support blue-green deployment

Author: lycbrian

CHANGELOG.md

@@ -5,8 +5,13 @@
 ### Added
 
 - Support blue-green deployment
-    - var: is_enable_blue_green_deployment
-    - resource:  aws_lb_target_group.green
+    - var: 
+        - is_enable_blue_green_deployment
+        - green_header_value
+    - resource:  
+        - aws_lb_target_group.green
+        - aws_lb_listener_rule.green
+
 
 ## [v1.3.1] - 2025-04-09
 

main.tf

@@ -217,6 +217,57 @@ resource "aws_lb_listener_rule" "this" {
 
   tags = local.tags
 }
+
+/* ------------------------------ Green Listener Rule ----------------------------- */
+resource "aws_lb_listener_rule" "green" {
+  count = local.is_create_target_group && var.is_enable_blue_green_deployment ? 1 : 0
+
+  listener_arn = var.alb_listener_arn
+  priority     = var.alb_priority
+
+  action {
+    type             = "forward"
+    target_group_arn = aws_lb_target_group.green[0].arn
+  }
+
+  condition {
+    path_pattern {
+      values = var.alb_paths == [] ? ["*"] : var.alb_paths
+    }
+  }
+
+  dynamic "condition" {
+    for_each = var.alb_host_header == null ? [] : [true]
+    content {
+      host_header {
+        values = [var.alb_host_header]
+      }
+    }
+  }
+
+  dynamic "condition" {
+    for_each = var.custom_header_token == "" ? [] : [true]
+    content {
+      http_header {
+        http_header_name = "custom-header-token" # Match value within cloudfront module
+        values           = [var.custom_header_token]
+      }
+    }
+  }
+
+  dynamic "condition" {
+    for_each = var.green_header_value == null ? [] : [true]
+    content {
+      http_header {
+        http_header_name = "green-header-name"
+        values           = [var.green_header_value]
+      }
+    }
+  }
+
+  tags = local.tags
+}
+
 /* -------------------------------------------------------------------------- */
 /*                                   Secret                                   */
 /* -------------------------------------------------------------------------- */

variables.tf

@@ -315,3 +315,10 @@ variable "is_enable_blue_green_deployment" {
   default     = false
 }
 
+variable "green_header_value" {
+  description = "green header value in alb listener rule for blue-green deployment"
+  type        = string
+  default     = "green"
+}
+
+