String functions (join, split, format) in Terraform - Mini Project: Build & Apply

Using String Functions in Terraform

📖 Scenario: You are setting up a Terraform configuration to manage cloud resources. You need to work with strings to create resource names and parse input values.

🎯 Goal: Build a Terraform configuration that uses join, split, and format string functions to manipulate resource names and tags.

📋 What You'll Learn

Create a list of strings representing environment names

Create a variable to hold a delimiter string

Use join to combine environment names into a single string

Use split to break the combined string back into a list

Use format to create a formatted resource name string

💡 Why This Matters

🌍 Real World

Cloud engineers often need to manipulate strings to create resource names, tags, and configuration values dynamically in Terraform.

💼 Career

Understanding string functions in Terraform helps you write flexible and reusable infrastructure code, a key skill for cloud infrastructure roles.

1

Create a list of environment names

Create a Terraform variable called environments with the exact list of strings: ["dev", "test", "prod"].

Terraform

# Create a variable called environments with the list ["dev", "test", "prod"]
# Your code here

Need a hint?

Use the variable block and set default to the list.

2

Create a delimiter variable

Create a Terraform variable called delimiter and set its default value to the string "-".

Terraform

variable "environments" {
  type = list(string)
  default = ["dev", "test", "prod"]
}

# Create a variable called delimiter with default "-"
# Your code here

Need a hint?

Use a variable block with default = "-".

3

Join environment names into a single string

Create a Terraform local variable called env_string that uses the join function with var.delimiter and var.environments to combine the list into a single string.

Terraform

variable "environments" {
  type = list(string)
  default = ["dev", "test", "prod"]
}

variable "delimiter" {
  type = string
  default = "-"
}

# Create a local variable env_string that joins var.environments with var.delimiter
# Your code here

Need a hint?

Use locals block and join function.

4

Split the string and format a resource name

Add to the locals block a variable called env_list that uses split with var.delimiter and local.env_string. Then add a variable called resource_name that uses format to create the string "resource-%s-%s" with the first two elements of local.env_list.

Terraform

variable "environments" {
  type = list(string)
  default = ["dev", "test", "prod"]
}

variable "delimiter" {
  type = string
  default = "-"
}

locals {
  env_string = join(var.delimiter, var.environments)
  # Add env_list using split
  # Add resource_name using format with first two elements of env_list
  # Your code here
}

Need a hint?

Use split and format inside the locals block.