ZMQ JsonRpc

This is my experimentation and proof of concept using ZMQ as task distribution for JSONRPC 2.0 based service.

#Features

• REQ/REP for client and worker communication
• Attributes based service class and method registration
• Asynchronous and synchronous client
• Method namespacing to group methods or to identify a class
• PUB/SUB for notification
• ROUTER/DEALER for worker distribution to provide basic scalability (*)
• Windows service that can install multiple service modes and names using single executable (*)

#Goal

• Provide simple .NET based system for internal task distribution
• Easy to scale by adding more workers behind ROUTER/DEALER socket (*)
• Easy to monitor the message flow

#Todos

• Code comments
• More tests
• Improve a lot of things if not all

#Usages

##Class and method registration

    [JsonRpcServiceHandler]
    class SimpleHandler
    {
        [JsonRpcMethod(Authorize = true, LogCall = false, Description = "Just echoing")]
        public string Echo(string message)
        {
            return message;
        }

        [JsonRpcMethod]
        public double AddNumber(double v1, double v2)
        {
            return v1 + v2;
        }
    }

	....

    var worker = Worker.Create("127.0.0.1", 3001);
    worker.AddTaskHandler(new TaskHandlerDescriptor(typeof(SimpleHandler), "namespace:"));
    worker.Start();

##Client's method call

	// asynchronous call
	var client = MSA.Zmq.JsonRpc.Client.CreateJsonRpcContext("tcp://127.0.0.1:3001");
    client.CallMethodAsync<double>("namespace:AddNumber", (ret) => 
	{
        Console.WriteLine(ret);
    }, 200, 50);

	....

	// synchronous call
	var ret = client.CallMethod<double>("namespace:AddNumber", 200, 50);

##PUB/SUB

	// Publisher setup
	// It will bind PUB on 3002 and PULL socket on 3003
	var publisher = Publisher.Create("127.0.0.1", 3002, 3003, context);

	....

	// Subscriber
	var subscriber = MSA.Zmq.JsonRpc.Client.CreateSubscriberContext("tcp://127.0.0.1:3002");

    // subscribe for event triggered from another agent
    subscriber.Subscribe("oob:notification", (s) =>
    {
		// react with the event
    });
	
	....

	// Publisher / PUSH
	var client = Client.CreatePushContext("tcp://127.0.0.1:3003");
	pusher.Push("oob:notification", "some data here");

Please refer to Server.Demo, Client.Demo and Push.Demo projects for working samples Run them together as multiple startup projects

##Service usages (*)

• Put the required assemblies in the same folder with service executable
• Register the each assembly containing the handler class

  <zmsa-handlers>
    <handlers>
      <!--<add handlerName="sampleHandler" assemblyName="SameHandlerAssembly" endpointPrefix=""/>-->
    </handlers>
  </zmsa-handlers>

• Execute the service executable with --help for more information

(*) Not ready, need modifications to work on zmq 3.x .NET client (ClrZmq)