NSSpain 2023: Moving from Cocoapods to SwiftPM

Discover the realities and challenges of adopting Swift Package Manager in the XING iOS app, to be able to organize and design the modularization of more than 100 internal libraries.

Transcript

1. Moving from Cocoapods to
   Swift Package Manager
   Oswaldo Rubio & Juantri Jimenez
   Our journey
   

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2. Who we are?
   iOS Platform team members at XING
   Oswaldo Rubio Juantri Jimenez
   

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3. What is XING?
   

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4. The problems and solutions we found while
   adopting gradually Swift Package Manager
   in a large codebase
   What’s the point?
   

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5. A bit of context
   🎒
   👨💻
   👩💻
   + 30 iOS Developers
   +120 Development Pods
   ~30%
   ⏳ + 13 years old codebase (monorepo)
   📈 + 300K daily unique visitors
   📚 + 300K LOC
   📐 50% UIKit + 50% SwiftUI
   

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6. The reasons behind
   1. Reduce our technical debt
   2. Having a more
   f
   lexible and
   capable Package manager
   3. Having better build times &
   developer experience
   moving to SPM
   

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7. The problem
   🤯
   

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8. The problem
   🤯
   1. More than 20 dependencies per
   module (average)
   2. High transitive dependency
   usage
   3. 30% of mixed Objective-C code
   across the project
   

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9. 🧪 The experiment
   … and what we learned during a Hackweek
   1. Dependencies from our features modules needs to be removed
   2. Inter-dependency between modules needs to be reduced
   3. A roadmap needs to be de
   f
   ined
   4. Our managers and community needs to be convinced
   

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10. Our journey starts here
    

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11. 📦 Dependencies
    

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12. Third party dependencies
    

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13. Third party dependencies
    App
    Dependency1 Dependency2
    Dependency3
    Feature1
    Feature2 Common1 Common2
    🟦 Pod.xcodeProj
    

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14. Third party dependencies
    App
    Dependency1 Dependency2 Dependency3
    Feature1
    Feature2 Common1 Common2
    🟦 Pod.xcodeProj
    

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15. Third party dependencies
    App
    Dependency1 Dependency2 Dependency3 Feature1
    Feature2 Common1 Common2
    📦 dependencies Package 🟦 Pod.xcodeProj
    

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16. Conditional Dependencies
    

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17. 📉 Complexity reduction
    

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18. Thomas J. McCabe, Sr in 1976 - Wikipedia
    "It´s a quantitative measure of the number
    of linearly independent paths through a
    program’s source code.”
    

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19. Predicting Subsystem failures using dependency graphs, 2016 - Microsoft
    “The complexity of the dependency
    structure predicts the number of defects.”
    

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20. Tooling - jungle
    https://github.com/xing/jungle
    Complexity = E - V + P
    
    E - Edges
    
    V - Nodes
    
    P - Weakly connected components
    Complexity: 4 - 5 + 1 = 0
    Complexity: 6 - 5 + 1 = 2
    

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21. You can’t improve what you don’t measure.
    

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22. Reducing complexity in our project
    Last 3 years
    

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23. Less complexity, less build time
    Complexity: 55
    Complexity: 3
    

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24. 🛣 We need a roadmap
    

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25. 🛣 We need a roadmap
    • De
    f
    ine a migration plan
    • Document our migration process
    • Get a time estimation of the overall process
    • Get our managers and community approval
    

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26. Migration plan tooling
    

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27. We have a roadmap
    

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28. 🛠 The Migration
    

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29. 🛠 The Migration
    Gradual and using both package managers
    Non invasive for other teams
    Integrate as fast as possible
    

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30. • Module migration status
    • Product containers
    • SPM Schemes management
    • One or Multiple Swift Packages
    • Using SPM products in Cocoapods
    • Cyclic dependencies between languages
    Migration challenges
    

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31. • Module migration status
    • Product containers
    • SPM Schemes management
    • One or Multiple Swift Packages
    • Using SPM products in Cocoapods
    • Cyclic dependencies between languages
    Migration challenges
    

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32. Module migration status
    Migrated Integrated
    Module Availability Cocoapods and SPM Only SPM
    Module usage for running With CocoaPods With SPM
    Module usage for Testing With SPM With SPM
    

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33. Original status
    📲 XING App
    🟦 Pod.xcodeProj
    JobsCoreTests
    JobsCore
    📂 JobsCore/Sources 📂 JobsCore/Tests
    

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34. Migrated status
    📦 features Package
    📲 XING App
    🟦 Pod.xcodeProj
    JobsCoreTests JobsCore
    📂 JobsCore/Sources
    JobsCoreModule
    📂 JobsCore/Tests
    

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35. Integrated status
    📦 features Package
    📲 XING App
    JobsCoreTests JobsCore
    📂 JobsCore/Sources
    📂 JobsCore/Tests
    

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37. • Module migration status
    • Product containers
    • SPM Schemes management
    • One or Multiple Swift Packages
    • Using SPM products in Cocoapods
    • Cyclic dependencies between languages
    Migration challenges
    

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38. Product container
    

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39. • Module migration status
    • Product containers
    • SPM Schemes management
    • One or Multiple Swift Packages
    • Using SPM products in Cocoapods
    • Cyclic dependencies between languages
    Migration challenges
    

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40. SPM schemes management
    

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41. • Module migration status
    • Product containers
    • SPM Schemes management
    • One or Multiple Swift Packages
    • Using SPM products in Cocoapods
    • Cyclic dependencies between languages
    Migration challenges
    

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42. One package or multiple ones?
    

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43. New Swift 5.9 Package Access modi
    f
    ier
    Private
    Open
    Public
    Internal
    Fileprivate
    Package
    🆕
    

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44. One package or multiple ones?
    Cocoapods App
    Pod1 Pod2 Pod3
    Pod4 Pod5 Pod6
    SPM App
    Prod1
    Package1 Package2
    Prod2 Prod10 Prod11
    Target1 Target2 Target10 Target11
    Target3
    Pod
    f
    ile
    All dependencies allowed Only Products are accessible to other
    packages
    

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45. One package or multiple ones?
    

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46. • Module migration status
    • Product containers
    • SPM Schemes management
    • One or Multiple Swift Packages
    • Using SPM products in Cocoapods
    • Cyclic dependencies between languages
    Migration challenges
    

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47. Using SPM modules inside Cocoapods
    Can we do this?
    📦 features Package
    📲 XING App
    🟦 Pod.xcodeProj
    MyCPModule
    Common https://github.com/CocoaPods/CocoaPods/pull/11953
    💥
    

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48. Using SPM modules inside Cocoapods
    Yes, we can
    

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49. Using SPM modules inside Cocoapods
    And that’s how we do it
    

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50. Using SPM modules inside Cocoapods
    How to create .xcframeworks
    swift package generate-xcodeproj
    xcodebuild archive
    xcodebuild -create-xcframework
    Swift 5.8
    Create Xcode Project from .podspec
    xcodebuild archive
    xcodebuild -create-xcframework
    Swift 5.9
    

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51. • Module migration status
    • Product containers
    • SPM Schemes management
    • One or Multiple Swift Packages
    • Using SPM products in Cocoapods
    • Cyclic dependencies between languages
    Migration challenges
    

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52. Cyclic dependencies between languages
    

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53. Cyclic dependencies between languages
    Not allowed!
    

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54. Conclusions
    

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55. Conclusions
    • De
    f
    ining more than one package helps to create good practices
    boundaries for your internal modules
    • Having a roadmap before starting helps to convince your team and
    management
    • Build time was not reduced by using only SPM, but because we improved
    f
    irst our architecture
    • Gradual migration helps us to not having unexpected surprises
    

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56. Evolution and status
    

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57. $ bundle exec pod deintegrate
    

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58. Thanks to all our mates
    Markus Faßbender
    Shammi Didla
    Andreas Koslowski
    Mark Schütte
    Özgün Zor
    Eslam Foad
    Akshay Shetty
    

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