Merge pull request #223 from mr-miles/mr-miles-lifecycle-patch

Enable setting up lifecycle hooks on the ASG

main.tf

@@ -10,10 +10,11 @@
 # REQUIRE A SPECIFIC TERRAFORM VERSION OR HIGHER
 # ----------------------------------------------------------------------------------------------------------------------
 terraform {
-  # This module is now only being tested with Terraform 0.15.x. However, to make upgrading easier, we are setting
-  # 0.12.26 as the minimum version, as that version added support for required_providers with source URLs, making it
-  # forwards compatible with 0.15.x code.
-  required_version = ">= 0.12.26"
+  # This module is now only being tested with Terraform 0.14.x. However, to make upgrading easier, we are setting
+  # 0.14.0 as the minimum version, as that version added support for validation and the alltrue function
+  # Removing the validation completely will yield a version compatible with 0.12.26 as that added support for 
+  # required_providers with source URLs
+  required_version = ">= 0.14.0"
 }
 
 # ---------------------------------------------------------------------------------------------------------------------

modules/consul-cluster/main.tf

@@ -52,6 +52,20 @@ resource "aws_autoscaling_group" "autoscaling_group" {
     ]
   )
 
+  dynamic "initial_lifecycle_hook" {
+    for_each = var.lifecycle_hooks
+
+    content {
+      name                    = initial_lifecycle_hook.key
+      default_result          = lookup(initial_lifecycle_hook.value, "default_result", null)
+      heartbeat_timeout       = lookup(initial_lifecycle_hook.value, "heartbeat_timeout", null)
+      lifecycle_transition    = initial_lifecycle_hook.value.lifecycle_transition
+      notification_metadata   = lookup(initial_lifecycle_hook.value, "notification_metadata", null)
+      notification_target_arn = lookup(initial_lifecycle_hook.value, "notification_target_arn", null)
+      role_arn                = lookup(initial_lifecycle_hook.value, "role_arn", null)
+    }
+  }
+
   lifecycle {
     # As of AWS Provider 3.x, inline load_balancers and target_group_arns
     # in an aws_autoscaling_group take precedence over attachment resources.

modules/consul-cluster/variables.tf

@@ -122,6 +122,32 @@ variable "termination_policies" {
   default     = "Default"
 }
 
+variable "lifecycle_hooks" {
+  description = "The lifecycle hooks to create that are triggered by the launch event. This is a map where the keys are the name of the hook and the values are an object with the keys and values defined in the lifecycle_hook block of the aws_autoscaling_group resource.  Default is no launch hooks"
+  type        = map(any)
+  default     = {}
+
+  #    example = {
+  #      name = {
+  #        default_result          = string : CONTINUE | ABANDON
+  #        heartbeat_timeout       = int
+  #        lifecycle_transition    = string : "autoscaling:EC2_INSTANCE_LAUNCHING" | "autoscaling:EC2_INSTANCE_TERMINATING"
+  #        notification_metadata   = string
+  #        notification_target_arn = string
+  #        role_arn                = string
+  #    }
+
+  validation {
+    condition     = alltrue([for x in values(var.lifecycle_hooks) : contains(["CONTINUE", "ABANDON"], lookup(x, "default_result", "CONTINUE"))])
+    error_message = "Lifecycle_hooks[x].default_result must be set to either \"CONTINUE\" or \"ABANDON\"."
+  }
+
+  validation {
+    condition     = alltrue([for x in values(var.lifecycle_hooks) : contains(["autoscaling:EC2_INSTANCE_LAUNCHING", "autoscaling:EC2_INSTANCE_TERMINATING"], lookup(x, "lifecycle_transition", "BLANK"))])
+    error_message = "Lifecycle_hooks[x].lifecycle_transition must be set to either \"autoscaling:EC2_INSTANCE_LAUNCHING\" or \"autoscaling:EC2_INSTANCE_TERMINATING\"."
+  }
+}
+
 variable "associate_public_ip_address" {
   description = "If set to true, associate a public IP address with each EC2 Instance in the cluster."
   type        = bool