Help Collisions, Isolate the Worlds

Transcript

1. Satoshi Tagomori a.k.a., @tagomoris
   দߐRubyձٞ10 - Sep 16, 2023
   Help Collisions,
   Isolate the Worlds
   Names, Modules, Versions, and NameSpaces
   

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2. Satoshi Tagomori (@tagomoris)
   Independent developer
   
   Technical Consultant
   
   OSS Maintainer
   
   • Fluentd
   
   • MessagePack / msgpack-ruby
   
   • Norikra, Woothee, …
   tagomoris
   

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3. https://www.
   fl
   ickr.com/photos/takkanm/3978417669
   Asakusa.rb
   

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4. “Namespace on read“
   
   
   https://bugs.ruby-lang.org/issues/19744
   

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5. Collisions
   Destroy Developers’ Experience
   

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6. Collisions
   Names, Modules, Versions
   Name Collisions:
   
   No one can use a name in two ways.
   
   Module Collisions:
   
   Modules can be modified, globally, from anywhere.
   
   Version Collisions:
   
   Two different versions of a module can’t be loaded.
   

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7. Name Collisions
   No one can use a name in two ways.
   • A structured namespace:
   
   • Foo::Bar::Baz
   
   • Major scenario:
   
   • Top-level “Configuration” in gems
   
   • Typical RoR classes vs Ruby, Gems, etc (like “Guild”)
   
   • Two apps in a process (in the context of “Modular monolith”)
   

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8. Module Collisions
   Modules can be modi
   fi
   ed, globally, from anywhere.
   • A single Module/Class instance
   
   • Oj.default_options
   

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9. Version Collisions
   Two di
   ff
   erent versions of a library can’t be loaded.
   • Dependency hell
   
   • Module A depends on C ver 1.5.x
   
   • Module B depends on C ver 1.6.x
   
   • The App depends on A and B
   

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10. Avoid Collisions
    

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11. Isolate Worlds
    

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12. NameSpaces
    In other words: “Multiverse Ruby”
    https://rubykaigi.org/2023/presentations/shioyama.html#day2
    

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13. NameSpaces in Practice
    N languages, N ways
    • Library space
    
    • Global NameSpace (+ Version)
    
    • Local names only
    
    • Names in code
    
    • Library name
    
    • Local alias
    
    • Class loader
    

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14. NameSpaces in languages
    Many ways, Many hells…
    • JavaScript/TypeScript (npm)
    
    • Local names + Local Aliases
    
    • Java (classes w/ FQDN)
    
    • Global NameSpace + Library name
    
    • Class loaders (oops….)
    
    • Kotlin
    
    • Global NameSpace + Local Alias
    
    • Python (pip)
    
    • Global NameSpace (+ Local Alias)
    
    • Go
    
    • Local names + Local Aliases
    

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15. Ruby
    Many Libraries in a Global NameSpace
    

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16. Libraries and NameSpaces
    Libraries can’t be re-de
    fi
    ned
    • Once a library lives globally, it can’t be locally
    
    • Ruby has a huge library set - RubyGems
    

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17. NameSpace Requirements
    What is it?
    • One native extension libraries of two versions at a time
    
    • Same name, Di
    ff
    erent (native) code, Di
    ff
    erent access path (local name)
    
    • Isolate libraries in speci
    fi
    ed namespaces at the required time (“on read”)
    Ruby Process
    LibraryX
    
    
    version: a.b.c
    
    
    “x.so”
    LibraryX
    
    
    version: x.y.z
    
    
    “x.so”
    ns1::X ns2::X
    

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18. NameSpace Requirements
    What is it?
    • One native extension libraries of two versions at a time
    
    • Same name, Di
    ff
    erent (native) code, Di
    ff
    erent access path (local name)
    
    • Isolate libraries in speci
    fi
    ed namespaces at the required time (“on read”)
    Ruby Process
    LibraryX
    
    
    version: a.b.c
    
    
    “x.so”
    LibraryX
    
    
    version: x.y.z
    
    
    “x.so”
    ns1::X X
    

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19. My Proposal: module NameSpace < Module
    Respects load(
    fi
    lename, wrap)
    • The wrap of load(filename, wrap):
    
    • works as a simple namespace
    
    • Introduce a sub-class of Module: NameSpace
    
    • works like the wrap of load
    
    • has instance methods #require, #load
    
    • Dependencies will be required/loaded in the namespace recursively
    

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20. Let’s go!
    DEMO
    

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21. 🎉👏🍻
    “Namespace on read PoC”
    
    https://github.com/tagomoris/ruby/pull/1
    

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22. Hard Things, TODOs, Designs, …
    “How This Language Should Be?”
    • Hard Things: Native extension MAY need to be updated, in case
    
    • Native extensions using others’ C-functions

    https://github.com/tagomoris/sequel_pg/pull/1
    
    • TODOs: Upgrade path SHOULD be de
    fi
    ned
    
    • How can we mark a gem is namespace-ready?
    
    • How can we determine the namespace of a library? (RubyGems/Bundler)
    
    • Designs
    
    • What’s the namespace in Ruby?
    
    • Problems around the top-level names in namespaces
    

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23. Top-level Names in NameSpaces
    Should it be global? Or local?
    • “ns1::X” - A top-level name “X” de
    fi
    ned in a namespace “ns1”
    
    • It MUST be so, to isolate “ns1::X” from the “X”
    
    • “X” in the code isolated in “ns1”
    
    • It should be “ns1::X”, of course
    
    • But many gems add methods on “String” by “class String”…
    
    • “::X” in the code isolated in “ns1”
    
    • Should it be “ns1::X”? or the “X”?
    
    • “class ::String” should be possible
    

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24. The TODOs
    I need discussions
    • To Go? Or No Go?
    
    • In this way? Or another way? Or NO WAY?
    
    • Which way to go?
    
    • How can we break codes IN NAMESPACES? (Not globally)
    

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25. I NEED
    DISCUSSIONS
    For further developments.
    Thank you!
    

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