In this section, we will try to answer what CI is in two basic steps. We will first attempt to define CI, and then examine its key principles.

Defining continuous integration

CI is a software development practice in which developers regularly integrate their code changes into the project’s shared work area and inspect their changes for build issues and other quality-related problems.

Integration is the act of submitting your modified code to the project’s main branch (the potential software solution). This is technically done by merging your feature branch to the main branch in a trunk-based development (a Git-based branching strategy) and, additionally, by merging the feature branch into the development branch in a Gitflow Workflow-based development (another Git-based branching strategy), as shown in the following figure:

Figure 1.1: The process of frequently integrating your changes with the main code...

To understand how CI is practiced, you must first realize that it is a constantly evolving ecosystem of tools and technologies, and this section will go through most of them. At the end of this part, it will be obvious how these separate components and their associated tools contribute to the realization of the core concepts of CI outlined previously. Besides, the subsequent chapters of the book are a detailed, thorough elaboration on the practices presented here. As a result, the current section is crucial.

The topics discussed in the following sections are structured sequentially and in accordance with the various stages of an automated CI pipeline:

Figure 1.5: Various stages of a CI pipeline

So, let’s start with the first and foremost aspect of CI: the version control system.

Using a version control tool

A version control system helps the team in controlling changes to the project’s source...

The answer is straightforward: CI practices are critical because they enable teams to fulfill modern software development demands. But what are these demands, what benefits of CI help fulfill these demands, and how do they do so? This is what we'll look at in this section.

A faster time to market (TTM)

Also known as lead time or time to delivery, TTM is the time it takes a feature to get from its origin (typically a code change) to deployment in production. A higher TTM number indicates that features are being developed, tested, and delivered more slowly and infrequently. Most current software programs and services need more frequent software upgrades. So, let’s see some advantages of CI/CD that help achieve a lower TTM value:

Figure 1.12: Time to market (TTM)

Freedom from long integration – avoiding tolls

CI advocates for regular integration of your work with the main code. This method...

We began this chapter by studying the basics of CI and understanding its main principles. This was followed by a discussion of the numerous practices promoted by CI, as well as a look at the CI ecosystem of DevOps tools such as SonarQube, Git, and Artifactory. Finally, we learned how CI assists us in meeting the needs of modern software development. We learned a lot about several crucial CI/CD metrics that are used to assess the performance of CI and the productivity of software development while doing so. This taught us the what, how, and most importantly the why of CI.

The subsequent chapters of the book offer a practical step-by-step guide to the how of CI, that is, how to implement CI. And now that the concepts are clear, let’s start the very next chapter by learning how to set up and configure a Jenkins server.

1. Which of the following best defines continuous integration (CI)?
   1. A software development practice that advocates the integration of code changes into a shared repository, enabling frequent testing and early detection of integration issues
   2. A methodology for deploying software frequently and reliably, ensuring that new features and updates are delivered to users quickly and seamlessly
   3. A tool or platform that provides a centralized environment for managing code changes, builds, and tests, facilitating collaboration among developers
   4. A mindset and set of practices that emphasize continuous improvement, rapid feedback, and the delivery of high-quality software in short cycles
2. Which of the following best describes the concept of fail fast and shift left in software development?
   1. Identifying and fixing bugs early in the development process to minimize their impact and reduce costs
   2. Releasing software frequently with minimal testing to ensure rapid delivery and market responsiveness...

1. Correct answer: A

   Explanation of incorrect answer choices:

   B. While CI is often associated with CD, CI’s primary focus is on automating the integration and testing of code changes, not on the deployment process. CD, on the other hand, deals with automating the deployment of software to the staging and production environments.

   C. CI tools and platforms are essential to implementing a CI practice, but they are not the defining characteristics of CI. CI is a broader concept that encompasses the practices, principles, and mindset of integrating code changes frequently and automating testing to ensure early detection of issues.

   D. While CI does promote continuous improvement, rapid feedback, and the delivery of high-quality software, these are not the primary goals of CI.

2. Correct answer: A

   Explanation of incorrect answer choices:

   B. While releasing software frequently is a goal of many development teams, it should not come at the expense of thorough testing and bug fixing...

If you wish to know more about some of the concepts that weren’t covered in depth in this chapter, we are happy to provide you with some references:

• [1] TED: How great leaders inspire action | Simon Sinek: https://www.ted.com/talks/simon_sinek_how_great_leaders_inspire_action
• [2] Static code analysis; Metric definitions | SonarQube: https://docs.sonarqube.org/latest/user-guide/metric-definitions/
• [3] Rules Overview: | SonarQube: https://docs.sonarqube.org/9.7/user-guide/rules/overview/
• [4] DevSecOps Periodic Table: https://digital.ai/learn/devsecops-periodic-table/
• [5] Why every company needs to think like a tech company | Vation Ventures: https://www.vationventures.com/blog/thinking-like-a-tech-company