3-Tier Architecture

This project implements a 3-tier architecture using AWS, Terraform, and a Python backend.

Infrastructure Diagram

Architecture

A classic 3-tier architecture deployed on AWS using Terraform.

• Frontend: Static HTML site served by Nginx
• Backend: Flask REST API written in Python, running on Gunicorn, using PyMongo for database access and Redis for caching
• Data Layer:
  • Amazon DocumentDB (MongoDB-compatible) as the primary datastore
  • Amazon ElastiCache (Redis) for in-memory caching

Project Structure

.
├── diagram
└── src
    └── app
    │   ├── backend
    │   └── frontend
    └── aws
        └── modules
            ├── backend
            ├── documentdb
            ├── elasticache
            ├── frontend
            ├── iam
            └── network

Deployment

1. Configure AWS Credentials: Make sure you have your AWS credentials configured properly.

2. Initialize Terraform:

   cd aws
   terraform init

3. Apply Terraform:

   terraform apply

4. Destroy Infrastructure:

   terraform destroy

How the App Works

Data Retrieval Flow

1. Request: Client ➔ Backend
2. Check: Backend ➔ Redis (Search for data)
3. Decision:
   • IF HIT: Redis ➔ Backend ➔ Client ✅
   • IF MISS: Redis ➔ Backend (Not found) ➔ Step 4
4. Fetch: Backend ➔ MongoDB (Get original data)
5. Update: MongoDB ➔ Backend ➔ Redis (Save for next time)
6. Deliver: Backend ➔ Client 🏁

API Endpoints

The backend provides the following API endpoints:

• GET /system-status: Returns the status of the system.
• GET /get_data/<string:key>: Retrieves data from the cache or database.
• GET /list_all_data: Retrieves all data from the database.
• POST /set_data: Inserts new data into the database.
• DELETE /delete_data/<string:key>: Deletes data from the database.
• GET /health: Returns the health of the backend and its database connections.

Other Documentation

• AWS Architecture Center
• Terraform Documentation
• Flask Documentation
• DocumentDB Documentation
• ElastiCache Documentation

Idea Source

This project is for educational purposes and is based on a common architectural pattern. For more examples and best practices, please refer to the AWS Architecture Center.