Add ability to add tags (#12)

* feat: attempt to include tags

* feat: update readme

Author: dreamrace

README.md

@@ -165,6 +165,7 @@ This is an open source software. Feel free to open issues and pull requests.
 | private\_subnets\_cidr\_blocks | List of CIDR blocks of the private subnets. The NAT instance accepts connections from this subnets | string | n/a | yes |
 | public\_subnet | ID of the public subnet to place the NAT instance | string | n/a | yes |
 | vpc\_id | ID of the VPC | string | n/a | yes |
+| tags | Tags to be applied to resources | map(string) | {} | no |
 
 ## Outputs
 

main.tf

@@ -2,9 +2,7 @@ resource "aws_security_group" "this" {
   name_prefix = var.name
   vpc_id      = var.vpc_id
   description = "Security group for NAT instance ${var.name}"
-  tags = {
-    Name = "nat-instance-${var.name}"
-  }
+  tags        = local.common_tags
 }
 
 resource "aws_security_group_rule" "egress" {
@@ -30,17 +28,13 @@ resource "aws_network_interface" "this" {
   subnet_id         = var.public_subnet
   source_dest_check = false
   description       = "ENI for NAT instance ${var.name}"
-  tags = {
-    Name = "nat-instance-${var.name}"
-  }
+  tags              = local.common_tags
 }
 
 resource "aws_eip" "this" {
   count             = var.enabled ? 1 : 0
   network_interface = aws_network_interface.this.id
-  tags = {
-    Name = "nat-instance-${var.name}"
-  }
+  tags              = local.common_tags
 }
 
 resource "aws_route" "this" {
@@ -130,11 +124,7 @@ resource "aws_autoscaling_group" "this" {
     }
   }
 
-  tag {
-    key                 = "Name"
-    value               = "nat-instance-${var.name}"
-    propagate_at_launch = true
-  }
+  tags = local.asg_tags
 
   lifecycle {
     create_before_destroy = true

variables.tf

@@ -47,3 +47,32 @@ variable "key_name" {
   description = "Name of the key pair for the NAT instance. You can set this to assign the key pair to the NAT instance"
   default     = ""
 }
+
+variable "tags" {
+  description = "Tags applied to resources created with this module"
+  default     = {}
+}
+
+locals {
+  // Generate common tags by merging variables and default Name
+  common_tags = merge(
+    var.tags, {
+      Name = "nat-instance-${var.name}"
+  })
+
+  // Generate asg tags by merging variables in object format
+  asg_tags = concat([
+    for key, value in var.tags : {
+      key                 = key
+      value               = value
+      propagate_at_launch = true
+    }
+    ], [
+    {
+      key                 = "Name"
+      value               = "nat-instance-${var.name}"
+      propagate_at_launch = true
+    }
+    ]
+  )
+}