Simple Azure Table Persistence Usage

Component: Azure Table Persistence
NuGet Package NServiceBus.Persistence.AzureTable (3.x)
Target NServiceBus Version: 7.x

Prerequisites

Ensure that an instance of the latest Azure Storage Emulator or Azure Cosmos DB Emulator is running.

Projects

SharedMessages

The shared message contracts used by all endpoints.

Client

  • Sends the StartOrder message to Server.
  • Receives and handles the OrderCompleted event.

Server projects

  • Receive the StartOrder message and initiate an OrderSaga.
  • OrderSaga requests a timeout with an instance of CompleteOrder with the saga data.
  • OrderSaga publishes an OrderCompleted event when the CompleteOrder timeout fires.

Persistence config

Configure the endpoint to use Azure Table Persistence.

var useStorageTable = true;
var endpointConfiguration = new EndpointConfiguration("Samples.AzureTable.Simple.Server");

var persistence = endpointConfiguration.UsePersistence<AzureTablePersistence, StorageType.Sagas>();

var connection = useStorageTable ? "UseDevelopmentStorage=true" :
    "TableEndpoint=https://localhost:8081/;AccountName=AzureTableSamples;AccountKey=C2y6yDjf5/R+ob0N8A7Cgv30VRDJIWEHLM+4QDU5DE2nQ9nDuVTqobD4b8mGGyPMbIZnqyMsEcaGQy67XIw/Jw==";

var account = CloudStorageAccount.Parse(connection);
persistence.UseCloudTableClient(account.CreateCloudTableClient());

In the non-transactional mode the saga id is used as a partition key.

Order saga data

public class OrderSagaData :
    ContainSagaData
{
    public Guid OrderId { get; set; }
    public string OrderDescription { get; set; }
}

Order saga

public class OrderSaga :
    Saga<OrderSagaData>,
    IAmStartedByMessages<StartOrder>,
    IHandleTimeouts<CompleteOrder>
{
    static ILog log = LogManager.GetLogger<OrderSaga>();

    protected override void ConfigureHowToFindSaga(SagaPropertyMapper<OrderSagaData> mapper)
    {
        mapper.MapSaga(saga => saga.OrderId).ToMessage<StartOrder>(msg => msg.OrderId);
    }

    public Task Handle(StartOrder message, IMessageHandlerContext context)
    {
        var orderDescription = $"The saga for order {message.OrderId}";
        Data.OrderDescription = orderDescription;
        log.Info($"Received StartOrder message {Data.OrderId}. Starting Saga");

        var shipOrder = new ShipOrder
        {
            OrderId = message.OrderId
        };

        log.Info("Order will complete in 5 seconds");
        var timeoutData = new CompleteOrder
        {
            OrderDescription = orderDescription,
        };

        return Task.WhenAll(
            context.SendLocal(shipOrder),
            RequestTimeout(context, TimeSpan.FromSeconds(5), timeoutData)
        );
    }

    public Task Timeout(CompleteOrder state, IMessageHandlerContext context)
    {
        log.Info($"Saga with OrderId {Data.OrderId} completed");
        MarkAsComplete();
        var orderCompleted = new OrderCompleted
        {
            OrderId = Data.OrderId
        };
        return context.Publish(orderCompleted);
    }
}

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