Easily manage a pool of Node.js Worker Threads

worker-threads-pool

Easily manage a pool of Node.js Worker Threads.

Installation

npm install worker-threads-pool --save

Prerequisites

Worker Threads in Node.js are still an experimental feature and is only supported in Node.js v10.5.0 and above. To use Worker Threads, you need to run node with the --experimental-worker flag:

node --experimental-worker app.js

Usage

const Pool = require('worker-threads-pool')

const pool = new Pool({max: 5})

for (let i = 0; i < 100; i++) {
  pool.acquire('/my/worker.js', function (err, worker) {
    if (err) throw err
    console.log(`started worker ${i} (pool size: ${pool.size})`)
    worker.on('exit', function () {
      console.log(`worker ${i} exited (pool size: ${pool.size})`)
    })
  })
}

API

pool = new Pool([options])

options is an optional object/dictionary with the any of the following properties:

• max - Maximum number of workers allowed in the pool. Other workers will be queued and started once there’s room in the pool (default: 1)
• maxWaiting - Maximum number of workers waiting to be started when the pool is full. The callback to pool.acquire will be called with an error in case this limit is reached

pool.size

Number of active workers in the pool.

pool.acquire(filename[, options], callback)

The filename and options arguments are passed directly to new Worker(filename, options).

The callback argument will be called with the an optional error object and the worker once it’s created.

pool.destroy([callback])

Calls worker.terminate() on all workers in the pool.

Will call the optional callback once all workers have terminated.

License

MIT