This is documentation for the next version of K6. For the latest stable release, go to the latest version.
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.
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 });
}