What is Continuous Integration and Why Do You Need It?
Continuous Integration (CI) is a developer's best friend, ensuring that code changes are regularly integrated and tested to keep your codebase in a stable and deployable state. The main goal of CI is to catch and fix issues early in the development process, which can save you time, effort, and headaches in the long run. It's like having a built-in safety net for your code!
The Benefits of Continuous Integration
Here are the top four benefits of using CI in your development process:
- Improved code quality: CI helps catch and fix issues early in the development process, which leads to higher overall code quality.
- Faster development: By catching and fixing issues early, CI can speed up development by reducing the amount of time and effort required to fix issues later on.
- Improved collaboration: Regular integration and testing of code changes can help improve collaboration among team members by providing a shared point of reference and helping to identify and resolve conflicts early on.
- Reduced risk: By catching and fixing issues early, CI can help reduce the risk of costly issues being introduced into the codebase later on.
Prerequisites for Continuous Integration
Before you can start using CI, you'll need a few things:
- A version control system: GIT - let’s ignore the others, shall we? 😀
- CI automated checks: automatically execute static analysis and run tests before accepting the code. If using branches, GitHub Actions can do this on the branch at every push - to do it locally before even pushing, use GIT hooks
- A deployment process: An automated process with all the steps used to deploy the codebase to a production or staging environment. Did someone already say GitHub Actions?
First Steps to Continuous Integration
Ready to get started with CI? Follow these three simple steps:
- Trust your tests: If you don't have tests, start adding them to the codebase. If you have them but don't trust them, work on improving them. Once you feel that having all green tests is enough to deploy safely, you are there!
- Learn how to write a pipeline: A simple way to start is by using GitHub to store your repository and GitHub Actions to write your pipeline. The web is full of documentation about them, you will learn very fast!
- Set up your first pipeline: Your first pipeline can be as simple as building the app, running tests, and deploying if everything is okay.
Once you've got your CI process up and running, the sky's the limit! You can start pushing to master as often as every five minutes, ensuring that your code is always in a deployable state.
Advanced Tips
Once you will start merging the code often, you might want to raise the bar even more and become a master - here is some topic you should look into:
- Test-Driven Development: TDD is a great way to have feedback on what is a deployable state; following the TDD cycle red-green-refactor, commit at every red and green, push after each refactor
- Feature Flags: if you keep using CI, sooner or later you will feel the need to go into production with a non-complete feature; use feature flags to hide unfinished features to the users are able to deploy them in production while working on it
- Feature Environment: being able to deploy a branch to a dedicated domain is a great feature, especially when using feature flags - imagine having the feature off everywhere and being able to turn it on in the feature environment to test it or demo it
Go Deeper
Here are some resources you can check if you want to go deeper and learn more about how to face fears thanks to Agile practices.
Books
- Continuous Integration: Improving Software Quality and Reducing Risk - the primary book on the topic by Martin Fowler
Online
- Continuous Integration - by Martin Fowler
- What is CI - by Atlassian blog