[usage-plan] add throttle settings (#28)

* [usage-plan] add throttle settings

Author: hong-yi

modules/usage_plan/main.tf

@@ -21,6 +21,14 @@ resource "aws_api_gateway_usage_plan" "usage_plan" {
     }
   }
 
+  dynamic "throttle_settings" {
+    for_each = var.enable_throttling == true ? [1] : []
+    content {
+      burst_limit = var.burst_limit
+      rate_limit  = var.rate_limit
+    }
+  }
+
   tags = {
     Name = var.name
   }

modules/usage_plan/variables.tf

@@ -48,6 +48,24 @@ variable "period" {
   default     = "MONTH"
 }
 
+variable "enable_throttling" {
+  description = "whether to enable throttling"
+  type        = bool
+  default     = false
+}
+
+variable "burst_limit" {
+  description = "The maximum number of requests that API Gateway allows to be bursted across the entire API at the same moment."
+  type        = number
+  default     = 5000
+}
+
+variable "rate_limit" {
+  description = "The rate limit, as a number of requests per second, to apply to this usage plan."
+  type        = number
+  default     = 100
+}
+
 variable "api_keys" {
   description = "List of api keys created and assigned to the usage plan"
   type = map(