Selenium Docker

The project is made possible by volunteer contributors who have put in thousands of hours of their own time, and made the source code freely available under the Apache License 2.0.

Docker images for Selenium Standalone Server Hub and Node configurations with Chrome and Firefox


Images included:

• selenium/base: Base image which includes Java runtime and Selenium JAR file
• selenium/hub: Image for running a Selenium Grid Hub
• selenium/node-base: Base image for Selenium Grid Nodes which includes a virtual desktop environment and VNC support
• selenium/node-chrome: Selenium node with Chrome installed, needs to be connected to a Selenium Grid Hub
• selenium/node-firefox: Selenium node with Firefox installed, needs to be connected to a Selenium Grid Hub
• selenium/standalone-chrome: Selenium standalone with Chrome installed
• selenium/standalone-firefox: Selenium standalone with Firefox installed
• selenium/standalone-chrome-debug: Selenium standalone with Chrome installed and runs a VNC server
• selenium/standalone-firefox-debug: Selenium standalone with Firefox installed and runs a VNC server
• selenium/node-chrome-debug: Selenium node with Chrome installed and runs a VNC server, needs to be connected to a Selenium Grid Hub
• selenium/node-firefox-debug: Selenium node with Firefox installed and runs a VNC server, needs to be connected to a Selenium Grid Hub

Running the images

When executing docker run for an image with chrome browser please add volume mount -v /dev/shm:/dev/shm to use the host's shared memory.

$ docker run -d -p 4444:4444 -v /dev/shm:/dev/shm selenium/standalone-chrome:2.48.2

This is a workaround to node-chrome crash in docker container issue: https://code.google.com/p/chromium/issues/detail?id=519952

Standalone Chrome and Firefox

$ docker run -d -p 4444:4444 selenium/standalone-chrome:2.48.2
# OR
$ docker run -d -p 4444:4444 selenium/standalone-firefox:2.48.2

Note: Only one standalone image can run on port 4444 at a time.

To inspect visually what the browser is doing use the standalone-chrome-debug or standalone-firefox-debug images. See Debugging section for details.

Selenium Grid Hub

$ docker run -d -p 4444:4444 --name selenium-hub selenium/hub:2.48.2

Chrome and Firefox Grid Nodes

$ docker run -d --link selenium-hub:hub selenium/node-chrome:2.48.2
$ docker run -d --link selenium-hub:hub selenium/node-firefox:2.48.2

JAVA_OPTS Java Environment Options

You can pass JAVA_OPTS environment variable to java process.

$ docker run -d -p 4444:4444 -e JAVA_OPTS=-Xmx512m --name selenium-hub selenium/hub:2.48.2

SE_OPTS Selenium Configuration Options

You can pass SE_OPTS variable with additional commandline parameters for starting a hub or a node.

$ docker run -d -p 4444:4444 -e SE_OPTS=-debug --name selenium-hub selenium/hub:2.48.2

Building the images

Ensure you have the ubuntu:15.04 base image downloaded, this step is optional since Docker takes care of downloading the parent base image automatically.

$ docker pull ubuntu:15.04

Clone the repo and from the project directory root you can build everything by running:

$ VERSION=local make build

If you need to configure environment variable in order to build the image (http proxy for instance), simply set an environment variable BUILD_ARGS that contains the additional variables to pass to the docker context (this will only work with docker >= 1.9)

$ BUILD_ARGS="--build-arg http_proxy=http://acme:3128 --build-arg https_proxy=http://acme:3128" make build

Note: Omitting VERSION=local will build the images with the current version number thus overwriting the images downloaded from Docker Hub.

Using the images

Example: Spawn a container for testing in Chrome:

$ docker run -d --name selenium-hub -p 4444:4444 selenium/hub:2.48.2
$ CH=$(docker run --rm --name=ch \
    --link selenium-hub:hub -v /e2e/uploads:/e2e/uploads \
    selenium/node-chrome:2.48.2)

Note: -v /e2e/uploads:/e2e/uploads is optional in case you are testing browser uploads on your web app you will probably need to share a directory for this.

Example: Spawn a container for testing in Firefox:

This command line is the same as for Chrome. Remember that the Selenium running container is able to launch either Chrome or Firefox, the idea around having 2 separate containers, one for each browser is for convenience plus avoiding certain :focus issues your web app may encounter during end-to-end test automation.

$ docker run -d --name selenium-hub -p 4444:4444 selenium/hub:2.48.2
$ FF=$(docker run --rm --name=fx \
    --link selenium-hub:hub -v /e2e/uploads:/e2e/uploads \
    selenium/node-firefox:2.48.2)

Note: Since a Docker container is not meant to preserve state and spawning a new one takes less than 3 seconds you will likely want to remove containers after each end-to-end test with --rm command. You need to think of your Docker containers as single processes, not as running virtual machines, in case you are familiar with Vagrant.

Debugging

In the event you wish to visually see what the browser is doing you will want to run the debug variant of node or standalone images:

$ docker run -d -P --link selenium-hub:hub selenium/node-chrome-debug:2.48.2
$ docker run -d -P --link selenium-hub:hub selenium/node-firefox-debug:2.48.2

And for standalone:

$ docker run -d -p 4444:4444 selenium/standalone-chrome-debug:2.48.2
# OR
$ docker run -d -p 4444:4444 selenium/standalone-firefox-debug:2.48.2

You can acquire the port that the VNC server is exposed to by running:

$ docker port <container-name|container-id> 5900
#=> 0.0.0.0:49338

In case you have RealVNC binary vnc in your path, you can always take a look, view only to avoid messing around your tests with an unintended mouse click or keyboard interrupt:

$ ./bin/vncview 127.0.0.1:49160

If you are running Boot2Docker on OS X then you already have a VNC client built-in. You can connect by entering vnc://<boot2docker-ip>:49160 in Safari or Alfred.

When you are prompted for the password it is secret. If you wish to change this then you should either change it in the /NodeBase/Dockerfile and build the images yourself, or you can define a Docker image that derives from the posted ones which reconfigures it:

#FROM selenium/node-chrome-debug:2.48.2
#FROM selenium/node-firefox-debug:2.48.2
#Choose the FROM statement that works for you.

RUN x11vnc -storepasswd <your-password-here> /home/seluser/.vnc/passwd

Look around

$ docker images
#=>
REPOSITORY                      TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
selenium/node-firefox           2.48.2              69f762d0d79e        29 minutes ago      552.1 MB
selenium/node-chrome            2.48.2              9dd73160660b        30 minutes ago      723.6 MB
selenium/node-base              2.48.2              1b7a0b7024b1        32 minutes ago      426.1 MB
selenium/hub                    2.48.2              2570bbb98229        33 minutes ago      394.4 MB
selenium/base                   2.48.2              33478d455dab        33 minutes ago      362.6 MB
ubuntu                          15.04               013f3d01d247        6 days ago          131.4 MB

Troubleshooting

All output is sent to stdout so it can be inspected by running:

$ docker logs -f <container-id|container-name>