Python, Selenium Grid and Docker

Français

With Docker you can quickly and easily install, configure and use Selenium Grid. This tutorial shows the respective steps that you need as a software tester (or Developer). Instead of Python you can also use other languages, which are supported by Selenium​.

Preconditions

• Python installed (min. 2.7)
• virtualenv installed (optional)
• docker-machine installed
• docker-compose installed

Preparation of files

$ mkdir -p ~/Project/SeleniumTutorial && cd ~/Project/SeleniumTutorial
 
# create docker-compose.yml (version 1)
$ vim v1-docker-compose.yml
 
# or create docker-compose.yml (version 2)
$ vim v2-docker-compose.yml
 
# create python example.py
$ vim example.py

Docker-compose.yml file

version: '2'
services:
  selenium_hub:
    image: selenium/hub
    ports:
      - 4444:4444
  node_1:
    image: selenium/node-chrome
    depends_on:
      - selenium_hub
    environment:
      - HUB_PORT_4444_TCP_ADDR=selenium_hub
  node_2:
    image: selenium/node-firefox
    environment:
      - HUB_PORT_4444_TCP_ADDR=selenium_hub
    depends_on:
      - selenium_hub

 

example.py file

import os
import datetime
import time
import unittest
from selenium import webdriver
 
 
class Example(unittest.TestCase):
 
    def setUp(self):
 
        self.driver = webdriver.Remote(
            command_executor='http://192.168.99.100:4444/wd/hub',
            desired_capabilities={
                'browserName': 'firefox',
                'javascriptEnabled': True
            }
        )
 
        self.driver.get('http://softwaretester.info/')
 
    def test_something(self):
 
        dt_format = '%Y%m%d_%H%M%S'
        cdt = datetime.datetime.fromtimestamp(time.time()).strftime(dt_format)
        current_location = os.getcwd()
        img_folder = current_location + '/images/'
 
        if not os.path.exists(img_folder):
            os.mkdir(img_folder)
 
        picture = img_folder + cdt + '.png'
        self.driver.save_screenshot(picture)
 
    def tearDown(self):
 
        self.driver.quit()
 
 
if __name__ == "__main__":
 
    unittest.main(verbosity=1)

Create environment

# create new VM
$ docker-machine create -d virtualbox Grid
 
# pointing shell
$ eval $(docker-machine env Grid)
 
# show status (optional)
$ docker-machine ls
...
NAME   ACTIVE   DRIVER       STATE     URL                         SWARM   DOCKER    ERRORS
Grid   *        virtualbox   Running   tcp://192.168.99.100:2376           v1.11.1 
 
# run docker-compose
$ docker-compose -f docker-compose.yml up -d
 
# show status
$ docker-compose -f docker-compose.yml ps
...
             Name                         Command           State           Ports          
------------------------------------------------------------------------------------------
seleniumtutorial_node_1_1         /opt/bin/entry_point.sh   Up                           
seleniumtutorial_node_2_1         /opt/bin/entry_point.sh   Up                           
seleniumtutorial_selenium_hub_1   /opt/bin/entry_point.sh   Up      0.0.0.0:4444->4444/tcp
 

Open Browser

Run Python script

# run python selenium script
$ python -B ~/Projects/Selenium/example.py

# create 2 instances (Version: 1)
$ docker-compose -f v1-docker-compose.yml scale node_1=2
 
# create 3 instances (Version: 2)
$ docker-compose -f v2-docker-compose.yml scale node_2=3