Menu

Important: This documentation is about an older version. It's relevant only to the release noted, many of the features and functions have been updated or replaced. Please view the current version.

DocumentationGrafana k6ExamplesWebSockets
Open source

WebSockets

Here’s a load test for CrocoChat - a WebSocket chat API available on https://test-api.k6.io/.

Multiple VUs join a chat room and discuss various things for up to 1 minute, after which they disconnect.

Each VU receives messages sent by all chat participants.

JavaScript 
import { randomString, randomIntBetween } from 'https://jslib.k6.io/k6-utils/1.2.0/index.js';
import ws from 'k6/ws';
import { check, sleep } from 'k6';

const sessionDuration = randomIntBetween(10000, 60000); // user session between 10s and 1m
const chatRoomName = 'publicRoom'; // choose your chat room name

export const options = {
  vus: 10,
  iterations: 10,
};

export default function () {
  const url = `wss://test-api.k6.io/ws/crocochat/${chatRoomName}/`;
  const params = { tags: { my_tag: 'my ws session' } };

  const res = ws.connect(url, params, function (socket) {
    socket.on('open', function open() {
      console.log(`VU ${__VU}: connected`);

      socket.send(JSON.stringify({ event: 'SET_NAME', new_name: `Croc ${__VU}` }));

      socket.setInterval(function timeout() {
        socket.send(JSON.stringify({ event: 'SAY', message: `I'm saying ${randomString(5)}` }));
      }, randomIntBetween(2000, 8000)); // say something every 2-8seconds
    });

    socket.on('ping', function () {
      console.log('PING!');
    });

    socket.on('pong', function () {
      console.log('PONG!');
    });

    socket.on('close', function () {
      console.log(`VU ${__VU}: disconnected`);
    });

    socket.on('message', function (message) {
      const msg = JSON.parse(message);
      if (msg.event === 'CHAT_MSG') {
        console.log(`VU ${__VU} received: ${msg.user} says: ${msg.message}`);
      } else if (msg.event === 'ERROR') {
        console.error(`VU ${__VU} received:: ${msg.message}`);
      } else {
        console.log(`VU ${__VU} received unhandled message: ${msg.message}`);
      }
    });

    socket.setTimeout(function () {
      console.log(`VU ${__VU}: ${sessionDuration}ms passed, leaving the chat`);
      socket.send(JSON.stringify({ event: 'LEAVE' }));
    }, sessionDuration);

    socket.setTimeout(function () {
      console.log(`Closing the socket forcefully 3s after graceful LEAVE`);
      socket.close();
    }, sessionDuration + 3000);
  });

  check(res, { 'Connected successfully': (r) => r && r.status === 101 });
}