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Deno Web Worker Pool

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Why Poolifier?

Poolifier is used to perform CPU and/or I/O intensive tasks on Deno servers, it implements worker pools using web worker API Deno module.
With poolifier you can improve your performance and resolve problems related to the event loop.
Moreover you can execute your tasks using an API designed to improve the developer experience.
Please consult our general guidelines.

  • Easy to use ✔
  • Fixed and dynamic pool size ✔
  • Easy switch from a pool type to another ✔
  • Performance benchmarks ✔
  • No runtime dependencies ✔
  • Support for ESM and TypeScript ✔
  • Support for web worker API Deno module ✔
  • Support for multiple task functions ✔
  • Support for task functions CRUD operations at runtime ✔
  • Support for sync and async task functions ✔
  • Tasks distribution strategies ✔
  • Lockless tasks queueing ✔
  • Queued tasks rescheduling:
    • Task stealing on empty queue ✔
    • Tasks stealing under back pressure ✔
    • Tasks redistribution on worker error ✔
  • General guidelines on pool choice ✔
  • Error handling out of the box ✔
  • Widely tested ✔
  • Active community ✔

Table of contents

Overview

Poolifier contains web worker pool implementation, you don’t have to deal with web worker API complexity.
The first implementation is a fixed worker pool, with a defined number of workers that are started at creation time and will be reused.
The second implementation is a dynamic worker pool, with a number of worker started at creation time (these workers will be always active and reused) and other workers created when the load will increase (with an upper limit, these workers will be reused when active), the newly created workers will be stopped after a configurable period of inactivity.
You have to implement your worker by extending the ThreadWorker class.

Usage

You can implement a web worker in a simple way by extending the class ThreadWorker:

import { ThreadWorker } from 'https://deno.land/x/poolifier@v0.0.3/src/index.ts'

function yourFunction(data) {
  // this will be executed in the worker thread,
  // the data will be received by using the execute method
  return { ok: 1 }
}

export default new ThreadWorker(yourFunction, {
  maxInactiveTime: 60000,
})

Instantiate your pool based on your needs :

import {
  availableParallelism,
  DynamicThreadPool,
  FixedThreadPool,
  PoolEvents,
} from 'https://deno.land/x/poolifier@v0.0.3/src/index.ts'

// a fixed worker_threads pool
const pool = new FixedThreadPool(availableParallelism(), './yourWorker.js')

pool.emitter?.on(PoolEvents.ready, () => console.info('Pool is ready'))
pool.emitter?.on(PoolEvents.busy, () => console.info('Pool is busy'))

// or a dynamic worker_threads pool
const pool = new DynamicThreadPool(
  Math.floor(availableParallelism() / 2),
  availableParallelism(),
  new URL(
    './yourWorker.js',
    import.meta.url,
  ),
)

pool.emitter?.on(PoolEvents.full, () => console.info('Pool is full'))
pool.emitter?.on(PoolEvents.ready, () => console.info('Pool is ready'))
pool.emitter?.on(PoolEvents.busy, () => console.info('Pool is busy'))

// the execute method signature is the same for both implementations,
// so you can easily switch from one to another
pool
  .execute()
  .then((res) => {
    console.info(res)
  })
  .catch((err) => {
    console.error(err)
  })

See examples for more details:

Remember that workers can only send and receive structured-cloneable data.

Deno versions

Deno versions >= 1.37.x are supported.

API

General guidelines

Worker choice strategies

Contribute

Choose your task here, propose an idea, a fix, an improvement.

See CONTRIBUTING guidelines.

Team

Creator/Owner:

Maintainers:

Contributors:

License

MIT