🔗 Javalin REST API + Traefik Deployment Pipeline

A lightweight REST API built with Javalin and a full production-ready DevOps pipeline using Docker, Traefik, and GitHub Actions.
Includes routing, controllers, exception handling, middleware-style security, PostgreSQL integration, and automated CI/CD deployment.

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🧿 Status & CI/CD

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📌 Summary

This repository contains:

1. A modular, production-ready REST API (main branch)

• Javalin routing
• DAO → Service → Controller
• Exception & validation handling
• JWT or custom authentication (depending on your config)
• Unit + integration tests
• PostgreSQL integration

2. A complete deployment pipeline (traefik-pipeline branch)

• Dockerfile + docker-compose
• Traefik reverse proxy & TLS certificates
• GitHub Actions CI/CD
• DigitalOcean deployment (SSH + Docker Compose)
• Environment-based configuration

Branch link:
🔗 https://github.com/tysker/javalin_rest_api_pipeline/tree/traefik-pipeline

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🧰 Tech Stack

Backend

• Java + Javalin
• PostgreSQL
• JUnit testing

DevOps

• Docker & Docker Compose
• Traefik v3 reverse proxy
• GitHub Actions CI/CD
• DigitalOcean droplet (Ubuntu)

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📂 Project Structure

src/
├── main/java/
│   ├── controllers/      # HTTP endpoints
│   ├── daos/             # Database layer
│   ├── services/         # Business logic
│   ├── exceptions/       # Custom exceptions
│   ├── security/         # Access manager / filters
│   ├── util/             # Helpers
│   └── App.java          # Application entrypoint
│
└── test/
├── unit/             # Unit tests
└── integration/      # Integration tests

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📂 Deployment Pipeline (traefik-pipeline branch)

deployment/
├── docker/
│   ├── Dockerfile
│   ├── docker-compose.yml
│   ├── docker-compose.prod.yml
│   └── .env
│
├── traefik/
│   ├── traefik.yml              # Static config
│   ├── traefik_dynamic.yml      # Routers / TLS
│   └── acme.json                # Certificate storage
│
└── github/workflows/
└── deploy.yml               # CI/CD pipeline

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🧪 Testing

Run tests:

mvn test

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🚀 Local Development

mvn clean package
java -jar target/app.jar

Runs at:

http://localhost:7000

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🚀 CI/CD Pipeline Overview

flowchart TD
    A[Push to GitHub] --> B[GitHub Actions]
    B --> C[Run Tests / Build JAR]
    C --> D[Build Docker Image]
    D --> E[Push Image to Docker Hub]
    E --> F[SSH into DigitalOcean Server]
    F --> G[docker compose pull]
    G --> H[docker compose up -d]
    H --> I[Traefik Routes Traffic + HTTPS]

Loading

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🛰️ Deployment Architecture

                     ┌──────────────────────────┐
                     │        Traefik v3         │
                     │  Automatic HTTPS / Routing │
                     └──────────────┬────────────┘
                                    │
                   ┌────────────────┴────────────────┐
                   │                                 │
         ┌─────────▼──────────┐          ┌──────────▼─────────┐
         │   Javalin API       │          │   Admin Dashboard   │
         │   (Docker Container)│          │   (Optional)        │
         └─────────┬──────────┘          └──────────┬──────────┘
                   │                                 │
                   └────────────────┬────────────────┘
                                    │
                         ┌──────────▼─────────┐
                         │    PostgreSQL       │
                         │ (Docker Container)  │
                         └─────────────────────┘

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📄 Full Documentation

Api

• All routes
• Example requests
• Example JSON responses
• Error model

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API Documentation

Base URL:

`/api/*`

User Endpoints

GET /api/users

Returns list of users.

GET /api/users/:id

Returns a user by ID.

POST /api/users

Creates a new user.

Body:

{
  "username": "john",
  "password": "secret"
}

PATCH /api/users/:id

Updates a user.

DELETE /api/users/:id

Deletes a user.

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Error Model

{
  "status": "error",
  "message": "User not found",
  "path": "/api/users/999",
  "timestamp": "2025-01-20T10:15:14Z"
}

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Pipeline

• Docker architecture
• Traefik configuration
• GitHub Actions workflow explanation
• Deployment steps
• Environment variables

Deployment Pipeline Documentation

This project includes a complete CI/CD pipeline with:

• Docker
• Docker Compose
• Traefik v3
• GitHub Actions
• DigitalOcean (remote server)

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1. Build Process

GitHub Actions performs:

1. Checkout
2. Java build (mvn -B package)
3. Run tests
4. Build Docker image
5. Push to Docker Hub

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2. Deployment Process

1. GitHub connects to the remote server via SSH
2. Server pulls the latest Docker image
3. Traefik reloads routes automatically
4. New version goes live instantly

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3. Traefik Overview

Traefik handles:

• HTTPS certificates via Let’s Encrypt
• Routing to API container
• Middleware
• Logging
• Security headers

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4. Environment Variables

.env contains:

DOMAIN=mydomain.com
EMAIL=[admin@mydomain.com](mailto:admin@mydomain.com)
POSTGRES_URL=jdbc:postgresql://db:5432/app
POSTGRES_USER=user
POSTGRES_PASSWORD=password
APP_PORT=7000

5. Deployment Trigger

Push to main automatically triggers deployment.

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