c# - Akka.net 动态添加子

Question

有一个配置ActorSystem了按层次组织的参与者，如下所示：

/user
  /processes
    /process1
    /process2
    /process3

为了生成这个方案，我使用了下一个 C# 代码：

// in entry point
IActorRef processesCoordinatorActorRef = ActorSystem.ActorOf(Props.Create<ProcessesCoordinatorActor>(), "processes");

// in ProcessesCoordinatorActor.cs:
IActorRef processOneActorRef = Context.ActorOf(Props.Create<ProccessActor>(), "process1");
IActorRef processTwoActorRef = Context.ActorOf(Props.Create<ProccessActor>(), "process2");
IActorRef processThreeActorRef = Context.ActorOf(Props.Create<ProccessActor>(), "process3");

我的问题是我想将一个子角色添加到process1，process2或者process3从入口点代码（在 ProcessActor 之外）。但是现在我的手被束缚了，因为IActorRef对我隐藏了某些演员实例。

我该如何解决？

Answer 1

子actor必须在Context父actor中创建。如果您想从外部触发这种情况，只需向父级发送一条消息并让它创建子actor（例如CreateChildActor）。没有办法在一个地方创建一个演员，然后让它作为另一个演员的孩子被“收养”。

通常（并且不知道您实际上要做什么），我的直觉是从您的顶级/入口点代码的层次结构中创建演员对您来说不是一个好的方向。您应该让层次结构中的父角色完成创建和监督子角色的工作。

如果您必须从入口点触发此过程，您可以CreateChildActor使用 anActorSelection和/或将其解析为IActorRef.

这是一个代码示例，展示了如何执行此操作，并让子流程在准备好后通知协调器（这里也作为 Fiddle）：

using System;
using System.Threading;
using Akka.Actor;

namespace ProcessActors
{
    class Program
    {
        /// <summary>
        /// Top-level process coordinator actor.
        /// </summary>
        public class ProcessesCoordinatorActor : ReceiveActor
        {
            public ProcessesCoordinatorActor()
            {
                Receive<CreateChildActor>(createRequest =>
                {
                    Console.WriteLine("{0} creating child actor: {1}", Self.Path, createRequest.ChildName);

                    var child = Context.ActorOf(createRequest.ChildProps, createRequest.ChildName);
                    if (createRequest.ActorToNotify != null)
                        createRequest.ActorToNotify.Tell(new ReadyForWork(child));
                });

                Receive<ReadyForWork>(ready =>
                {
                    Console.WriteLine("Coordinator sees worker ready: {0}", ready.Worker.Path);
                });

                ReceiveAny(o =>
                {
                    Console.WriteLine("{0} received {1}", Self.Path, o);
                });

            }
        }

        /// <summary>
        /// Actor for a given process.
        /// </summary>
        public class ProcessActor : ReceiveActor
        {
            public ProcessActor()
            {
                Receive<CreateChildActor>(createRequest =>
                {
                    Console.WriteLine("{0} creating child actor: {1}", Self.Path, createRequest.ChildName);

                    var child = Context.ActorOf(createRequest.ChildProps, createRequest.ChildName);
                    if (createRequest.ActorToNotify != null)
                        createRequest.ActorToNotify.Tell(new ReadyForWork(child));
                });

                ReceiveAny(o =>
                {
                    Console.WriteLine("{0} received {1}", Self.Path, o);
                });
            }
        }

        /// <summary>
        /// Sub-process.
        /// </summary>
        public class SubprocessActor : ReceiveActor
        {
            public SubprocessActor()
            {
                ReceiveAny(o =>
                {
                    Console.WriteLine("{0} received {1}", Self.Path, o);
                });
            }
        }

        public static void Main(string[] args)
        {
            using (var system = ActorSystem.Create("MyActorSystem"))
            {

                Console.WriteLine("Starting up.");

                var coordinator = system.ActorOf(Props.Create(() => new ProcessesCoordinatorActor()), "processes");
                var processProps = Props.Create(() => new ProcessActor());

                // create process actors
                coordinator.Tell(new CreateNewProcess("process1", processProps));
                coordinator.Tell(new CreateNewProcess("process2", processProps));
                coordinator.Tell(new CreateNewProcess("process3", processProps));

                var subprocessProps = Props.Create(() => new SubprocessActor());

                // tiny sleep to let everything boot
                Thread.Sleep(TimeSpan.FromMilliseconds(50));

                // get handle to an actor somewhere down in the hierarchy
                var process1 = system.ActorSelection("/user/processes/process1").ResolveOne(TimeSpan.FromSeconds(1)).Result;

                // create subprocess of process1 and notify the coordinator of new subprocess actor
                process1.Tell(new CreateNewSubprocess("subprocess1", subprocessProps, coordinator));

                Console.ReadLine();
            }
        }

        #region Messages
        /// <summary>
        /// Command to create ChildProps actor and notify another actor about it.
        /// </summary>
        public class CreateChildActor
        {
            public CreateChildActor(string childName, Props childProps, IActorRef actorToNotify)
            {
                ChildName = childName;
                ActorToNotify = actorToNotify;
                ChildProps = childProps;
            }

            public CreateChildActor(string childName, Props childProps)
                : this(childName, childProps, null)
            {
            }

            public Props ChildProps { get; private set; }
            public string ChildName { get; private set; }
            public IActorRef ActorToNotify { get; private set; }
        }

        public class CreateNewProcess : CreateChildActor
        {
            public CreateNewProcess(string childName, Props childProps, IActorRef actorToNotify)
                : base(childName, childProps, actorToNotify)
            {
            }

            public CreateNewProcess(string childName, Props childProps)
                : this(childName, childProps, null)
            {
            }
        }

        public class CreateNewSubprocess : CreateChildActor
        {
            public CreateNewSubprocess(string childName, Props childProps, IActorRef actorToNotify)
                : base(childName, childProps, actorToNotify)
            {
            }

            public CreateNewSubprocess(string childName, Props childProps)
                : this(childName, childProps, null)
            {
            }
        }

        /// <summary>
        /// Report to another actor when ready.
        /// </summary>
        public class ReadyForWork
        {
            public ReadyForWork(IActorRef worker)
            {
                Worker = worker;
            }

            public IActorRef Worker { get; private set; }
        }

        #endregion

    }
}