I am trying to load test a websocket server where I want to add a JSON Web Token (JWT) as a header which is different per user – and that gets passed when establishing the connection.
Here are the files
processor.js

let tokens = [
  "token1",
  "token2,
  "token3"
]
function generateRandomToken (userContext, events, done) {
  userContext.vars.token = tokens[Math.floor(Math.random() * tokens.length)];
  return done()
}

module.exports = {
    generateRandomToken
};

Here is the main yaml file where the load test script is executed

config:
  target: "ws://localhost:8080/userMessages"
  phases:
    - duration: 1
      arrivalRate: 1
  processor: "./processor.js"
  function: "generateRandomToken"
  ws:
    headers:
      x-jwt-token: "{{ token }}"

scenarios:
  - engine: "ws"
    flow:
      - send: "Test message"
      - think: 30

The error that I am getting when executing this is worker error, id: 1 TypeError [ERR_HTTP_INVALID_HEADER_VALUE]: Invalid value "undefined" for header "x-jwt-token"

I see there is a similar issue open here for socketio – it is closed but without any answer – https://github.com/artilleryio/artillery/issues/2003

I am expecting a proper token to be generated on each request.