🏦 Banking System Backend

This is a robust, modular, and scalable banking system backend built with Go (Golang). It uses the gorilla/mux router for request handling and follows a clean separation of concerns.

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✨ Features

• User Management: Create, retrieve, update, and delete user accounts.
• Transaction Handling: Perform transfers, withdrawals, and deposits. Handle race condition using row-level locking.
• Modular Design: Clear separation between handlers, internal logic (database/transaction), and data models.
• Environment Configuration: Uses a .env file for sensitive configuration.

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Demo

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🛠️ Project Structure

The key components of the application are organized as follows:

Directory/File	Purpose
handlers/	HTTP request controllers for User and Transaction actions.
internal/db/	Database connection and specific data access methods.
internal/transaction/	Core business logic for handling funds and transfers.
internal/user/	Core business logic for managing user accounts.
internal/models/	Structs defining application data (e.g., User, Transaction).
main.go	Application entry point, configuration loading, and route definition.
schema.sql	SQL script for creating necessary database tables.
.env.example	Template for required environment variables.

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🚀 Getting Started

Prerequisites

• Go (version 1.24+ recommended)
• A running PostgreSQL or equivalent database instance.
• Docker (optional, for containerized deployment)

Local Setup

1. Clone the repository:

   git clone [repo-link]
   cd banking

2. Set up environment variables: Create a file named .env by copying the example and filling in your database credentials and secrets.

   cp .env.example .env

3. Install dependencies:

   go mod tidy

4. Initialize the database: Run the setup script or manually execute the SQL from schema.sql to create tables.

   ./setup.sh
   # OR manually run the contents of schema.sql

5. Run the application:

   go run main.go

   The server will start on http://localhost:8080.

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🌎 API Endpoints

The API is accessible on port 8080 and handles the following routes:

User Management

Method	Path	Description
POST	/user	Creates a new user account.
GET	/user/{id}	Retrieves a specific user by ID.
GET	/user	Retrieves a list of users.
PUT	/user/{id}	Updates user details (e.g., name).
DELETE	/user/{id}	Deletes a user account.

Transaction Handling

Method	Path	Description
PUT	/transaction/transfer	Transfers funds between two accounts.
PUT	/transaction/withdraw	Withdraws funds from an account.
PUT	/transaction/deposit	Deposits funds into an account.