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WebSockets

Here’s a load test for the QuickPizza WebSocket API, available on https://quickpizza.grafana.com/ws.

Multiple VUs connect using a VU-indexed user name, and send random messages.

Each VU receives messages sent by all other VUs.

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(3000, 6000); // user session between 3s and 6s

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

export default function () {
  const url = `wss://quickpizza.grafana.com/ws`;
  const params = { tags: { my_tag: 'my ws session' } };
  const user = `user_${__VU}`;

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

      socket.send(JSON.stringify({ msg: 'Hello!', user: user }));

      socket.setInterval(function timeout() {
        socket.send(
          JSON.stringify({
            user: user,
            msg: `I'm saying ${randomString(5)}`,
            foo: 'bar',
          })
        );
      }, randomIntBetween(1000, 2000)); // say something every 1-2 seconds
    });

    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 data = JSON.parse(message);
      console.log(`VU ${__VU} received message: ${data.msg}`);
    });

    socket.setTimeout(function () {
      console.log(`VU ${__VU}: ${sessionDuration}ms passed, leaving the website`);
      socket.send(JSON.stringify({ msg: 'Goodbye!', user: user }));
    }, 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 });
  sleep(1);
}