Dan Čermák

Keeping the size of of your containers small is more important than ever, especially when distributing container images for others to build upon them. However, once multiple container layers get involved, even the data collection aspect becomes challenging and most existing tools do not primarily focus on visualization.

We will present a simple tool that we created for this: it is a simple web app that produces sunburst graphs for each layer of a container image and can thereby aid you in finding out where the size bloat comes from. Go and grab it from https://github.com/dcermak/container-layer-sizes and give it a spin yourself!

Contributions to Open Source Projects are always encouraged, especially from Newcomers and Non-coders. However, actually contributing as someone not familiar with the project, its workflows and its tools is usually everything but simple and requires a substantial time investment. This is especially the case if you are not a programmer or not as experienced with the technology in use, which can ultimately discourage otherwise potential willing contributors.

This talk will illustrate concrete steps that you, the maintainers of Open Source Projects, can undertake to simplify the hoops one has to jump through for their first contribution. We will cover various tools that you can use for this, be it for communication, localization, editing or publishing, how to provide good introductory material and how to build a welcoming atmosphere.

Visual Studio Code is an extremely popular editor and has a very rich ecosystem of extensions. However, testing these extensions is rather tricky in practice. Often extensions require external resources which have to be injected into the development environment. Unit tests are quite bad at testing the UI itself, as they require extensive setup code and a lot of mocking (= implementation of the production API in the testing environment that exposes the same interface). Checking the results of them still requires one to manually verify that the UI looks correct. All this combined can easily lead to false-positives and false-negatives. Integration tests on the other hand are not a silver bullet either as they can be rather brittle, slow, lengthy to write, hard to set up while also not being able to cover edge-cases very efficiently. This talk will focus on what we learned while developing the Open Build Service Connector: which testing strategies work, which don't and what tools to use. We will cover some viable approaches to unit testing and the vscode-extension-tester module that we used for integration tests.