Merge pull request #1806 from alphagov/turn_review_apps_off_overnight

.review_apps: use app autoscaling to turn review apps off at night, weekends

.review_apps/app_autoscaling.tf

@@ -0,0 +1,38 @@
+resource "aws_appautoscaling_target" "review_app" {
+  service_namespace  = "ecs"
+  resource_id        = "service/${data.terraform_remote_state.review.outputs.ecs_cluster_id}/${aws_ecs_service.app.name}"
+  scalable_dimension = "ecs:service:DesiredCount"
+
+  max_capacity = 1
+  min_capacity = 1
+}
+
+resource "aws_appautoscaling_scheduled_action" "shutdown_at_night" {
+  name = "pr-${var.pull_request_number}-shutdown-at-night"
+
+  service_namespace  = aws_appautoscaling_target.review_app.service_namespace
+  resource_id        = aws_appautoscaling_target.review_app.resource_id
+  scalable_dimension = aws_appautoscaling_target.review_app.scalable_dimension
+
+  schedule = "cron(0 18 * * ? *)" # daily at 1800
+
+  scalable_target_action {
+    min_capacity = 0
+    max_capacity = 0
+  }
+}
+
+resource "aws_appautoscaling_scheduled_action" "startup_weekday_mornings" {
+  name = "pr-${var.pull_request_number}-startup-weekday-mornings"
+
+  service_namespace  = aws_appautoscaling_target.review_app.service_namespace
+  resource_id        = aws_appautoscaling_target.review_app.resource_id
+  scalable_dimension = aws_appautoscaling_target.review_app.scalable_dimension
+
+  schedule = "cron(0 8 ? * MON-FRI *)" # Monday-Friday at 0800
+
+  scalable_target_action {
+    min_capacity = 1
+    max_capacity = 1
+  }
+}