Automate Web App Deployment with Git and NPM

#!/bin/bash

# --- Configuration ---
APP_DIR="/var/www/mywebapp"
BRANCH="main"
PM2_APP_NAME="mywebapp-api" # Or systemd service name, e.g., "mywebapp.service"

# --- Deployment Steps ---
echo "Starting deployment for ${PM2_APP_NAME}..."

# Navigate to application directory
cd "${APP_DIR}" || { echo "Error: Application directory not found!"; exit 1; }

# Pull latest code from Git
echo "Pulling latest code from Git branch '${BRANCH}'..."
git reset --hard HEAD
git clean -df
git pull origin "${BRANCH}" || { echo "Error: Git pull failed!"; exit 1; }

# Install Node.js dependencies
if [ -f "package.json" ]; then
    echo "Installing Node.js dependencies..."
    npm install --production || { echo "Error: npm install failed!"; exit 1; }
else
    echo "No package.json found, skipping npm install."
fi

# Restart application service (using PM2 or systemd)
if command -v pm2 &> /dev/null; then
    echo "Restarting application with PM2: ${PM2_APP_NAME}..."
    pm2 reload "${PM2_APP_NAME}" || { echo "Error: PM2 reload failed!"; exit 1; }
elif command -v systemctl &> /dev/null; then
    echo "Restarting application with systemctl: ${PM2_APP_NAME}..."
    sudo systemctl restart "${PM2_APP_NAME}" || { echo "Error: systemctl restart failed!"; exit 1; }
else
    echo "Neither PM2 nor systemctl found. Manual restart might be needed."
fi

echo "Deployment completed successfully for ${PM2_APP_NAME}."