Building µfeatures

Part of the success of most mobile apps these days is having the ability to iterate and deliver features fast. This becomes a challenge when the project and the team grows, and dependencies and friction between teams become more apparent.

In this talk, I’ll introduce the concept of Microfeatures architecture for mobile apps. I’ll go through the core ideas behind it, show practical examples, and explain how development workflow has improved at SoundCloud since we started applying these principles.

Transcript

1. Building µfeatures Pedro Piñera / @pepibumur
2. twitter.com/pepibumur - github.com/pepibumur Core iOS Engineer at SoundCloud ppinera.es Personal blog github.com/xcodeswift Open source GIF Meister
3. –Esteban Torres “An app is the tiny cute boxes you have in your phone that show some other bigger boxes when you touch them.” Photo by Andreas Kind on Unsplash
4. Building Search Background Synchroniser Home Session Settings Database Client User actions System events
5. Problem #1 Strongly coupled features, and no clear APIs Photo by Artem Sapegin on Unsplash
6. Session Building Search Background Synchroniser Home Session Settings Database Client Search Database Client APP
7. Building Search Background Synchroniser Home Session Settings Database Client Search Tests BS
 Tests Home
 Tests Session Tests Settings Tests Database Tests Client Tests APP TESTS Client Tests " #
10. Problem #2 Slow iterations building and testing features Photo by Lindsay Malatesta on Unsplash
11. µfeatures Photo by Alex Galperin on Unsplash
12. What is a µfeature µfeature Sources Tests App BTT Build, test and try
13. What is a µfeature µfeature Sources Tests App Source Source code (.swift / .h / .m) Resources (.ttf, .storyboard, .xib)
14. What is a µfeature µfeature Sources Tests App Tests Unit tests Integration tests
15. What is a µfeature µfeature Sources Tests App App Example app to try out the feature/s
16. Problem #1 Strongly coupled features, and no clear APIs Photo by Artem Sapegin on Unsplash
17. Types of µfeatures Foundation Product
18. Foundation µfeatures Other µfeatures “know” about them Provide tools and extensions to develop other µfeatures
19. Foundation µfeatures SCCore Client Reachability Keychain Logger Foundation Ext. SCTesting Custom assertions XCTest Ext. SCUI Fonts Colors Custom Views UIKit Ext.
20. Foundation µfeatures Foundation
 µfeature Classes Extensions Public Interface
21. Product µfeatures Built using foundation µfeatures µfeatures that the user can feel/consume
22. Product µfeatures SCSearch SCPlayback SCPayments SCOffline View where user can search for SoundCloud content Payment handling and subscription button/views Player queue handling and views Service to synchronise tracks
 offline
23. Product µfeatures Product
 µfeature View / View Controller Service Public Interface
24. Using µfeatures Product
 µfeature Application Product
 µfeature Product
 µfeature Product
 µfeature Navigation View Controller View Controller View Controller View Controller
25. Using µfeatures Product
 µfeature Application Product
 µfeature Product
 µfeature Product
 µfeature Services Service Service Service Service Lifecycle Events External Events
26. Dependencies Application (glue layer) Product µfeatures Foundation µfeatures Sources Sources Sources Sources
27. Dependency with Foundation Application (glue layer) Product Foundation Sources State-free component Creates an instance and uses it (e.g Font, Color, View) Stateful component A shared instance is retained from the app
 and shared with the features (e.g Client, Store, Analytics)
28. Dependency between features Application (glue layer) A Sources Link between them Problem 1 It might eventually lead to circular dependencies that can’t be resolved B Sources Problem 2 We need to also compile dependencies, and their dependencies
29. Dependency Inversion Application (glue layer) A Sources B Sources C Sources D Sources Dependency Inversion <B> <C> <D> <A> Foundation µfeatures
30. Compiling A Application (glue layer) A Sources B C D Dependency Inversion <B> <C> <D> <A> Foundation µfeatures <B>
31. Compiling the app Application (glue layer) A Sources B Sources C Sources D Sources Dependency Inversion <B> <C> <D> <A> Foundation µfeatures B
32. Problem #2 Slow iterations building and testing features Photo by Lindsay Malatesta on Unsplash
33. Example: Home µfeature Home µfeature Core µfeature UI App class Client class Analytics class Logger client analytics logger View Controller Service Track Cell Colors Fonts
34. µfeatures & Xcode Workspace App App Unit Tests UI Tests µfeature Sources Unit Tests Example app µfeature Sources Unit Tests Example app Pods Dependency 1 Dependency 2 Pods App Tests Feature Tests Feature Tests Per-project Schemes Features tests Features examples Features Workspace schemes
35. Demo Photo by LoboStudio Hamburg on Unsplash
36. Downsides Photo by Samuel Zeller on Unsplash
37. Maintenance Build settings Schemes / Targets / Dependencies
38. Maintenance XcodeGen github.com/yonaskolb/xcodegen
39. Dependencies clarity What depends on what?
40. Takeaways • Scale your project architecture with your team growth • Split things before they grow a lot. • Developers shouldn’t spend time fighting the tools. • Keep an eye on how your project/team evolves.
41. References • Microservices: A definition of this new architectural term. • Introduction to Framework Programming Guide. • Embedding frameworks in an app. • Framework Oriented Programming. • Static & Dynamic libraries. • Modular Xcode projects.
42. Dziękuję (Thank you) Photos from Unsplash
 Slides: https://goo.gl/4XUj3Y Twitter: @pepibumur