D Language Web API with Multi-threading

A high-performance web API built with D language using the vibe.d framework, featuring multi-threading support and Nginx load balancing.

Features

• RESTful API endpoints
• Multi-threaded architecture
• Nginx load balancing
• Docker containerization
• Performance stress testing with k6

Prerequisites

Before running the application, ensure you have the following installed:

• D compiler (dmd)
• DUB package manager
• Docker and Docker Compose
• Required system libraries

Installation

1. Install system dependencies:

sudo apt-get update
sudo apt-get install -y libssl-dev libevent-dev zlib1g-dev

2. Install D compiler and DUB:

sudo apt install dub
curl -fsS https://dlang.org/install.sh | bash -s dmd
source ~/dlang/dmd-2.111.0/activate

Running the Application

Local Development

To run the application locally:

dub clean
dub upgrade
dub run

The API will be available at: http://localhost:8081

Docker Deployment

To run the application with Docker:

docker-compose down
docker-compose build --no-cache
docker-compose up

The API will be available at: http://localhost

API Endpoints

- `GET /` - Returns status message
  - Response: `{"status": "running ..."}`

- `GET /run` - Returns success message
  - Response: `{"message": "everything is working"}`

curl -X POST http://localhost:8081/users/random
curl http://localhost:8081/users/1
curl "http://localhost:8081/users?limit=10&offset=0"
curl -X PUT http://localhost:8081/users/1 \
  -H "Content-Type: application/json" \
  -d '{
    "username": "newusername",
    "email": "newemail@example.com",
    "age": 25,
    "country": "Canada"
  }'
curl -X DELETE http://localhost:8081/users/1

Performance Testing

The project includes k6 stress testing configuration. To run the tests:

# Start the application
docker-compose up -d app nginx

# Run stress tests
docker-compose exec k6 /bin/sh
docker-compose run k6 run /scripts/load-test.js
docker-compose run k6 run /scripts/stress-test.js

Test Parameters

The stress test will:

• Start with 20 virtual users
• Gradually increase to 50 users
• Then to 100 users
• Finally ramp down to 0

Architecture

The application uses:

• D language with vibe.d framework
• Nginx for load balancing
• Docker for containerization
• k6 for performance testing

Current API Endpoints

• GET / - Root endpoint
• GET /run - Test endpoint
• GET /time - Time endpoint with random delay
• POST /upload - File upload endpoint
• POST /users/random - Create random user
• GET /users/:id - Get user by ID
• GET /users - List users with pagination
• PUT /users/:id - Update user
• DELETE /users/:id - Delete user