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Monorepo

The decision to consolidate multiple projects into a single mono repo is driven by a desire to enhance the development workflow, streamline project management, and improve collaboration among the team. This approach offers a multitude of benefits:

  • Unified Codebase: A mono repo provides a full view of the entire codebase, making it easier to understand how different parts of the system interact and how changes in one area might affect others.

  • Simplified Code Review and Dependency Management: With all projects under one roof, code reviews and dependency management become more straightforward and more efficient across projects.

  • Efficient Cross-Project Changes: Handling multiple changes that span multiple projects becomes more manageable. There's no need to maintain multiple branches across repositories for a single feature or bug fix, streamlining the development process.

  • Improved Automation: The mono repo setup allows for the development of multiple scripts that can automate common tasks, such as testing and deployment, across all projects within the repository.

Steps

1. Add Remote Repositories First, we need to add each of the existing repositories as a remote to our new monorepo. This step is crucial for being able to fetch the histories of these repositories into your mono repo.

    git remote add -f repo-a <url-to-repo-a>
    git remote add -f repo-b <url-to-repo-b>

2. Fetch Remote Branches & Commits Next, fetch the branches from the remote repositories:

git fetch repo-a
git fetch repo-b

3. Create a New Branch for Each SubProject For each subproject, create a new branch in your monorepo. This step is optional but can be useful for managing the integration of each subproject separately.

git checkout -b feat/repo-a repo-a/main
git checkout -b feat/repo-b repo-b/main

4. Merge each Repository Finally, use git subtree add to merge each repository into your monorepo. This command integrates the history of each repository into a specified directory within your mono repo.

git subtree add --prefix=repo-a-dir-name repo-a-main
git subtree add --prefix=repo-b-dir-name repo-b-main

Risks & Challenges

Adopting the monorepo approach comes with several risks and challenges, such as:

  • Complexity: As the codebase grows, monorepos can become complex, making it challenging to navigate and understand the structure and different dependencies within the repository.

  • Slower Cloning and Build Times: Initial repository cloning can be time-consuming. Additionally, the larger the repository, the longer it can take for developers to clone and build it.

  • Tooling Overhead: managing monorepos often requires specialized tools, which can add complexity to the development workflow.

  • Access Control: When all code is stored in the same repository, it can be difficult to track and manage access to different parts of the codebase.

  • Risk of breaking changes: In a mono repo, changes made in one project can potentially break the code in another project due to its interdependencies.