Introducing the Hats for Cats web app
Hats for Cats is a pretend web app for selling baseball caps, cowboy hats, and bowlers for your favorite furry friends. Imagine that it’s a standard online store like hundreds or thousands of others that you’ve used. It lets people browse through the catalog of hats, put items in a shopping cart, and enter billing and shipping information.
The user experience or graphic design of Hats for Cats doesn’t matter for this book. The web app framework that it’s based on doesn’t matter. Even the computer language that it’s written in doesn’t matter. I’ll say that again because it’s an important but possibly surprising point: this book is language-agnostic. It will include examples in several computer languages, to increase the chances that at least some of the examples are in a language that you’re familiar with. But whether your apps – or the Hats for Cats web app – are written in Java, JavaScript, Python, Ruby, or any other language doesn’t matter. The general GitLab CI/CD principles described in this book apply regardless.
What does matter are the general steps that you need to take to make sure the code is of high quality, behaves as expected, is secure, has adequate performance, is packaged sensibly, and is deployed to the right environments at the right times. This book focuses on how GitLab CI/CD pipelines can make various steps in the software development life cycle (SDLC) easier, faster, and more reliable. It won’t show you how to write the Hats for Cats web app. It will be assumed that all the coding happens behind the scenes, after which you’ll be shown how to build, verify, secure, package, and release that code.
With that in mind, let’s walk through the high-level steps that you’d need to follow to get your code ready for users, in a world before GitLab existed. These are all the manual equivalents of what GitLab CI/CD pipelines can do for you automatically. But understanding the limitations of the manual processes, and the pain and tedium involved with following them, will help you understand the real power of GitLab.
