Using selenium/standalone-chrome in docker-compose connecting with Python's selenium

Question

I've been having trouble getting Python selenium to connect to selenium/standalone-chrome, and was looking for insight on how to fix my issue. I would like to avoid using selenium/hub, but including it does not seem to fix my issue.

Here is my docker-compose.yml

version: '3.1'

networks:
  web:
    external: true

services:

  chrome:
    image: selenium/standalone-chrome:latest
    hostname: chrome
    networks:
      - web
    ports:
      - "5900:5900"
      - "4444:4444"
    privileged: true
    shm_size: 2g

  tests:
    build: ./tests
    networks:
      - web

And the test I'm running inside the test container. The entrypoint checks to make sure that chrome is up and running before running the scripts.

#!/usr/bin/env python3
"""Tests that the remote webdriver works."""
import unittest
from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities


class LocalGoogleTestCase(unittest.TestCase):

    def setUp(self):
        self.browser = webdriver.Chrome()
        self.addCleanup(self.browser.quit)

    def testPageTitle(self):
        self.browser.get('http://www.google.com')
        self.assertIn('Google', self.browser.title)


class RemoteGoogleTestCase(unittest.TestCase):

    def setUp(self):
        self.browser = webdriver.Remote(
            command_executor='http://chrome:4444/wd/hub',
            desired_capabilities=DesiredCapabilities.CHROME)
        self.addCleanup(self.browser.quit)

    def testPageTitle(self):
        self.browser.get('http://www.google.com')
        self.assertIn('Google', self.browser.title)


if __name__ == '__main__':
    unittest.main(verbosity=2)

For the test results, the Local test succeeds, it's only when trying to use the remote. Occasionally I will get the error hub not found in PATH, but that error is intermittent.

I am able to access the web interface via http://server:444/wd/hub and can start sessions and run scripts from there.

I believe this may be an issue related to containers not being able to reach out to each other and I have evaluated the following resources for trying to workout that issue:

• https://forums.docker.com/t/cant-connect-to-other-containers-inside-docker-network/66512
• https://forums.docker.com/t/docker-compose-doesnt-let-my-images-connect-with-each-other/54951

Posts I've examined which did not work:

• Docker: using container with headless Selenium Chromedriver
• docker selenium/standalone-chrome unable to connect to docker web server
• Easiest way to run Selenium tests in a Docker container over Jenkins CI
• Selenium webdriver.Remote driver does not work with tor proxy(webdriver.Chrome does)
• How do I link and scale multiple docker containers?
• How to point RemoteWebDriver to one of the multiple standalone docker selenium standalone chrome browsers?

Thanks for looking!

Update: From within the tests container, I am able to curl http://chrome:4444/wd/hub/status to retrieve the status that the connection is up and running, and this is part of the entryscript.sh, so I know the containers can talk to each other in some fashion.

Answer 1

First, of al, I'd like to thank you for all this. After reaching this post it gave me the hope that I'm not the one who is trying to do such a thing.

So, the thing is I'm successfully able to run everything from docker-compose and everything executed as expected.

Got hints from your post and made a few changes and it actually worked.

Here goes the solution.

FileName: docker-compose.yml

version: '3.8'

networks:
    web:
      external: true
      driver:  bridge

services:
    chrome:
        image: selenium/standalone-chrome:latest
        hostname: chrome
        networks:
          - web
        privileged: true
        shm_size: 2g
    framework:
        build: .
        networks:
            - web
        depends_on: 
            - chrome

Also, note that the grid url is http://chrome:4444/wd/hub With this change in configuration, I was able to run my code successfully and I was also able to send out emails.

I hope this helps someone who is stuck with docker-compose.yml

Answer 2

Thanks for the solution I was struggling with the same error, but in my case the fail was that I didn't add the following lines:

privileged: true
shm_size: 2g

I will add just one "fix" if you want to call it to your solution. As all the containers are built under the same docker-compose file you don't need to create a network, it is automatically created for all of them.

version: '3.8'

services:
    chrome:
        image: selenium/standalone-chrome:latest
        hostname: chrome
        privileged: true
        shm_size: 2g
    framework:
        build: .
        depends_on: 
            - chrome

Once again. Thanks!