Quick and dirty nodejs s3 sync from gruntfile. Not 100% yet

Gruntfile

require('js-yaml');
var _ = require('lodash');
var fs = require('fs');
var aws = require('aws-sdk');
var path = require('path');
var exec = require('exec-sync');

module.exports = function (grunt) {

  grunt.initConfig({
		pkg: grunt.file.readJSON('package.json')
	});

	// Deploy
	grunt.registerTask('deploy', 'Deploy staging', function() {

		var done = this.async();
		var current_sha = exec('git rev-parse HEAD');

		try {
			var config = require('./project.yaml');
		}
		catch (error) {
			console.log(error);
			console.warn('Unable to continue with deploy.');
			return;
		}
		aws.config.update({
			region: config.s3['region'],
			accessKeyId: config.s3['access-key'],
			secretAccessKey: config.s3['secret']
		});

		var all_paths = [];

		var traverse = function(basepath) {
			_.each(fs.readdirSync(basepath), function(filepath) {
				if(filepath.match(/^.+\..+$/)) {
					all_paths.push(basepath + path.sep + filepath);
				}
				else if(filepath.match(/^[^\.]+$/)) {
					// Folder, traverse deeper
					traverse(basepath + path.sep + filepath);
				}
				else {
					// Dotfiles
				}
			});
		};


		traverse(config['build-dir']);
		var files = {};
		_.each(all_paths, function(filepath) {
			files[filepath.replace(config['build-dir'] + path.sep, '')] = fs.statSync(filepath).size
		});

		var s3 = new aws.S3({params: {
			apiVersion: '2006-03-01'
		}});
		var upload_files = [];
		s3.listObjects({Bucket: config.s3['bucket-name']}, function(error, data) {
			if(error) {
				console.error('Unable to list bucket "%s"', config.s3['bucket-name'])
			}
			else {
				_.each(data.Contents, function(obj) {
					if(files[obj.Key] !== undefined) {
						if(files[obj.Key] !== obj.Size) {
							upload_files.push(obj.Key);
						}
					}
				});
			}

			_.each(upload_files, function(remote_filename) {
				var local_filename = config['build-dir'] + path.sep + remote_filename;
				var file_data;
				try {
					file_data = fs.readFileSync(local_filename, 'utf-8');
				}
				catch(error) {
					console.log(error);
					console.error('Upload of %s failed', local_filename);
					return;
				}
					
				console.log('Uploading %s', local_filename);
				// TODO: Make sure the content type is set correctly
				s3.putObject({
					Bucket: config.s3['bucket-name'],
					Key: remote_filename,
					Body: file_data
				}, function(error, data) {
					if(error) {
						console.log(error);
						console.error('Upload of %s failed', local_filename);
					}
					else {
						console.log('Successfully uploaded %s', local_filename);
					}
				});

			});

			// TODO: Make this work without timeout, it should call done when all files are uploaded
			setTimeout(function(){
				done();
			},4000);
		});


	});

};