Building scalable breakout rooms with Node.js worker threads

NodeJS worker threads have opened doors to many exciting implementations and functionalities on the server-side. Multiplayer networked games, and live engagement and collaboration, among others, make a really good candidate for CPU intensive applications which would greatly benefit from this multi-threaded-ness of NodeJS.

In this talk, we’ll understand everything about NodeJS worker threads and see a real implementation of this concept to simulate dedicated server instances to enable various groups of players to play private instances of a live quiz simultaneously.

Transcript

1. BUILDING SCALABLE
   BREAKOUT ROOMS
   USING NODE.JS
   WORKER THREADS
   Srushtika Neelakantam
   Developer Relations Engineer at Ably Realtime
   

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2. HELLO!
   I’M SRUSHTIKA
   DevRel
   Engineer
   @Srushtika
   

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3. Let’s see
   breakout rooms
   in action
   TIME FOR A FUN QUIZ!
   3
   @Srushtika |
   Brighton Web Dev Meetup |
   https://quiz.ably.dev/
   

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4. BREAKOUT ROOMS
   FUNCTIONALITY
   1. How does realtime messaging
   work?
   2. How to make use of Node.js worker
   threads to efficiently simulate
   dedicated server instances for each
   breakout room?
   @Srushtika |
   Brighton Web Dev Meetup |
   

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5. HTTP WebSockets
   vs.
   @Srushtika |
   Brighton Web Dev Meetup |
   

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6. Publish/Subscribe
   messaging pattern
   Feature add-ons
   ● Presence
   ● Message History
   ● Integrations
   .
   .
   .
   Infrastructure add-ons
   ● Auto reconnection
   ● Scale
   ● Guaranteed delivery
   ● Message ordering
   .
   .
   .
   P.S. This is an old gif, Ably has moved on to new branding now.
   @Srushtika |
   Brighton Web Dev Meetup |
   

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7. BREAKOUT ROOMS
   FUNCTIONALITY
   1. How does realtime messaging
   work? ✅
   2. How to make use of Node.js worker
   threads to efficiently simulate
   dedicated server instances for each
   breakout room?
   @Srushtika |
   Brighton Web Dev Meetup |
   

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8. WORKER THREADS
   IN NODE.JS
   @Srushtika |
   Brighton Web Dev Meetup |
   

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9. HOW DOES
   NODE.JS WORK?
   @Srushtika |
   Brighton Web Dev Meetup |
   

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10. KEY ELEMENTS THAT MAKE NODE.JS WORK
    The chrome v8 engine
    converts JavaScript to
    machine readable
    code
    The libuv library
    provides and
    manages the event
    loop and thread pool
    @Srushtika |
    Brighton Web Dev Meetup |
    

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11. GREAT EXPLANATION OF EVENT LOOP BY PHILIP ROBERTS (JSConfEU on
    YouTube)
    @Srushtika |
    Brighton Web Dev Meetup |
    

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12. “Node.js is a CPU bottleneck due to
    its single-threaded nature. That’s
    one of its major drawbacks”
    @Srushtika |
    Brighton Web Dev Meetup |
    

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13. WORKER THREADS
    IN NODE.JS
    @Srushtika |
    Brighton Web Dev Meetup |
    

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14. NODE.JS WORKER THREADS ARCHITECTURE
    @Srushtika |
    Brighton Web Dev Meetup |
    Image source: The NodeSource Blog
    

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15. @Srushtika |
    Brighton Web Dev Meetup |
    

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16. Let’s see some real code
    https://github.com/ably-labs/realtime-quiz-framework
    @Srushtika |
    Brighton Web Dev Meetup |
    

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17. BREAKOUT ROOMS
    FUNCTIONALITY
    1. How does realtime messaging
    work? ✅
    2. How to make use of Node.js worker
    threads to efficiently simulate
    dedicated server instances for each
    breakout room? ✅
    @Srushtika |
    Brighton Web Dev Meetup |
    

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18. CAVEATS AND
    OTHER THINGS
    - Don’t use Worker threads for parallelizing
    I/O operations, the native Node
    architecture can do that more quickly
    - Creating worker threads is not cheap, so it’s
    better to create and use a thread pool
    instead
    - If there are async methods available, it’s
    better to use them, rather than off-loading
    to your own worker thread
    @Srushtika |
    Brighton Web Dev Meetup |
    

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19. Thankyou!
    @Srushtika |
    Brighton Web Dev Meetup |
    Further reading
    - NodeJS docs: https://nodejs.org/api/worker_threads.html
    - Demo source code: https://github.com/Srushtika/realtime-quiz-framework
    - “What the heck is an event loop anyway?”: https://youtu.be/8aGhZQkoFbQ
    - “Introduction to libuv: What's a Unicorn Velociraptor?”: https://youtu.be/_c51fcXRLGw
    - Realtime concepts: https://ably.com/topics
    

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