fix external task definition must exist before first run (#204)

* fix external task definition must exist before first run

* update readme

* fix lint warnings

README.md

@@ -366,7 +366,7 @@ Available targets:
 | <a name="input_subnet_ids"></a> [subnet\_ids](#input\_subnet\_ids) | Subnet IDs used in Service `network_configuration` if `var.network_mode = "awsvpc"` | `list(string)` | `null` | no |
 | <a name="input_tags"></a> [tags](#input\_tags) | Additional tags (e.g. `{'BusinessUnit': 'XYZ'}`).<br>Neither the tag keys nor the tag values will be modified by this module. | `map(string)` | `{}` | no |
 | <a name="input_task_cpu"></a> [task\_cpu](#input\_task\_cpu) | The number of CPU units used by the task. If using `FARGATE` launch type `task_cpu` must match [supported memory values](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task_definition_parameters.html#task_size) | `number` | `256` | no |
-| <a name="input_task_definition"></a> [task\_definition](#input\_task\_definition) | Reuse an existing task definition family and revision for the ecs service instead of creating one | `string` | `null` | no |
+| <a name="input_task_definition"></a> [task\_definition](#input\_task\_definition) | A `list(string)` of zero or one ARNs of task definitions, to reuse<br>reuse an existing task definition family and revision for the ecs<br>service instead of creating one<br>DEPRECATED: you can also pass a `string` with the ARN, but that<br>string must be known a "plan" time. | `any` | `[]` | no |
 | <a name="input_task_exec_policy_arns"></a> [task\_exec\_policy\_arns](#input\_task\_exec\_policy\_arns) | A list of IAM Policy ARNs to attach to the generated task execution role.<br>Changes to the list will have ripple effects, so use `task_exec_policy_arns_map` if possible. | `list(string)` | `[]` | no |
 | <a name="input_task_exec_policy_arns_map"></a> [task\_exec\_policy\_arns\_map](#input\_task\_exec\_policy\_arns\_map) | A map of name to IAM Policy ARNs to attach to the generated task execution role.<br>The names are arbitrary, but must be known at plan time. The purpose of the name<br>is so that changes to one ARN do not cause a ripple effect on the other ARNs.<br>If you cannot provide unique names known at plan time, use `task_exec_policy_arns` instead. | `map(string)` | `{}` | no |
 | <a name="input_task_exec_role_arn"></a> [task\_exec\_role\_arn](#input\_task\_exec\_role\_arn) | A `list(string)` of zero or one ARNs of IAM roles that allows the<br>ECS/Fargate agent to make calls to the ECS API on your behalf.<br>If the list is empty, a role will be created for you.<br>DEPRECATED: you can also pass a `string` with the ARN, but that<br>string must be known a "plan" time. | `any` | `[]` | no |

docs/terraform.md

@@ -119,7 +119,7 @@
 | <a name="input_subnet_ids"></a> [subnet\_ids](#input\_subnet\_ids) | Subnet IDs used in Service `network_configuration` if `var.network_mode = "awsvpc"` | `list(string)` | `null` | no |
 | <a name="input_tags"></a> [tags](#input\_tags) | Additional tags (e.g. `{'BusinessUnit': 'XYZ'}`).<br>Neither the tag keys nor the tag values will be modified by this module. | `map(string)` | `{}` | no |
 | <a name="input_task_cpu"></a> [task\_cpu](#input\_task\_cpu) | The number of CPU units used by the task. If using `FARGATE` launch type `task_cpu` must match [supported memory values](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task_definition_parameters.html#task_size) | `number` | `256` | no |
-| <a name="input_task_definition"></a> [task\_definition](#input\_task\_definition) | Reuse an existing task definition family and revision for the ecs service instead of creating one | `string` | `null` | no |
+| <a name="input_task_definition"></a> [task\_definition](#input\_task\_definition) | A `list(string)` of zero or one ARNs of task definitions, to reuse<br>reuse an existing task definition family and revision for the ecs<br>service instead of creating one<br>DEPRECATED: you can also pass a `string` with the ARN, but that<br>string must be known a "plan" time. | `any` | `[]` | no |
 | <a name="input_task_exec_policy_arns"></a> [task\_exec\_policy\_arns](#input\_task\_exec\_policy\_arns) | A list of IAM Policy ARNs to attach to the generated task execution role.<br>Changes to the list will have ripple effects, so use `task_exec_policy_arns_map` if possible. | `list(string)` | `[]` | no |
 | <a name="input_task_exec_policy_arns_map"></a> [task\_exec\_policy\_arns\_map](#input\_task\_exec\_policy\_arns\_map) | A map of name to IAM Policy ARNs to attach to the generated task execution role.<br>The names are arbitrary, but must be known at plan time. The purpose of the name<br>is so that changes to one ARN do not cause a ripple effect on the other ARNs.<br>If you cannot provide unique names known at plan time, use `task_exec_policy_arns` instead. | `map(string)` | `{}` | no |
 | <a name="input_task_exec_role_arn"></a> [task\_exec\_role\_arn](#input\_task\_exec\_role\_arn) | A `list(string)` of zero or one ARNs of IAM roles that allows the<br>ECS/Fargate agent to make calls to the ECS API on your behalf.<br>If the list is empty, a role will be created for you.<br>DEPRECATED: you can also pass a `string` with the ARN, but that<br>string must be known a "plan" time. | `any` | `[]` | no |

main.tf

@@ -7,6 +7,7 @@ locals {
   create_exec_role        = local.enabled && length(var.task_exec_role_arn) == 0
   enable_ecs_service_role = module.this.enabled && var.network_mode != "awsvpc" && length(var.ecs_load_balancers) >= 1
   create_security_group   = local.enabled && var.network_mode == "awsvpc" && var.security_group_enabled
+  create_task_definition  = local.enabled && length(var.task_definition) == 0
 
   volumes = concat(var.docker_volumes, var.efs_volumes, var.fsx_volumes, var.bind_mount_volumes)
 
@@ -46,7 +47,7 @@ module "exec_label" {
 }
 
 resource "aws_ecs_task_definition" "default" {
-  count                    = local.enabled && var.task_definition == null ? 1 : 0
+  count                    = local.create_task_definition ? 1 : 0
   family                   = module.this.id
   container_definitions    = var.container_definition_json
   requires_compatibilities = [var.launch_type]
@@ -360,7 +361,7 @@ resource "aws_security_group_rule" "nlb" {
 resource "aws_ecs_service" "ignore_changes_task_definition" {
   count                              = local.ecs_service_enabled && var.ignore_changes_task_definition && !var.ignore_changes_desired_count ? 1 : 0
   name                               = module.this.id
-  task_definition                    = coalesce(var.task_definition, "${join("", aws_ecs_task_definition.default.*.family)}:${join("", aws_ecs_task_definition.default.*.revision)}")
+  task_definition                    = local.create_task_definition ? "${join("", aws_ecs_task_definition.default[*].family)}:${join("", aws_ecs_task_definition.default[*].revision)}" : var.task_definition[0]
   desired_count                      = var.desired_count
   deployment_maximum_percent         = var.deployment_maximum_percent
   deployment_minimum_healthy_percent = var.deployment_minimum_healthy_percent
@@ -459,7 +460,7 @@ resource "aws_ecs_service" "ignore_changes_task_definition" {
 resource "aws_ecs_service" "ignore_changes_task_definition_and_desired_count" {
   count                              = local.ecs_service_enabled && var.ignore_changes_task_definition && var.ignore_changes_desired_count ? 1 : 0
   name                               = module.this.id
-  task_definition                    = coalesce(var.task_definition, "${join("", aws_ecs_task_definition.default.*.family)}:${join("", aws_ecs_task_definition.default.*.revision)}")
+  task_definition                    = local.create_task_definition ? "${join("", aws_ecs_task_definition.default[*].family)}:${join("", aws_ecs_task_definition.default[*].revision)}" : var.task_definition[0]
   desired_count                      = var.desired_count
   deployment_maximum_percent         = var.deployment_maximum_percent
   deployment_minimum_healthy_percent = var.deployment_minimum_healthy_percent
@@ -558,7 +559,7 @@ resource "aws_ecs_service" "ignore_changes_task_definition_and_desired_count" {
 resource "aws_ecs_service" "ignore_changes_desired_count" {
   count                              = local.ecs_service_enabled && !var.ignore_changes_task_definition && var.ignore_changes_desired_count ? 1 : 0
   name                               = module.this.id
-  task_definition                    = coalesce(var.task_definition, "${join("", aws_ecs_task_definition.default.*.family)}:${join("", aws_ecs_task_definition.default.*.revision)}")
+  task_definition                    = local.create_task_definition ? "${join("", aws_ecs_task_definition.default[*].family)}:${join("", aws_ecs_task_definition.default[*].revision)}" : var.task_definition[0]
   desired_count                      = var.desired_count
   deployment_maximum_percent         = var.deployment_maximum_percent
   deployment_minimum_healthy_percent = var.deployment_minimum_healthy_percent
@@ -657,7 +658,7 @@ resource "aws_ecs_service" "ignore_changes_desired_count" {
 resource "aws_ecs_service" "default" {
   count                              = local.ecs_service_enabled && !var.ignore_changes_task_definition && !var.ignore_changes_desired_count ? 1 : 0
   name                               = module.this.id
-  task_definition                    = coalesce(var.task_definition, "${join("", aws_ecs_task_definition.default.*.family)}:${join("", aws_ecs_task_definition.default.*.revision)}")
+  task_definition                    = local.create_task_definition ? "${join("", aws_ecs_task_definition.default[*].family)}:${join("", aws_ecs_task_definition.default[*].revision)}" : var.task_definition[0]
   desired_count                      = var.desired_count
   deployment_maximum_percent         = var.deployment_maximum_percent
   deployment_minimum_healthy_percent = var.deployment_minimum_healthy_percent

variables.tf

@@ -439,9 +439,15 @@ variable "wait_for_steady_state" {
 }
 
 variable "task_definition" {
-  type        = string
-  description = "Reuse an existing task definition family and revision for the ecs service instead of creating one"
-  default     = null
+  type        = any
+  description = <<-EOT
+    A `list(string)` of zero or one ARNs of task definitions, to reuse
+    reuse an existing task definition family and revision for the ecs
+    service instead of creating one
+    DEPRECATED: you can also pass a `string` with the ARN, but that
+    string must be known a "plan" time.
+    EOT
+  default     = []
 }
 
 variable "force_new_deployment" {