Order Service API

A RESTful API for managing orders built with Go. This project demonstrates a production-ready microservice with two implementations: in-memory storage and PostgreSQL persistence.

Features

• Create, read, update, and delete orders
• RESTful API design
• JSON request/response format
• Input validation
• Error handling
• Two implementations (in-memory and PostgreSQL)

Tech Stack

• Go (standard library net/http)
• PostgreSQL
• github.com/lib/pq (PostgreSQL driver)

API Endpoints

Method	Endpoint	Description
GET	/orders	Get all orders
POST	/orders	Create a new order
GET	/orders/{id}	Get a specific order
PUT	/orders/{id}	Update an order
DELETE	/orders/{id}	Delete an order

Request Examples

Create an Order

curl -X POST http://localhost:8080/orders \
  -H "Content-Type: application/json" \
  -d '{"item":"laptop","quantity":1}'

Get All Orders

curl http://localhost:8080/orders

Update an Order

curl -X PUT http://localhost:8080/orders/1 \
  -H "Content-Type: application/json" \
  -d '{"item":"gaming laptop","quantity":2}'

Delete an Order

curl -X DELETE http://localhost:8080/orders/1

Branches

This repository contains two branches showing the evolution of the project:

• main: Simple implementation with in-memory storage using a Go slice. Perfect for understanding the basic API structure.
• add-postgresql: Production-ready version with PostgreSQL database integration. Data persists across server restarts.

Getting Started

Prerequisites

• Go 1.16 or higher
• PostgreSQL (for the database branch)

Running the In-Memory Version (main branch)

git checkout main
go run main.go

The server will start at http://localhost:8080

Running the PostgreSQL Version (add-postgresql branch)

git checkout add-postgresql

1. Create a PostgreSQL database:

CREATE DATABASE orderdb;

2. Create the orders table:

CREATE TABLE orders (
    id SERIAL PRIMARY KEY,
    item VARCHAR(255) NOT NULL,
    quantity INTEGER NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

3. Run the application:

go run main.go

Project Structure

.
├── main.go          # Main application code
├── go.mod           # Go module file
├── go.sum           # Go module checksum
└── README.md        # This file

Error Handling

The API returns appropriate HTTP status codes:

200 OK: Successful request

201 Created: Resource created successfully

204 No Content: Resource deleted successfully

400 Bad Request: Invalid input

404 Not Found: Resource not found

405 Method Not Allowed: HTTP method not supported

500 Internal Server Error: Server-side error

Author

NabeelOG