'Connection refused! Is selenium server started?\n' while running Nightwatch.js tests against Selenium Grid - selenium

Question

I use Nightwatch-Cucumber based on Nightwatch.js to automate my tests. And now I want to use Selenium Grid with a Selenium hub and several Selenium nodes to execute my tests.
These are my current dependencies I actually use:
"devDependencies": {
"chromedriver": "2.37.0",
"cucumber": "3.0.2",
"geckodriver": "1.11.0",
"nightwatch": "0.9.19",
"nightwatch-cucumber": "9.0.0",
"selenium-server-standalone-jar": "3.9.1",
},
And this is my nightwatch.conf.js:
const config = {
globals_path: "globals.js",
output_folder: "reports",
custom_commands_path: "commands",
// custom_assertions_path: 'assertions',
live_output: false,
page_objects_path: "pageobjects",
disable_colors: false,
selenium: {
start_process: true,
server_path: seleniumServer.path,
host: "127.0.0.1",
port: 4444
},
test_settings: {
default: {
launch_url: "http://mywebsite.com"
},
firefox_grid: {
selenium_host: "127.0.0.1",
selenium_port: 4444,
desiredCapabilities: {
browserName: "firefox"
}
selenium: {
start_process: false
}
}
}
};
module.exports = config;
So, and these are the steps I executed to realize everything:
1. Start the Selenium Hub on localhost
java -jar selenium-server-standalone-3.9.1.jar -port 4444 -role hub
2. Start the Selenium Node on localhost
java -jar selenium-server-standalone-3.9.1.jar -port 5555 -role node
3. Start the Nightwatch tests
./node_modules/.bin/nightwatch --env firefox_grid --tag=myCucumberTag
Current result:
I get an error while executing the Nightwatch tests and I don't know why. It looks like this:
{ Error: Unhandled "error" event. ([object Object])
at ClientManager.emit (events.js:185:19)
at Nightwatch.<anonymous> (/Users/GRme/projects/Aservo/DP/lcm2/testautomation/end2end-web-tests/node_modules/nightwatch/lib/runner/clientmanager.js:68:10)
at Object.onceWrapper (events.js:316:30)
at emitOne (events.js:115:13)
at Nightwatch.emit (events.js:210:7)
at HttpRequest.<anonymous> (/Users/GRme/projects/Aservo/DP/lcm2/testautomation/end2end-web-tests/node_modules/nightwatch/lib/index.js:501:10)
at emitThree (events.js:135:13)
at HttpRequest.emit (events.js:216:7)
at IncomingMessage.<anonymous> (/Users/GRme/projects/Aservo/DP/lcm2/testautomation/end2end-web-tests/node_modules/nightwatch/lib/http/request.js:172:16)
at emitNone (events.js:110:20)
at IncomingMessage.emit (events.js:207:7)
at endReadableNT (_stream_readable.js:1057:12)
at _combinedTickCallback (internal/process/next_tick.js:138:11)
at process._tickCallback (internal/process/next_tick.js:180:9)
context:
{ message: 'Connection refused! Is selenium server started?\n',
data: { value: [Object], status: 33 } } }
The request to the Selenium hub seems to be successful from Nightwatch:
21:50:52.393 INFO - Got a request to create a new session: Capabilities {acceptSslCerts: true, browserName: chrome, javascriptEnabled: true}
21:50:52.399 INFO - Trying to create a new session on test slot {seleniumProtocol=WebDriver, se:CONFIG_UUID=037e48a7-b5bc-44f2-a25b-e85c752095a7, browserName=chrome, maxInstances=5, platformName=MAC, platform=MAC}
And the request also was navigated to the Selenium node:
2018-05-03 21:50:52.418:INFO:osjshC.ROOT:qtp1300393335-22: org.openqa.selenium.remote.server.WebDriverServlet-49d904ec: Initialising WebDriverServlet
21:50:52.450 INFO - Found handler: org.openqa.selenium.remote.server.commandhandler.BeginSession#31a65f95
21:50:52.454 INFO - /session: Executing POST on /session (handler: BeginSession)
21:50:52.546 INFO - Capabilities are: Capabilities {acceptSslCerts: true, browserName: chrome, javascriptEnabled: true}
21:50:52.548 INFO - Capabilities {acceptSslCerts: true, browserName: chrome, javascriptEnabled: true} matched class org.openqa.selenium.remote.server.ServicedSession$Factory (provider: org.openqa.selenium.chrome.ChromeDriverService)
So, what I'm doing wrong and how can I fix it? Is it maybe a problem with the Nightwatch.js and/or Selenium Server Standalone Version?

Answer 1

This error message...
message: 'Connection refused!
...implies that the Selenium Grid Node was unable to initiate/spawn a new WebClient i.e. Web Browsing session.
Your main issue is in the command being used to start / initialize Selenium Grid Node. The Selenium Grid Node should be started with the desired WebDriver variant as an argument as follows :
Start the Selenium Grid Hub (default on port 4444):
java -jar selenium-server-standalone-3.9.1.jar -role hub
Start the Selenium Grid Node (default on port 5555):
java -Dwebdriver.chrome.driver=C:/path/to/chromedriver.exe -jar selenium-server-standalone-3.9.1.jar -role node -hub http://localhost:4444/grid/register
You can find a similar detailed discussion in Connection refused! Is selenium server started nightwatch on edge