What is Continuous Integration?
As engineers work on their parts of the code, their changes need to be regularly integrated with the changes their colleagues make. These integrations commonly lead to merge conflicts or test failures as incompatible changes are merged together. Fixing these issues can account for a significant chunk of engineering costs.
To reduce the cost of conflicts, DevOps engineers practice continuous integration by uploading the code they’re working on to a shared repository at least once a day—if not several times a day. Engineers are increasingly adopting continuous integration thanks to the success agile DevOps teams have enjoyed in recent years because they release software considerably faster than their slower-moving competitors.
Continuous integration grew out of the fact that much of development used to occur in isolation. Engineers would spend weeks or months writing code and then merge that code onto the master trunk when they were done, which typically led to massive complications. Not only did this slow down the organization’s ability to iterate, it also allowed minor bugs to persist—which ultimately made integration even harder.
Continuous integration allows teams to bypass this inefficiency, ensuring everyone stays on the same page and products are delivered on schedule. Each time code changes are shared, automated builds and tests occur. This enables DevOps teams to easily detect problems earlier and therefore bring better products to market faster. Since code contributions are generally small, it’s much simpler to locate precisely where bugs are.
Thanks to the automation continuous integration brings to the development process, engineers are able to reclaim a lot of time they’d otherwise spend on manual tasks—which increases productivity.
Successful continuous integration requires both the technology to support it and a culture shift that employees buy in to. Best practices include:
- Creating and maintaining a single repository for each project
- Automating each build every time code is submitted
- Implementing automated testing for each build
- Submitting commits daily and automatically building each one
- Keeping each build fast
- Testing in an environment that mimics the production environment
- Balancing speed and high code coverage in the tests
- Making the latest builds easily accessible by any team member
- Broadcasting the results of each build
- Automating deployment
Here’s what a typical continuous integration workflow might look like:
- DevOps engineers write code on their own computers
- They commit code changes to the central repository several times a day
- Continuous integration tools monitor the repository
- When commits are detected, automated builds and testing occurs
- The team is notified whether the build was successful
- If not, they identify defects and fix the issues
- The process is repeated for the duration of the project
The bottom line: Continuous integration enables agile DevOps teams to increase productivity, detect, pinpoint and fix problems quicker and roll out updates faster.