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Continuous Integration: How It Works

It’s not rocket science, but it’s pretty close.

Continuous integration is a holistic method of quickly converting ideas into code by employing development and testing methodologies meant to improve communication and collaboration between team members and optimize the development process. A few hallmarks of continuous integration:

  • Shared repositories
  • Automatic integration
  • Frequent bug checks
  • Automated testing

Before we go over each of these these concepts, you should know that continuous integration is one of the most efficient development methods in use today. It generally allows for faster development, less redundant work, and fewer glitches in the code. Continuous integration lends itself very well to agile development strategies, which are focused on project evolution, early deployment, and flexible responses to change.

Now, let’s strap in and get down to the details of continuous integration.

Code Repositories

A repository is basically a single location that contains all of the source code for a software project. When using a shared repository like those hosted on Github, all of the code is accessible to all programmers involved, so everyone have a clear line of sight to their teammates. In projects using continuous integration, the repository is usually updated several times a day.

Integration

Every time a team member creates or updates a specific piece of code, he or she submits it to the shared repository. It might be a particular mircoservice, an API, or even an onboarding feature. A service called Integration watches the repository and reacts to changes. After detecting new code it pulls in the latest layer of changes and runs regression tests to make sure all systems are go.

Bug Testing

In this step, teams employ automated testing measures. Process automation runs code checks allowing teams to test code as a whole quickly and efficiently, without wasting man hours. They use “pipelines,” or set steps in a cascade of events that automatically test the code for bugs. The steps in any particular pipeline vary from team to team, but Ravello Systems has a good outline:

  1. Commit. When a developer finishes a change to an application, he or she commits it to a central source code repository.
  2. Build. The change is checked out from the repository and the software is built so that it can be run by a computer. This step depends a lot on what language is used and in interpreted languages this step can even be absent.
  3. Automated tests. This is where the meat of the CI/CD pipeline is. The change is tested from multiple angles to ensure it works and that it doesn’t break anything else.
  4. Deploy. The built version is deployed to production.

The fundamental benefit of continuous integration is that it removes sessions where people spend time hunting bugs where one person’s work has stepped on someone else’s work without either person realizing what happened. –Martin Fowler

These steps form a pipeline that allows code changes to be submitted and checked for feasibility against all the rest of the code in the repository and also ensures that the project as a whole works the way it should. This results in a project that is constantly evolving, reliably and measurably.

Flexibility

A client wants a new feature built in? Bugs have been reported by users? A few iterations later, the team can have updates ready. Why so many iterations (versions)? Constant integration of new sections of code with the overall source allows developers to check the holistic success of the project. With constant updating and testing of the shared repository, continuous integration allows teams to prepare software for the launchpad faster than ever before. Excelsior!

To find out more about how Cuttlesoft uses continuous integration to make development more efficient, visit cuttlesoft.com.