Azure Terraform: azurerm_lb_rule should be type list, got type string

Question

I'm trying to create an azure lb rule using element and here's the error message and the code listed below.

What should I be changing within my main.tf file or variables.tf file to get the element to work. However, when I provide ports directly (which are commented) the code executes without any issues.

1 error(s) occurred:

azurerm_lb_rule.test: 1 error(s) occurred:

azurerm_lb_rule.test: At column 3, line 1: element: argument 1 should be type list, got type string in:

${element(var.lb_port["${element(keys(var.lb_port), count.index)}"], 2)}

main.tf

resource "azurerm_lb_rule" "test" {
  resource_group_name            = "${azurerm_resource_group.test.name}"
  loadbalancer_id                = "${azurerm_lb.lb.id}"
  name                           = "LBRule"
  protocol                       = "Tcp"
  #frontend_port                  = 3389
  #backend_port                   = 3389
 protocol                       = "${element(var.lb_port["${element(keys(var.lb_port), count.index)}"], 0)}"
 frontend_port                  = "${element(var.lb_port["${element(keys(var.lb_port), count.index)}"], 1)}"
 backend_port                   = "${element(var.lb_port["${element(keys(var.lb_port), count.index)}"], 2)}"
  frontend_ip_configuration_name = "${var.frontend_name}"
}

variables.tf

variable "lb_port" {
  description = "Protocols to be used for lb health probes and rules."
  default     = {"var1" = "tcp,3389,3389"}
}

try casting it to list? ${tolist(element(var.lb_port["${element(keys(var.lb_port), count.index)}"], 2))} — 4c74356b41

Nancy Xiong Nancy Xiong · Accepted Answer · 2019-09-18T07:17:14

According to your requirement, you could define variable lb_port as a map type, then use the lookup function to retrieve the value of a single element from a map given its key.

For example,

variable "lb_port" {
  description = "Protocols to be used for lb health probes and rules."
   default = {
    "protocol" = "TCP"
    "frontend_port" = "3389"
    "backend_port" = "3389"
  }
}
...

resource "azurerm_lb_rule" "test" {
  resource_group_name            = "${azurerm_resource_group.test.name}"
  loadbalancer_id                = "${azurerm_lb.lb.id}"
  name                = "LBRule"
  #protocol            = "Tcp"
  #frontend_port                  = 3389
  #backend_port                   = 3389
  protocol                       = "${lookup(var.lb_port, "protocol" )}"
  frontend_port                  = "${lookup(var.lb_port, "frontend_port" )}"
  backend_port                   = "${lookup(var.lb_port, "backend_port" )}"
  frontend_ip_configuration_name = "${var.frontend_name}"
  ...
}

More example references here.

Azure Terraform: azurerm_lb_rule should be type list, got type string

1 Answers