unknown error: DevToolsActivePort file doesn't

Question

I have an ubuntu server having the UI as well. U can execute the test cases by firing mvn test command. But the problem is when I do ssh of the machine through the terminal from another machine I get the following error-

unknown error: DevToolsActivePort file doesn't exist
  (Driver info: chromedriver=2.40.565383 (76257d1ab79276b2d53ee976b2c3e3b9f335cde7),platform=Linux 4.4.0-121-generic x86_64) (WARNING: The server did not provide any stacktrace information)
Command duration or timeout: 60.04 seconds
Build info: version: '3.8.1', revision: '6e95a6684b', time: '2017-12-01T18:33:54.468Z'
System info: host: 'ubuntu-test', ip: 'X.X.X.X', os.name: 'Linux', os.arch: 'amd64', os.version: '4.4.0-121-generic', java.version: '1.8.0_171'
Driver info: driver.version: ChromeDriver

but the same command starts chrome successfully if I take remote of the machine through remmina and then execute the same command of this machines terminal.

Answer 1

I had a similar issue when I was trying to selenium UI test cases in headless mode. This occurred as I did not have a display server. Starting Xvfb worked for me.

sudo yum -y install Xvfb libXfont Xorg

sudo yum -y groupinstall "X Window System" "Desktop" "Fonts" "General Purpose Desktop"

Xvfb :99 -screen 0 1024x768x24 &

export DISPLAY=:1

Answer 2

This error message...

unknown error: DevToolsActivePort file doesn't exist

...implies that the ChromeDriver was unable to initiate/spawn a new WebBrowser i.e. Chrome Browser session.

Your code trials and the versioning information of all the binaries would have given us some hint about what's going wrong.

However as per Add --disable-dev-shm-usage to default launch flags seems adding the argument --disable-dev-shm-usage will temporary solve the issue.

If you desire to initiate/span a new Chrome Browser session you can use the following Java solution:

System.setProperty("webdriver.chrome.driver", "C:\\path\\to\\chromedriver.exe");
ChromeOptions options = new ChromeOptions();
options.addArguments("--disable-dev-shm-usage"); // overcome limited resource problems
options.addArguments("start-maximized"); // open Browser in maximized mode
options.addArguments("disable-infobars"); // disabling infobars
options.addArguments("--disable-extensions"); // disabling extensions
options.addArguments("--disable-gpu"); // applicable to windows os only
options.addArguments("--no-sandbox"); // Bypass OS security model
WebDriver driver = new ChromeDriver(options);
driver.get("https://google.com");

---

disable-dev-shm-usage

As per base_switches.cc disable-dev-shm-usage seems to be valid only on Linix OS:

#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
// The /dev/shm partition is too small in certain VM environments, causing
// Chrome to fail or crash (see http://crbug.com/715363). Use this flag to
// work-around this issue (a temporary directory will always be used to create
// anonymous shared memory files).
const char kDisableDevShmUsage[] = "disable-dev-shm-usage";
#endif

In the discussion Add an option to use /tmp instead of /dev/shm David mentions:

I think it would depend on how are /dev/shm and /tmp mounted. If they are both mounted as tmpfs I'm assuming there won't be any difference. if for some reason /tmp is not mapped as tmpfs (and I think is mapped as tmpfs by default by systemd), chrome shared memory management always maps files into memory when creating an anonymous shared files, so even in that case shouldn't be much difference. I guess you could force telemetry tests with the flag enabled and see how it goes.

As for why not use by default, it was a pushed back by the shared memory team, I guess it makes sense it should be useing /dev/shm for shared memory by default.

Ultimately all this should be moving to use memfd_create, but I don't think that's going to happen any time soon, since it will require refactoring Chrome memory management significantly.

You can also find a detailed discussion in org.openqa.selenium.WebDriverException: unknown error: DevToolsActivePort file doesn't exist while trying to initiate Chrome Browser

Answer 3

Try to running selenium-server without sudo-privileges:

java -jar path/to/selenium-server-standalone.jar

Answer 4

Simply use headless mode

ChromeOptions options = new ChromeOptions();
options.addArguments("--headless");
driver = new ChromeDriver(options);

Answer 5

If you run from ssh without an X-forward your chrome browser will crash. To prevent that you can use the options DebanjanB posted, the most important being --headless. If running as root ( not recommended ) you need --no-sandbox as well.

I also had this error when I used al older version of selenium-java (3.5.3) with the newer chromedriver (75.x). It worked for me to use the 2.46 version of the chromedriver with the 3.5.3, or the 75.x with 3.141.59 of selenium java.

Running a local Xvfb should work too, but I suggest to use headless, it can be much faster.

Check the suggested duplicate post to and please update and mark as solved whatever helped you.

Answer 6

I use this configuration using python

import os
from selenium import webdriver 
from selenium.webdriver.chrome.options import Options 

chrome_options = webdriver.ChromeOptions()
chrome_options.add_argument("no-sandbox")
chrome_options.add_argument("--disable-extensions")
chrome_options.add_argument("--headless")
driver = os.path.join("path/of/driver","chromedriver")

browser = webdriver.Chrome(executable_path=driver,chrome_options=chrome_options)
browser.get("https://www.example.com")
print(browser.title)