To gain a better understanding of specific CI/CD and its relationship with design patterns, it is important to first understand the origin of design patterns and get an overview of the various types that are available. This will help you to understand the purpose and usage of design patterns in general.

Design patterns are general, reusable solutions to common problems that occur during the design and development of software. They represent best practices to solve specific types of issues and provide developers with a way to communicate effective design solutions. These patterns contain the best practices that have evolved over time by experienced software developers to address specific challenges in designing robust, maintainable, and scalable software systems.

The book Design Patterns – Elements of Reusable Object-Oriented Software, published in 1994 by four authors known as the Gang of Four, popularized the term design patterns. However...

In this section, we will explore the basics of design patterns in general, which gives you a good foundation for the following sections of this chapter, where we will focus more on the CI/CD part of design patterns.

Design patterns can help enforce CI/CD pipelines by providing guidance on how to structure code, manage dependencies, handle errors, and perform software testing. Design patterns and CI/CD serve the same purpose of improving the efficiency and quality of software development. For example, the adapter pattern can be used to combine different tools or services in the pipeline, the Observer pattern can be used to notify various stakeholders of the pipeline status, and the Strategy pattern can be used to encapsulate different deployment algorithms, such as blue-green, canary, or rolling, and select them at runtime.

Conversely, CI/CD may also influence the selection of design patterns by imposing specific code constraints or requirements...

In this section, we will start with the basic definition and purpose of CI/CD, and their related processes, practices, and tools. The most widely referred definition of CD is provided by Jez Humble (and can be found at https://continuousdelivery.com/):

“Continuous Delivery is the ability to get the changes of all types of new features, config changes, bug fixes, and experiments into production or into the hands of the user safely and quickly in a sustainable way.”

According to the CD Foundation, continuous integration is defined as follows (which can be found at https://bestpractices.cd.foundation/learn/ci/):

“Continuous Integration, the CI in CI/CD, is the practice of combining code changes frequently where each change is verified on check-in.”

Over time, CI/CD practices and their application have evolved, providing practitioner tools to implement CI/CD efficiently. The evolution has also resulted in exponential...

In this section, we will discuss the next step after deployment approaches, which is introducing the building blocks for the CI/CD design pattern. We will focus on the crucial aspects of design patterns, which are associated with pipelines and infrastructures. We will do this while keeping in mind the implementations discussed in the Understanding CI/CD and design patterns section. It’s important to understand that design patterns are reusable solutions that help software developers solve common programming problems. These patterns make it easier to write code that can be maintained, extended, and tested effectively.

Let’s outline the key components of the CI/CD design patterns:

• Pipelines: These are a series of steps that process data to convert raw input into meaningful output. Design patterns such as the Chain of Responsibility, Iterator, Pipeline, and Pipes and Filters can be used...

Deployment strategies are a set of practices and methods that are used to deliver software to different environments, such as development, testing, staging, and production, with minimal downtime and risk. The advantages and disadvantages of different deployment strategies depend on the type, complexity, and requirements of the software. CI/CD processes can improve software delivery in terms of quality, reliability, and efficiency, as they ensure that code meets the required standards and requirements before it is released. This section discusses some common deployment strategies.

Rolling deployments

Rolling deployments are a strategy for updating software applications without causing downtime or disrupting the user experience. They involve gradually replacing the old version of the application with the new one, usually by deploying the update to a subset of servers or users at a time. This way, if there are any issues with the new version, they can be...

In this chapter, we introduced the concept of CI/CD design patterns and their benefits in designing and developing reliable, efficient, and adaptable software systems. These patterns require a shift in mindset from traditional software development approaches, as they are not just technical solutions but also cultural and operational ones. CI/CD design patterns have evolved over time, influenced by software engineering principles, agile methodologies, DevOps practices, and cloud computing.

By applying these patterns, we can achieve faster feedback loops, higher quality standards, lower costs, improved collaboration, and continuous innovation. These benefits enable us to deliver value to our customers and stakeholders more frequently and effectively, while also ensuring that our software systems are secure, scalable, and resilient.

This chapter has set the context for the rest of the book, where we will explore specific CI/CD design patterns that can help address common...

Here, you can find the sources to expand your knowledge about the specific concepts in this chapter:

• Design Patterns – Elements of Reusable Object-Oriented Software (1994) by Erich Gamma, Richard Helm, Ralph Johnson, John Vlissides.
• A Pattern Language (1977) by Christopher Alexander.
• Continuous Delivery – Reliable Software Releases through Build, Test, and Deployment Automation (2010) by Jez Humble and David Farley.
• Strategizing Continuous Delivery in the Cloud (2023) by Garima Bajpai and Thomas Schuetz.