Add healthcheck variables to support deploying non-custom docker containers

infra/modules/service/load-balancer.tf

@@ -80,14 +80,17 @@ resource "aws_lb_target_group" "app_tg" {
   target_type          = "ip"
   deregistration_delay = "30"
 
-  health_check {
-    path                = "/health"
-    port                = var.container_port
-    healthy_threshold   = 2
-    unhealthy_threshold = 10
-    interval            = 30
-    timeout             = 29
-    matcher             = "200-299"
+  dynamic "health_check" {
+    for_each = var.enable_healthcheck ? [0] : []
+    content {
+      path                = "/${local.healthcheck_path}"
+      port                = var.container_port
+      healthy_threshold   = 2
+      unhealthy_threshold = 10
+      interval            = 30
+      timeout             = 29
+      matcher             = "200-299"
+    }
   }
 
   lifecycle {

infra/modules/service/main.tf

@@ -11,6 +11,7 @@ locals {
   log_stream_prefix       = var.service_name
   task_executor_role_name = "${var.service_name}-task-executor"
   image_url               = "${data.aws_ecr_repository.app.repository_url}:${var.image_tag}"
+  healthcheck_path        = trimprefix(var.healthcheck_path, "/")
 
   base_environment_variables = [
     { name : "PORT", value : tostring(var.container_port) },
@@ -76,14 +77,16 @@ resource "aws_ecs_task_definition" "app" {
       # Need to define all parameters in the healthCheck block even if we want
       # to use AWS's defaults, otherwise the terraform plan will show a diff
       # that will force a replacement of the task definition
-      healthCheck = {
-        interval = 30,
-        retries  = 3,
-        timeout  = 5,
-        command = ["CMD-SHELL",
-          "wget --no-verbose --tries=1 --spider http://localhost:${var.container_port}/health || exit 1"
-        ]
-      },
+      healthCheck = var.enable_healthcheck ? {
+        interval    = 30,
+        retries     = 3,
+        timeout     = 5,
+        startPeriod = var.healthcheck_start_period,
+        command = [
+          "CMD-SHELL",
+          var.healthcheck_type == "curl" ? "curl --fail http://localhost:${var.container_port}/${local.healthcheck_path} || exit 1" : "wget --no-verbose --tries=1 --spider http://localhost:${var.container_port}/${local.healthcheck_path} || exit 1",
+        ],
+      } : null,
       environment = local.environment_variables,
       portMappings = [
         {

infra/modules/service/variables.tf

@@ -67,3 +67,35 @@ variable "db_vars" {
   })
   default = null
 }
+
+#-------------------
+# Healthcheck
+#-------------------
+
+variable "enable_healthcheck" {
+  type        = bool
+  description = "Enable container healthcheck"
+  default     = true
+}
+
+variable "healthcheck_path" {
+  type        = string
+  description = "The path to the application healthcheck"
+  default     = "/health"
+}
+
+variable "healthcheck_type" {
+  type        = string
+  description = "Whether to configure a curl or wget healthcheck. use wget for alpine-based images"
+  default     = "wget"
+  validation {
+    condition     = contains(["curl", "wget"], var.healthcheck_type)
+    error_message = "choose either: curl or wget"
+  }
+}
+
+variable "healthcheck_start_period" {
+  type        = number
+  description = "The optional grace period to provide containers time to bootstrap in before failed health checks count towards the maximum number of retries"
+  default     = 0
+}