websockets

import { randomString, randomIntBetween } from 'https://jslib.k6.io/k6-utils/1.1.0/index.js';
import { WebSocket } from 'k6/experimental/websockets';
import { setTimeout, clearTimeout, setInterval, clearInterval } from 'k6/experimental/timers';

const chatRoomName = 'publicRoom'; // choose any chat room name
const sessionDuration = randomIntBetween(5000, 60000); // user session between 5s and 1m

export default function () {
  for (let i = 0; i < 4; i++) {
    startWSWorker(i);
  }
}

function startWSWorker(id) {
  // create a new websocket connection
  const ws = new WebSocket(`wss://test-api.k6.io/ws/crocochat/${chatRoomName}/`);

  ws.addEventListener('open', () => {
    // change the user name
    ws.send(JSON.stringify({ event: 'SET_NAME', new_name: `Croc ${__VU}:${id}` }));

    // listen for messages/errors and log them into console
    ws.addEventListener('message', (e) => {
      const msg = JSON.parse(e.data);
      if (msg.event === 'CHAT_MSG') {
        console.log(`VU ${__VU}:${id} received: ${msg.user} says: ${msg.message}`);
      } else if (msg.event === 'ERROR') {
        console.error(`VU ${__VU}:${id} received:: ${msg.message}`);
      } else {
        console.log(`VU ${__VU}:${id} received unhandled message: ${msg.message}`);
      }
    });

    // send a message every 2-8 seconds
    const intervalId = setInterval(() => {
      ws.send(JSON.stringify({ event: 'SAY', message: `I'm saying ${randomString(5)}` }));
    }, randomIntBetween(2000, 8000)); // say something every 2-8 seconds

    // after a sessionDuration stop sending messages and leave the room
    const timeout1id = setTimeout(function () {
      clearInterval(intervalId);
      console.log(`VU ${__VU}:${id}: ${sessionDuration}ms passed, leaving the chat`);
      ws.send(JSON.stringify({ event: 'LEAVE' }));
    }, sessionDuration);

    // after a sessionDuration + 3s close the connection
    const timeout2id = setTimeout(function () {
      console.log(`Closing the socket forcefully 3s after graceful LEAVE`);
      ws.close();
    }, sessionDuration + 3000);

    // when connection is closing, clean up the previously created timers
    ws.addEventListener('close', () => {
      clearTimeout(timeout1id);
      clearTimeout(timeout2id);
      console.log(`VU ${__VU}:${id}: disconnected`);
    });
  });
}