Browser is not starting in headless mode

As mentioned in the title the browser does not start in headless mode despite overriding the headless user class variable. After inspecting the Selenium Server logs I noticed that the --headless option is not passed down. The issue can be fixed if the --headless option is added as an argument to the options instead of assigning it as a property.

Here is portion of the logs:

12:51:48.865 INFO [LocalDistributor.newSession] - Session request received by the Distributor: 
 [Capabilities {acceptInsecureCerts: true, browserName: chrome, goog:chromeOptions: {args: [--disable-translate, --disable-extensions, --disable-background-networ..., --safebrowsing-disable-auto..., --disable-sync, --metrics-recording-only, --disable-default-apps, --no-first-run, --disable-setuid-sandbox, --hide-scrollbars, --no-sandbox, --no-zygote, --autoplay-policy=no-user-g..., --disable-notifications, --disable-logging, --disable-permissions-api, --ignore-certificate-errors], excludeSwitches: [enable-automation], extensions: []}, pageLoadStrategy: eager}]
12:51:50.739 INFO [LocalNode.newSession] - Session created by the Node. Id: 4b29f0e02bb7d3f731c8ef7c865f74fc, Caps: Capabilities {acceptInsecureCerts: true, browserName: chrome, browserVersion: 120.0.6099.199, chrome: {chromedriverVersion: 120.0.6099.109 (3419140ab66..., userDataDir: /tmp/.org.chromium.Chromium...}, fedcm:accounts: true, goog:chromeOptions: {debuggerAddress: localhost:44391}, networkConnectionEnabled: false, pageLoadStrategy: eager, platformName: linux, proxy: Proxy(), se:bidiEnabled: false, se:cdp: ws://192.168.0.14:4444/sess..., se:cdpVersion: 120.0.6099.199, setWindowRect: true, strictFileInteractability: false, timeouts: {implicit: 0, pageLoad: 300000, script: 30000}, unhandledPromptBehavior: dismiss and notify, webauthn:extension:credBlob: true, webauthn:extension:largeBlob: true, webauthn:extension:minPinLength: true, webauthn:extension:prf: true, webauthn:virtualAuthenticators: true}

Environment

OS

Ubuntu 22.04.3 LTS x86_64

Python

3.11.7

Selenium Server

selenium-server-4.16.1.jar

Chrome WebDriver

120.0.6099.109

Packages

locust==2.20.1
locust-plugins==4.3.2
selenium==4.16.0

Code

Here is my locustfile.py

class MyUser(WebdriverUser):  
    wait_time = constant(2)  
    headless = True  
    tasks = [Tasks]

Fix

I fixed this issue by modifying the locust_plugins/users/webdriver.py file.

From:

options.headless = self.user.headless

To:

if self.user.headless:
    options.add_argument("--headless")

SvenskaSpel / locust-plugins