Best Practice

Trunk-Based Development Guidelines

Trunk-Based Development is a vital best practice that encourages short-lived branches, frequent commits to the main branch, and the use of feature flags. By implementing these guidelines, teams can minimize integration issues, foster collaboration, and ensure a continuous flow of quality code, greatly enhancing the efficiency of software migrations across various platforms.

Organization
Paul Hammant
Published
Jan 10, 2017

Best Practice: Trunk-Based Development Guidelines

What This Best Practice Entails and Why It Matters

Trunk-Based Development (TBD) is a branching strategy that promotes short-lived branches, frequent commits to the trunk (the main branch of your codebase), and the use of feature flags. This approach is essential for modern software development as it enables teams to deliver features faster, reduces integration headaches, and fosters a culture of collaboration. By committing frequently to the trunk, developers can minimize merge conflicts and ensure that the codebase remains in a deployable state at all times.

Step-by-Step Implementation Guidance

  1. Establish a Clear Trunk: Ensure that there is a main branch (often called main or master) that serves as the definitive version of your code. This should be protected to prevent direct commits from unauthorized users.

  2. Encourage Short-Lived Branches: Limit the lifespan of branches to a few days at most. Developers should create branches only for specific features or fixes and merge them back into the trunk as soon as possible.

  3. Integrate Feature Flags: Use feature flags to enable or disable features without requiring separate branches. This allows you to deploy incomplete features while maintaining a stable trunk.

    • Example: If a new feature is being developed, wrap it in a feature flag to deploy it without exposing it to users until it's ready.

  4. Automate CI/CD Pipelines: Set up Continuous Integration/Continuous Deployment (CI/CD) pipelines that automatically build and test code on each commit to the trunk. This ensures that new changes are validated before being integrated.

  5. Conduct Regular Code Reviews: Implement a code review process to maintain code quality and share knowledge among team members. This can be done using pull requests before merging into the trunk.

  6. Monitor and Measure: Track metrics such as deployment frequency, lead time for changes, and the mean time to recover from failures. Use these insights to improve your TBD practices continuously.

Common Mistakes Teams Make When Ignoring This Practice

  • Long-Lived Branches: Teams that hold onto branches for extended periods often face significant integration challenges and merge conflicts.
  • Lack of Automation: Not automating the CI/CD process can lead to inconsistent builds and decreased confidence in deployment.
  • Neglecting Feature Flags: Failing to use feature flags can complicate the deployment of incomplete features, leading to unstable releases.
  • Infrequent Commits: Teams that do not commit frequently risk falling behind and may find it challenging to keep the codebase aligned with new changes.

Tools and Techniques That Support This Practice

  • Version Control Systems: Tools like Git enable easy branching and merging.
  • CI/CD Tools: Platforms such as Jenkins, CircleCI, and GitHub Actions automate the testing and deployment process.
  • Feature Flag Management: Tools like LaunchDarkly and Unleash allow teams to manage feature flags effectively.
  • Code Review Tools: Services such as GitHub, GitLab, and Bitbucket provide built-in code review functionalities.

How This Practice Applies to Different Migration Types

  • Cloud Migration: Use TBD to continuously integrate cloud-specific configurations and changes, ensuring a smooth transition to cloud environments.
  • Database Migration: Frequent commits can help manage schema changes alongside application code, reducing the risk of desynchronization.
  • SaaS Migration: Implementing TBD allows teams to gradually shift features to a new SaaS platform while maintaining user access to existing functionalities.
  • Codebase Migration: When transitioning codebases, TBD facilitates quick iterations and integration of new code, minimizing downtime and disruption.

Checklist or Summary of Key Actions

  • Establish a clear trunk for your codebase.
  • Encourage short-lived branches with a focus on quick merges.
  • Implement feature flags for incomplete features.
  • Automate CI/CD processes to validate changes.
  • Conduct regular code reviews to maintain quality.
  • Monitor key metrics to refine your practices continuously.

By following these Trunk-Based Development guidelines, teams can enhance their migration processes and achieve a more agile, collaborative development environment.

Tags

trunk based developmentci cdbranching strategydevopsbest practices