Ping

Overview

A ping is a lightweight liveness check — you call it to confirm the broker is actually reachable before sending real traffic, without standing up a publisher, subscriber, or queue client just to find out. It's the tool of choice for startup readiness checks, container liveness/readiness probes, and connection-health dashboards that need a fast, cheap go/no-go signal.

client.ping() issues a minimal gRPC Ping request to the server and returns a ServerInfo object (host, version, serverUpTime) confirming the broker answered. It works over the same connection regardless of which messaging pattern you use elsewhere on that client — events, queues, commands, or queries.

Gotchas: a failed ping() doesn't close the client — the SDK's reconnect logic keeps retrying in the background, so catch the thrown error yourself (err.code) rather than assume the client tears itself down. A successful ping only confirms the broker process answered, not that a specific channel or queue exists or has capacity. And ping() is on-demand — it's not called automatically by KubeMQClient.create(), so a client can construct successfully yet still be unable to reach the broker.

Prerequisites

• KubeMQ server running on localhost:50000
• Node.js SDK installed (npm install kubemq-js)

Code

import { KubeMQClient } from 'kubemq-js';

async function main() {
  const client = await KubeMQClient.create({
    address: 'localhost:50000',
    clientId: 'js-connection-ping-client',
  });

  try {
    const info = await client.ping();
    console.log('Server host:', info.host);
    console.log('Server version:', info.version);
    console.log('Uptime (s):', info.serverUpTime);
  } finally {
    await client.close();
  }
}

main().catch(console.error);

How It Works

• client.ping() sends a gRPC Ping request and returns a ServerInfo object with host, version, and serverUpTime — the call fails fast with KubeMQTimeoutError if the server is unreachable.
• Unlike KubeMQClient.create(), ping() is an explicit on-demand health check; use it in readiness probes or before batch operations to confirm connectivity.
• The serverUpTime field is in seconds since the server process started and can be used to detect recent restarts.
• If ping() throws, inspect err.code — ConnectionTimeout means no response, AuthFailed means credentials are rejected.

Related

• Node.js SDK Reference
• Connect
• Close