functionpool v0.1.1

Function Pool

Function Pool provides a fixed-size pool that can be used to execute potentially expensive tasks in Node.js.

Conceptually similar to a thread pool, but adapted to Node's single-threaded model, Function Pool organizes tasks into a queue, which will be executed by a limited number of workers. The number of workers corresponds to the number of tasks that will be allowed to execute concurrently. After the limit has been reached, tasks will be queued and executed when prior tasks complete.

Installation

$ npm install functionpool

Usage

Allocate a Pool

Create a new pool, specifying the maximum number of workers in the size option. The worker function must accept a done callback, which it must call with the result when it completes work (or error, if an exception occurs).

var pool = new functionpool.Pool({ size: 4 }, function(x, y, done) {
  setTimeout(function() { done(null, x + y) }, 5000);
});

Add Tasks to the Pool

Add tasks to the pool, which will be executed if workers are available and queued for later execution otherwise.

pool.task(3, 14, function(err, res) {
  console.log('3 + 14 = ' + res);
});

Tests

$ npm install --dev
$ make test

Credits

• Jared Hanson

License

(The MIT License)

Copyright (c) 2011 Jared Hanson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.