when to use node? lessons learned

When to use Node.js? Lessons learned

Coen Stevens - Amsterdam Node Meetup 2012

@beatlevic BeatleTech.com

Saturday, March 31, 12

W2010


Why not Node.js• We never heard of Node.js at the time (2009)

and were experienced in Ruby

• Lots of server-side computations / statistics / map-reduce (blocking the node event-loop)

• Typical dashboard (view on a database)

• Not that many concurrent users

• No need for open connections

Yes, I would use Ruby again


Pivot: Penny auctions

• Swoopo and Bigdeal (real goods)

• Newcope a platform for pay-per-bid auction games for virtual goods


http://newcope-heyzap.heroku.com/home

Flash game platform


http://newcope-heyzap.heroku.com/


• The Broth: BarnBuddy

• Facebook app

• Similar to Farmville

• Over 1 million active users per month


Challenge

• Build iframe / facebook app solution

• Have the auctions as realtime as possible

• Long polling (later websockets) vs pulling

• Lots of users with open connections

• Scalable


Languages considered

• Ruby (Eventmachine, no Goliath yet)

• JRuby

• Scala (Twitter had just moved from ruby)

• Erlang

• Javascript Node.js


Node.js experiences• Functional programming

• Javascript for both client and server

• Very good performance (30k users the first day)

• Node v0.1.25 and no packet manager (npm)

• MySQL with DBSlayer (later Mongodb)

• Nginx to serve static files

• Easy to setup/deploy on EC2 (upstart deamon)

• Everything async (annoying to test)

• Fun!Yes, I would use Node.js again


Auction.prototype.startTimer = function() { var self = this; if (this.timer) clearTimeout(this.timer); this.emit("start"); this.timer = setTimeout(function() { self.emit("end"); }, self.timeLeft() * 1000);}

Auction.prototype.bid = function(user) { var self = this; return function (callback, errback) { if (user.bid_count > 0 && self.status() === "running") { user.bid_count -= 1; dbUser.updateUser(user.id, {'bid_count': user.bid_count})(function(result){ if (self.timeLeft() < self.bidTimeDelta) { self.setTime(me.bidTimeDelta); }; self.price += self.bidPriceDelta; var bid = { user: user, ts: new Date() } self.bids.push(bid); self.bidCount++; callback(self); }, function(error) { user.bid_count += 1; errback("Could not update new bid count"); }) } else { errback("Bid could not be placed"); } };}


// continuation stylevar bid = function(user) { return function (callback, errback) { if (!user) return errback("No user") callback(user) }}

bid(user)(function(result){ console.log(result)}, function(error) { console.log(error)})


// promise stylevar bid = function(user) { var promise = new Promise() if (!user) { promise.emitError("No user") } else { promise.emitSuccess(user) } return promise}

var promise = bid(user)promise.addErrback(function(error){ console.log(error)})promise.addCallback(function(result) { console.log(result)})


• // callback stylevar bid = function(user, callback) { if (!user) return callback("No user") callback(null, user);}

bid(user, function(err, result){ if (err) console.log(err) console.log(result)})


• Bottlenose is the smartest social media dashboard.

• Helping you manage the information overload on streams like twitter and Facebook

• Bottlenose analyzes and filters messages using NLP and clustering techniques

• Beta launched December 2011

http://bottlenose.comSaturday, March 31, 12



Why Node.js?

• It began (2009) with NLP in javascript, run it both on the client and the server

• Fat client and lean server

• Realtime stream updates

• Lots of users (with open connections)

• Alternatives?

Yes, I would use Node.js again


Summary: When to use Node?

• When you are building more of an app than a website and require lots of open connections to the server

• When you want your users to get data in realtime (chat, streams)

• When you have to serve lots of requests that do not take too many cpu cycles (blocking the loop)

• When you like to work with Javascript all the way


Thanks!

@beatlevic


when to use node? lessons learned

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