 }
 
@@ -43,7 +43,7 @@ variable "engine_version" {
 
 variable "port" {
   default     = 6379
-  type        = string
+  type        = number
   description = "The port number on which each of the cache nodes will accept connections."
 }
 
@@ -60,8 +60,8 @@ variable "snapshot_window" {
 }
 
 variable "snapshot_retention_limit" {
-  default     = "30"
-  type        = string
+  default     = 30
+  type        = number
   description = "The number of days for which ElastiCache will retain automatic cache cluster snapshots before deleting them."
 }
 
@@ -72,25 +72,25 @@ variable "auto_minor_version_upgrade" {
 
 variable "automatic_failover_enabled" {
   default     = true
-  type        = string
+  type        = bool
   description = "Specifies whether a read-only replica will be automatically promoted to read/write primary if the existing primary fails."
 }
 
 variable "at_rest_encryption_enabled" {
   default     = true
-  type        = string
+  type        = bool
   description = "Whether to enable encryption at rest."
 }
 
 variable "transit_encryption_enabled" {
   default     = true
-  type        = string
+  type        = bool
   description = "Whether to enable encryption in transit."
 }
 
 variable "apply_immediately" {
   default     = false
-  type        = string
+  type        = bool
   description = "Specifies whether any modifications are applied immediately, or during the next maintenance window."
 }