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Message Scheduler Setup

The message scheduler is a background service that automatically sends scheduled WhatsApp messages. It needs to run continuously on a server, separate from the Vercel-hosted frontend.
Important: The scheduler must run 24/7 on a VPS. Vercel’s serverless functions are not suitable for long-running background tasks. We recommend DigitalOcean, AWS EC2, or similar VPS providers.

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How the Scheduler Works

The scheduler service:
  • Checks for pending messages every 30 seconds
  • Automatically sends messages when scheduled time arrives
  • Updates campaign status and tracking in real-time
  • Handles errors with retry logic and detailed logging
  • Runs independently from the web application

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DigitalOcean VPS Setup

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1. Create a Droplet

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Recommended specifications:
  • OS: Ubuntu 22.04 LTS (or latest LTS)
  • Plan: Basic Droplet with 1GB RAM minimum
  • CPU: 1 vCPU (sufficient for scheduler)
  • Storage: 25GB SSD
  • Region: Choose closest to your WAHA server
Authentication:
  • For beginners: Use password authentication
  • Recommended: Use SSH keys for better security

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2. Initial Server Setup

Connect to your server and perform initial setup: 
# Connect to your server
ssh root@your-server-ip
# Enter your password or use your SSH key

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3. Deploy the Scheduler

# Clone your repository
git clone https://github.com/yourusername/whatsapp-group-manager.git
cd whatsapp-group-manager

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4. Start Scheduler with PM2

PM2 ensures the scheduler runs continuously and restarts automatically if it crashes. 
# Start the scheduler service
pm2 start src/scripts/messageScheduler.ts \
  --interpreter ./node_modules/.bin/tsx \
  --name whatsapp-scheduler \
  --env production
PM2 Startup: After running pm2 startup, it will output a command that you need to copy and execute. This ensures PM2 starts automatically when the server reboots.

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PM2 Management Commands

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Monitor the Scheduler

# View all PM2 processes
pm2 status

# View detailed info for scheduler
pm2 show whatsapp-scheduler

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Control the Scheduler

# Restart the scheduler
pm2 restart whatsapp-scheduler

# Restart with zero-downtime
pm2 reload whatsapp-scheduler

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PM2 Configuration File

For advanced configuration, create an ecosystem.config.js file: 
module.exports = {
  apps: [{
    name: 'whatsapp-scheduler',
    script: 'src/scripts/messageScheduler.ts',
    interpreter: './node_modules/.bin/tsx',
    instances: 1,
    exec_mode: 'fork',
    env_production: {
      NODE_ENV: 'production',
      DATABASE_URL: process.env.DATABASE_URL,
      WAHA_API_KEY: process.env.WAHA_API_KEY,
      WAHA_API_URL: process.env.WAHA_API_URL,
    },
    error_file: './logs/scheduler-error.log',
    out_file: './logs/scheduler-out.log',
    log_date_format: 'YYYY-MM-DD HH:mm:ss Z',
    max_memory_restart: '500M',
    autorestart: true,
    watch: false,
    max_restarts: 10,
    min_uptime: '10s',
  }]
};

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Updating the Scheduler

When you need to deploy updates: 
# Navigate to project directory
cd whatsapp-group-manager

# Pull latest changes
git pull origin main

# Install any new dependencies
pnpm install

# Regenerate Prisma client if schema changed
pnpm prisma:generate

# Restart the scheduler
pm2 restart whatsapp-scheduler

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Troubleshooting

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Scheduler Not Starting

Check logs: 
pm2 logs whatsapp-scheduler --err --lines 50
Common issues:
  • Missing environment variables
  • Database connection failure
  • Invalid Prisma client (run pnpm prisma:generate)
  • Node.js version mismatch

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Database Connection Issues

# Test database connection
pnpm prisma db push

# If successful, restart scheduler
pm2 restart whatsapp-scheduler

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High Memory Usage

# Check current memory usage
pm2 monit

# Set memory limit in ecosystem.config.js
max_memory_restart: '500M'

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Scheduler Stopped After Reboot

# Verify PM2 startup is configured
pm2 startup

# Save current process list
pm2 save

# Check if PM2 is running
systemctl status pm2-root

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Alternative VPS Providers

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AWS EC2

# Similar process on Amazon Linux 2
sudo yum update -y
sudo yum install -y nodejs npm
npm install -g pnpm pm2

# Follow same deployment steps

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Google Cloud Platform

# On Debian/Ubuntu image
sudo apt update && sudo apt upgrade -y
# Follow DigitalOcean steps above

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Linode

# On Ubuntu 22.04 image
# Follow DigitalOcean steps above

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Security Best Practices

  1. Firewall Configuration 
    # Enable UFW firewall
ufw allow OpenSSH
ufw enable
  2. Keep System Updated 
    # Regular updates
apt update && apt upgrade -y
  3. Use SSH Keys
    • Disable password authentication
    • Use strong SSH key passphrases
  4. Environment Variables
    • Never commit .env.production to git
    • Use strong, unique credentials
  5. Monitor Logs 
    # Regularly check for errors
pm2 logs whatsapp-scheduler --lines 100

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Performance Optimization

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Log Rotation

# Install PM2 log rotate
pm2 install pm2-logrotate

# Configure retention (keep 7 days)
pm2 set pm2-logrotate:retain 7

# Configure max file size (10MB)
pm2 set pm2-logrotate:max_size 10M

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Resource Monitoring

# Enable PM2 Plus for advanced monitoring (optional)
pm2 link [secret-key] [public-key]

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Next Steps

Environment Variables

Review all configuration options

Vercel Deployment

Deploy the web application

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