A SignalR backplane implemented in Orleans
When running SignalR on more than one web server (a common scenario in the cloud) you need a backplane to connect together each of the servers. This allows messages broadcast from a user connected to one server, to reach the users on the other servers.
There are already some backplane options in Azure:
- SQL Server
- Service Bus Topics/Subscriptions
- Redis (you should probably use this)
I thought it would be interesting to implement a backplane in Orleans.
The projects required to implement a system:
- OrleansR.GrainInterfaces The Oreans grain interfaces.
- OrleansR.Grains The Orleans grain implementations.
- OrleansR.MessageBus The
IMessageBusimplementation which plugs into SignalR, and connects to the Orleans Silos.
Sample/test projects included in the solution:
- OrleansR.Cloud A sample project to deploy the solution to Azure.
- OrleansR.UnitTests Unit tests for the grains.
- OrleansR.Web A sample web application.
- OrleansR.WorkerRoleSiloHost A sample Worker Role to host the Orleans Silo.
Configure Orleans in the usual way, by starting up a Silo, and connecting a web application to it as described here.
When configuring SignalR in the Startup class of your web application, register the OrleanMessageBus class like this:
using Microsoft.AspNet.SignalR;
using Microsoft.AspNet.SignalR.Messaging;
using OrleansR.MessageBus;
using Owin;
namespace OrleansR.Web
{
public class Startup
{
public void Configuration(IAppBuilder app)
{
// configure the OrleansR message bus
var config = new ScaleoutConfiguration { MaxQueueLength = 10, QueueBehavior = QueuingBehavior.Always };
var omb = new OrleansMessageBus(GlobalHost.DependencyResolver, config);
GlobalHost.DependencyResolver.Register(typeof(IMessageBus), () => omb);
// register SignalR as ususal
app.MapSignalR();
}
}
}MIT