"Failed to decode response from marionette" message in Python/Firefox headless scraping script

For anyone else experiencing this issue when running selenium webdriver in a Docker container, increasing the container size to 2gb fixes this issue.

I guess this affects physical machines too if the OP fixed their issue by upgrading their server RAM to 2Gb, but could be coincidence.

The likely real issue behind this is that the DOM has not loaded yet and you are triggering searches on the next page. That’s why the sleep(3) is working in most cases. The proper fix is to use a wait class.

This is an example test case using a wait function for Nextcloud. It’s from my docker-selenium-firefox-python image: https://hub.docker.com/r/nowsci/selenium

Notice how the wait class is called surrounding any click or get calls. Basically, what this does is takes advantage of the fact that selenium changes the ID for the HTML tag on page load. The wait function checks if the new ID is different than the old, and when it is, the DOM has loaded.

import time
from selenium.webdriver import Firefox
from selenium.webdriver.firefox.options import Options
from selenium.webdriver.common.keys import Keys

class wait(object):

    def __init__(self, browser):
        self.browser = browser

    def __enter__(self):
        self.old_page = self.browser.find_element_by_tag_name('html')

    def page_has_loaded(self):
        new_page = self.browser.find_element_by_tag_name('html')
        return new_page.id != self.old_page.id

    def __exit__(self, *_):
        start_time = time.time()
        while time.time() < start_time + 5:
            if self.page_has_loaded():
                return True
            else:
                time.sleep(0.1)
        raise Exception('Timeout waiting for page load.')

def test():
    try:
        opts = Options()
        opts.headless = True
        assert opts.headless  # Operating in headless mode
        browser = Firefox(options=opts)
    except Exception as e:
        print("  -=- FAIL -=-: Browser setup - ", e)
        return

    # Test title
    try:
        with wait(browser):
            browser.get('https://nextcloud.mydomain.com/index.php/login')
        assert 'Nextcloud' in browser.title
    except Exception as e:
        print("  -=- FAIL -=-: Initial load - ", e)
        return
    else:
        print("  Success: Initial load")

    try:
        # Enter user
        elem = browser.find_element_by_id('user')
        elem.send_keys("MYUSER")

        # Enter password
        elem = browser.find_element_by_id('password')
        elem.send_keys("MYPASSWORD")

        # Submit form
        elem = browser.find_element_by_id('submit')
        with wait(browser):
            elem.click()

        # Check title for success
        assert 'Files' in browser.title
    except Exception as e:
        print("  -=- FAIL -=-: Login - ", e)
        return
    else:
        print("  Success: Login")

    print("  Finished.")

print("Testing nextcloud...")
test()

Combine this with the answer from @myol if you are using Docker.

The problem is that you do not close the driver. I made the same mistake. Whit htop in Linux, I have noticed that I occupy all the 26 GB of my pc whit firefox unclosed process.

I hope this saves some other poor soul the hours I just spent on this.

Download an old version of firefox (specifically, v66 for me), and point selenium there:

firefox_binary='/home/user/Downloads/old_firefox/firefox/firefox'

Try this, for Ubuntu 16.04:

1. Install firefox

sudo apt update
sudo apt install firefox

2. Check that firefox is well installed

which firefox

Will return /usr/bin/firefox

3. Go to the geckodriver releases page. Find the latest version of the driver for your platform and download it. For example:

wget https://github.com/mozilla/geckodriver/releases/download/v0.24.0/geckodriver-v0.24.0-linux64.tar.gz

4. Extract the file with:

tar -xvzf geckodriver*

5. Make it executable:

chmod +x geckodriver

6. Move it to $PATH and give root access

sudo mv geckodriver /usr/bin/
cd /usr/bin
sudo chown root:root geckodriver

7. Install selenium

pip3 install selenium

8. Add firefox and geckodriver to $PATH

sudo vim ~/.bashrc

Add the two lines:

export PATH=$PATH:"/usr/bin/firefox"
export PATH=$PATH:"/usr/bin/geckodriver"

9. Reboot your instance

sudo reboot

This error message…

Message: failed to decode response from marionette

…implies that the communication between GeckoDriver and Marionette was interrupted/broken.

Some of the reasons and solution for this issue are as follows:

• In the discussion Crash during command execution results in “Internal Server Error: Failed to decode response from marionette” @whimboo mentions, while executing your tests Selenium may force a crash of the parent process of Firefox with an error as:

  DEBUG   <- 500 Internal Server Error {"value":{"error":"unknown error","message":"Failed to decode response from marionette","stacktrace":...}...}
  

  • Analysis: The current message is somewhat misleading and Geckdriver needs to handle this situation and reporting that the application has unexpectedly quit, in a better way. This issue is still open.

• In the discussion Failed to decode response from marionette with Firefox >= 65 @rafagonc mentioned, this issue can occur when using GeckoDriver / FirefoxDriver or ChromeDriver in docker environment, due to presence of Zombie process that hangs even after invoking driver.quit(). At times, when you open many browsing instances one after another, your system may run out of memory or out of PIDs. See: Selenium using too much RAM with Firefox

  • As a solution @andreastt mentions, the following configuration should resolve the out of memory issue with Docker:

    --memory 1024mb --shm-size 2g
    

Steps: Configure SHM size in the docker container

• Similarly, while executing your test in your localhost, it is advisable to keep the following (minimum) configuration:

  --memory 1024mb
  

Additional Considerations

This issue can also occur due to incompatibility between the version of the binaries you are using.

Solution:

• Upgrade JDK to recent levels JDK 8u341.
• Upgrade Selenium to current levels Version 3.141.59.
• Upgrade GeckoDriver to GeckoDriver v0.26.0 level.
• Upgrade Firefox version to Firefox v72.0 levels.
• Execute your Test as a non-root user.

GeckoDriver, Selenium and Firefox Browser compatibility chart

tl; dr

[e10s] Crash in libyuv::ARGBSetRow_X86

Reference

You can find a relevant detailed discussion in:

• Browsing context has been discarded using GeckoDriver Firefox through Selenium

This error may be caused by starting the browser too many times without properly closing it.

In case of the OP’s Python code driver.quit() should be called after either successful or failed run. All exceptions must be caught.

No matter how much memory you system has, if the browser is not properly closed, subsequent runs will eventually make it impossible to start yet another one. In that case adding more memory would only postpone that moment.

1. To check for orphaned browser processes use ps aux command on Linux (or in Powershell on Windows).
2. To kill such processes use killall firefox command or killall firefox-esr when using Firefox Extended Support Release). This might require sudo.

References:

• https://www.selenium.dev/documentation/webdriver/browser/windows/#quitting-the-browser-at-the-end-of-a-session
• https://www.selenium.dev/selenium/docs/api/py/index.html?highlight=quit#example-1