Transaction-Processing-System

The Transaction Processing System (TPS) is a scalable and resilient system that handles high transaction volumes, performance, reliability, and operational visibility. The system is designed with a microservices architecture that can scale horizontally and automatically recover from failures.

The TPS includes the following components:

• API Service - FastAPI - Exposes RESTful APIs for transaction management.

• Database - The system interacts with a relational database (PostgreSQL) to store transaction data.

• Caching - Uses Redis to cache transaction data and reduce database load.

• Prometheus Monitoring - Provides detailed metrics and monitoring of the application.

• Auto-Scaling - Kubernetes Horizontal Pod Autoscaler (HPA) automatically adjusts the number of pods based on CPU utilization.

• High Availability and Resilience - The system is designed for fault tolerance with features like rolling updates and pod disruption budgets.

Prerequisites

1. Docker and Docker Compose: Ensure you have Docker and Docker Compose installed on your machine.

   • Install Docker
   • Install Docker Compose

   Alternatively you can Install Docker Desktop which include both.

2. Python 3.9+: Ensure you have Python 3.9 or newer installed if you plan to run parts of the project outside of Docker.

   • Install Python

Project Structure

tps/
│── app/
│   │── __init__.py
│   │── main.py
│   │── models.py
│   │── database.py
│   │── transactions.py
│   │── schemas.py
│   │── cache.py
│   │── auth.py
│   │── worker.py
│── infra/
│   │── docker-compose.yml
│   │── k8s/
│   │   │── deployment.yaml
│   │   │── prometheus.yaml
│── requirements.txt
│── Dockerfile
│── README.md

Setup Instructions

git clone https://github.com/Yuda4/Transaction-Processing-System.git

cd Transaction-Processing-System

1. Build and Start the Services:

   • Open a terminal on project-root location
   • Run the build command: docker-compose up --build
   • Want to delete the container with all data? Run this command: docker-compose down -v
   • Want to stop the running of container? docker-compose stop or press Ctrl-C

2. API's endpoints:

   After docker is running and all services are up run this CURL in the terminal or using Postman:

   POST: /transactions

   curl --location 'http://localhost:8000/transactions' \
   --header 'Content-Type: application/json' \
   --data '{
       "user_id": "user_11",
       "amount": 12.75,
       "currency": "USD"
   }'
   

   GET: /transactions/{txn_id}

   curl --location 'http://localhost:8000/transactions/1'
   

   GET: /metrics

   curl --location 'http://localhost:8000/metrics'
   

3. Connecting to DB:

   Open the terminal and use this command:

   docker exec -it infra-db-1 psql -U user -d tps which will connect to DB named tps that is hosted in infra-db-1 docker container.

   \l - List all databases.

   \dt - List database tables.

   \d <table-name> - Describe a table.

   SELECT * FROM transactions; - shows transactions table's records.

Exmaple of records in table: