What is trunk based development?

Ever felt overwhelmed by endless merge conflicts and complicated branching strategies while coding? You're not alone. Many of us have been there, struggling to keep the codebase stable and deployments smooth.

But there's a better way—welcome to trunk-based development. It's a version control practice that simplifies collaboration, accelerates delivery, and keeps your main branch always in a releasable state.

In this blog, we'll explore what trunk-based development is all about, its core principles, the advantages it brings, and how you can adopt it in your team. Let's dive in!

Understanding trunk-based development

Trunk-based development is all about collaboration on a single "trunk" branch. Instead of working on long-lived feature branches, developers merge small, frequent updates directly into the main branch. This keeps the codebase streamlined and reduces the headaches of merging complex branches.

This approach emerged as an alternative to traditional branching strategies like GitFlow, which often led to "integration hell" due to complicated merges. By integrating code changes frequently, trunk-based development minimizes branch divergence and merge conflicts. It aligns perfectly with the principles of continuous integration, ensuring the main branch is always stable and ready to deploy.

Trunk-based development is a cornerstone for modern CI/CD pipelines and rapid releases. With a stable trunk, teams can deploy updates to production anytime with confidence. This supports agile methodologies, allowing organizations to respond quickly to customer needs and market shifts.

To make trunk-based development work, teams use techniques like feature flags and branch by abstraction. These let developers integrate code incrementally without breaking the main branch's stability. Automated testing and continuous integration pipelines are also crucial to catch issues early and maintain code quality.

While this approach offers many benefits, it's not a one-size-fits-all solution. In situations where you need to maintain multiple production versions or long-term release branches, alternative strategies might be better. But if you're aiming for continuous delivery and rapid iteration, trunk-based development is a streamlined and effective choice.

Core principles and practices of trunk-based development

At its heart, trunk-based development revolves around a few key principles that keep the codebase stable and releasable, all while enabling continuous integration and delivery.

One of the main ideas is frequent integration. Developers commit small, incremental changes directly to the main branch. By doing this continuously, we minimize merge conflicts and avoid the nasty surprises that come from long-lived branches.

Another crucial practice is avoiding long-lived branches. By keeping feature branches short-lived and merging them back quickly, we prevent significant divergence from the mainline. This reduces the complexity of merging and keeps the codebase cohesive.

Feature flags are a game-changer in trunk-based development. They allow us to safely merge incomplete features into the main branch without affecting its stability. With feature toggles, we control the visibility of new features, enable gradual rollouts, and reduce the need for separate feature branches.

Continuous testing and integration are also key. With frequent commits to the main branch, automated testing becomes essential. Continuous integration pipelines run tests on each commit, providing rapid feedback and catching issues early in the process.

At Statsig, we've embraced these principles to streamline our development process. By integrating small changes frequently and leveraging feature flags, we've been able to maintain stability while delivering value to our users at a rapid pace.

Advantages of trunk-based development

So, why should you consider trunk-based development? For starters, it accelerates software delivery by enabling rapid integration and deployment cycles. With small, frequent updates, you get faster time-to-market and quicker feedback loops. Continuous integration is a big part of this, ensuring your codebase stays stable and deployable.

Collaboration and code quality get a boost too. Frequent code reviews and continuous integration mean developers are constantly sharing work and feedback. This fosters a transparent culture and encourages everyone to write high-quality code that meets team standards.

Release management becomes a breeze when you maintain a stable main branch that's always ready to deploy. No more juggling complex branching strategies or worrying about merge conflicts. With a single source of truth, you can confidently push new features and fixes to production.

And let's not forget about feature flags. They let you control the visibility of new features without affecting the main branch. This means developers can work on multiple features simultaneously without stepping on each other's toes. Plus, feature flags enable gradual rollouts and A/B testing, giving you valuable insights into how users interact with new features.

At Statsig, we've seen these advantages firsthand. Trunk-based development has allowed us to move quickly, collaborate effectively, and deliver high-quality software to our users.

Best practices for adopting trunk-based development

Ready to give trunk-based development a shot? Here are some best practices to help you get started.

First off, focus on developing in small batches. This makes quick merges and deployments possible and keeps code reviews streamlined. By keeping changes small and focused, you reduce the risk of conflicts and make integration smoother.

Implementing automated testing is a must. Automated tests are your safety net, catching issues before they hit the main branch. Incorporate testing into your workflow so you can merge changes confidently, knowing the codebase remains stable.

Consider adopting asynchronous code reviews. With automated tests pre-verifying code quality, reviewers can efficiently assess changes without slowing down development. This promotes collaboration and ensures code meets team standards before integration.

Effective communication is key. Regular sync-ups and clear guidelines keep everyone on the same page. By fostering a culture of collaboration and transparency, you ensure a smooth flow of changes.

Don't overlook the importance of the right tooling and infrastructure. Continuous integration systems, version control platforms, and code review tools are vital for streamlining the process. Investing in the right tools and integrating them seamlessly into your workflow makes trunk-based development much more effective.

At Statsig, we've invested in the tools and practices that support trunk-based development. It's helped us maintain high standards while moving quickly, and it can do the same for your team.

Closing thoughts

Trunk-based development is a powerful approach that can simplify your workflow, boost collaboration, and speed up delivery. By integrating small changes frequently and leveraging practices like feature flags and automated testing, you keep your codebase stable and always ready to deploy.

If you're interested in learning more, check out resources like trunkbaseddevelopment.com or explore how Statsig can support your team's transition to trunk-based development.

Hope you find this useful!