无界面访问谷物

Question

I'm planning my IoT system and comparing Akka.NET with Orleans. Generally Orleans API is more close to .NET standards but I'm wondering is there any other way to communicate with Grain? In documentation I see that we define interface like

public interface IDevice : IGrainWithGuidKey
{
  Task TurnOn(TurnOnCommand command);
  Task TurnOff(TurnOffCommand command);
}

And use it like this

IDevice device = GrainFactory.GetGrain<IDevice>(id);

This is fine when we have actors that have very strict interface but in home we have a lot of devices and I don't want to define 100x interfaces for each of them. I would prefer to each of them have set of handlers for commands that it can handle and client could invoke

device.Execute(new TurnOnCommand()) 

without defining interface for each. Is this possible in Orleans?

Answer 1

You can define an interface which accepts a base class/interface, such as ICommandProcessor<TCommand> and implement multiple versions of that, so you might have IMyDeviceGrain implementing ICommandProcessor<TurnOnCommand>, ICommandProcessor<TurnOffCommand> , and so on.

In that case, you might define ICommandProcessor<TCommand> as:

public interface ICommandProcessor<TCommand>
{
    Task Process(TCommand command);   
}

The grain interface might look like:

public class IDeviceGrain :
  IGrainWithStringKey,
  ICommandProcessor<TurnOnCommand>,
  ICommandProcessor<TurnOffCommand>
{
}

The grain class could then look like:

public class DeviceGrain : Grain, IDeviceGrain
{
    Task Process(TurnOnCommand command) { /* turn on */ }
    Task Process(TurnOffCommand command) { /* turn off */ }
}

I've also seen people implement this by having a grain which has a single Task Process(object command) call which internally used dynamic to dispatch based on the type of command .

I hope that helps. Please let me know if there are any points which you would like clarified.