Guide to using Node.js in PanOS, running applications, npm packages, and development workflows

Node.js Integration and Development

Node.js in PanOS

PanOS includes Node.js v24.0.0 as a first-class component. It's not an afterthought - it's integrated into the system kernel and filesystem.

What's Included

# Core runtime
/bin/node                 # 50 MB Node.js binary

# Package manager
/bin/npm                  # NPM v10.7.0
/bin/npx                  # NPM executor

# Core modules
/node_modules             # npm packages directory

Instant Access

Node.js works immediately after boot:

/ # node --version
v24.0.0

/ # npm --version
10.7.0

/ # node -e "console.log('Ready to code!')"
Ready to code!

Creating Your First Node.js App

1. Create Project Directory

/ # mkdir -p /home/hello-panos
/ # cd /home/hello-panos

2. Initialize npm Project

/home/hello-panos # npm init -y

Wrote to /home/hello-panos/package.json:
{
  "name": "hello-panos",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

3. Create Main File

/home/hello-panos # cat > index.js << 'EOF'
console.log('👋 Hello from PanOS!');
console.log('Running Node.js', process.version);
console.log('Platform:', process.platform);
console.log('Architecture:', process.arch);
EOF

4. Run Application

/home/hello-panos # node index.js
👋 Hello from PanOS!
Running Node.js v24.0.0
Platform: linux
Architecture: x64

Success! You have a running Node.js application.

Building a Web Server

1. Create HTTP Server

/home/hello-panos # cat > server.js << 'EOF'
const http = require('http');
const port = 8080;

const server = http.createServer((req, res) => {
  if (req.url === '/') {
    res.writeHead(200, {'Content-Type': 'text/html'});
    res.end(`
      <h1>Welcome to PanOS</h1>
      <p>Node.js Server Running on Port ${port}</p>
      <p>OS: ${process.platform}</p>
      <p>Memory: ${Math.round(process.memoryUsage().rss / 1024 / 1024)} MB</p>
    `);
  } else {
    res.writeHead(404, {'Content-Type': 'text/plain'});
    res.end('404 Not Found');
  }
});

server.listen(port, () => {
  console.log(`Server running on http://0.0.0.0:${port}/`);
});
EOF

2. Run Server

/home/hello-panos # node server.js
Server running on http://0.0.0.0:8080/

3. Test from Another Terminal

In another terminal on your host:

# If using QEMU port forwarding (configured in ./2-run.sh)
curl http://localhost:8080/

Or inside PanOS on another terminal:

/ # wget -q -O - http://localhost:8080/
<h1>Welcome to PanOS</h1>
...

Installing npm Packages

Install Locally

/home/hello-panos # npm install express
+ express@4.18.2

This downloads and installs Express.js into node_modules/.

Using Installed Package

/home/hello-panos # cat > app.js << 'EOF'
const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.json({ 
    message: 'Express app running on PanOS',
    node_version: process.version
  });
});

app.listen(3000, () => {
  console.log('Express app listening on port 3000');
});
EOF

/home/hello-panos # node app.js
Express app listening on port 3000

Install Global Package

/ # npm install -g lodash
+ lodash@4.17.21

# Now available anywhere
/ # node -e "const _ = require('lodash'); console.log(_)"
[Function: lodash]

Useful npm Packages for PanOS

Productivity Tools

npm install -g @angular/cli      # Angular development
npm install -g vue               # Vue.js
npm install -g next              # Next.js framework
npm install -g vite              # Vite build tool

Utilities

npm install -g typescript        # TypeScript support
npm install -g eslint            # Code linting
npm install -g prettier          # Code formatting
npm install -g dotenv            # Environment variables

Servers & Frameworks

npm install express              # Express web framework
npm install fastify              # Fastify server
npm install koa                  # Koa server
npm install nestjs               # NestJS framework

Advanced Node.js Usage

Environment Variables

/home/hello-panos # export NODE_ENV=production
/home/hello-panos # export MY_VAR=hello

/home/hello-panos # node -e "console.log(process.env.MY_VAR)"
hello

Node Inspector (Debugging)

Enable debugging:

/home/hello-panos # node --inspect server.js
Debugger listening on ws://127.0.0.1:9229/...

Connect from host with Chrome DevTools or VS Code.

Performance Profiling

/home/hello-panos # node --prof app.js
# Generates isolate-*.log file

/home/hello-panos # node --prof-process isolate-*.log > profile.txt
# Analyze profile.txt

Cluster Module

Multi-process Node.js:

const cluster = require('cluster');
const os = require('os');

if (cluster.isMaster) {
  // Master process
  const numCPUs = os.cpus().length;
  for (let i = 0; i < numCPUs; i++) {
    cluster.fork();
  }
} else {
  // Worker process
  const http = require('http');
  http.createServer((req, res) => {
    res.end('Response from worker ' + process.pid);
  }).listen(8000);
}

Package Management

Check Installed Packages

/home/hello-panos # npm list
hello-panos@1.0.0 /home/hello-panos
└── express@4.18.2
    ├── accepts@1.3.8
    ├── content-disposition@0.5.4
    └── ... (many more)

Update Packages

/home/hello-panos # npm update

Remove Package

/home/hello-panos # npm uninstall express

Lock Dependencies

Create package-lock.json:

/home/hello-panos # npm install
# Automatically creates package-lock.json
# Guarantees reproducible installs

Development Workflows

Watchable Development

Install nodemon for auto-restart:

/home/hello-panos # npm install --save-dev nodemon
/home/hello-panos # npx nodemon server.js
[nodemon] watching extensions: js,json
[nodemon] starting `node server.js`
Server running on http://0.0.0.0:8080/

# Now edit server.js and nodemon auto-restarts

TypeScript Development

/home/hello-panos # npm install -g typescript

/home/hello-panos # cat > app.ts << 'EOF'
interface User {
  name: string;
  age: number;
}

const user: User = {
  name: 'PanOS Developer',
  age: 30
};

console.log(`Hello ${user.name}!`);
EOF

/home/hello-panos # tsc app.ts
/home/hello-panos # node app.js
Hello PanOS Developer!

Building Projects

Example: Vite build

/home/hello-panos # npm create vite@latest my-app -- --template vue
/home/hello-panos # cd my-app
/home/hello-panos/my-app # npm install
/home/hello-panos/my-app # npm run dev

Module System

CommonJS (Node.js native)

// math.js
module.exports = {
  add: (a, b) => a + b,
  subtract: (a, b) => a - b
};

// app.js
const math = require('./math');
console.log(math.add(5, 3));  // 8

ES Modules (Node.js 12+)

Enable in package.json:

{
  "type": "module"
}

Then use:

// math.js
export const add = (a, b) => a + b;
export const subtract = (a, b) => a - b;

// app.js
import { add, subtract } from './math.js';
console.log(add(5, 3));  // 8

File Operations

Reading/Writing Files

const fs = require('fs');

// Write file
fs.writeFileSync('output.txt', 'Hello from Node.js!');

// Read file
const content = fs.readFileSync('output.txt', 'utf8');
console.log(content);  // Hello from Node.js!

// Async version
fs.writeFile('async.txt', 'Async write', (err) => {
  if (err) throw err;
  console.log('File written!');
});

Working with JSON

const fs = require('fs');

// Write JSON
const data = { name: 'PanOS', version: '1.0.0' };
fs.writeFileSync('data.json', JSON.stringify(data, null, 2));

// Read JSON
const read = JSON.parse(fs.readFileSync('data.json', 'utf8'));
console.log(read.name);  // PanOS

System Integration

Working with Processes

const { execSync } = require('child_process');

// Run shell command
const result = execSync('ps aux | wc -l').toString();
console.log(`Running processes: ${result}`);

// Run command asynchronously
const { exec } = require('child_process');
exec('uptime', (err, stdout, stderr) => {
  if (err) throw err;
  console.log(stdout);
});

Environment & System Info

const os = require('os');

console.log('Platform:', os.platform());                    // linux
console.log('Arch:', os.arch());                            // x64
console.log('CPUs:', os.cpus().length);                     // 2-8
console.log('Free Memory:', Math.round(os.freemem() / 1024 / 1024), 'MB');
console.log('Total Memory:', Math.round(os.totalmem() / 1024 / 1024), 'MB');
console.log('Temp Directory:', os.tmpdir());                // /tmp

Performance Tips

1. Memory Management

Monitor memory usage:

console.log(process.memoryUsage());
// Output:
// {
//   rss: 50000000,        // Resident set size
//   heapTotal: 20000000,  // Total heap
//   heapUsed: 10000000,   // Heap in use
//   external: 5000000
// }

2. CPU Usage

Check CPU availability:

/ # nproc
4  # 4 cores available

Use all cores with clustering:

const cluster = require('cluster');
const os = require('os');

if (cluster.isMaster) {
  const numCPUs = os.cpus().length;
  for (let i = 0; i < numCPUs; i++) cluster.fork();
} else {
  // Worker code
}

3. Disk I/O Optimization

Use streams for large files:

const fs = require('fs');

// Bad: loads entire file into memory
const data = fs.readFileSync('huge.txt');

// Good: streams data in chunks
fs.createReadStream('huge.txt')
  .on('data', (chunk) => {
    // Process chunk
  });

Next Steps

Troubleshoot Issues: Read 08-troubleshooting.mdx
Create Bootable Media: Read 09-creating-iso.mdx
Advanced Customization: Read 10-advanced.mdx

Previous: 06-architecture.mdx
Next: 08-troubleshooting.mdx

Node.js Integration and Development

On this page