modular-development-model

What is it

Create a separate Rails project for reasonably complicated pieces of functionality.

Use a simple script to copy it into the main repo (this could also be soft-links).

When to use

• only makes sense for more complicated features
• how separable is the logic?

Advantages

• ensures a clean interface and separation (part of reason why tests run quickly is the lack of prerequisites)
• limits the code under consideration
• everything is much faster (tests, finding stuff)
• some things are possible that aren't really in Instacart (mutation testing)
• separately sharable, easier sub-project for others to grok
• can eventually cut cord and just have it be code in Instacart

Data model flexibility

• especially early on when it has not been integrated with Instacart yet, you can simply update migrations in-place
• with minor editor tweaks, you can cause a migration reset right from the editor

Speed

• for testing-concept-mutation-testing
• for keeping context while developing

Specs as documentation

• needs to be even easier than running rspec docs

Integration

• blacklist files which shouldn't be integrated
• automate the integration with simple scripts

Revisiting

• gives you a nice place to return to when bugs crop up. Quick to get context back.

Even after integration

• keep a concept of the module within Instacart's codebase using symlinks

Downsides

• not great at round-tripping... if someone else changes the code associated with the feature, you have to be able to pull it back into the separate project

Referring Pages