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What is Continuous Integration (CI) in software engineering and what benefits does it bring to an in-house and dedicated development team setting? In this article, we'll try to shed some light on this fundamental concept that can be used to improve software delivery.
In case you don't know what Continuous Integration actually is, or how it works, let's start with a brief introduction to the concept.
In software development, Continuous Integration (CI) is the process of integrating code into a shared repository and automatically testing one’s software. This is done multiple times a day with the help of a version control system (VCS).
The term "Continuous Integration" was introduced in 1997 by Extreme Programming creator Kent Beck, a renowned software engineer and co-signatory of the Agile manifesto.
Why should you adopt CI?
When properly implemented, Continuous Integration is able to detect any problems in the code before they ever have the chance to manifest, making software systems a lot more secure and providing a number of other advantages as well.
For instance, because integration occurs so frequently, a significant amount of time is saved, which allows developers to increase their focus on delivering features.
Continuous Integration: a Part of the CI/CD System
Paired with Continuous Delivery (CD), Continuous Integration is particularly helpful, as the combined practices of CI/CD make up the essential components of DevOps.
Continuous Delivery
With developers continually testing software (CI), it becomes theoretically possible to release your product at any time. This is Continuous Delivery in a nutshell, as it aims to keep the code in a release-ready state. Of course, this does not mean that a new product version will be released every day, but it does imply that — if necessary, at least — that could indeed be done at any moment.
Continuous Deployment
Now onto the exciting part! Once both CI/CD practices are in place, you can finally start delivering code changes (i.e features and improvements) as soon as these are ready for release. This is meant by "Continuous Deployment" (CDb), a practice that builds upon Continuous Delivery and Integration to deliver their fully realized potential.
CDb has become particularly prevalent in the cloud, as DevOps specialists can update their services at the touch of a button, without ever bothering users in the slightest. In fact, Netflix reportedly releases new code thousands of times each day, while Amazon is said to do the same every 11 seconds.
Without a doubt, companies embracing CI/CD — and Continuous Deployment especially — are empowered to deliver quality features at unprecedented speeds.
What are the benefits of Continuous Integration?
So now that we’ve covered both Continuous Delivery and Deployment, what are the advantages of Continuous Integration specifically?
Enable collaboration
Beyond improving communication amongst software developers, CI and DevOps enable collaborative programming. After all, when integrating code into the main database, a so-called "pull request" is generated, allowing developers to not only visualize but also comment on their team members’ code.
Reduce expenses
Particularly with a Time and Materials Contract (T&M), hiring developers can often be rather costly. Yet thankfully, by automating tests through Continuous Integration, we release features a lot faster than expected. This not only should be appreciated by end users, but also by your company as a whole, as it could help bring down expenses considerably.
Help make better decisions
Finally, Continuous Integration enables product teams to iterate and test designs faster than ever before, as any changes that are tentatively released may be quickly evaluated by their target audiences. In practice, if your users are dissatisfied with your latest iteration, you can easily roll back the changes as if they’d never taken place to begin with! This makes users the ultimate arbiters, which by extension leads to better business decisions.
Improve Development Process and QA
Of course, things weren’t always this straightforward and simple. Prior to the advent of Continuous Integration, it was not unusual at all for different company departments to work in silos, making communication unnecessarily complex and clunky. This not only resulted in slower releases but also in much higher failure rates. As a result, CI is often considered indispensable for Quality Assurance and the wider development process.
Top Popular CI Tools
Here's a list of some popular tools that can help you implement Continuous Integration in your existing software development processes.
Jenkins
Jenkins is an open-source CI tool that is able to run tests, create builds and carry out repetitive tasks. Owing to its uncomplicated installation and configuration process, Jenkins is one of the most popular CI/CD solutions today. The tool can also be enhanced with plugins that offer countless options for Continuous Deployment.
TeamCity
TeamCity is a general-purpose CI/CD platform enabling greater collaboration and customizable workflows. A true veteran of DevOps, it essentially acts as a server for build management and Continuous Integration. TeamCity is available under proprietary and open-source licenses, depending on your company’s project.
Azure
Cloud computing platform Microsoft Azure provides their own Azure Pipelines service which supports CI/CD for all main platforms (Linux, Windows and macOS). The service is incredibly user-friendly and useful, offering analytics, categorized tasks, and an intuitive user interface to boot. It also includes the Azure DevOps Marketplace, where further extensions may be evaluated and purchased.
Conclusions
In the end, the importance of CI/CD in web development cannot be overstated, but if you’re still left wondering “what is CI?” or why Continuous Integration even exists, let’s turn to Hollywood for further clarification: in the American sci-fi film Minority Report, the character played by Tom Cruise worked for a specialized police department that, with the help of psychic beings known as "precogs," was able to arrest offenders before a crime was even committed.
In a similar fashion, by implementing CI and DevOps — or partnering with a software development company that can do this for you — you empower your organization’s web developers with the ability to spot "pre-bugs," stopping code errors in their tracks so no bug will see the light of day.
(Header illustration courtesy of Henry & Co.)
