Terraform - Join multi-count resources for ASG - terraform

Question

See structure of the terraform for context
################### terraform.hcl
InstanceCFG = [
{
"Name" = "instance_0001"
"Alias" = "cookie"
},
{
"Name" = "instance_0002"
"Alias" = "cake"
},
{
"Name" = "instance_0003"
"Alias" = "cupcake"
},
{
"Name" = "instance_0004"
"Alias" = "chocolate"
},
{
"Name" = "instance_0005"
"Alias" = "icecream"
}
]
NLBCFG = [
{
"Name" = "8000-tg"
"Port" = "8000"
"Protocol" = "TCP"
},
{
"Name" = "9000-tg"
"Port" = "9000"
"Protocol" = "TCP"
},
]
################### loadbalancer.tf
resource "aws_lb_target_group" "tg" {
count = length(var.NLBConfig)
name = "${var.NLBConfig[count.index]["Name"]}"
port = "${var.NLBConfig[count.index]["Port"]}"
protocol = "${var.NLBConfig[count.index]["Protocol"]}"
vpc_id = var.VPCID
}
resource "aws_lb_listener" "lb_listener" {
count = length(var.NLBConfig)
load_balancer_arn = aws_lb.lb.arn
port = "${var.NLBConfig[count.index]["Port"]}"
protocol = "${var.NLBConfig[count.index]["Protocol"]}"
default_action {
type = "forward"
target_group_arn = aws_lb_target_group.tg[count.index].arn
}
}
################### autoscalinggroup.tf
# AWS AutoScaling Group
resource "aws_autoscaling_group" "asg" {
count = length(var.ClientConfig)
name = "${var.ClientConfig[count.index]["Name"]}_${local.name_postfix}"
min_size = 1
max_size = 1
desired_capacity = 1
force_delete = true
termination_policies = [ OldestLaunchConfiguration ]
health_check_type = "EC2" # TODO: Change to ELB for Healthchecks
health_check_grace_period = 300
target_group_arns = [ aws_lb_target_group.tg.arn, aws_lb_target_group.tg_wss.arn ] # < Issue HERE!
}
I am able to create two groups of resources separately, 5 ASGs and 3 Target Groups, these numbers will change constantly but I need to make sure X number of ASG instances can join X number of target groups independently of one another, is this even possible?

Answer 1

I find the answer as follow:
Note I am using two count statements in two different resources.
################### loadbalancer.tf
# Consolidate Target Groups ARNs for ASG
data "aws_lb_target_group" "data_tg" {
depends_on = [ aws_lb_target_group.tg ]
count = length(var.NLBCFG)
arn = aws_lb_target_group.tg[count.index].arn
}
################### autoscalinggroup.tf
# AWS AutoScaling Group
resource "aws_autoscaling_group" "asg" {
count = length(var.ClientConfig)
name = "${var.ClientConfig[count.index]["Name"]}_${local.name_postfix}"
min_size = 1
max_size = 1
desired_capacity = 1
force_delete = true
termination_policies = [ OldestLaunchConfiguration ]
health_check_type = "EC2" # TODO: Change to ELB for Healthchecks
health_check_grace_period = 300
target_group_arns = [ data.aws_lb_target_group.data_tg[*].arn ] # < Issue HERE!
}