Day 6 : Understanding Terraform File loading,Project Structure & .gitignore Essentials

Today was one of those days where everything finally clicked. Most of the confusion I had around Terraform files, structure, and hidden configs disappeared once I understood how Terraform actually loads .tf files and why project organization matters.

Below is my full breakdown of what I learned and the exact commands and files I worked with.

What I Learned Today

How Terraform Loads .tf Files

Terraform doesn’t care about the order of the .tf files.
It scans the entire working directory and automatically loads every .tf file before running planning or applying.

That means:

• main.tf
• backend.tf
• provider.tf
• variable.tf
• locals.tf
• output.tf

…all get merged by Terraform internally during processing.

This is why a clean structure matters not for Terraform, but for your sanity as the human reading the code.

Why Project Structure Matters

I finally understand why Terraform setups use separate files.

A simple structure like:

main.tf  
backend.tf  
providers.tf  
variables.tf  
locals.tf  
output.tf  

keeps everything clear:

• Resources in main.tf
• Backend in backend.tf
• Variables in variable.tf
• Local values in locals.tf
• Output values in output.tf
• Provider config in provider.tf

It’s not required by Terraform, but it makes the project clean, predictable, and scalable.

Using .gitignore to Protect Sensitive Files

This one is crucial.

I learned how to use .gitignore to hide files that should NEVER be pushed to GitHub like state files, logs, or crash reports.

My .gitignore:

.terraform.lock.hcl
terraform.tfvars
.terraform/
*.tfvars.json
*.log
crash.log
*.terraform.*backup
*.tfstate
*.tfstate.backup

This prevents accidental exposure of secrets or cloud infrastructure data.

Commands I Used Today

These are the exact commands I worked with:

• terraform validate :
  checks for syntax errors.

• terraform fmt -recursive :
  formats every .tf file in the project.

• terraform plan :
  shows the expected infrastructure changes.

Very basic commands, but they form the foundation of clean Terraform workflow.

The Full Terraform Project Structure I Built Today

main.tf

# Create s3 bucket
resource "aws_s3_bucket" "first_bucket" {
  bucket = local.bucket_name

  tags = {
    Name        = local.bucket_name
    Environment = var.environment
  }
}

# Create a vpc
resource "aws_vpc" "sample" {
  cidr_block = "10.0.1.0/24"
  region     = var.region

  tags = {
    Environment = var.environment
    Name        = local.vpc_name
  }
}

resource "aws_instance" "example" {
  ami           = "resolve:ssm:/aws/service/ami-amazon-linux-latest/al2023-ami-kernel-default-x86_64"
  instance_type = "t3.micro"
  region        = var.region

  tags = {
    Environment = var.environment
    Name        = "${var.environment}-EC2-Instance"
  }
}

backend.tf

terraform {
  backend "s3" {
    bucket       = "devopswithzacks-terraform-state"
    key          = "dev/terraform.tfstate"
    region       = "us-east-1"
    encrypt      = true
    use_lockfile = true
  }
}

locals.tf

locals {
  bucket_name = "${var.channel_name}-bucket-${var.environment}-${var.region}"
  vpc_name    = "${var.environment}-VPC"
}

output.tf

output "vpc_id" {
  value = aws_vpc.sample.id
}

output "ec2_id" {
  value = aws_instance.example.id
}

provider.tf

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 6.0"
    }
  }
}

provider "aws" {
  region = "us-east-1"
}

variables.tf

variable "environment" {
  default = "dev"
}

variable "channel_name" {
  default = "dwz"
}

variable "region" {
  default = "us-east-1"
}

.gitignore

.terraform.lock.hcl
terraform.tfvars
.terraform/
*.tfvars.json
*.log
crash.log
*.terraform.*backup
*.tfstate
*.tfstate.backup

Summary

Day 6 was all about fundamentals:

• Understanding how Terraform loads files.
• Seeing the importance of clean project structure.
• Using .gitignore to protect sensitive data.
• Running essential validation and formatting commands.
• Splitting Terraform files into clean, readable units.

Nothing fancy just solid engineering practice.