Callbacks + Async

proc.js

async.waterfall([
	download,
	process,
	upload
], function (err, results) {
	if (err) {
		return console.error('processing failed, error: ', err);
	}
	console.log('processing completed, results: ', results);
});

function download(callback) {
	ftp.download(url, function (err, stream) {
		// ... check errors and read stream, callback then ready
		callback(null, file);
	})
}

function process(file, callback) {
	// read file, read data from files..
	callback(null, file, stats);
}

function upload(file, stats, callback) {
	ftp.upload(file, function (err) {
		// ... check errors and stuff
		callback(null, {file: file.name, stats: stats});
	})
}