For expressions for transformation in Terraform - Mini Project: Build & Apply

Transforming a List of Server Names with Terraform For Expressions

📖 Scenario: You are managing cloud servers and have a list of server names. You want to create a new list where each server name is transformed to include a prefix that indicates the environment.

🎯 Goal: Build a Terraform configuration that uses a for expression to transform a list of server names by adding the prefix "prod-" to each name.

📋 What You'll Learn

Create a variable called server_names with the exact list: ["app1", "db1", "cache1"]

Create a variable called env_prefix with the exact value "prod-"

Use a for expression to create a local variable called prefixed_servers that adds env_prefix to each server name in server_names

Output the prefixed_servers list

💡 Why This Matters

🌍 Real World

Cloud engineers often need to manage lists of resources and apply consistent naming conventions automatically. Using for expressions in Terraform helps transform data efficiently.

💼 Career

Understanding for expressions in Terraform is essential for infrastructure as code roles, enabling automation and reducing manual errors in cloud resource management.

1

Create the server_names variable

Create a Terraform variable called server_names with the exact list ["app1", "db1", "cache1"].

Terraform

# Create the variable server_names with the list ["app1", "db1", "cache1"]
# Your code here

Need a hint?

Use variable "server_names" block with default set to the list.

2

Create the env_prefix variable

Create a Terraform variable called env_prefix with the exact string value "prod-".

Terraform

variable "server_names" {
  type    = list(string)
  default = ["app1", "db1", "cache1"]
}

# Create the variable env_prefix with the value "prod-"
# Your code here

Need a hint?

Use a variable block with type = string and default = "prod-".

3

Create the prefixed_servers local variable using a for expression

Create a local variable called prefixed_servers that uses a for expression to add the env_prefix to each server name in var.server_names.

Terraform

variable "server_names" {
  type    = list(string)
  default = ["app1", "db1", "cache1"]
}

variable "env_prefix" {
  type    = string
  default = "prod-"
}

# Create local.prefixed_servers using a for expression to add env_prefix to each server name
# Your code here

Need a hint?

Use locals block with a for expression inside square brackets to transform the list.

4

Output the prefixed_servers list

Create an output called prefixed_servers that outputs the local variable prefixed_servers.

Terraform

variable "server_names" {
  type    = list(string)
  default = ["app1", "db1", "cache1"]
}

variable "env_prefix" {
  type    = string
  default = "prod-"
}

locals {
  prefixed_servers = [for name in var.server_names : "${var.env_prefix}${name}"]
}

# Create an output prefixed_servers that outputs local.prefixed_servers
# Your code here

Need a hint?

Use an output block with value = local.prefixed_servers.