Terraform local-exec to pass new resource( not hard-coding) - terraform

Question

I'm executing a bash script using terraform. My null_resource configuration code is given below
resource "null_resource" "mytest" {
triggers = {
run = "${timestamp()}"
}
provisioner "local-exec" {
command = "sh test.sh"
}
}
Let us take git repo as an example resource. I'm doing bunch of operations using the batch script on the resource. This resource names are passed using terraform.tfvars
resource_list = ["RS1","RS2","RS3","RS4"]
If I want to add a new repo named RS5 then I can update the the above list by adding RS5 to it.
How I will pass the new resource name to the batch script. Here I'm not looking to hard code the parameter as given below
sh test.sh "RS5"
How i will pass the most recent resource to the batch script?

Answer 1

Use for_each to execute the batch script once per resource in the resource_list variable
resource "null_resource" "mytest" {
for_each = toset(var.resource_list)
# using timestamp() will cause the script to run again for every value on
# every run since the value changes every time.
# you probably don't want that behavior.
# triggers = {
# run = "${timestamp()}"
# }
provisioner "local-exec" {
command = "sh test.sh ${each.value}"
}
}
When you run this the first time it will execute the script once for each of the resources in resource_list. Then the terraform state file will be updated to know what has already run, so any subsequent runs will only include new items added to resource_list.