Drop-in Replacement for fs to prevent too many open files


Filequeue was born out of my encounter with Error: EMFILE, too many open files, which occurs when you try to open too many files at once on your system. Due to Node's asynchronous nature, if you perform a lot of fs.readFile or similar operations in quick succession, you can easily hit your system's maxfiles limit, usually set to 256 on a dev box.

Filequeue creates a replacement for fs, that I use as fq with many of the same operations. However, it keeps track of how many files are open at once, and queues them if there are too many.

Through NPM

$ npm install filequeue

or using Git

$ git clone git:// node_modules/filequeue/
  var FileQueue = require('filequeue');
  var fq = new FileQueue(100);
  // additional instances will attempt to use the same instance (and therefore the same maxfiles) unless the `newQueue` is explicitly passed. 
  var FileQueue2 = require('filequeue');
  var fq2 = new FileQueue(100);
  console.log(fq === fq2); // => true 
  • readFile
  • writeFile
  • readdir
  • stat
  • exists
  for(var i=0; i<1000; i++) {
    fq.readFile('/somefile.txt', function(errsomefile) {
      console.log("data from somefile.txt without crashing!", somefile);

Pull requests to add other fs methods are welcome - these are the methods I use most often, so I built in support for them.