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[WIP] Questions/Brainstorming #50

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[WIP] Questions/Brainstorming#50

Description

@GretaCB
GretaCB
opened on Jun 30, 2017

Per discussion with @springmeyer , outlining possible next steps for node-cpp-skel and capturing best practices to document and integrate into the skel design.

Questions to answer

  • What does it look like to have the variable that represents an instance of a class accessible in the threadpool?

  • What is the role of a singleton and how is it related to other design patterns for sync/async?

  • When passing data to thread pool, the data needs to be a type that is safe to pass into the thread pool. What makes a type safe to pass into the thread pool?

    • Two scenarios that are safe:
      • Copy data to a C++ object (pure, part of the C++ std lib...not V8)
      • Copy V8 data: Extra work to keep the V8 object alive, avoids the object perhaps getting deleted (trick: use v8::Persistant)

Designing skel:

Goal 1)

  • Provide examples of objects that feel real-world, actionable, and sturdy
  • Unlocks: ability to fork and run fast and feel confidence the foundation is a best practice

Goal 2)

  • Provide incremental examples that build complexity gradually
  • Unlocks: easier for beginning developers to understand gradually why extra complexity is needed

Preliminary conclusion: object-sync is caught between these worlds

Terms to learn

Standard C++

  • Singleton - is a general programming concept for creating a instance once in the process
    • mapnik uses singletons for datasource plugin and font registration
  • static keyword
  • reference (what does the & mean?)

V8

  • Nan::Persistent (which is really v8::Persistent)
  • v8::FunctionTemplate and v8::Function
  • Nan::ObjectWrap

Possible next steps:

  • @springmeyer could add/edit comments and provide them in another PR
  • Build ^^ items into the cpp glossary (@GretaCB first pass)
  • Object async example: Demonstrate how we safely and efficiently utilize the threadpool to do work on data.
    Two options:
    • vt-shaver example:
      • Filters class, exposed in JS
      • Able to create the Filters class once (as object in JS)
      • Standalone shave function access Filters as an argument
      • Filters is passed into the threadpool
    • node-mapnik design: Classes expose method

Activity

  1. GretaCB commented on Jul 11, 2017

    @GretaCB
    GretaCB
    on Jul 11, 2017
    ContributorAuthor

    Update

    Per chat with @springmeyer when running through #51, I plan to:

    • split the README into different docs:
      • /docs/*.md: Info about C++ best practices, add-on conventions, explanation of files, and general 101
      • README.md: The main README will be a great template README that developers can use for their own add-ons when using the skel as a baseline (how to install, run tests, build, publish, etc)
    • Finalize object_async example
    • Expand in the docs why each example is relevant/useful and when you would use each
    • Comment sweep: Run through each example and config files to make sure relevant info is included and consistent within the comments, and that API.md is up to date
    • Run .clang-format
    • Performance section? Per chat with @springmeyer , we discussed that we should iterate on the bench/performance docs after having a realworld module in progress using the skel. See next check box below. But really want to make this a highlight since this is one of the main inspirations behind this skel, how to write high performance code.
    • Put it into action by creating a new module from scratch (chat with @springmeyer about what module that could be). And use this as a way to feed missing docs/comments/examples back into the skel.
    • Get feedback from mapbox team

  2. springmeyer commented on Jul 12, 2017

    @springmeyer
    springmeyer
    on Jul 12, 2017
    Contributor

    Build ^^ items into the cpp glossary (@GretaCB first pass)

    mapbox/cpp@92af068 and mapbox/cpp@beb75bf

  3. springmeyer commented on Aug 2, 2017

    @springmeyer
    springmeyer
    on Aug 2, 2017
    Contributor

    @GretaCB thanks for catching up on skel today voice. To help get to the finish line for this phase I've reviewed all open issues and commented on ones that I think are actionable. Of those that are actionable I think these are the priority things to finish before you move along:

  4. springmeyer commented on Aug 25, 2017

    @springmeyer
    springmeyer
    on Aug 25, 2017
    Contributor

    woot @GretaCB - everything above is checked. Shall we close?

  5. GretaCB
    closed this as completedon Nov 14, 2017
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