The world is going reactive

Not long ago, response times in the seconds were considered appropriate. Browser refreshes were the norm in web applications. Systems would go down for hours of maintenance, or even be rebooted nightly, and this was ok because people only expected the systems to be up during business hours. Applications didn't have to scale because they didn't have big user bases. And the complexity requirements put on web applications meant that typical requests could easily be handled by a thread per request model.

Things are changing though. People expect web applications to react instantly. They expect them to be up all the time, while the applications are moving into the cloud, where failures are not exceptional, but rather are the norm, and so applications need to react to failure. Load on a web application can peak unpredictably, to be many orders of magnitude greater than normal, and so applications need to react to load and scale out. The complexity of business requirements means that in order to respond quickly to requests, things must be processed in parallel, reacting to events rather than waiting so as to utilise resources as efficiently as possible.

This application is an example of how to implement the tenets of the Reactive Manifesto.

It uses Play, combined with the latest in client side technologies to implement a reactive user interface. It uses Akka to provide horizontally scalable and resilient message passing and data management.

At the moment, this is purely an example to demonstrate that the Typesafe Reactive Platform runs on Azure. Check back for more exciting offerings in the coming months!

This demonstration shows how the Typesafe Reactive Platform (Play, Akka & Scala) can be used to implement scalable, resilient, responsive event driven applications. The application shows the location of every user currently connected on a map, updated in real time. Akka clustering with distributed pub sub allows it to scale horizontally. It has been tested with 50000 simulated concurrent users, each sending position updates every second, on just 10 nodes.