How do you set up Selenium Grid using the docker images in GitLab-CI?

Question

Does anyone know how to configure the Selenium Docker images as services in GitLab-CI for running integration tests as part of a CI pipeline?

I'm testing a Django application, and I've set up the tests to connect to Selenium thus.

class SeleniumTestCase(LiveServerTestCase):
    host = os.environ.get('LIVE_TEST_CASE_HOST', os.environ('HOSTNAME'))

    @classmethod
    def setUpClass(cls):
        super().setUpClass()

        options = webdriver.FirefoxOptions()
        options.headless = True

        cls.browser = webdriver.Remote(
            'http://selenium:4444/wd/hub',
            webdriver.DesiredCapabilities.FIREFOX,
            options=options,
        )

I've configured the Selenium Docker images locally using docker-compose and it works great.

docker-compose.yml

selenium:
  image: selenium/hub:3.141.59-titanium

firefox:
  image: selenium/node-firefox:3.141.59-titanium
  volumes:
    - /dev/shm:/dev/shm
  depends_on:
    - selenium
  environment:
    - HUB_HOST=selenium
    - HUB_PORT=4444
    - START_XVFB=false

But when I try to create a similar configuration for GitLab-CI using a Docker executor, I get a WebDriverException.

.gitlab-ci.yml

test:
  stage: test
  image: $CMS_IMAGE_NAME
  variables:
    HUB_HOST: selenium
    HUB_PORT: 4444
    START_XVFB: 'false'
  services:
    - name: $DB_IMAGE_NAME
      alias: db
    - name: selenium/hub:3.141.59-titanium
      alias: selenium
    - name: selenium/node-firefox:3.141.59-titanium
  script:
    - export LIVE_TEST_CASE_HOST=$(ip addr show eth0 | grep inet | awk '{ print $2 }' | sed -En 's/^([^/]+)\/.*/\1/p'
    - cd /code
    - coverage run manage.py test

The $LIVE_TEST_CASE_HOST variable is just a way for me to make the IP address of the container in CI available for use as the host in the URLs used in my test cases. I've found that $HOSTNAME works locally in Docker, but not in CI for some reason. This configuration works if I drop selenium/hub and use selenium/standalone-firefox. But the above configuration causes the following exception.

selenium.common.exceptions.WebDriverException: Message: Error forwarding the new session Empty pool of VM for setup Capabilities {acceptInsecureCerts: true, browserName: firefox, marionette: true, moz:firefoxOptions: {args: [-headless]}}
Stacktrace:
    at org.openqa.grid.web.servlet.handler.RequestHandler.process (RequestHandler.java:118)
    at org.openqa.grid.web.servlet.DriverServlet.process (DriverServlet.java:85)
    at org.openqa.grid.web.servlet.DriverServlet.doPost (DriverServlet.java:69)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:707)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.seleniumhq.jetty9.servlet.ServletHolder.handle (ServletHolder.java:865)
    at org.seleniumhq.jetty9.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    at org.seleniumhq.jetty9.server.handler.ScopedHandler.handle (ScopedHandler.java:146)
    at org.seleniumhq.jetty9.security.SecurityHandler.handle (SecurityHandler.java:548)
    at org.seleniumhq.jetty9.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.seleniumhq.jetty9.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:257)
    at org.seleniumhq.jetty9.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.seleniumhq.jetty9.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:255)
    at org.seleniumhq.jetty9.server.handler.ContextHandler.doHandle (ContextHandler.java:1340)
    at org.seleniumhq.jetty9.server.handler.ScopedHandler.nextScope (ScopedHandler.java:203)
    at org.seleniumhq.jetty9.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.seleniumhq.jetty9.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.seleniumhq.jetty9.server.handler.ScopedHandler.nextScope (ScopedHandler.java:201)
    at org.seleniumhq.jetty9.server.handler.ContextHandler.doScope (ContextHandler.java:1242)
    at org.seleniumhq.jetty9.server.handler.ScopedHandler.handle (ScopedHandler.java:144)
    at org.seleniumhq.jetty9.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.seleniumhq.jetty9.server.Server.handle (Server.java:503)
    at org.seleniumhq.jetty9.server.HttpChannel.handle (HttpChannel.java:364)
    at org.seleniumhq.jetty9.server.HttpConnection.onFillable (HttpConnection.java:260)
    at org.seleniumhq.jetty9.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:305)
    at org.seleniumhq.jetty9.io.FillInterest.fillable (FillInterest.java:103)
    at org.seleniumhq.jetty9.io.ChannelEndPoint$2.run (ChannelEndPoint.java:118)
    at org.seleniumhq.jetty9.util.thread.strategy.EatWhatYouKill.runTask (EatWhatYouKill.java:333)
    at org.seleniumhq.jetty9.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:310)
    at org.seleniumhq.jetty9.util.thread.strategy.EatWhatYouKill.tryProduce (EatWhatYouKill.java:168)
    at org.seleniumhq.jetty9.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:126)
    at org.seleniumhq.jetty9.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:366)
    at org.seleniumhq.jetty9.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:765)
    at org.seleniumhq.jetty9.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:683)
    at java.lang.Thread.run (Thread.java:748)

I can't figure out why this works locally, but not in GitLab-CI.

How do you set up Selenium Grid using the docker images in GitLab-CI?

0 Answers0