🚀 Mini Project – Build a User Management HTTP Service

In this mini-project, you will build a production-style HTTP service in Go that manages users.

This project consolidates everything you’ve learned:

• HTTP handlers
• JSON APIs
• Middleware
• Error handling
• Testing
• Clean architecture

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🎯 Project Objective

Build a User Management Service with the following capabilities:

• Create a user
• Fetch all users
• Health check endpoint
• Middleware for logging
• Proper error handling
• Testable design

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🧱 Functional Requirements

1. Health Check API

GET /health

Response:

{ "status": "UP" }

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2. Create User

POST /users

Request:

{
  "name": "Aditya",
  "age": 30
}

Response:

{
  "message": "User created"
}

Requirements:

• Validate input
• Return 400 for invalid data
• Return 201 Created on success

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3. Get Users

GET /users

Response:

[
  { "name": "Aditya", "age": 30 }
]

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🧠 Non-Functional Requirements

• Use idiomatic Go
• Keep handlers small and clean
• Separate business logic from HTTP layer
• Use interfaces for services
• Add middleware (logging + headers)
• Use proper HTTP status codes

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🏗️ Suggested Project Structure

project/
│
├── main.go
├── handler/
│   └── user_handler.go
├── service/
│   └── user_service.go
├── middleware/
│   └── middleware.go
├── model/
│   └── user.go
├── test/
│   └── handler_test.go

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🔌 Middleware Requirements

Implement:

• Logging middleware → logs method + path

• Header middleware → adds:

  X-App-Version: 1.0
  

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🧪 Testing Requirements

You must write tests for:

• /health endpoint
• /users (GET and POST)

• Error scenarios:

  • Invalid JSON
  • Missing fields

Use:

• httptest
• Table-driven tests

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⚠️ Error Handling Expectations

Handle:

• Invalid JSON → 400 Bad Request
• Missing fields → 400 Bad Request
• Internal errors → 500 Internal Server Error

Return meaningful messages.

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🧩 Bonus Features (Optional)

• Add in-memory storage (slice/map)
• Add request ID middleware
• Add timeout using context
• Add basic logging format (timestamped)

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📊 Evaluation Criteria

Area	Expectation
Code Structure	Clean, modular
Readability	Simple, idiomatic
Error Handling	Explicit and correct
Testing	Coverage + table-driven tests
Design	Separation of concerns

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🧠 Mentor Guidance

• Encourage iterative development
• Start simple → improve gradually
• Focus on correctness first, optimization later

• Review code for:

  • Handler size
  • Error handling
  • Naming clarity

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🚀 Expected Outcome

By completing this project, you will:

• Build a real HTTP service in Go
• Understand backend service design
• Gain confidence in production-style coding

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📌 Final Insight

“If you can build and test this service cleanly, you are ready to contribute to real Go backend systems.”

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