File functions (file, templatefile) in Terraform - Mini Project: Build & Apply

Using File Functions in Terraform

📖 Scenario: You are setting up infrastructure using Terraform. You want to include configuration data stored in external files. Terraform provides functions to read file contents and templates from files.

🎯 Goal: Learn how to use Terraform's file() and templatefile() functions to read static files and render templates with variables.

📋 What You'll Learn

Create a Terraform variable to hold the path to a static file

Create a Terraform variable to hold the path to a template file

Use the file() function to read the static file content

Use the templatefile() function to render the template with variables

💡 Why This Matters

🌍 Real World

Reading configuration files and rendering templates is common when provisioning cloud infrastructure with Terraform. This helps keep configurations modular and reusable.

💼 Career

Cloud engineers and DevOps professionals often use Terraform file functions to manage infrastructure as code efficiently.

1

Create variables for file paths

Create two Terraform variables: static_file_path with value "./config.txt" and template_file_path with value "./template.tpl".

Terraform

# Your code here

Need a hint?

Use variable blocks with default values for the file paths.

2

Create variables for template values

Create a Terraform variable called template_vars with a map containing "app_name" = "MyApp" and "env" = "production".

Terraform

variable "static_file_path" {
  default = "./config.txt"
}

variable "template_file_path" {
  default = "./template.tpl"
}

# Your code here

Need a hint?

Use a variable block with a default map for template variables.

3

Use file() and templatefile() functions

Create two local variables: static_content using file(var.static_file_path) and rendered_template using templatefile(var.template_file_path, var.template_vars).

Terraform

variable "static_file_path" {
  default = "./config.txt"
}

variable "template_file_path" {
  default = "./template.tpl"
}

variable "template_vars" {
  default = {
    app_name = "MyApp"
    env      = "production"
  }
}

# Your code here

Need a hint?

Use a locals block to define static_content and rendered_template using the file() and templatefile() functions.

4

Output the file contents and rendered template

Create two outputs: output_static with value local.static_content and output_template with value local.rendered_template.

Terraform

variable "static_file_path" {
  default = "./config.txt"
}

variable "template_file_path" {
  default = "./template.tpl"
}

variable "template_vars" {
  default = {
    app_name = "MyApp"
    env      = "production"
  }
}

locals {
  static_content    = file(var.static_file_path)
  rendered_template = templatefile(var.template_file_path, var.template_vars)
}

# Your code here

Need a hint?

Use output blocks to expose the contents of the static file and the rendered template.