Registering Appium Nodes to the Grid Hub

To integrate Appium nodes with a Selenium Grid Hub, you must define node configurations in JSON format. When running multiple Appium instances on a single host, each instance requires its own port and corresponding configuration file.

Use the following command to launch an Appium node, ensuring you specify unique ports for multiple instances:

appium -p 5723 --nodeconfig node_config_02.json

The configuration file (e.g., node_config_02.json) should be structured as follows:

{
 "capabilities": [
   {
     "browserName": "android",
     "version": "7.0",
     "maxInstances": 1,
     "platform": "ANDROID"
   }
 ],
 "configuration": {
   "cleanUpCycle": 2000,
   "timeout": 30000,
   "proxy": "org.openqa.grid.selenium.proxy.DefaultRemoteProxy",
   "url": "http://127.0.0.1:5723/wd/hub",
   "host": "127.0.0.1",
   "port": 5723,
   "maxSession": 1,
   "register": true,
   "registerCycle": 5000,
   "hubPort": 4444,
   "hubHost": "192.168.31.69",
   "hubProtocol": "http"
 }
}

Managing Multiple Devices and Emulators

When executing tests across multiple emulators or real devices, it is crtiical to target the specific device using the -s flag with the adb utility:

adb -s emulator-5554 shell am start -n com.example.app/.MainActivity

In your test scripts, replace the direct Appium server URL with the Grid Hub address. Use the udid capability to ensure the test is routed to the corect device:

import os
from appium import webdriver

class TestMobileGrid:
   def setup_method(self):
       options = {
           'platformName': 'Android',
           'platformVersion': '6.0',
           'appPackage': 'com.example.app',
           'appActivity': '.MainActivity',
           'udid': os.getenv('TARGET_UDID')
       }
       self.driver = webdriver.Remote('http://192.168.31.69:4444/wd/hub', options)
       self.driver.implicitly_wait(10)

   def teardown_method(self):
       self.driver.quit()

   def test_search_functionality(self):
       self.driver.find_element_by_id('search_bar').click()
       self.driver.find_element_by_id('input_field').send_keys('Keyword')
       self.driver.find_element_by_xpath("//*[@text='Keyword']").click()

Parallel Execution with Shell Scripts

To trigger tests across all connected devices simultaneously, you can automate the process using a shell script. The & operator allows for background, concurrent execution:

#!/bin/bash
for device_id in $(adb devices | grep "device$" | awk '{print $1}')
do
   echo "Launching test on: ${device_id}"
   TARGET_UDID=$device_id pytest test_suite.py &
done

Key Considerations:

• Session Cleanup: Always include driver.quit() in your teardown methods. Failing to close sessions will keep nodes occupied, preventing them from accepting new tasks from the Hub.
• Routing: The Hub acts as a proxy; ensure your script points to the Hub's IP/port, not the local Appium server.
• Device Targeting: When multiple devices share the same version, the udid parameter takes precedence over platformVersion or deviceName for ensuring test isolation.