Worker Options

Piscina allows you to customize the environment and runtime options for worker threads. You can set environment variables, command-line arguments, and other options for the worker processes.

This is useful when you need to:

• Pass configuration or environment-specific data to workers
• Control Node.js runtime behavior in workers
• Provide initial data to workers without including it in every task

Javascript

index.js

'use strict';

const Piscina = require('../..');
const { resolve } = require('path');

const piscina = new Piscina({
  filename: resolve(__dirname, 'worker.js'),
  env: { A: '123' },
  argv: ['a', 'b', 'c'],
  execArgv: ['--no-warnings'],
  workerData: 'ABC'
});

(async function () {
  const result = await piscina.run({ a: 4, b: 6 });
  console.log(result); // Prints 10
})();

worker.js

'use strict';

const Piscina = require('../..');
const { format } = require('util');

module.exports = ({ a, b }) => {
  console.log(`
process.argv: ${process.argv.slice(2)}
process.execArgv: ${process.execArgv}
process.env: ${format({ ...process.env })}
workerData: ${Piscina.workerData}`);
  return a + b;
};

Typescript

index.ts

import { resolve } from 'path';
import Piscina from 'piscina';
import { filename } from './worker';

const piscina = new Piscina({
  filename: resolve(__dirname, 'workerWrapper.js'),
  workerData: { fullpath: filename },
  env: { A: '123' },
  argv: ['a', 'b', 'c'],
  execArgv: ['--no-warnings'],
});

(async function () {
  const result = await piscina.run({ a: 4, b: 6 });
  console.log(result); // Prints 10
})();

worker.ts

import Piscina from 'piscina';
import { format } from 'util';

export default ({ a, b }: { a: number, b: number }): number => {
  console.log(`
process.argv: ${process.argv.slice(2)}
process.execArgv: ${process.execArgv}
process.env: ${format({ ...process.env })}
workerData: ${Piscina.workerData}`);
  return a + b;
};

workerWrapper.js

const { workerData } = require('worker_threads');

if (workerData.fullpath.endsWith(".ts")) {
require("ts-node").register();
}
module.exports = require(workerData.fullpath);

You can also check out this example on github.