feat: Support weight in forward action (#224)

Author: alexbricepalo

examples/complete-alb/main.tf

@@ -246,6 +246,35 @@ module "alb" {
         }]
       }]
     },
+    {
+      https_listener_index = 0
+      priority             = 4
+
+      actions = [{
+        type = "weighted-forward"
+        target_groups = [
+          {
+            target_group_index = 1
+            weight             = 2
+          },
+          {
+            target_group_index = 0
+            weight             = 1
+          }
+        ]
+        stickiness = {
+          enabled  = true
+          duration = 3600
+        }
+      }]
+
+      conditions = [{
+        query_strings = [{
+          key   = "weighted"
+          value = "true"
+        }]
+      }]
+    },
     {
       https_listener_index = 0
       priority             = 5000

main.tf

@@ -247,6 +247,37 @@ resource "aws_lb_listener_rule" "https_listener_rule" {
     }
   }
 
+  # weighted forward actions
+  dynamic "action" {
+    for_each = [
+      for action_rule in var.https_listener_rules[count.index].actions :
+      action_rule
+      if action_rule.type == "weighted-forward"
+    ]
+
+    content {
+      type = "forward"
+      forward {
+        dynamic "target_group" {
+          for_each = action.value["target_groups"]
+
+          content {
+            arn    = aws_lb_target_group.main[target_group.value["target_group_index"]].id
+            weight = target_group.value["weight"]
+          }
+        }
+        dynamic "stickiness" {
+          for_each = [lookup(action.value, "stickiness", {})]
+
+          content {
+            enabled  = try(stickiness.value["enabled"], false)
+            duration = try(stickiness.value["duration"], 1)
+          }
+        }
+      }
+    }
+  }
+
   # Path Pattern condition
   dynamic "condition" {
     for_each = [

variables.tf

@@ -178,7 +178,6 @@ variable "http_tcp_listeners_tags" {
   default     = {}
 }
 
-
 variable "security_groups" {
   description = "The security groups to attach to the load balancer. e.g. [\"sg-edcd9784\",\"sg-edcd9785\"]"
   type        = list(string)