Building for Open Source

A Multiple Repository Architecture

It started with an email from Wink entitled "Help :)" - after joining Aletheia Ware's Open Source Community he had run into some confusion about all the repositories and dependencies.

Aletheia Ware uses multiple repositories to split code into many pieces each with a specific purpose. The alternative approach is a monolithic repository where all code related to a project is stored in a single place. Choosing between these two architectures has been a topic of hot debate among the software community.

The Perspective Android app is made up of 12 repositories:

12 Repositories of Perspective

Similarly, the S P A C E Android app is composed of 13 repositories:

13 Repositories of S P A C E

Compartmentalizing and isolating code allows for better testing and code reuse; Common Libraries are shared between Perspective and S P A C E. Future games can share Joy while future blockchain apps can share BC, Alias, and Finance.

This architecture unfortunately creates a challenge for developers joining the open source project. Whereas my development machine already has all the repositories synced, scripts to perform the build steps, and symbolic links to chain the build artifacts; other developers would need to sync each of the 12 repositories separately, build each in turn, and make the output of each step available to the next.

Wink addressed these issues by;

The developer workflow is now much simplier:

            # Clone
            git clone
            # Clean
            ./gradlew clean
            # Sync
            ./gradlew sync
            # Build
            ./gradlew build

To create such a suite for your project 'FooBar' first initialize a new repository, add the submodules, and push to a remote:

            # Initialize repository
            git init FooBarSuite
            # Add submodules
            git submodule add
            git submodule add
            # Add remote
            git remote add origin
            # Push
            git push -u origin master

Submodules give the best of both worlds - each repository is highly specific with a single purpose but multiple repositories are linked together into a single suite.