Load Test your Facebook Application!!

Once again, the need to load test your Facebook application before deployment has been proven out in the wild. Another company has seen their application crash and burn under a load that it either wasn’t expecting, or unable to deal with. The interesting part of this story, which seems to get told over and over, is the company that was the victim of the crash and the source of the load.

In this case, the application was Facebook’s newly released Facebook Stories application. This application allows users to tell the story about how they got onto Facebook and how it changed their life. The application became overwhelmed and eventually crashed due to the load placed on it by …

… rabid Justin Bieber fans

That’s right, I just wrote the most unlikely string of words that can show up in a blog about technology. The crash was reported by Justin himself, ironically on Twitter.

 Kids, don’t let this happen to your application. Before deployment, load test it with a tool like FriendRunner.

Update

Ahhh geez! Okay, this will teach me to trust Justin Bieber. All Facebook is now reporting that the rabid Justin Bieber fans never crashed the Facebook Stories app. Instead, he was asked to remove the tab for the application from his page because he was using it to solicit stories about himself instead of using it for the purpose it was intended for (How has Facebook changed your life?).

Okay, I was fooled, but the original story did have a believable provenance. I originally heard it from Randi Zuckerberg, who after all is the sister of …. She got it from All Facebook, which is a reliable source of great FB information.

I apologize to you dear reader, and will now make the commitment that this blog will never ever disseminate any more news about Justin Bieber, regardless of what it is or where it comes from.

How does Facebook get tested?

The focus of this blog has always been to talk about testing Facebook applications. There are plenty of places to read about software testing or Facebook, but this is the one place to get that intersection. With this in mind I’m going to stray from our charter and talk about testing Facebook. No, not how to test your Facebook app, but how does Facebook test Facebook.

That’s right. Have you ever thought about how Facebook tests its own product? Well wonder no more as the good people at Quora have already asked that question, and Steven Grimm, Facebook’s test engineering tech lead has provided quite a good answer.

A few interesting take-aways:

• For a company that’s so grounded in PHP, it’s interesting to see that they’re so heavily invested in Watir, a tool from the Ruby world.
• “Facebook has no dedicated QA team.” Now for many people, this will come as no surprise. For others from a more traditional development background, no dedicated QA for something as large and mission critical as Facebook seems like a really bad idea.
• They don’t talk about load testing. From what we can tell, they probably don’t even do it. In a lot of respects, a proper load test of Facebook is probably far more trouble than it’s worth.

Arrested for load testing your Facebook app??

Yes, it sounds crazy that you could get arrested for load testing a Facebook application, but that’s the implication for what’s been reported on All Facebook.

All Facebook reports that Power Ventures, creator of the social network aggregator Power.com is being sued by Facebook for violating their Terms Of Service. Power.com allows users to log into multiple social networking sites simultaneously – you log into their service and they log into the sites automatically. The problem is that Facebook has a very clear prohibition in their TOS against accessing their service by automated means, which is exactly what Power.com is doing. How Facebook sees this as a criminal act seems kind of crazy, but that’s exactly what’s happening.

So what does this have to do with load testing? Everything! The Facebook TOS (as well as a few other technical hurdles) prevent you from hooking a standard load testing tool up to Facebook to load test your newly created Facebook app. Kids, don’t try this at home, lest you get arrested. Better stick with a dedicated tool like FriendRunner that allows you to load test your Facebook app outside of the Facebook infrastructure.

K&R and thoughts on the Graph API

With this post I’m going to do something I promised myself I wouldn’t do while writing this blog - kvetch like an old grumpy man. But there’s a point:

While I was in San Francisco for f8, I had the good fortune to attend an informal meeting of Facebook developers to discuss the changes to the Platform that were announced at f8. It was graciously hosted at the offices of one of the leading Facebook development companies in the city. They were beautiful offices high up in an historical building with great views, and more Red Bull than a developer could drink.

While there, I noticed a copy of the iconic Kernighan and Ritchie (K&R) book on the C language sitting on a desk. What transpired was a short conversation between myself and one of the employees of the company:

Me  : Very impressive, someone still reads K&R.
Him : <Blank Stare>
Me  : The Kernighan and Ritchie book on C – it’s a classic
Him : <Blank Stare>
Me  : You should read this book, it’s so beautifully written. Look how thin it is, and the whole language is thoroughly described with examples and exercises.
Him : Yeah, the Rails documentation is much thicker
Me  : <Blank Stare>
Him : That’s our CTO’s desk – it’s probably his book

Okay, so the point here is that I’m realizing that you can actually get a degree in Computer Science without ever reading K&R. Without learning C. Without really understanding what goes on at all levels inside the computer without it all getting abstracted away. I was starting to feel bad that this whole drag-and-drop Rubyization of the world was creating developers who weren’t grounded in the basics. Who didn’t deeply understand how to properly analyze an algorithm. And who probably didn’t read stuff from guys like Joel Spolsky who kvetched about it all.

But then something else crossed my mind. The reason I love C and K&R so much is because it works on so many levels. You can use it to develop (practically) on the bare metal. You can use it to write customer-facing applications. You can use it to build a server. However, it’s becoming true that the higher off the metal you get, the harder it is to use C (or even C++). Web apps, Application Servers, Multi-tiered architectures, virtualization – all of these things are so much easier to do with more “modern” languages. And you know what, I’m okay with that.

So here’s my wish: Go get a copy of K&R and read it. I used to own 3 copies: one for work, one for home, and one for lending out. Even if you never plan to use C, please read it. It’s the best technical documentation you’ll ever read, and something you should aspire to. And the reason this is true is that the language is robust and, most importantly, simple.

Which brings me to the new Facebook Graph API and the way it simplifies everything. I think we should all say Hurray. K&R reminds us that simple does not have to mean not powerful. And what the Facebook guys did with this API reminds me of what Dr. Kernighan and Dr. Ritchie had done previously. Go read the book so you too can be inspired to continue building things that are both powerful and simple.

Postscript

For sheer entertainment value, you can’t beat the first version of the Java Language spec. In particular, check out the index entry for index entries to see all of the great references they included, and see how many you can understand. Their description of multiple inheritance (Section 20.3.5) is inspired, obscure, and absolutely brilliant.

Bye Bye Facebook Lite

Facebook just announced the end of their slimmed down version known as Facebook Lite. Announced only 7 months ago, they’ve now put it to rest with this post.

So why am I talking about this event on a place dedicated to testing Facebook apps? Simple, it’s because the most important thing taken out of Facebook to create the Lite version was applications. You can’t run applications on Facebook Lite (or more correctly you couldn’t run apps on Lite). One of the reasons that Lite failed was because users like apps. Apps are important.

Test your apps.

Load testing Facebook apps (Part 1)

Calvin's dad on load testing

Load testing Facebook applications is really important. Usually the whole point of deploying onto Facebook is to leverage the social graph and go viral. Developers want their applications to go viral, but there’s a nagging concern about what will happen if they do. Is the app as scalable as you think? Are the hosting choices correct? What’s the cost of deploying and crashing?

The way to alleviate these concerns is to load test your app, but how do you do that in a Facebook environment? The simple answer is that it’s very hard due to two issues central to Facebook:

Issue1: You must control enough Facebook users

Testing your application with one or two simultaneous users is easy: simply use your own Facebook account and call up some friends and have them do the same. But running a test with hundreds or even thousands of simultaneous users is much more difficult. Where do you get the users from? That answer isn’t so simple. You can say “I’ll just go into Facebook and define a few hundred ‘phony’ people that I can control”. While this may seem like a good idea, it isn’t:

• It violates the Facebook Terms of Use (section 4.1) which prohibits you from creating phony accounts. When Facebook finds your phony account, they will delete it.
• Real users have friends, become fans of pages, post updates, and hundreds of other things that Facebook allows you to do. This creates the richness of the social graph, and applications often need to take these things into account. Unless you’re willing to spend an inordinate amount of time “humanizing” your phony user army, your tests with them will not be realistic.
• While Facebook does provide the concept of a Test Account to developers to test with, these accounts are very limited in what they can do so are not of very much use for load testing.

Issue 2: Load testing must be automated

Load testing web applications is hard. Traditionally, to test an application you’d deploy it into a “staging area” and then simulate many people using it with a tool such as HP’s LoadRunner or a cloud-based solution such as BrowserMob.

Load testing by it’s very nature must be an automated process. But this is a problem since Facebook applications must be accessed through the Facebook servers (for API support, FBML-to-HTML rendering, etc.)

 

Load testing the traditional way

This is a problem because it violates Facebook’s Terms of Use (section 3.2) which prohibits the use of accessing the Facebook servers with automated tools. This will force us to rethink our Facebook application load testing strategy.

In Part 2 of article, we’ll discuss why Facebook has a prohibition against automated tools, and why that is ultimately good for you, the developer.

 

Welcome to Test Facebook

Welcome to Test Facebook, a resource for Facebook application developers who are interested in testing their apps.

You may be wondering… since Facebook apps are Web apps, why do I need a special place to discuss testing them? Can’t I apply the same tools and techniques for developing and testing web apps to my Facebook apps?

Well, as with many things in life, the answer is yes and no. Sure you can use PHP and your favorite tools to build your app. However, because of the uniqueness of the Facebook Platform, there are special considerations that you need to think about when testing a Facebook app. Perhaps you’ve already encountered some of these special issues:

• How can I perform load testing on my app without defining hundreds, if not thousands of phony Facebook users, and how do I control them all? (…and BTW, defining phony users violates the Facebook Terms of Use Section 4.1)
• If I’m doing performance testing, how do I factor out the time spent at the Facebook servers during API calls and FBML-to-HTML rendering?
• Are there special security issues for social media applications, and how do I test for these?
• How do I tell if if my application is usable?
• How do I test my application when our development schedule is already behind?
• Are there any special issues when testing applications written for Facebook Connect?
• How do I do proper load testing when Facebook doesn’t allow me to hook up automated test tools? (Again, check the Facebook Terms of Use Section 3.2)
• Now that Facebook will proactively apply their Developer Principles, how can I be sure that my app doesn’t violate them?
• How do I test in an environment where the Platform is constantly changing?
• How can I simulate some of the error conditions that Facebook returns when I call API functions so I’ll know my app is robust?

We plan to discuss these, and many other similar topics here. But mostly, we want this to be a resource for you. If you have a question or topic that you’d like discussed, or want to be a part of our ongoing knowledge base of Facebook testing, please let us know at admin@testfacebook.com