workforce/lib/plugins/watch.js

A cluster manager inspired by Learnboost's cluster.

/**
 * Deps.
 */

var fs = require('fs')
  , path = require('path')
  , debug = require('debug')('workforce:plugins:watch');

/**
 * Restarts the server when `files` have changed.
 *
 * Attribution -- learnbooster/cluster:
 * https://github.com/LearnBoost/cluster/blob/master/lib/plugins/reload.js
 *
 * Options:
 *
 *  - `interval` Watch interval, defaults to 100
 *  - `extensions` File extensions to watch, defaults to ['.js']
 *  - `ignore` Directores to ignore. Merges with ['.git', 'node_modules']
 */

module.exports = exports = function(files, options){
  options = options || {};

  var interval = options.interval || 100
    , ignore = options.ignore || ['.git', 'node_modules']
    , extensions = options.extensions || ['.js'];

  return function(workforce){
    if (!files) files = [workforce.dir];
    if (!Array.isArray(files)) files = [files];

    debug('loaded');
    files.forEach(traverse);

    function traverse(file){
      fs.stat(file, function(err, stat){
        if (err) return console.error(err.messsage);
        if (stat.isDirectory()) {
          readDirectory(file);
        } else if (stat.isFile()) {
          watchFile(file);
        }
      });
    }

    function readDirectory(file){
      if (~ignore.indexOf(path.basename(file))) return;
      debug('watching %s', file);
      var join = path.join.bind(path, file);
      fs.readdir(file, function(err, files){
        files
          .map(join)
          .forEach(traverse);
      });
    }

    function watchFile(file){
      if (!~extensions.indexOf(path.extname(file))) return;
      var settings = { interval: interval, persistent: false };
      fs.watchFile(file, settings, function(curr, prev){
        if (curr.mtime > prev.mtime) {
          debug('file change -- %s', file);
          workforce.restart();
        }
      });
    }
  };
};