Selenium leaves behind running processes?

As already pointed out you should run browser.quit()

But on linux (inside docker) this will leave defunct processes. These are typically not really a problem as they are mere an entry in the process-table and consume no resources. But if you have many of those you will run out of processes. Typically my server melts down at 65k processes.

It looks like this:

# root@dockerhost1:~/odi/docker/bf1# ps -ef | grep -i defunct | wc -l28599root@dockerhost1:~/odi/docker/bf1# ps -ef | grep -i defunct | tailroot     32757 10839  0 Oct18 ?        00:00:00 [chrome] <defunct>root     32758   895  0 Oct18 ?        00:00:02 [chrome] <defunct>root     32759 15393  0 Oct18 ?        00:00:00 [chrome] <defunct>root     32760 13849  0 01:23 ?        00:00:00 [chrome] <defunct>root     32761   472  0 Oct18 ?        00:00:00 [chrome] <defunct>root     32762 19360  0 01:35 ?        00:00:00 [chrome] <defunct>root     32763 30701  0 00:34 ?        00:00:00 [chrome] <defunct>root     32764 17556  0 Oct18 ?        00:00:00 [chrome] <defunct>root     32766  8102  0 00:49 ?        00:00:00 [cat] <defunct>root     32767  9490  0 Oct18 ?        00:00:00 [chrome] <defunct>

The following code will solve the problem:

def quit_driver_and_reap_children(driver):    log.debug('Quitting session: %s' % driver.session_id)    driver.quit()    try:        pid = True        while pid:            pid = os.waitpid(-1, os.WNOHANG)            log.debug("Reaped child: %s" % str(pid))            #Wonka's Solution to avoid infinite loop cause pid value -> (0, 0)            try:                if pid[0] == 0:                    pid = False            except:                pass            #---- ----    except ChildProcessError:        pass

Whats happening is that your code is throwing an exception, halting the python process from continuing on. As such, the close/quit methods never get called on the browser object, so the chromedrivers just hang out indefinitely.

You need to use a try/except block to ensure the close method is called every time, even when an exception is thrown. A very simplistic example is:

from selenium import webdriverbrowser = webdriver.Chrome("path/to/chromedriver")try:    browser.get("http://stackoverflow.com")    browser.find_element_by_id('...').click()except:    browser.close()    browser.quit()  # I exclusively use quit

There are a number of much more sophisticated approaches you can take here, such as creating a context manager to use with the with statement, but its difficult to recommend one without having a better understanding of your codebase.

Chromedriver.exe crowds the TaskManager ( in case of Windows) everytime Selenium runs on Chrome.Sometimes, it doesn't clear even if the browser didn't crash.

I usually run a bat file or a cmd to kill all the existing chromedriver.exe processes before launching another one.

Take a look at this : release Selenium chromedriver.exe from memory

• I know this is a Unix-related question but I am sure the way it has been handled in Windows can be applied there.