Real-time Events

Subscribe to real-time events from your machines.

Overview

Cmdop uses WebSockets (via Centrifugo) for real-time communication:

Machine status changes
Command output streaming
File system events
Metrics updates


const subscription = client.subscribe('machine-id');
 
subscription.on('connect', () => {
  console.log('Connected');
});
 
subscription.on('disconnect', () => {
  console.log('Disconnected');
});
 
// Cleanup
subscription.unsubscribe();

Event Types

Status Events


subscription.on('status', (event) => {
  console.log(event.status); // 'online' | 'offline'
  console.log(event.timestamp);
});

Output Events

Command output in real-time:


subscription.on('output', (event) => {
  console.log(event.type); // 'stdout' | 'stderr'
  console.log(event.data);
  console.log(event.commandId);
});

Metrics Events

System metrics:


subscription.on('metrics', (event) => {
  console.log(event.cpu.usage);
  console.log(event.memory.used);
  console.log(event.disk.used);
});

File Events

File system changes:


subscription.on('file', (event) => {
  console.log(event.type); // 'created' | 'modified' | 'deleted'
  console.log(event.path);
});


const subscription = client.subscribeMany([
  'machine-1',
  'machine-2',
]);
 
subscription.on('status', (event) => {
  console.log(event.machineId, event.status);
});

React Hook


import { useRealtime } from '@cmdop/react';
 
function StatusMonitor({ machineId }) {
  const { status, metrics, connected } = useRealtime(machineId);
 
  return (
    <div>
      <p>Connected: {connected ? 'Yes' : 'No'}</p>
      <p>Status: {status}</p>
      <p>CPU: {metrics?.cpu.usage}%</p>
    </div>
  );
}

Connection Options


const subscription = client.subscribe('machine-id', {
  reconnect: true,
  reconnectDelay: 1000,
  maxReconnectAttempts: 10,
});

Error Handling


subscription.on('error', (error) => {
  console.error('Subscription error:', error);
});
 
subscription.on('reconnecting', (attempt) => {
  console.log(`Reconnecting (attempt ${attempt})...`);
});

Channel Filtering

Subscribe to specific event types:


const subscription = client.subscribe('machine-id', {
  channels: ['status', 'metrics'], // Only these events
});

Presence

See who’s connected:


subscription.on('presence', (event) => {
  console.log('Users viewing:', event.users);
});
 
const presence = await subscription.presence();
console.log(presence.users);