Continuous Delivery in Java

Chapter 9. Continuous Integration: The First Steps in Creating a Build Pipeline

In this chapter, you will learn how to implement continuous integration (CI). You will learn why CI is important, and then explore the fundamental topic of version control systems (VCSs). You will also learn the basics of the Git-distributed VCS, and how best to organize your team to work with this tool. The topic of code reviewing can be challenging, but you will also explore some of the core benefits of doing this, along with a guide on how to get started. The final topic you will explore in this chapter is automating CI builds.

Why Continuous Integration?

Continuous integration (CI) is the practice of frequently integrating your new or changed code with the existing code repository, merging all working copies to a shared mainline or trunk regularly. The use of the word “regularly” here is open to interpretation, but to truly practice CI, this should be several times a day. A well-accepted best practice is to trigger code builds upon every commit made to a shared code repository, and to schedule a regular “nightly” build in order to catch any integration issues within externally modified systems or issues outside our control (e.g., a new security vulnerability being found within one of your dependencies).

The main aim of CI is to prevent integration problems, referred to as integration hell in early descriptions of extreme programming (XP), which is recognizable to many developers. In XP, CI was ...