Trunk-Based Development in Software Development

In earlier days of software development, programmers didn't have the richness of modern version control systems but they developed two versions of their software concurrently as it means of monitoring small changes and backing them if possible and only in necessary conditions. As time increases it has become more costly, and inefficient.

At present various version control systems are developed and managed. It made it more mature, and various departments have merged which enables programmers to find bugs or errors more easily. As of today, most developers hold one of the two development models to deliver quality software which is Git flow and trunk-based development. Trunk-based development is an additional open model since all developers have easier access to the main code which also enables teams to implement CI/CD and so on.

What is Trunk-Based Development?

In software development, Trunk based development is a version control management technique or practice where developers from various organizations merge small, regular updates to a base code.

• It is a common practice among DevOps teams and part of DevOps lifecycle since it streamlines merging and integration phases. Copies made from the source code is called branches.
• It is considered as an branching model. In fact, trunk-based development is a required practice of CI/CD. As codebase complexity and team size grow, trunk-based development helps us to keep production releases flowing and here errors are addressed quickly and remediated before they go live.

What is Feature-Based Development?

Feature-Based Development (FBD) is an approach to software development where the focus is on delivering features or functionalities in small, incremental steps rather than large, monolithic releases. This methodology emphasizes the following principles:

• Incremental Delivery: Software is developed and delivered in small increments or iterations, each of which adds a new feature or improves an existing one.
• Feature-Centric Approach: Development efforts are organized around specific features or functionalities that provide direct value to the end-users.
• Iterative Development: FBD promotes iterative cycles of development, where feedback from users and stakeholders is continuously incorporated to refine and improve the product.
• Cross-functional Teams: Teams are typically organized around features, consisting of members with diverse skills (developers, testers, designers, etc.) necessary to implement and deliver each feature.
• Prioritization of Features: Features are prioritized based on their importance and impact on users, allowing teams to focus on delivering the most valuable functionalities early.
• Flexibility and Adaptability: FBD enables teams to respond quickly to changing requirements and priorities, as each feature is developed independently and can be adjusted based on feedback.

Importance of Trunk-Based Development

1. Faster Time to Market: By promoting simple terms, frequent contributions and continuous integration, trunk-based development speeds up delivery.
2. Reduced Integration Problems: Early problem detection and resolution are achieved by continuous integration, and working directly on the main branch reduces conflicts.
3. Enhanced Cooperation: By collaborating on the main root, solitary work on different branches is avoided and communication and information sharing are encouraged.
4. Simpler Code Reviews: Code reviews are easier to manage when changes are smaller and more frequent, which allows for quicker iterations and quicker feedback.
5. Enhanced Transparency: The main branch offers a transparent picture of the project's status and the present state of the codebase since it acts as a single source of truth.
6. Adaptability to Change: Trunk-Based Development facilitates quick pivots, responsiveness to changing requirements, and effective feedback assimilation, all of which help to increase adaptability to change.

How to implement trunk-based development?

Implementing trunk-based development (TBD) involves following a set of practices and principles that revolve around maintaining a single, main branch (often called 'trunk' or 'master') as the central hub for all development activity. Here’s a step-by-step guide on how to implement trunk-based development effectively:

1. Establish Clear Version Control Guidelines:

• Main Branch: Designate a single main branch (e.g., master, main) as the trunk of your repository. This branch should always reflect the latest stable version of your application.
• Feature Branches: Encourage developers to create short-lived feature branches off the trunk for implementing new features or fixing bugs. These branches should be merged back into the trunk once the feature is complete.

2. Keep Branches Short-Lived:

• Developers should work in small, focused increments on their feature branches. Aim to keep these branches active for a short duration to minimize integration issues and merge conflicts.

3. Continuous Integration (CI):

• Implement CI practices to ensure that every change made to the trunk branch is automatically built, tested, and validated. This helps catch integration issues early.

4. Automated Testing:

• Have a comprehensive suite of automated tests (unit tests, integration tests, etc.) that run as part of the CI process. Tests should validate the correctness and stability of the trunk branch.

5. Code Reviews:

• Require code reviews for all changes before they are merged into the trunk. This helps maintain code quality, share knowledge, and identify potential issues early.

Git flow vs. Trunk-Based Development

Below is the side by side comparison between Git-Flow and Trunk Based Development:

Considerations for Choosing:

• Team Size and Structure:
  • Git Flow may be suitable for larger teams with a structured development process, while Trunk Based Development might be more agile and suitable for smaller teams.
• Release Requirements:
  • Git Flow may be preferable for projects with strict release schedules and version management needs. Trunk Based Development is ideal for continuous delivery approaches.
• Risk Tolerance:
  • Teams with a lower tolerance for integration risks may find Git Flow more reassuring, while teams emphasizing continuous integration may lean towards Trunk Based Development.

Why we prefer Trunk-Based Development?

Trunk-based development (TBD) is preferred for several reasons, which stem from its ability to streamline the software development process, improve collaboration, and enhance overall efficiency. Here are some key reasons why TBD is often favored:

1. Simplicity and Clarity:

• Single Source of Truth: TBD maintains a single main branch (trunk or master), which serves as the definitive source of the latest stable code. This simplicity reduces confusion about where the authoritative code resides and simplifies the branching model compared to more complex branching strategies.

2. Faster Integration and Reduced Merge Issues:

• Continuous Integration: TBD encourages frequent integration of changes into the main branch. This approach minimizes the risk of large merge conflicts that can arise from long-lived feature branches or complex branching structures. Developers merge their changes into the trunk more frequently, leading to smoother integrations and faster resolutions of conflicts.

3. Early Detection of Integration Issues:

• Continuous Testing: With continuous integration practices in place, every change made to the trunk is automatically tested. This early testing helps detect integration issues, bugs, or regressions sooner in the development process when they are typically easier and less costly to fix.

4. Agility and Responsiveness:

• Quick Feedback Loops: TBD facilitates rapid feedback loops because changes are integrated and tested continuously. This agility allows teams to respond quickly to customer feedback, market changes, or emerging requirements by delivering updates and features more frequently.

5. Improved Collaboration and Knowledge Sharing:

• Team Alignment: Working on a single trunk promotes a shared understanding of the codebase across the team. It encourages collaboration, knowledge sharing, and collective ownership of the code, as developers can see each other’s changes more regularly.

Benefits of using Trunk-based development

Reduced complexity is a major emphasis of trunk-based software design. Trunk based development is a required practice for continuous integration. Here if the build and test processes are automated then developers work on isolated, lengthy feature branches that are infrequently integrated into a shared branch, continuous integration is not living up to its potential.

1. Allows continuous code integration:- In trunk based development model, there will be a repository with a steady stream of commits flowing into the main branch. By including an automated test suite and code coverage tracking or monitoring for the stream of commits that enables CI. When new code is merged into the trunk, automated integration and code coverage tests run to validate the code quality.
2. Ensures continuous code review:- The rapid, small commits of trunk-based development make code review a more efficient process. With small branches, developers can quickly see and review small changes. This is far easier compared to a long-lived feature branch where a reviewer reads pages of code or manually inspects a large surface area of code changes.
3. Foster collaboration:- Developers from companies can see all changes and can cross pollinate each others contributions.
4. Enables consecutive production code releases:- The teams should make frequent, daily merges to the main branch. Trunk-based development strives to keep the trunk branch "green", which means its ready to deploy at any commit. Automated tests, code coverage, and code reviews provides a trunk-based development project with the assurances its ready to deploy to production at any time. This gives team agility to frequently deploy to production and set further goals of daily production releases.
5. Improve refactoring:- Decomposing an application story into a continuous small components takes less time.

Best practices of Trunk based development

The principle behind trunk-based development is to assimilate every change as soon as possible in version control. It ensures the teams to release code quickly and consistently. The following is a list of exercises and practices that will help will refine your teams cadence and develop an optimized release schedule. In Software Development best practices for trunk-based development include the following steps as mentioned here.

• Develop in small batches: It follows a quick rhythm to deliver code to production. if trunk-based development was like music it would be a short notes in rapid succession, with the repository commits being the notes.
• Feature flags:- It is nicely complement trunk-based development by enabling developers to wrap new changes in an inactive code path and activate it at a later time. This allows developers to forgo creating a separate repository feature branch and instead commit new feature code directly to the main branch within a feature flag path.
• Build fast and execute immediately:- In order to maintain a quick release cadence, build and test execution times should be optimized. CI/CD build tools should use caching layers where appropriate to avoid expensive computations for static.
• Having reduced number of code freezes and integration phases:- Trunk based development teams should try to avoid blocking code freezes and plan accordingly to ensure the release pipeline is not stalled. It updates are constantly flowing.
• It perform asynchronous code reviews:- In trunk-based development, code review should be performed immediately and not put into an asynchronous system for later review. Automated tests provide a layer of pre-emptive code review. It gives the reviewer immediate reassurance that the new code meets specific specifications.
• It simple to conclude that Develop, Code, Commit, Plan, Test, Manage.

Future Trends in Trunk-Based Development

1. Practices for Collaborative Coding: Ongoing development of more cooperative coding techniques, maybe including functionalities like in-development real-time pair programming support.
2. Integration of Security: Direct integration of security measures with the TBD workflow guarantees smooth security scans and checks as part of the ongoing integration process.
3. International Cooperation and Support for Remote Work: Modifying TBD procedures to more effectively facilitate remote work and international collaboration, with an emphasis on lowering obstacles to communication for dispersed teams.
4. Immutable Infrastructure and Infrastructure as Code (IaC): Alignment of TBD with new paradigms such as Infrastructure as Code (IaC) and Immutable Infrastructure, with a focus on versioning and configuration management of infrastructure changes within the main branch.

Conclusion

In this article we have came across trunk based development and its benefits, practices. It is currently the standard for high performing engineering teams since it sets and maintains a software release cadence by using a simplified git branching strategy. Trunk-based development gives engineering teams more flexibility and control over how they deliver software to the end user.