Sunday, April 15, 2012

Review: Scalability Rules

0 comments
This is the review I posted to Amazon on the book Scalability Rules:

Get this book if you're transitioning to the services world or want to improve your skillset without having to make all the mistakes yourself.

The proposal of this book is to present the topics briefly. Once you read these rules, take them to your heart and, from there, learn how to apply it specifically in your environment. It will probably involve doing a lot more reading and experimenting, but at least this book will give you the starting points.

If you have some experience developing and operating a world class service, then you will quickly notice that the authors do know what they're talking about. I've had this experience as a service developer and operator and can definitely relate to most of these lessons.

Also these lessons do not apply only to web sites, but to any web services; and it's beyond scalability, it's about the mind shift to the services world. Developers that did not work on services tend to think they are relatively similar to product - and they are NOT. Companies transitioning from a product to a services focus should buy several copies of this book and give one to each developer, because you can get most of these rules if they are taken into account from day one, not as an afterthought.

Friday, April 06, 2012

.NET - Reactive Extensions (Rx) for event-based programming

0 comments
One of the nice .NET features I learned recently is called Reactive Extensions. This is a very nice library that allows asynchronous and event-based programs to be used as collections. I found it particularly compelling to learn it as I see more and more code being written in async way and event-driven. However, if you're not so used to this kind of programming, it is hard to wrap your mind around code that makes use of it - and debug and find where issues can be when they arise.

Reactive Extensions moves from a pull-model to a push-model, where instead of having a collection that implements an IEnumerable, you have an IObservable that you subscribe to. Your delegate is then called whenever an event is dispatched by your source. But it's not only that. You can make use of many Linq operators to make your code much simpler.

I'd recommend that you watch the videos on the following page:
http://msdn.microsoft.com/en-us/data/gg577611

Out of these videos, do the workshops and try the challenges. Since they are not ordered on the page above, let me list them in order here:
http://channel9.msdn.com/Series/Rx-Workshop/Rx-Workshop-Introduction
http://channel9.msdn.com/Series/Rx-Workshop/Rx-Workshop-Observables-versus-Events
http://channel9.msdn.com/Series/Rx-Workshop/Rx-Workshop-Unified-Programming-Model
http://channel9.msdn.com/Series/Rx-Workshop/Rx-Workshop-Writing-Queries
http://channel9.msdn.com/Series/Rx-Workshop/Rx-Workshop-Schedulers
http://channel9.msdn.com/Series/Rx-Workshop/Rx-Workshop-Event-Processing

Finally, another good link is this page with tens of Rx samples:
http://rxwiki.wikidot.com/101samples