taskwork

Taskwork

Efficient multi-threaded task scheduler using generic re-usable WebWorkers.

Taskwork is a task scheduler that is able to delegate tasks to WebWorkers. These WebWorkers are special in the sense that they are able to execute and return the results from of arbitrary tasks. At the start of the application a static amount of threads are spawned, are re-used and are kept alive throughout the lifetime of the application. This has the advantage of only paying the spawn-cost of WebWorkers (~45 ms) and the overhead of spawning only once.

Another feature of Taskwork is the ability to schedule a task with a certain priority. By automatically sorting the task queue based on priority we can make sure that tasks with the highest priority are executed first. This is important because the goal is to stay within the frameTarget (usually 60 fps) budget. Taskwork internally checks wether there is enough time left in the frame to run a task and automatically defers it to the next frame if not.

Status

UNSTABLE

Installation

Make sure you have Node.js installed.

 $ npm install taskwork

Usage

// Priorities is just an enum with default levels, you can use your own
import { Priorities, Scheduler } from 'taskwork';

// Any function, sync or async (this will be serialized and executed inside of a WebWorker)
const getUser = async (username: string) => {
  const url = `https://api.github.com/users/${username}`;
  const res = await fetch(url);
  const profile = await res.json();
  return profile.name;
};

const scheduler = new Scheduler({
  frameTarget?: number; // (Default, 60) Time available per frame to execute tasks
  threadCount?: number; // (Default, 2 - 4 depending on CPU architecture) Amount of threads to spawn
});

async () => {
  await Promise.all([
    // Add task to the scheduler .addTask(priority, fn name, [fn arguments])
    // Executed in parallel across multiple executors, returns a Promise<result>
    scheduler.addTask(Priorities.LowPriority, getUser, ['microsoft']),
    scheduler.addTask(Priorities.ImmediatePriority, getUser, [
      'timvanscherpenzeel',
    ]),
  ]).then((response: any) => {
    console.log(response); // -> ['Microsoft', 'Tim van Scherpenzeel']
  });

  // Or alternatively

  // Gets executed on first executor, returns a Promise<result>
  const taskAp = scheduler.addTask(Priorities.LowPriority, getUser, [
    'microsoft',
  ]);
  // Gets executed on second executor, returns a Promise<result>
  const taskBp = scheduler.addTask(Priorities.ImmediatePriority, getUser, [
    'timvanscherpenzeel',
  ]);

  // Await results
  const taskA = await taskAp;
  const taskB = await taskBp;

  console.log(taskA, taskB); // -> 'Microsoft', 'Tim van Scherpenzeel'
};

Licence

My work is released under the MIT license.