[snap] chromedriver doesn't work without --headless under Wayland

[Marius Gedminas]

Since I upgraded my Ubuntu 19.04 laptop to Ubuntu 19.10 I've been unable to run Robot Framework tests using SeleniumLibrary with Chrome. I keep getting errors from chromedriver:

Parent suite setup failed:
WebDriverException: Message: unknown error: Chrome failed to start: exited abnormally.
  (unknown error: DevToolsActivePort file doesn't exist)
  (The process started from chrome location /snap/chromium/current/command-chromium.wrapper is no longer running, so ChromeDriver is assuming that Chrome has crashed.)

Things work somewhat better when I ask chromium to run in headless mode, although I still get weird failures partway through the test suite (I think on the first test that uses Select Window): TimeoutException: Message: timeout: Timed out receiving message from renderer: 300.000.

It would be easier to debug this if I could _see_ what the browser is doing, which brings us back to the original problem: non-headless chromium doesn't work in 19.10.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Olivier Tilloy (osomon)]

I am able to successfully run the chromium snap's (admittedly very basic) tests without headless mode. The tests are at https://git.launchpad.net/~chromium-team/chromium-browser/+git/snap-from-source/tree/tests?h=stable.

Marius, could you maybe share a minimal reproducer that fails, so I can investigate further?

[Marius Gedminas (mgedmin)]

Here's my minimal example:

#!/usr/bin/env python3
import time
import sys
from selenium import webdriver

options = webdriver.chrome.options.Options()
if '--headless' in sys.argv:
    options.add_argument("headless")
driver = webdriver.Chrome(options=options)
driver.get("https://ubuntu.com")
time.sleep(1)
print(driver.current_url)
driver.quit()

I can run python3 ex.py --headless, and it works (prints https://ubuntu.com after 10 seconds).
I can run it without --headless and I get

selenium.common.exceptions.WebDriverException: Message: unknown error: Chrome failed to start: exited abnormally.
  (unknown error: DevToolsActivePort file doesn't exist)
  (The process started from chrome location /snap/chromium/current/command-chromium.wrapper is no longer running, so ChromeDriver is assuming that Chrome has crashed.)

[Olivier Tilloy (osomon)]

That minimal example doesn't run here in a clean 20.04 VM with the chromium snap. However if I apply this minimal modification to the script, it succeeds, with and without the headless switch:

    -driver = webdriver.Chrome(options=options)
    +driver_path = "/snap/bin/chromium.chromedriver"
    +driver = webdriver.Chrome(options=options, executable_path=driver_path)

Does this work for you?

[Marius Gedminas (mgedmin)]

This is interesting information!

I have the chromium and chromium-chromedriver packages installed via apt. I wonder if that is why my example (headless) can work without overriding executable_path? chromium-chromedriver ships a /usr/bin/chromedriver that's a shell script that exec's /snap/bin/chromium.chromedriver.

> Does this work for you?

No. I get

seleniumwhy.py:10: DeprecationWarning: executable_path has been deprecated, please pass in a Service object
  driver = webdriver.Chrome(options=options, executable_path=driver_path)
Traceback (most recent call last):
  File "seleniumwhy.py", line 10, in <module>
    driver = webdriver.Chrome(options=options, executable_path=driver_path)
  File "/usr/lib/python3/dist-packages/selenium/webdriver/chrome/webdriver.py", line 95, in __init__
    RemoteWebDriver.__init__(
  File "/usr/lib/python3/dist-packages/selenium/webdriver/remote/webdriver.py", line 152, in __init__
    self.start_session(capabilities, browser_profile)
  File "/usr/lib/python3/dist-packages/selenium/webdriver/remote/webdriver.py", line 249, in start_session
    response = self.execute(Command.NEW_SESSION, parameters)
  File "/usr/lib/python3/dist-packages/selenium/webdriver/remote/webdriver.py", line 318, in execute
    self.error_handler.check_response(response)
  File "/usr/lib/python3/dist-packages/selenium/webdriver/remote/errorhandler.py", line 242, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: unknown error: Chrome failed to start: exited abnormally.
  (unknown error: DevToolsActivePort file doesn't exist)
  (The process started from chrome location /snap/chromium/current/command-chromium.wrapper is no longer running, so ChromeDriver is assuming that Chrome has crashed.)

Meanwhile --headless emits the same DeprecationWarning, but works.

I'm also on Ubuntu 20.04 today (was on 19.10 when I filed the bug). Possibly relevant: I use the Ubuntu on Wayland session.

[Olivier Tilloy (osomon)]

Indeed, your last comment is relevant, I can now reproduce the problem in a Wayland session. The same test runs fine in an X11 session.

[Marius Gedminas (mgedmin)]

I can no longer observe this on Ubuntu 22.04 LTS (Wayland session) with chromium snap 101.0.4951.64 (1993).

(An xeyes test confirms that the selenium-driven chromium is using Xwayland.)

[Olivier Tilloy (osomon)]

Confirmed, this now works in 22.04.

[Ian Russel Adem (ianrussel)]

I'm still facing this issue on ubuntu 22.04

The process started from chrome location /snap/chromium/2168/usr/lib/chromium-browser/chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.)

Any help would be appreciated

[Ian Russel Adem (ianrussel)]

Exception in thread Thread-1 (start):
Traceback (most recent call last):
  File "/usr/lib/python3.10/threading.py", line 1016, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.10/threading.py", line 953, in run
    self._target(*self._args, **self._kwargs)
  File "/home/ian/projects/fame/fame/./webdriver.py", line 136, in start
    driver = get_chromedriver(use_proxy=True)
  File "/home/ian/projects/fame/fame/./webdriver.py", line 134, in get_chromedriver
    driver = webdriver.Chrome(executable_path='/snap/bin/chromium.chromedriver', options=options)
  File "/home/ian/projects/fame/lib/python3.10/site-packages/selenium/webdriver/chrome/webdriver.py", line 69, in __init__
    super().__init__(DesiredCapabilities.CHROME['browserName'], "goog",
  File "/home/ian/projects/fame/lib/python3.10/site-packages/selenium/webdriver/chromium/webdriver.py", line 92, in __init__
    super().__init__(
  File "/home/ian/projects/fame/lib/python3.10/site-packages/selenium/webdriver/remote/webdriver.py", line 272, in __init__
    self.start_session(capabilities, browser_profile)
  File "/home/ian/projects/fame/lib/python3.10/site-packages/selenium/webdriver/remote/webdriver.py", line 364, in start_session
    response = self.execute(Command.NEW_SESSION, parameters)
  File "/home/ian/projects/fame/lib/python3.10/site-packages/selenium/webdriver/remote/webdriver.py", line 429, in execute
    self.error_handler.check_response(response)
  File "/home/ian/projects/fame/lib/python3.10/site-packages/selenium/webdriver/remote/errorhandler.py", line 243, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: unknown error: Chrome failed to start: exited abnormally.
  (unknown error: DevToolsActivePort file doesn't exist)
  (The process started from chrome location /snap/chromium/2168/usr/lib/chromium-browser/chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.)
Stacktrace:
#0 0x5581d9dfe3a3 <unknown>
#1 0x5581d9bda698 <unknown>
#2 0x5581d9c017e6 <unknown>
#3 0x5581d9bfc9be <unknown>
#4 0x5581d9c401a4 <unknown>
#5 0x5581d9c3fccf <unknown>
#6 0x5581d9c383d3 <unknown>
#7 0x5581d9c089ce <unknown>
#8 0x5581d9c09d51 <unknown>
#9 0x5581d9e447b6 <unknown>
#10 0x5581d9e46d8e <unknown>
#11 0x5581d9e4758d <unknown>
#12 0x5581d9e2dd7e <unknown>
#13 0x5581d9e47c7c <unknown>
#14 0x5581d9e217a8 <unknown>
#15 0x5581d9e62e58 <unknown>
#16 0x5581d9e62ff8 <unknown>
#17 0x5581d9e7d6d8 <unknown>
#18 0x7f4551ef8609 <unknown>

[Marius Gedminas (mgedmin)]

I'm now using Xephyr to confine my ChromeDriver-based Selenium tests

    Xephyr :2 -screen 1300x720
    export DISPLAY=:2
    unset WAYLAND_DISPLAY

This works fine for me on Ubuntu 22.10 in a Wayland session (and it also worked on 22.04 LTS).

As a bonus, the Chromium window doesn't steal focus any more when my Selenium tests close and open new browser windows!

But since things worked fine for me on 22.04 even before I implemented the Xephyr sandboxing, I'm not sure if this will be helpful to you or not.