如何避免在Terraform中重复变量？

Terraform不允许在变量文件中插入变量，否则会出现错误：

错误：不允许使用变量

在variables.tf第9行的变量“resource\u group\u name”中：9:
default=“${var.prefix}-terraform-dev_rg”

这里不能使用变量

这就意味着，当我试图为资源组创建名称时，我会复制variables.tf文件中前缀的值

有没有一个很好的方法来避免重复变量的值

变量。tf

variable "prefix" {
  description = "The prefix used for all resources in this plan"
  default     = "terraform-dev"
}

variable resource_group_name {
  type = "string"
  default = "terraform-dev_rg"
}

variable resource_group_location {
  type = "string"
  default = "eastus"
}

# Configure the Microsoft Azure Provider
provider "azurerm" {
  version         = "=1.28.0"
}

# Create a resource group
resource "azurerm_resource_group" "resource-group" {
  name     = var.resource_group_name
  location = var.resource_group_location
}

#Create an application gateway with web app firewall
module "firewall" {
  source                  = "./firewall"
  resource_group_name     = var.resource_group_name
  resource_group_location = var.resource_group_location
}

#Passed down from the root variables.tf
variable "prefix" {}
variable "resource_group_name" {}
variable "resource_group_location" {}

# Create a virtual network for the firewall
resource "azurerm_virtual_network" "firewall-vnet" {
  name = "${var.prefix}-waf-vnet"
  address_space = ["10.0.0.0/16"]
  resource_group_name = var.resource_group_name
  location            = var.resource_group_location
}

main.tf

variable "prefix" {
  description = "The prefix used for all resources in this plan"
  default     = "terraform-dev"
}

variable resource_group_name {
  type = "string"
  default = "terraform-dev_rg"
}

variable resource_group_location {
  type = "string"
  default = "eastus"
}

# Configure the Microsoft Azure Provider
provider "azurerm" {
  version         = "=1.28.0"
}

# Create a resource group
resource "azurerm_resource_group" "resource-group" {
  name     = var.resource_group_name
  location = var.resource_group_location
}

#Create an application gateway with web app firewall
module "firewall" {
  source                  = "./firewall"
  resource_group_name     = var.resource_group_name
  resource_group_location = var.resource_group_location
}

#Passed down from the root variables.tf
variable "prefix" {}
variable "resource_group_name" {}
variable "resource_group_location" {}

# Create a virtual network for the firewall
resource "azurerm_virtual_network" "firewall-vnet" {
  name = "${var.prefix}-waf-vnet"
  address_space = ["10.0.0.0/16"]
  resource_group_name = var.resource_group_name
  location            = var.resource_group_location
}

/firewall/variables.tf

variable "prefix" {
  description = "The prefix used for all resources in this plan"
  default     = "terraform-dev"
}

variable resource_group_name {
  type = "string"
  default = "terraform-dev_rg"
}

variable resource_group_location {
  type = "string"
  default = "eastus"
}

# Configure the Microsoft Azure Provider
provider "azurerm" {
  version         = "=1.28.0"
}

# Create a resource group
resource "azurerm_resource_group" "resource-group" {
  name     = var.resource_group_name
  location = var.resource_group_location
}

#Create an application gateway with web app firewall
module "firewall" {
  source                  = "./firewall"
  resource_group_name     = var.resource_group_name
  resource_group_location = var.resource_group_location
}

#Passed down from the root variables.tf
variable "prefix" {}
variable "resource_group_name" {}
variable "resource_group_location" {}

# Create a virtual network for the firewall
resource "azurerm_virtual_network" "firewall-vnet" {
  name = "${var.prefix}-waf-vnet"
  address_space = ["10.0.0.0/16"]
  resource_group_name = var.resource_group_name
  location            = var.resource_group_location
}

/firewall/main.tf

variable "prefix" {
  description = "The prefix used for all resources in this plan"
  default     = "terraform-dev"
}

variable resource_group_name {
  type = "string"
  default = "terraform-dev_rg"
}

variable resource_group_location {
  type = "string"
  default = "eastus"
}

# Configure the Microsoft Azure Provider
provider "azurerm" {
  version         = "=1.28.0"
}

# Create a resource group
resource "azurerm_resource_group" "resource-group" {
  name     = var.resource_group_name
  location = var.resource_group_location
}

#Create an application gateway with web app firewall
module "firewall" {
  source                  = "./firewall"
  resource_group_name     = var.resource_group_name
  resource_group_location = var.resource_group_location
}

#Passed down from the root variables.tf
variable "prefix" {}
variable "resource_group_name" {}
variable "resource_group_location" {}

# Create a virtual network for the firewall
resource "azurerm_virtual_network" "firewall-vnet" {
  name = "${var.prefix}-waf-vnet"
  address_space = ["10.0.0.0/16"]
  resource_group_name = var.resource_group_name
  location            = var.resource_group_location
}

尝试使用本地值，

变量“前缀”{
description=“用于此计划中所有资源的前缀”
default=“地形开发”
}
可变资源组位置{
type=“string”
default=“eastus”
}
当地人{
资源组名称=“${var.prefix}\u rg”
}
资源“azurerm\u资源组”“资源组”{
name=local.resource\u group\u name
位置=变量资源组位置
}