Routing Slip Activity Configuration

Add a saga state machine

To add a saga state machine, use the AddSagaStateMachine method. There are several overloads for this method.

using MassTransit;

services.AddMassTransit(x =>
{
    // Adds the saga state machine
    x.AddSagaStateMachine<OrderStateMachine, OrderState>();

    // Adds the saga state machine by type using the saga definition (optional)
    x.AddSagaStateMachine(typeof(OrderStateMachine), typeof(OrderStateDefinition))

    // Adds all saga state machines from the specified assembly, including any saga definitions
    x.AddSagaStateMachines(Assembly.GetExecutingAssembly());

    // Adds all saga state machines from the namespace containing the type, including any saga definitions
    x.AddSagaStateMachinesFromNamespaceContaining<OrderStateMachine>();

    // Adds all saga state machines from the namespace containing the type, including any saga definitions
    x.AddSagaStateMachinesFromNamespaceContaining(typeof(OrderStateMachine));
});

Add a consumer saga

Consumer sagas are added using the AddSaga method.

Caution

Saga state machines should be added before consumer sagas. Do not use the consumer saga methods to add saga state machines.

using MassTransit;

services.AddMassTransit(x =>
{
    // Adds a consumer saga
    x.AddSaga<OrderSaga>();

    // Adds a saga by type
    x.AddSaga(typeof(OrderSaga));

    // Adds a saga by type using the saga definition
    x.AddSaga(typeof(OrderSaga), typeof(OrderSagaDefinition));

    // Adds all sagas in the specified assembly, including any saga definitions
    x.AddSagas(Assembly.GetExecutingAssembly());

    // Adds all sagas from the namespace containing the type, including any saga definitions
    x.AddSagasFromNamespaceContaining<OrderSaga>();
    x.AddSagasFromNamespaceContaining(typeof(OrderSaga));
});

Create a saga definition

Saga definitions are used to specify the endpoint configuration of a saga so that the saga can be automatically configured. Definitions may be explicitly added when calling AddSagaStateMachine / AddSaga or can be discovered automatically using any of the AddSagaStateMachines / AddSagas methods.

An example saga definition is shown below.

public class OrderStateDefinition :
    SagaDefinition<OrderState>
{
    public OrderStateDefinition()
    {
        ConcurrentMessageLimit = 16;

        // alternatively, configure the endpoint directly using the Endpoint method
        Endpoint(e => e.ConcurrentMessageLimit = 16);
    }

    protected override void ConfigureSaga(IReceiveEndpointConfigurator endpointConfigurator,
        ISagaConfigurator<OrderState> sagaConfigurator,
        IBusRegistrationContext context)
    {
        endpointConfigurator.UseMessageRetry(r => r.Interval(2, 100));

        endpointConfigurator.UseInMemoryOutbox();

        var partition = endpointConfigurator.CreatePartitioner(16);

        sagaConfigurator.Message<SubmitOrder>(x => x.UsePartitioner(partition, m => m.Message.CorrelationId));
        sagaConfigurator.Message<OrderAccepted>(x => x.UsePartitioner(partition, m => m.Message.CorrelationId));
        sagaConfigurator.Message<OrderCanceled>(x => x.UsePartitioner(partition, m => m.Message.CorrelationId));
    }
}

The ConfigureSaga method is used to configure the endpoint for the saga state machine when ConfigureEndpoints or ConfigureSaga is called.

Configure the saga repository

Add the repository with the saga

When adding a saga state machine, the saga repository can be configured using the appropriate extension method. In the example below, the saga state machine is configured to use an in-memory saga repository.

using MassTransit;

services.AddMassTransit(x =>
{
    x.AddSagaStateMachine<OrderStateMachine, OrderState>()
        .InMemoryRepository();
});

Add the repository separately

A saga repository can be added separately using the AddSagaRepository<TSaga> method. Using this method, the saga repository type must be specified using the appropriate extension method. In the example below, the saga state machine is configured to use an in-memory saga repository.

using MassTransit;

services.AddMassTransit(x =>
{
    x.AddSagaStateMachine<OrderStateMachine, OrderState>();

    x.AddSagaRepository<OrderState>()
        .InMemoryRepository();
});

Use the repository provider

The saga repository provider can be used to configure multiple saga repositories using the same repository type. Any saga state machines without an explicitly configured repository will use the repository provider to determine the repository type.

using MassTransit;

services.AddMassTransit(x =>
{
    x.AddSagaStateMachine<OrderStateMachine, OrderState>();

    x.SetInMemorySagaRepositoryProvider();
});

Configure the saga endpoint

When adding a saga state machine (or consumer saga), the endpoint can be configured using the Endpoint method.

In this example, the saga state machine is configured to use an in-memory saga repository, and the endpoint is configured using the name order-state with a concurrent message limit of 8.

services.AddMassTransit(r =>
{
    r.AddSagaStateMachine<OrderStateMachine, OrderState>()
        .InMemoryRepository()
        .Endpoint(e =>
        {
            e.Name = "order-state";
            e.ConcurrentMessageLimit = 8;
        });
});