- An Introduction to Using Selenium-Docker Containers for End-to-End Testing
- How to Use Selenium and Docker to Scrape and Test Websites
- Callum Taylor
- Install Docker Toolbox on Windows
- What is Zalenium? Docker based Selenium Grid
An Introduction to Using Selenium-Docker Containers for End-to-End TestingIt used to be that in order to get your Selenium tests running on a given machine you had to install each individual browser and then the browser drivers for instance ChromeDriver for Chrome. Some of my most popular posts are about installing these drivers. Simply download and run a single Docker container with both the the browser and the driver pre-installed. Instead you get a command line to run and debug your tests. The upside is we can manage the installation and running of the browsers and drivers in an easier way. In this exercise we will download a single standalone Chrome browser with ChromeDriver already configured. Then we will simply run a test! When we save our file and run it e. There you go! We managed to install a container with both Chrome and ChromeDriver installed on it and then wrote and ran a test to demonstrate it works. After having done this half a dozen times I think it has huge advantages over the old ways link to Installing ChromeDriver on macOS. Press Enter. The Old Way It used to be that in order to get your Selenium tests running on a given machine you had to install each individual browser and then the browser drivers for instance ChromeDriver for Chrome. Problem solved! Docker Desktop and Container Installation: In this exercise we will download a single standalone Chrome browser with ChromeDriver already configured. We will use this later in our test file.
How to Use Selenium and Docker to Scrape and Test Websites
Posted by: jeato in Uncategorized 2 Comments. To help us accomplish this goal in a timely fashion, we employ a fleet of automated tests, running concurrently on a Selenium Grid. Selenium Grid is a great way to speed up your tests by running them in parallel on multiple machines. However, rolling your own grid also means maintaining it. Not to mention troubleshooting when something goes wrong on an individual node. God help you when it comes time to perform any updates. Sure, you could always go with third-party solutions like SauceLabs or BrowserStackbut these can be expensive to justify. It would also be great if we had a way to quickly recover in case an individual node crashes or otherwise ends up in a bad state. For the uninitiated, Docker is a lightweight container read: a scaled-down VM that provides a fast and programmatic way to run distributed applications. Selenium Grid is distributed system of nodes for running tests. Instead of running your grid across multiple machines or VMs, you can run them all on a single large machine using Docker. The two are practically destined for each other. Enter Docker Compose formerly known as Fig. This is what lets us take our Docker images and spin them up as a pre-configured Selenium Grid cluster. A huge benefit of using Docker is its capacity to scale. Running Selenium Grid on separate machines or even a set of VMs requires a lot of unnecessary computing overhead. Docker images run as userspace processes on a shared OS; so your images share some system resources, but are still isolated and require far fewer resources to run than a VM. This means you can cram more nodes into a single instance. Docker and Compose also take care of the networking for you! So if one of your nodes ends up in a bad state, rather than figuring out which node is wedged and digging through its logs looking for a clue you can just restart the entire grid. Luckily, both projects have great documentation on this topic:. The Grid is basically a single hub connected to any number of different nodes. So, our hub image should look something like this:. Finally, we need a single Dockerfile for all of our nodes. In this example, every node will be a copy of this Dockerfile. Because Selenium is often incompatible with the last 1 or 2 versions of Firefox. See the Selenium change log or their support policy for the most recently supported Firefox versions. For this reason, specifying a specific version of Firefox in our Dockerfile is a good rule of thumb:.
Selenoid is a powerful Golang implementation of original Selenium hub code. It is using Docker to launch browsers. Please refer to GitHub repository if you need source code. Download Configuration Manager Selenoid quick installation binary for your platform from releases page. We deliver ready to use images with Selenoid and Selenoid UI. Take a look at Cloud Platforms section for more details. If something does not work, you can easily check that Selenoid is running with opening status url:. This guide shows how to start Selenoid manually. When in doubt take a look at Configuration Manager first. This guide assumes you already know how to deal with command line and know basic Docker commands. All these images are free to use. See image tags for a list of supported versions. Build files are stored in selenoid-images repository. Feel free to create issues or request images for new versions. Complete list of browser images can be found in Browser Image information. These images support all UTF-8 locales. This can be important if you want to save files using national alphabet symbols. You can enable your preferred locale in browsers configuration file by setting respective environment variables:. Download binary for your operating system from releases page and save it as selenoid or selenoid. If you have Docker installed you can omit downloading binary and run it inside container. Prepare config, pull browser image, then run:. While we normally recommend to start Selenoid using Configuration Manager on any platform, it is possible to start it under Windows manually. The main difference from Unix operating systems is how volumes are mounted. Also start with forward slash and remove colon. We are very frequently asked whether it is possible to run Selenoid in Kubernetes cluster. The answer is - it is possible but we do not recommend doing this :. Selenoid can only work directly with Docker API and was created to be run on a workstation or a virtual machine with Docker installed. Kubernetes contrarily has a completely different API and can be using Docker as a container runtime backend. In some clusters rkt is used instead of Docker and in that case Selenoid will not work. Even if Selenoid works - all browser containers will be started on the same Kubernetes node where it is running. This is dangerous and can potentially lead to overloaded Kubernetes nodes. You can only have one Selenoid replica maximum. This is because Selenoid internally stores a list of running sessions in memory. If you need Selenium in Kubernetes or Openshiftwe have a separate solution called Moon. Selenoid outputs its logs to stdout. Selenoid launched as a binary should output logs to the screen. To see Selenoid logs launched as Docker container type:.
Install Docker Toolbox on Windows