AWS NLB Module - For_each help

Terraform
1

Terraform version - 0.14

I am creating a simple module that will create a NLB/Listner/Target_group/Target_group_attachment

I am struggling to combine this with a EC2 module. The Target_group_attachment needs to take the Id’s of the EC2’s that are created in the EC2 module. But I am unsure how to do this.

##################################
# Network Loadbalancer                                      #
##################################

resource "aws_lb" "this" {
  name               = var.nlb_name
  internal           = var.internal
  load_balancer_type = "network"
  subnets            = var.nlb_subnets

  enable_deletion_protection       = var.enable_deletion_protection
  enable_cross_zone_load_balancing = var.enable_cross_zone_load_balancing
  tags                             = var.tags # specific tags?
}

################################
# Target Group                                                 #
################################

resource "aws_lb_target_group" "this" {
  for_each = var.nlb_target_group
  name        = each.value.nlb_target_name
  port        = each.value.nlb_target_port
  protocol    = each.value.nlb_target_protocol
  target_type = each.value.nlb_target_type
  vpc_id      = var.vpc_id

  health_check {
    healthy_threshold   = var.health_check_healthy_threshold
    unhealthy_threshold = var.health_check_unhealthy_threshold
    interval            = var.health_check_interval
    protocol            = var.health_check_protocol
  }
  tags = var.tags
}

################################
# Target Group Attachment                            #
################################

resource "aws_lb_target_group_attachment" "this" {
  for_each         = var.nlb_target_group
  target_group_arn = aws_lb_target_group.this[each.key].arn
  target_id        = var.target_id[each.value.id]
  port             = var.target_group_attachment_port
}

################################
# Listner                      #
################################

resource "aws_lb_listener" "this" {
  for_each = var.nlb_target_group
  load_balancer_arn = aws_lb.this.arn
  port              = var.nlb_listner_port
  protocol          = var.nlb_listner_protocol
  default_action {
    type             = var.nlb_listner_default_action_type
    target_group_arn = aws_lb_target_group.this[each.key].arn
  }
}

var.target_id & nlb_target_group are below

variable "target_id" {
  type = map(object({
    id                = string
    availability_zone = string
    tags              = map(string)
  }))
}


variable "nlb_target_group" {
  type = map(object({
    nlb_target_name     = string
    nlb_target_port     = string
    nlb_target_protocol = string
    nlb_target_type     = string
  }))
}

Which I know could be simplified but I might want to bring more values from the EC2 module.

In the resource “aws_lb_target_group_attachment” “this” resource I need to know how to use both the var.target_id and loop through the var.target_id for the target id.

2

I think I need to somehow merge the 2 vars using a local which can then be used as the for_each key. But I cannot work out a way to get it in the correct format.