Fighting Legacy Codebases with GraphQL and Rails

GraphQL is one of the hottest technologies of the past year or two. Still, very little is talked about GraphQL outside of the realm of front-end applications.

We used a different approach at IFTTT and applied GraphQL as an integration layer for different backends and client apps.

This talk goes beyond the basic configuration of a GraphQL endpoint with Rails. I’ll cover topics such ActiveRecord Query optimization, performance monitoring, batching and share some of the challenges we ran into while building a GraphQL API that serves over 10 thousand queries per minute.

Transcript

1. Rescuing legacy codebases
   with GraphQL and Rails
   @nettofarah
   

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2. Netto Farah
   @nettofarah
   !"
   

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3. Conference speakers are
   professional enthusiasts
   Take this with a grain
   of salt
   

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5. Context
   • Website, iOS app, Android app
   • Seasoned Rails 3 codebase
   

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6. Technical Challenge
   • Build an entirely new website and mobile apps
   • Iterate fast (9 months deadline)
   

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7. We knew we needed
   to make some changes
   

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8. Majestic Monoliths
   vs
   Micro-services
   

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9. Not a binary
   decision
   

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10. A hybrid approach:
    Rich API + specific clients
    

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11. Challenges with
    Traditional APIs
    

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12. Multiple use cases
    

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13. with different
    access patterns
    
    

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14. Documentation
    and Conventions
    

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15. [%,",&..'] => ✅
    )
    

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16. )
    [!] =>
    ask me later…
    

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17. GraphQL
    a language specification for 

    defining and querying APIs
    

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18. Describe your data
    with TYPES
    

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19. type Rubygem {
    name: String
    downloads: Int
    versions: [Version]
    }
    

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20. Load just what
    you need
    

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21. query {
    rubygems {

    name
    downloads
    }
    }
    

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22. You can even load
    multiple entities at once
    

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23. query {
    rubygems {

    name, downloads
    }
    current_user {
    login, email
    }
    }
    

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24. Get predictable
    results
    

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25. {
    "data": {
    "rubygem": {
    "name": "rails",
    "downloads": 89321853
    },
    “current_user": {
    "login": "nettofarah",
    "email": “nettofarah@gmail.com"
    }
    }
    }
    

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26. GraphQL focuses on
    the clients
    

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27. GraphQL + Ruby = ❤
    

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28. Demo time!
    

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29. RubyGems API
    Rubygem Version
    Dependency
    has_many
    has_many
    

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30. RubyGems API - use cases
    • list all available rubygems
    • search one specific rubygem by name
    

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31. Let’s see some code!
    http://bit.ly/gql-demo
    

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32. We built a GraphQL API
    on top of our data model
    

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33. GraphQL API
    as an integration layer
    for multiple (not so micro) services
    and front-ends
    

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34. GraphQL
    API
    
    
    ☁
    A
    P
    I
    

    G

    A

    T
    E

    W

    A
    Y
    Service A
    Service B
    Service C
    

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35. GraphQL
    API
    
    
    ⛈
    A
    P
    I
    

    G

    A

    T
    E

    W

    A
    Y
    Service A
    Service B
    Service C
    
    
    
    

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36. GraphQL in
    production
    

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37. What happened
    to semantic status codes?
    

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38. N+1 queries
    

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39. github.com/nettofarah/graphql-query-resolver
    

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40. Monitoring and
    Errors
    

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44. http://bit.ly/gql-rb-nr
    

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45. Where to go next?
    • graphql.org
    • graphql.slack.com (#ruby - I hang out there)
    • https://github.com/rmosolgo/graphql-ruby
    

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46. @nettofarah
    nettofarah@gmail.com
    

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