Terraform For_each

Using Terraform Count

The example below uses the count meta-argument to loop through a list of storage account names and create a storage account with the name specified for each.

The name argument uses the count.index expression to access the current index of the loop (starting from 0) and select the storage account name from the storage_account_names list using the index. The rest of the arguments are the same for each storage account.

variable "storage_account_names" {
  type    = list(string)
  default = ["jackuksstr001", "jackuksstr002", "jackuksstr003"]
}

resource "azurerm_resource_group" "example" {
  name     = "storage-rg"
  location = "UK South"
}

resource "azurerm_storage_account" "my_storage" {
  count                    = length(var.storage_account_names)
  name                     = var.storage_account_names[count.index]
  resource_group_name      = azurerm_resource_group.example.name
  location                 = azurerm_resource_group.example.location
  account_tier             = "Standard"
  account_replication_type = "GRS"
}

Using Terraform For_each

The example below uses a for_each loop to iterate through a list of the same storage account names and create a storage account with the name specified for each. The rest of the arguments are the same for each storage account.

The result will be the same as the example using count above.

variable "storage_account_names" {
  type    = list(string)
  default = ["jackuksstr001", "jackuksstr002", "jackuksstr003"]
}

resource "azurerm_resource_group" "example" {
  name     = "storage-rg"
  location = "UK South"
}

resource "azurerm_storage_account" "my_storage" {
  for_each                 = toset(var.storage_account_names)
  name                     = each.value
  resource_group_name      = azurerm_resource_group.example.name
  location                 = azurerm_resource_group.example.location
  account_tier             = "Standard"
  account_replication_type = "GRS"
}

Using the For Expression

The example below builds on the previous one and shows how to output a list of storage account IDs from the given list. The for expression is used to iterate over the storage_account_names list and retrieve the ID for each storage account instance with the corresponding name.

variable "storage_account_names" {
  type    = list(string)
  default = ["jackuksstr001", "jackuksstr002", "jackuksstr003"]
}

resource "azurerm_resource_group" "example" {
  name     = "storage-rg"
  location = "UK South"
}

resource "azurerm_storage_account" "my_storage" {
  for_each                 = toset(var.storage_account_names)
  name                     = each.value
  resource_group_name      = azurerm_resource_group.example.name
  location                 = azurerm_resource_group.example.location
  account_tier             = "Standard"
  account_replication_type = "GRS"
}

output "storage_account_names" {
  value = [
    for storage in var.storage_account_names:
    azurerm_storage_account.my_storage.example[storage].id
  ]
}

The For Expression With If Clause

A for expression can also include an if clause to filter elements from the source variable, producing a value with fewer elements than the source value, and is commonly used to split lists based on a condition.

The syntax looks like the below:

[for VAR in COLLECTION: IF CONDITION_EXPRESSION: VAR]

VAR is the name of the variable that represents each item in the collection, COLLECTION is the collection to be filtered, and CONDITION_EXPRESSION is the boolean expression that determines whether each item should be included in the filtered collection.

In the example below, we use the for expression with the if condition to output a list of storage account names that have the account_replication_type set to GRS. This example will output the three storage account names provided in the storage_account_names variable, as they will all have their account_replication_type set to GRS.

variable "storage_account_names" {
  type    = list(string)
  default = ["jackuksstr001", "jackuksstr002", "jackuksstr003"]
}

resource "azurerm_resource_group" "example" {
  name     = "storage-rg"
  location = "UK South"
}

resource "azurerm_storage_account" "my_storage" {
  count                    = length(var.storage_account_names)
  name                     = var.storage_account_names[count.index]
  resource_group_name      = azurerm_resource_group.example.name
  location                 = azurerm_resource_group.example.location
  account_tier             = "Standard"
  account_replication_type = "GRS"
}

locals {
  grs_storage_accounts = [for sa in azurerm_storage_account.my_storage: sa if sa.account_replication_type == "GRS"]
}

output "grs_storage_account_names" {
  value = [for sa in local.grs_storage_accounts: sa.name]
}

The For_each Expression With If Clause

The if clause can be used to conditionally include or exclude certain expressions based on a boolean condition.

The syntax for using the if clause in an expression is as follows:

${condition ? true_value : false_value}

In the example below, we use the if condition to set the account_replication_type to GRS if the environment variable is set to prod , if it is not, then the account_replication_type will be set to LRS .

Because the default value for the environment variable is set to prod in the below example, the three storage accounts created using the for_each loop will all have their account_replication_typeset to GRS.

variable "storage_account_names" {
  type    = list(string)
  default = ["jackuksstr001", "jackuksstr002", "jackuksstr003"]
}

variable "environment" {
  default = "prod"
}

resource "azurerm_resource_group" "example" {
  name     = "storage-rg"
  location = "UK South"
}

resource "azurerm_storage_account" "my_storage" {
  for_each                 = toset(var.storage_account_names)
  name                     = each.value
  resource_group_name      = azurerm_resource_group.example.name
  location                 = azurerm_resource_group.example.location
  account_tier             = "Standard"
  account_replication_type = "${var.environment == "prod" ? "GRS" : "LRS"}"
}

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