URL Shortener on AWS (Terraform + Go Lambda)

This project implements a serverless URL shortener using AWS Lambda (Go), API Gateway, DynamoDB, and WAF, all provisioned and managed via Terraform. It includes CI/CD support, multi-environment deployment, and built-in rate limiting.

Table of Contents

• Features
• Architecture
• Prerequisites
• CI/CD Deployment (GitHub Actions)
  • How it works
  • Required GitHub Secrets
  • Multi-Environment Support
• Setup
• Testing
  • API Gateway via AWS Console
  • Lambda Console
  • WAF Rate Limit Test
• Clean Up
• License

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Features

• Shorten URLs: POST a URL to receive a short code.
• Redirect: GET a short code to be redirected to the original URL.
• Serverless & Scalable: Powered by AWS Lambda and DynamoDB (on-demand) for persistence.
• Secure: Protected with AWS WAF rate limiting per IP.
• IaC: Entire stack managed via Terraform.
• CI/CD: Automated deployment on push to dev, staging, and prod.
• Monitoring: Alarms, Logs, metrics, and error tracking.

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Architecture

• API Gateway: RESTful public interface for shorten and redirect.
• Lambda: Go-based handler for short URL generation and redirection.
• DynamoDB: Stores URL-to-code mappings (pay-per-request).
• WAF: Rate limits requests per IP (e.g., 10 requests per 5 minutes).
• CloudWatch: Logs, metrics, and error tracking.

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Prerequisites

• Go 1.24+
• Terraform 1.12+
• AWS credentials with access to Lambda, API Gateway, DynamoDB, WAF, CloudWatch.

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CI/CD Deployment (GitHub Actions)

This project uses GitHub Actions to deploy infrastructure automatically when changes are pushed to specific branches:

Git Branch	Environment	Terraform Path
dev	Development	terraform/environments/dev/
staging	Staging	terraform/environments/staging/
prod	Production	terraform/environments/prod/

How it works

When code is pushed to one of the environment branches:

• The Lambda function is compiled from terraform/modules/url-shortener/main.go
• Terraform is initialized in the appropriate environment folder
• Terraform apply is executed with -auto-approve

Required GitHub Secrets

In your GitHub repo settings, configure these secrets under Settings > Secrets and variables > Actions:

Secret Name	Description
AWS_ACCESS_KEY_ID	IAM access key for deployment
AWS_SECRET_ACCESS_KEY	Corresponding secret access key

Multi-Environment Support

This project supports isolated deployments for dev, staging, and prod environments using a folder-based structure:

terraform/
  environments/
    dev/
      providers.tf
      variables.tf
      ...
    staging/
      ...
    prod/
      ...
  modules/
    url-shortener/
      main.go
      ...

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Setup

1. Clone the repo

   git clone <repo-url>
   cd bb-test

2. Build & Deploy (CI/CDl)

   • Automated deployment on push to dev, staging, and prod.

3. Build & Deploy (Manual)

   ./build.sh

   This script:

   • Compiles the Go Lambda binary for Linux.
   • Deploys the infrastructure using Terraform.

4. Manual Terraform and Apply.

     cd terraform/environments/dev/ # or staging/prod
     terraform init
     terraform apply

5. Retrieve API URL

   cd terraform/environments/dev/  # or staging/prod
   terraform output rest_api_url

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Testing

1. API Gateway via AWS Console

• POST /v1/shorten Body:

  { "url": "https://google.com" }

• GET /v1/{shortcode}

  • Use the shortcode from POST method above to test redirection.

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2. Lambda Console

• Use test_events_lambda/post.json and get.json to simulate real requests in the Lambda Console.

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3. WAF Rate Limit Test

Test rate limiting from a single IP:

for i in {1..1000}; do
  curl -s -o /dev/null -w "[$i] %{http_code}\n" -X POST "<api-url>/v1/shorten" \
    -H "Content-Type: application/json" \
    -d "{\"url\": \"https://parallel${i}.com\"}" &
done
wait

Look for 403 responses and verify blocked requests in the WAF console.

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Clean Up

To remove all resources:

cd terraform/environments/dev/ # or staging/prod
terraform destroy

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License

MIT