Help me, Localstack. You're my only hope.

Source: Dev.to

Introduction

Last year I learned Terraform with a group on Discord. The instructor provided a solid introduction, covering how to set up an AWS EC2 instance inside a specific VPC and subnet using the latest Amazon Linux 2023 AMI, and storing the Terraform state in an S3 bucket. This gave me a strong foundation, but without regular practice the knowledge fades.

Because my daily job doesn’t involve AWS, I need a safe way to keep practicing. Using a real AWS account risks unexpected charges, even with the free tier.

LocalStack emulates AWS services locally, allowing you to practice Terraform without incurring costs.

Install LocalStack

1. Follow the official installation guide for your operating system.

2. Start LocalStack:

   localstack start

3. In another terminal, verify it’s running:

   curl http://localhost:4566/_localstack/health

A JSON response listing available services indicates that LocalStack is working correctly.

Configure an AWS CLI Profile for LocalStack

Even though LocalStack doesn’t validate credentials, you still need an AWS profile.

Create a profile named localstack:

aws configure --profile localstack

Use these dummy values:

• AWS Access Key ID: test
• AWS Secret Access Key: test
• Default region name: us-east-1
• Default output format: json

Edit ~/.aws/config and add the endpoint URL:

[profile localstack]
region = us-east-1
output = json
endpoint_url = http://localhost:4566

Note: Ensure you are using AWS CLI v2.13.0 or later, as older versions may ignore endpoint_url in the config file.

Check the version:

aws --version

You should see something like aws-cli/2.13.0 Python/3.x. Upgrade if necessary.

Terraform Setup

Create the following two files in a new directory.

terraform.tf

terraform {
  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.92"
    }
  }
  required_version = ">= 1.2"
}

main.tf

provider "aws" {
  profile = "localstack"
  region  = "us-east-1"

  s3_use_path_style           = true
  skip_credentials_validation = true
  skip_metadata_api_check     = true

  endpoints {
    s3 = "http://s3.localhost.localstack.cloud:4566"
  }

  default_tags {
    tags = {
      Environment = "tutorial"
      Project     = "localstack-terraform"
    }
  }
}

resource "aws_s3_bucket" "example" {
  bucket_prefix = "localstack-terraform"
}

Explanation of main.tf

Apply the Configuration

Initialize the working directory and apply the configuration:

terraform init
terraform apply

Terraform will create the S3 bucket inside LocalStack. This demonstrates how you can test AWS resources locally without a real AWS account.

Reducing Boilerplate with tflocal

Manually configuring service endpoints, provider flags, and other LocalStack‑specific settings can become cumbersome.

The tflocal wrapper simplifies this process by automatically handling endpoints and reducing the amount of configuration required in your Terraform code. In larger projects, using tflocal leads to cleaner and more maintainable Terraform files when working with LocalStack.