Bug in MassTransit 2.9.9 Combine method

[Kostas Cibulskas]

After many hours of headache I've finally tracked the issue I've been facing for quite some time now.

The problem being that my sagas are being started by messages which should NEVER start any sagas. And by definition that is not happening. Well, sort of, apparently.

The following is a code example which illustrates the bug.

The issue is that Combine method doesn't take into account the state during which events may happen. So the outcome is that saga is started by any events defined in During(Initial, ...) AND any events defined in Combine(...).

I have never send ThirdMessage which supposedly initializes SecondSaga yet my SecondSaga was initialized with the same Guid used in FirstSaga.

using Magnum.StateMachine;
using MassTransit;
using MassTransit.Saga;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace MassTransitBug
{
    public class Program
    {
        static void Main(string[] args)
        {
            var bus = ServiceBusFactory.New(sbc =>
            {
                sbc.UseRabbitMq();
                sbc.UseJsonSerializer();
                sbc.ReceiveFrom("rabbitmq://localhost/bugtest");
                sbc.DisablePerformanceCounters();
                sbc.Subscribe(subs =>
                {
                    subs.Saga<FirstSaga>(new InMemorySagaRepository<FirstSaga>()).Permanent();
                    subs.Saga<SecondSaga>(new InMemorySagaRepository<SecondSaga>()).Permanent();
                    subs.Consumer<Consumer>();
                });
            });


            bus.Publish(new FirstMessage()
            {
                CorrelationId = Guid.NewGuid(),
                Text = "what's up?"
            });
        }
    }


    public class Consumer : Consumes<SecondMessageRequest>.All
    {




        public void Consume(SecondMessageRequest request)
        {
            this.Context().Respond<SecondMessageResponse>(new SecondMessageResponse()
            {
                CorrelationId = request.CorrelationId,
                Response = "ok, " + request.Number
            });
        }
    }


    public class FirstMessage : CorrelatedBy<Guid> {
        public Guid CorrelationId { get; set; }
        public string Text { get; set; }
    }


    public class SecondMessageRequest : CorrelatedBy<Guid> {
        public Guid CorrelationId { get; set; }
        public int Number { get; set; }
    }


    public class SecondMessageResponse : CorrelatedBy<Guid>
    {
        public Guid CorrelationId { get; set; }
        public string Response { get; set; }
    }


    public class ThirdMessage : CorrelatedBy<Guid>
    {
        public Guid CorrelationId { get; set; }
    }


    public class FirstSaga : SagaStateMachine<FirstSaga>, ISaga
    {
        public Guid CorrelationId { get; set; }
        public IServiceBus Bus { get; set; }


        public static State Initial { get; set; }
        public static State Waiting { get; set; }
        public static State Completed { get; set; }


        public static Event<FirstMessage> FirstMessageReceived { get; set; }
        public static Event<SecondMessageResponse> SecondMessageResponseReceived { get; set; }


        public FirstSaga(Guid guid)
        {
            CorrelationId = guid;
        }


        static FirstSaga()
        {
            Define(() =>
            {
                During(Initial,
                    When(FirstMessageReceived)
                        .TransitionTo(Waiting)
                        .Publish((saga, message) =>
                        {
                            return new SecondMessageRequest()
                            {
                                CorrelationId = saga.CorrelationId,
                                Number = 123
                            };
                        }));


                During(Waiting,
                    When(SecondMessageResponseReceived)
                        .Then((saga, response) =>
                        {
                            Console.WriteLine(response.Response);
                        })
                        .TransitionTo(Completed));
            });
        }
    }


    public class SecondSaga : SagaStateMachine<SecondSaga>, ISaga
    {
        public Guid CorrelationId { get; set; }
        public IServiceBus Bus { get; set; }


        public static State Initial { get; set; }
        public static State Waiting { get; set; }
        public static State Completed { get; set; }


        public static Event<ThirdMessage> ThirdMessageReceived { get; set; }
        public static Event<SecondMessageResponse> SecondMessageResponseReceived { get; set; }
        public static Event Done { get; set; }


        public int Flags { get; set; }
        public SecondSaga(Guid guid)
        {
            CorrelationId = guid;


            if (guid != Guid.Empty)
            {
                Console.WriteLine("SecondSaga should never be initialized");
            }
        }


        static SecondSaga()
        {
            Define(() =>
            {
                During(Initial,
                    When(ThirdMessageReceived)
                        .TransitionTo(Waiting));


                Combine(SecondMessageResponseReceived).Into(Done, saga => saga.Flags);


                During(Waiting,
                    When(SecondMessageResponseReceived)
                        .Then(saga => {


                        }));
            });
        }
    }
}

packages.config file:

<packages>
  <package id="Magnum" version="2.1.3" targetFramework="net45" />
  <package id="MassTransit" version="2.9.9" targetFramework="net45" />
  <package id="MassTransit.RabbitMQ" version="2.9.9" targetFramework="net45" />
  <package id="Newtonsoft.Json" version="6.0.6" targetFramework="net45" />
  <package id="RabbitMQ.Client" version="3.4.0" targetFramework="net45" />
</packages>

[Chris Patterson]

These should be:

subs.StateMachineSaga<SecondSaga>(new inMmeoryRepository());

[Kostas Cibulskas]

Is that an extension method? It's not on SubscriptionBusServiceConfigurator and can't find it anywhere in Object Browser. Maybe it's in some missing NuGet package?

[Chris Patterson]

It's in http://www.nuget.org/packages/Automatonymous.MassTransit/ and it's required to properly map the events to the subscriptions.

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[Kostas Cibulskas]

But I'm dealing with Magnum-based sagas here, not Automatonymous-based ones. Isn't there a solution for this with Magnum?

On Monday, March 16, 2015 at 5:58:23 PM UTC+2, Chris Patterson wrote:

It's in http://www.nuget.org/packages/Automatonymous.MassTransit/ and it's required to properly map the events to the subscriptions.

On Sun, Mar 15, 2015 at 11:21 PM, Kostas Cibulskas <kost...@gmail.com> wrote:

Is that an extension method? It's not on SubscriptionBusServiceConfigurator and can't find it anywhere in Object Browser. Maybe it's in some missing NuGet package?

On Friday, March 13, 2015 at 5:46:20 PM UTC+2, Chris Patterson wrote:

These should be:

subs.StateMachineSaga<SecondSaga>(new inMmeoryRepository());

On Fri, Mar 13, 2015 at 4:09 AM, Kostas Cibulskas <kost...@gmail.com> wrote:

subs.Saga<FirstSaga>(new InMemorySagaRepository<FirstSaga>()).Permanent();
                    subs.Saga<SecondSaga>(new InMemorySagaRepository<SecondSaga>()).Permanent();
                    subs.Consumer<Consumer>();
                });

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