Continuous Integration (CI): the most important things to know about continuous integration
Continuous integration helps development teams to be more productive and improve the overall quality of the code. With Continuous Integration (CI), developers regularly integrate their code changes into a central database, after which automatic build and test processes run. In this article, we'll show you what you need to know about continuous integration, how it works, its benefits and best practices.
What is Continuous Integration (CI)?
Continuous Integration (CI) is a DevOps software development practice. It is a modern, valuable and well-established method of automated integration of code changes, where multiple contributors combine their work into a single software project where build and test processes are run. Automated tools ensure the correctness of the new code before integration.
Why is Continuous Integration important and what is its purpose?
Previously, team developers worked in isolation for long periods of time, and only integrated changes into the master branch when they had finished their work. This made merging code changes difficult and time-consuming, and led to bugs accumulating for long periods without being fixed. This also hampered the release of rapid updates to customers.
Continuous Integration allows software developers to work on features in parallel. When they are ready to integrate code into the final product, they can do so independently and quickly.
One of the key objectives of continuous integration is:
- detect and correct errors faster
- improving the quality of software
- reduce the validation and release time of new software updates
How does continuous integration work?
CI is usually used in conjunction with an agile software development workflow. The organisation puts together the tasks that make up the roadmap for a product. These tasks are distributed among the members of the software development team.
By facilitating continuous integration, software development tasks are done independently of each other. Developers write to a common repository using a version control system such as Git. Before each commit, developers may choose to run local unit tests on their code as an extra layer of verification before integration. The continuous integration service automatically builds and runs unit tests on new code changes to immediately surface any bugs.
With continuous delivery, code changes are automatically built, tested and released to the production environment. Continuous delivery extends continuous integration by deploying all code changes to a test and/or production environment after the build phase.
The benefits of Continuous Integration
The benefits of CI are not limited to engineering teams, but are shared by the whole organisation. Continuous integration provides greater transparency and insight into the software development and delivery process. These benefits enable the rest of the organisation to plan better and execute their go-to-market strategy more effectively.
Helps scaling
Continuous Integration enables organisations to scale their engineering teams, code base and infrastructure. It helps build DevOps and agile workflows by minimizing code integration bureaucracy and communication overhead. It enables all team members to take ownership of a new code change all the way to release.
Faster feedback
Product teams can test ideas and iterate product designs faster with an optimised CI platform. They can make and measure changes faster to ensure success.
Better communication
CI improves engineering communication and accountability, enabling better collaboration between development and operations in the DevOps team.
Best practices for continuous integration
To increase the efficiency and reliability of Continuous Intergration, it is important to apply some best practices.
Frequent and early code addition
It is always easier to fix small problems than big ones. One of the biggest benefits of continuous integration is that code is integrated with other changes in a shared repository at the same time. If the development team adds code changes early and often, bugs are easier to identify because there is less code to review.
Testing in smaller batches improves code quality and allows teams to iterate more efficiently.
Read the documentation
Continuous integration systems make documentation widely available, which can be very useful in the long term. It is important to update these frequently to reflect the latest processes and to help new team members.
It is worth referring to the documentation in README files or other accessible formats.
Optimisation of pipeline stages
CI pipelines contain tasks and stages. Tasks are the activities within a given stage. If all tasks are successful, the code moves to the next stage. To increase the efficiency of CI pipelines, it is essential to optimize the stages so that errors can be easily identified and corrected.
Quick and easy builds
Nothing slows down the pipeline more than when it's complicated. It's worth focusing on making builds fast and simple, because every minute saved by reducing build times is time saved for programmers for each commit that adds up.
According to Martin Fowler, the ten-minute build guideline is a good target that most modern projects can achieve.
Using errors to improve processes
When teams change their responses to mistakes, it promotes continuous improvement and cultural change. Instead of asking who caused the mistake, it is more important to look at what is responsible for the mistake. This shift in perspective means moving from a culture of blame to a culture of learning.
If teams commit frequently, it is much easier to identify and solve problems. If there are patterns of bad builds, the root causes need to be investigated. For example, are there non-code bugs that are causing build errors unnecessarily? You may need to include an allow_failure parameter. It's important to pay attention to fixing processes regularly, handling errors without blame, and finding the causes - not the culprits.
The test environment should reflect the production environment
In continuous integration, each commit starts a build. These builds run tests to identify if something is not correct due to new code changes. The test pyramid is a way for developers to balance testing. End-to-end testing is mostly used as a safety net, while unit testing is most often used to identify bugs.
It's important that the testing and production environments match, because this ensures that developers can trust the results and deploy with confidence.
Continuous integration helps developers deploy faster and get feedback in a short time.
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