问题描述

我们有一个名为A的集群分片参与者，并且它有多个子参与者使用每实体模式创建的子项，如下所示。 当我们将100条消息从演员B告知D并且演员D花费比方说500毫秒来处理每条消息时，同时，当我们使用Context.Parent.Tell(new钝化(PoisonPill.Instance))将毒丸发送给演员A时； 它会立即停止所有子执行元(包括执行元D)，而不处理挂起的消息。

    A
    |
    B    
   / 
  C   D

是否有办法等待执行元D处理所有消息？

推荐答案

https://stackoverflow.com/a/70286526/377476是一个良好的开端；您将需要一个自定义关闭消息。当父执行元终止时，其子级将通过/system消息自动终止，这些消息将取代其队列中任何未处理的/user消息。

public sealed class ActorA : ReceiveActor{
    private IActorRef _actorB;  
    
    private readonly ILoggingAdapter _log = Context.GetLogger();
    
    public ActorA(){
        Receive<StartWork>(w => {
            foreach(var i in Enumerable.Range(0, w.WorkCount)){
                _actorB.Tell(i);
            }
        });
        
        ReceiveAsync<MyStopMessage>(async _ => {
            _log.Info("Begin shutdown");
            
            // stop child actor B with the same custom message
            await _actorB.GracefulStop(TimeSpan.FromSeconds(10), _);
            
            // shut ourselves down after child is done
            Context.Stop(Self);
        });
    }
    
    protected override void PreStart(){
        _actorB = Context.ActorOf(Props.Create(() => new ActorB()), "b");
    }
}

public sealed class ActorB : ReceiveActor{
    private IActorRef _actorC;
    private IActorRef _actorD;
    
    private readonly ILoggingAdapter _log = Context.GetLogger();
    
    public ActorB(){
        Receive<int>(i => {
            _actorC.Tell(i);
            _actorD.Tell(i);
        });
        
        ReceiveAsync<MyStopMessage>(async _ => {
            
            _log.Info("Begin shutdown");
            
            // stop both actors in parallel
            var stopC = _actorC.GracefulStop(TimeSpan.FromSeconds(10));
            var stopD = _actorD.GracefulStop(TimeSpan.FromSeconds(10));
            
            // compose stop Tasks
            var bothStopped = Task.WhenAll(stopC, stopD);
            await bothStopped;
            
            // shut ourselves down immediately
            Context.Stop(Self);
        });
    }
    
    protected override void PreStart(){
        var workerProps = Props.Create(() => new WorkerActor());
        _actorC = Context.ActorOf(workerProps, "c");
        _actorD = Context.ActorOf(workerProps, "d");
    }
}

public sealed class WorkerActor : ReceiveActor {
    private readonly ILoggingAdapter _log = Context.GetLogger();
    
    public WorkerActor(){
        ReceiveAsync<int>(async i => {
            await Task.Delay(10);
            _log.Info("Received {0}", i);
        });
    }
}

我在这里创建了此示例的可运行版本：https://dotnetfiddle.net/xiGyWM-您将看到MyStopMessage在示例开始后不久收到，但在C和D完成工作后收到。在此方案中，所有工作都在任何参与者终止之前完成。

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