Transaction API Services

This repository contains two implementations of a transaction API service:

• Go Service - Located in ./go/ - See Go README
• Python Service - Located in ./python/ - See Python README

Both services provide identical REST APIs for managing financial transactions with PostgreSQL database integration and Prometheus metrics.

Database Setup

The services require a PostgreSQL database with the following configuration:

Local Development with Docker

# Start PostgreSQL database
docker run -d \
  --name transaction-db \
  -e POSTGRES_USER=root \
  -e POSTGRES_PASSWORD=rootpassword \
  -e POSTGRES_DB=transactions \
  -p 5432:5432 \
  postgres:15

Kubernetes Deployment

Deploy the database using the provided Kubernetes templates:

# Deploy PostgreSQL
kubectl apply -f database/postgresql.yaml

The database will be initialized by the Go/Python services on first connection with the required transactions table schema.

Database Schema

The transactions table includes:

• id (Serial Primary Key)
• user_id (Integer)
• amount (Decimal 10,2)
• type (VARCHAR 20) - 'credit' or 'debit'
• description (Text)
• created_at (Timestamp)

API Endpoints

Both services expose identical REST APIs:

• POST /transactions - Create a new transaction
• GET /transactions - List transactions (with pagination)
• GET /transactions/{id} - Get specific transaction
• GET /health - Health check endpoint
• GET /metrics - Prometheus metrics

Environment Variables

Both services use the DATABASE_URL environment variable:

DATABASE_URL=postgresql://root:rootpassword@localhost:5432/transactions?sslmode=disable

Quick Start

1. Start the database:

   docker run -d --name transaction-db -e POSTGRES_USER=root -e POSTGRES_PASSWORD=rootpassword -e POSTGRES_DB=transactions -p 5432:5432 postgres:15

2. Choose your service implementation:

   • Go Service Setup
   • Python Service Setup

Kubernetes Deployment

For full Kubernetes deployment with both services:

# Deploy database
kubectl apply -f database/postgresql.yaml

# Deploy Go service  
kubectl apply -f go/k8s/

# Deploy Python service
kubectl apply -f python/k8s/

Architecture

┌─────────────────┐    ┌─────────────────┐
│   Go Service    │    │ Python Service  │
│   (Port 8080)   │    │   (Port 8080)   │
└─────────┬───────┘    └─────────┬───────┘
          │                      │
          └──────────┬───────────┘
                     │
         ┌───────────▼────────────┐
         │   PostgreSQL Database  │
         │      (Port 5432)       │
         └────────────────────────┘

Both services are independently deployable and can run simultaneously, sharing the same PostgreSQL database.