How create step lad in k6 for websocket - performance

Question

I try to generate step load for performance test on k6 for websocket.
regular settings like
export let options = {
stages: [
{
"duration": "0m30s",
"target": 10
},
{
"duration": "0m30s",
"target": 10
},
{
"duration": "0m30s",
"target": 0
}
],
};
doesn't work for k6. I tried --vus 10 --i 10
but it just go through scenario 10 times and sleep till the end of 10 minutes.
Than I tried k6 run --vus 5 --stage 3m:10,5m:10,10m:35,1m30s:0 but result is almost the same. How create active load with step pattern for websocket testing? to connect every time after flow is done?
Test flow:
import ws from "k6/ws";
import { check } from "k6";
export default function() {
const url = "ws://URL:8000/";
const params = { tags: { my_tag: "hello" } };
const response = ws.connect(url, params, function(socket) {
socket.on("open", function open() {
console.log("connected");
socket.send(Date.now());
var url = "ws://URL:8000/";
var response = ws.connect(url, null, function(socket) {
socket.on('open', function() {
socket.send('Hello');
socket.send('How are you?');
});
socket.on("close", () => console.log("disconnected"));
socket.on("error", (e) => {
if (e.error() != "websocket: close sent") {
console.log("An unexpected error occured: ", e.error());
}
});
check(response, { "status is 101": r => r && r.status === 101 });
})
})
})
}

Answer 1

As mentioned in the documentation ws.connect blocks until the connection is closed either by calling socket.close() or the server closing the connection on the other end (or due to an error while doing something else).
So if you want to just send the 2 messages there you should call socket.close(). You can also close after receiving something on the other side using by using
socket.on("message", function(msg) {
console.log("got: "+ msg);
socket.close();
}
But if you don't need to reconnect but instead want to just send more messages you should probably use a timer:
socket.setInterval(function() {
socket.send('Hello');
socket.send('How are you?');
}, 1500);
will send messages each 1.5s
I don't know why you open another websocket connection inside the other, but that might be a mistake on your part and is likely going to make the code hard to read if you don't use a different variable name from socket

Answer 2

I wasted lots of time trying it with the K6 but it seems not supported till today, k6 does not support socket.io testing, check the links attached.
https://github.com/grafana/k6/issues/667
You can go for artillery, as suggested in the official socket.io docs
https://socket.io/docs/v4/load-testing/