How to create multiple target groups with specific naming conventions terraform - terraform

Question

I have a resource that creates a target group. I would like to modify the resource with a capability of creating n number of target groups with a specific naming convention.
resource "aws_lb_target_group" "main" {
name = "${var.name}-tg"
port = var.forward_port
protocol = var.forward_protocol
target_type = var.target_type
deregistration_delay = var.deregistration_delay
health_check {
interval = var.interval
path = var.path
}
stickiness {
type = var.cookie_type
}
}
I want to modify it in such a way that if only one target group is created it should name it as test-tg, but if there are more than one target group then it should add index to name like test-tg1. Also each target group can have their own specific set of variable value. How can I achieve that?

Answer 1

You can use for_each in that case as you want to create multiple TGs with different configurations. Create a variable with map(object()) type which allows you to put the values the way you expect. I have put a sample code. Take a reference of below.
Please put the values of below vars in terraform.tfvars file
cookie_type, path, deregistration_delay
var.tf
variable "TG_conf" {
type = map(object({
port = string
protocol = string
target_type = string
interval = string
cookie_type = string
path = string
deregistration_delay = string
}))
}
terrafor.tfvars
TG_conf = {
"test-tg" = {
port = 80
protocol = HTTP
target_type = "instance
interval = "5"
cookie_type = string
path = string
deregistration_delay = string
}
alb.tf
resource "aws_lb_target_group" "main" {
for_each = var.TG_conf
name = "${each.key}"
port = each.value.port
protocol = each.value.protocol
target_type = each.value.target_type
deregistration_delay = each.value.deregistration_delay
health_check {
interval = each.value.interval
path = each.value.path
}
stickiness {
type = each.value.cookie_type
}
}