Adding scheduler for ECS Tasks (#41)

* Adding scheduler for ECS Tasks * Running fmt * terraform-docs: automated update action --------- Co-authored-by: mvsnogueira-dnx <[email protected]>
DNXLabs · Apr 2, 2023 · 488b522 · 488b522
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diff --git a/README.md b/README.md
@@ -105,6 +105,7 @@ In addition you have the option to create or not :
 | dynamic\_stickiness | Target Group stickiness. Used in dynamic block. | `any` | `[]` | no |
 | ecs\_service\_capacity\_provider\_strategy | (Optional) The capacity provider strategy to use for the service. Can be one or more. These can be updated without destroying and recreating the service only if set to [] and not changing from 0 capacity\_provider\_strategy blocks to greater than 0, or vice versa. | `list` | <pre>[<br>  {}<br>]</pre> | no |
 | efs\_mapping | A map of efs volume ids and paths to mount into the default task definition | `map(string)` | `{}` | no |
+| enable\_schedule | Enables schedule to shut down and start up instances outside business hours. | `bool` | `false` | no |
 | fargate\_spot | Set true to use FARGATE\_SPOT capacity provider by default (only when launch\_type=FARGATE) | `bool` | `false` | no |
 | healthcheck\_interval | n/a | `string` | `"10"` | no |
 | healthcheck\_matcher | The HTTP codes to use when checking for a successful response from a target | `number` | `200` | no |
@@ -134,6 +135,8 @@ In addition you have the option to create or not :
 | port | Port for target group to listen | `number` | `80` | no |
 | protocol | Protocol to use (HTTP or HTTPS) | `string` | `"HTTP"` | no |
 | redirects | Map of path redirects to add to the listener | `map` | `{}` | no |
+| schedule\_cron\_start | Cron expression to define when to trigger a start of the auto-scaling group. E.g. 'cron(00 21 ? \* SUN-THU \*)' to start at 8am UTC time. | `string` | `""` | no |
+| schedule\_cron\_stop | Cron expression to define when to trigger a stop of the auto-scaling group. E.g. 'cron(00 09 ? \* MON-FRI \*)' to start at 8am UTC time | `string` | `""` | no |
 | security\_groups | The security groups associated with the task or service | `any` | `null` | no |
 | service\_deployment\_maximum\_percent | Maximum percentage of tasks to run during deployments | `number` | `200` | no |
 | service\_deployment\_minimum\_healthy\_percent | Minimum healthy percentage during deployments | `number` | `100` | no |

diff --git a/_variables.tf b/_variables.tf
@@ -482,3 +482,20 @@ variable "alarm_ecs_running_tasks_threshold" {
   default     = 0
   description = "Alarm when the number of ecs service running tasks is lower than a certain value. CloudWatch Container Insights must be enabled for the cluster."
 }
+
+variable "enable_schedule" {
+  default     = false
+  description = "Enables schedule to shut down and start up instances outside business hours."
+}
+
+variable "schedule_cron_start" {
+  type        = string
+  default     = ""
+  description = "Cron expression to define when to trigger a start of the auto-scaling group. E.g. 'cron(00 21 ? * SUN-THU *)' to start at 8am UTC time."
+}
+
+variable "schedule_cron_stop" {
+  type        = string
+  default     = ""
+  description = "Cron expression to define when to trigger a stop of the auto-scaling group. E.g. 'cron(00 09 ? * MON-FRI *)' to start at 8am UTC time"
+}
diff --git a/appautoscaling.tf b/appautoscaling.tf
@@ -76,3 +76,33 @@ resource "aws_appautoscaling_policy" "scale_custom" {
     }
   }
 }
+
+resource "aws_appautoscaling_scheduled_action" "scale_service_out" {
+  count              = var.enable_schedule ? 1 : 0
+  name               = "${var.name}-scale-out"
+  service_namespace  = aws_appautoscaling_target.ecs[0].service_namespace
+  resource_id        = aws_appautoscaling_target.ecs[0].resource_id
+  scalable_dimension = aws_appautoscaling_target.ecs[0].scalable_dimension
+  schedule           = var.schedule_cron_stop
+  timezone           = "UTC"
+
+  scalable_target_action {
+    min_capacity = 0
+    max_capacity = 0
+  }
+}
+
+resource "aws_appautoscaling_scheduled_action" "scale_service_in" {
+  count              = var.enable_schedule ? 1 : 0
+  name               = "${var.name}-scale-in"
+  service_namespace  = aws_appautoscaling_target.ecs[0].service_namespace
+  resource_id        = aws_appautoscaling_target.ecs[0].resource_id
+  scalable_dimension = aws_appautoscaling_target.ecs[0].scalable_dimension
+  schedule           = var.schedule_cron_start
+  timezone           = "UTC"
+
+  scalable_target_action {
+    min_capacity = var.autoscaling_min
+    max_capacity = var.autoscaling_max
+  }
+}