Migrating to Monorepo: A Step-by-Step Guide

Migrating to a monorepo structure from multiple repositories can streamline your development process, but it requires careful planning and execution. Here is a step-by-step guide to help you through the transition.

Step 1: Preparation

• Evaluate the benefits: Assess if the monorepo model aligns with your team's workflow and goals.

• Communication: Discuss the migration plan with your team to ensure everyone understands the benefits and the process.

• Choose the right tools: Select tools that support monorepo management, such as Lerna, Yarn Workspaces, or Bazel, which can aid in the transition and future management.

Step 2: Planning

• Structure your monorepo: Decide on the directory structure of the monorepo, considering how to group projects and shared code.

• Dependency management: Plan how to handle dependencies between projects, possibly using workspace tools or package managers that support monorepos.

Step 3: Combining Repositories

• Start with a new repository or designate one of the existing repositories as the monorepo.

• Gradually move other projects into the monorepo, ensuring to maintain their history. Tools like git subtree can be used for this purpose.

• Resolve any conflicts that arise from combining repositories, such as overlapping files or incompatible git histories.

Step 4: Configuring the Build System

• Set up build configurations that handle the newly structured projects. Ensure that the build system can handle incremental builds and can scale with the monorepo.

• Test the build process thoroughly to ensure that all projects build correctly in the new setup.

Step 5: Continuous Integration/Continuous Deployment (CI/CD)

• Adjust your CI/CD pipelines to work with the monorepo. This might involve setting up path filters to trigger builds only for changed projects.

• Optimize CI/CD for speed and efficiency, possibly using caching and parallelization techniques.

Step 6: Training and Documentation

• Update your documentation to reflect the new monorepo structure and workflows.

• Train your team on the new processes, ensuring everyone is comfortable with the new system.

Step 7: Monitoring and Optimization

• Monitor the monorepo for any issues that might arise post-migration.

• Continuously optimize the monorepo setup to handle the evolving needs of your projects.