Ruby on Rails 8 & React E-Learning Part 5: Single VPS Production Deployment – Docker Compose, Puma Multithreading & Auto-Recovery

# docker-compose.yml
services:
  postgres:
    image: postgres:16-alpine
    container_name: rails-elearning-postgres
    restart: always
    environment:
      POSTGRES_DB: ${POSTGRES_DB:-elearning}
      POSTGRES_USER: ${POSTGRES_USER:-postgres}
      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD:-postgres}
    ports:
      - "127.0.0.1:5433:5432"  # Bind strictly to localhost
    volumes:
      - postgres_data:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 5s
      timeout: 5s
      retries: 5
    networks:
      - elearning-network

  redis:
    image: redis:7-alpine
    container_name: rails-elearning-redis
    restart: always
    ports:
      - "127.0.0.1:6381:6379"  # Bind strictly to localhost
    volumes:
      - redis_data:/data
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 5s
      timeout: 5s
      retries: 5
    networks:
      - elearning-network

  backend:
    build:
      context: ./backend
      dockerfile: Dockerfile
    container_name: rails-elearning-backend
    restart: always
    depends_on:
      postgres:
        condition: service_healthy
      redis:
        condition: service_healthy
    environment:
      DATABASE_URL: postgresql://${POSTGRES_USER:-postgres}:${POSTGRES_PASSWORD:-postgres}@postgres:5432/${POSTGRES_DB:-elearning}
      REDIS_URL: redis://redis:6379/1
      SECRET_KEY: ${SECRET_KEY}
      RAILS_ENV: production
      RAILS_MAX_THREADS: 5
      WEB_CONCURRENCY: 2
    ports:
      - "127.0.0.1:8000:8000"
    volumes:
      - ./backend/storage:/app/storage
    networks:
      - elearning-network

  frontend:
    build:
      context: ./frontend
      dockerfile: Dockerfile
    container_name: rails-elearning-frontend
    restart: always
    ports:
      - "127.0.0.1:3001:80"
    networks:
      - elearning-network

volumes:
  postgres_data:
  redis_data:

networks:
  elearning-network:
    driver: bridge

# backend/Dockerfile
FROM ruby:3.3-slim

WORKDIR /app

# Install system dependencies needed for compiling native gems (pg, nokogiri, roo)
RUN apt-get update -qq && apt-get install -y --no-install-recommends \
    build-essential \
    libpq-dev \
    curl \
    git \
    && rm -rf /var/lib/apt/lists/*

# Install bundler
RUN gem install bundler --no-document

# Cache gems
COPY Gemfile Gemfile.lock ./
RUN bundle config set --local without 'development test' && \
    bundle install --jobs 4 --retry 3

# Copy application code
COPY . .

# Ensure storage directories exist
RUN mkdir -p storage log tmp/pids

EXPOSE 8000

# Automated database migration and Puma startup
CMD ["bin/docker-entrypoint"]

# backend/config/puma.rb
max_threads_count = ENV.fetch("RAILS_MAX_THREADS") { 5 }
min_threads_count = ENV.fetch("RAILS_MIN_THREADS") { max_threads_count }
threads min_threads_count, max_threads_count

port ENV.fetch("PORT") { 8000 }
environment ENV.fetch("RAILS_ENV") { "production" }
pidfile ENV.fetch("PIDFILE") { "tmp/pids/server.pid" }

# Enable multi-worker clustered mode on multi-core servers
workers ENV.fetch("WEB_CONCURRENCY") { 2 }

# Preload app code before forking workers to maximize Copy-on-Write (CoW) RAM efficiency
preload_app!

# /etc/nginx/sites-available/elearning-rails.conf

# 1. HTTP to HTTPS Redirection
server {
    listen 80;
    server_name rails-elearning.sekolah.id;
    return 301 https://$host$request_uri;
}

# 2. Production HTTPS Server
server {
    listen 443 ssl http2;
    server_name rails-elearning.sekolah.id;

    # SSL Certificates managed by Certbot
    ssl_certificate /etc/letsencrypt/live/rails-elearning.sekolah.id/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/rails-elearning.sekolah.id/privkey.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;

    # Maximum file upload limit for Excel spreadsheets and PDFs
    client_max_body_size 30M;

    # Hardened Security Headers
    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-XSS-Protection "1; mode=block" always;
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;

    # --- REST API Proxy ---
    location /api/ {
        proxy_pass http://127.0.0.1:8000/api/;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }

    # --- Action Cable WebSocket Tunneling ---
    location /cable {
        proxy_pass http://127.0.0.1:8000/cable;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        
        # CRITICAL: Prevent Nginx from terminating idle WebSocket proctoring streams after 60s
        proxy_read_timeout 86400s;
        proxy_send_timeout 86400s;
    }

    # --- Frontend SPA (React 19) ---
    location / {
        proxy_pass http://127.0.0.1:3001;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

#!/usr/bin/env bash
# ==============================================================================
# Production Health Monitor & Auto-Recovery Watchdog
# scripts/health-monitor.sh
# ==============================================================================
set -euo pipefail

TARGET_URL="${HEALTH_CHECK_URL:-http://localhost:8000/api/v1/health}"
WEBHOOK_URL="${ALERT_WEBHOOK_URL:-https://discord.com/api/webhooks/your_webhook_here}"
TIMEOUT_SECONDS=5
PROJECT_DIR="/var/www/ruby-rails-elearning-react"
LOG_FILE="/var/log/rails-elearning-health.log"

log() {
    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" | tee -a "$LOG_FILE"
}

send_alert() {
    local message="$1"
    if [ -n "$WEBHOOK_URL" ]; then
        curl -s -X POST -H "Content-Type: application/json" \
            -d "{\"content\": \"⚠️ **ALERT: Rails E-Learning System Incident**\n$message\"}" \
            "$WEBHOOK_URL" > /dev/null 2>&1 || true
    fi
}

HTTP_STATUS=$(curl -s -o /dev/null -w "%{http_code}" --max-time "$TIMEOUT_SECONDS" "$TARGET_URL" || echo "000")

if [ "$HTTP_STATUS" -eq 200 ]; then
    log "HEALTH OK: API returned HTTP 200"
    exit 0
else
    log "HEALTH FAILURE: Endpoint returned HTTP $HTTP_STATUS! Initiating container restart..."
    send_alert "Rails API backend returned HTTP $HTTP_STATUS at $(hostname). Auto-restarting container..."

    cd "$PROJECT_DIR"
    docker compose restart backend

    sleep 10
    RETRY_STATUS=$(curl -s -o /dev/null -w "%{http_code}" --max-time "$TIMEOUT_SECONDS" "$TARGET_URL" || echo "000")

    if [ "$RETRY_STATUS" -eq 200 ]; then
        log "AUTO-RECOVERY SUCCESS: Backend restored to healthy status (HTTP 200)"
        send_alert "✅ **RECOVERY SUCCESS**: Rails API successfully restored at $(hostname)."
    else
        log "CRITICAL: Auto-recovery failed! Manual engineer intervention required."
        send_alert "🚨 **CRITICAL ALERT**: Auto-recovery failed! Backend remains down (HTTP $RETRY_STATUS)."
    fi
fi

*/5 * * * * /var/www/ruby-rails-elearning-react/scripts/health-monitor.sh >> /var/log/rails-health-cron.log 2>&1