Lots of folks have been asking about Akka.NET and ASP.NET MVC integration on StackOverflow and in our Gitter chat room, so we thought it was time we created the definitive post on how to integrate these two amazing technologies together.
Note: Everything in this article also applies to Web API, Nancy, WCF, and ASP.NET WebForms.
So when would you want to use Akka.NET and a web framework like ASP.NET together at the same time?
Well, you might be like Joel in our “Akka.NET Goes to Wall Street” case study and need to manage concurrent reads / writes to a shared object model.
If you’re building anything resembling a chat room, web-based game, collaboration software, and more - then congratulations: managing concurrent mutations to shared state is something you’re going to have to do. Akka.NET actors are a tremendously better option than sprinkling your code with locks.
In general, what most people use Akka.NET for in the context of ASP.NET is to communicate with others network services the ASP.NET app might depend on, such as remote Windows Services via Akka.Remote and Akka.Cluster. This is especially useful if you need to do any sort of stateful web application programming, but that’s a story for a different day.
How to Start an
ActorSystem in ASP.NET
// config automatically loads from App.config / Web.config var actorSystem = ActorSystem.Create("myactorsystem"); var someActor = actorSystem.ActorOf(Props.Create(() => new FooActor
One of the topics I covered during my presentation about using Akka.NET in production at MarkedUp was the concept of stateful applications built with actors - the idea that state can reside within your application rather than outside of it by default, and how it was this idea that made our marketing automation product possible to build.
This tweet from an attendee sums up the realization well:
@Aaronontheweb A key take away for me is Actors are stateful and I do not have to get/post constantly from Redis. Wow that is liberating.— akshay123 (@akshay123) August 12, 2015
Exactly right! Actors can be stateful - and that means we no longer have to factor round-trip times to SQL Server, Redis, Cassandra, or whatever into the design of our applications. The application already has the state it needs to do its job by the time a request arrives!
The Limitations of Stateless Design
The traditional way of developing web applications is stateless - and that’s a natural consequence of HTTP, itself an inherently stateless protocol.
Many people in the Akka.NET community have been asking for case studies over the last few weeks, since we shared the MarkedUp case study. There are a ton of production deployments, but getting actual case studies out always has some lag time.
To that end, I wanted to share an email case study that I received from Joel Mueller, an Akka.NET community member, that just BLEW MY MIND (reprinted with permission).
Check out Joel’s story of how Akka.NET changed the trajectory of his business, which is now a part of McGraw Hill—owners of this little thing called Standard & Poor’s—and now proud users of Akka.NET, acquiring SNL Financial for $2 billion:
Joel Mueller, Software Architect, SNL Financial
One of the features of a larger product I’ve been working on for years is a budgeting/forecasting module for community banks. Picture an ASP.NET project that is roughly the equivalent of 200-300 interrelated Excel workbooks, using a custom mostly-Excel-compatible formula engine, lots of business rules, lots of back-end queries against both SQL and Analysis Services, and a front-end in SlickGrid that communicates with the back-end over XHR and Web API. The object model for Forecast instances is (was) stored in ASP.NET session state until changes are saved to the application database. That, of course, means one instance per session, even if two people open the same forecast.
Then, as an afterthought bullet point at the end of a list of other new features being requested, “oh by the way, can you make it work for multiple concurrent users in a single forecast, Google Docs style?”
After I was done freaking out and yelling at people, I sat down to figure out how...