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. Building ! Search Background Synchroniser Home Session Settings Database Client User actions System events
4. Problem #1 Strongly coupled features, and no clear APIs Photo by Artem Sapegin on Unsplash
5. Session Building ! Search Background Synchroniser Home Session Settings Database Client Search Database Client APP
6. 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 " #
9. Problem #2 Slow iterations building and testing features Photo by Lindsay Malatesta on Unsplash
10. µfeatures Photo by Alex Galperin on Unsplash
11. What is a µfeature µfeature Sources Tests App ! BTT Build, test and try
12. What is a µfeature µfeature Sources Tests App Source Source code (.swift / .h / .m) Resources (.ttf, .storyboard, .xib)
13. What is a µfeature µfeature Sources Tests App Tests Unit tests Integration tests
14. What is a µfeature µfeature Sources Tests App App Example app to try out the feature/s
15. Problem #1 Strongly coupled features, and no clear APIs Photo by Artem Sapegin on Unsplash
16. Types of µfeatures Foundation Product !
17. Foundation µfeatures Other µfeatures “know” about them Provide tools and extensions to develop other µfeatures
18. Foundation µfeatures SCCore Client Reachability Keychain Logger Foundation Ext. SCTesting Custom assertions XCTest Ext. SCUI Fonts Colors Custom Views UIKit Ext.
19. Foundation µfeatures $ Foundation
 µfeature Classes Extensions Public Interface
20. Product µfeatures ! Built using foundation µfeatures µfeatures that the user can feel/consume
21. 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
22. Product µfeatures $ Product
 µfeature View / View Controller Service Public Interface
23. Using µfeatures $ Product
 µfeature Application $ Product
 µfeature $ Product
 µfeature $ Product
 µfeature Navigation View Controller View Controller View Controller View Controller
24. Using µfeatures $ Product
 µfeature Application $ Product
 µfeature $ Product
 µfeature $ Product
 µfeature Services Service Service Service Service Lifecycle Events External Events
25. Dependencies Application (glue layer) Product µfeatures Foundation µfeatures Sources Sources Sources Sources
26. 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)
27. 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
28. Dependency Inversion Application (glue layer) A Sources B Sources C Sources D Sources Dependency Inversion <B> <C> <D> <A> Foundation µfeatures
29. Compiling A Application (glue layer) A Sources B C D Dependency Inversion <B> <C> <D> <A> Foundation µfeatures <B>
30. Compiling the app Application (glue layer) A Sources B Sources C Sources D Sources Dependency Inversion <B> <C> <D> <A> Foundation µfeatures B
31. Problem #2 Slow iterations building and testing features Photo by Lindsay Malatesta on Unsplash
32. 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
33. 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 Example Feature Tests Example Per-project Schemes Features tests Features examples Features Workspace schemes
34. Demo Photo by LoboStudio Hamburg on Unsplash
35. Downsides Photo by Samuel Zeller on Unsplash
36. Maintenance Build settings Schemes / Targets / Dependencies
37. Dependencies clarity What depends on what?
38. Xcode Project Manager github.com/xcode-project-manager App Payments Core UI Generate Xcode Project UI Sources/**/* Tests/**/* Name Sources Tests Dependencies Core, Testing More configuration
39. 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.
40. References % • Microservices: A definition of this new architectural term. • Introduction to Framework Programming Guide. • Embedding frameworks in an app. • Static & Dynamic libraries. • Modular Xcode projects.
41. Danke
 schön Photos from Unsplash
 Slides: https://goo.gl/RdjwF8 Twitter: @pepibumur