NServiceBus EntityFramework Persistence

This is a plugin for NServiceBus to use EntityFramework for your persistence layer.

Features Supported

• Saga Storage
• Subscription Storage
• Timeout Storage

Installation

PM> Install-Package GoodlyFere.NServiceBus.EntityFramework

Usage

The first step in using EntityFramework persistence is to configure your bus endpoint to use this persistence library.

Bus Configuration

When manually creating a bus configuration:

BusConfiguration configuration = new BusConfiguration();
configuration.UsePersistence<EntityFrameworkPersistence>();

Or, within an EndpointConfig:

public class EndpointConfig
{
    public void Customize(BusConfiguration configuration)
    {
        configuration.UsePersistence<EntityFrameworkPersistence>();
    }
}

EntityFramework DbContext

There are a couple of integration points that you must address in your client code. You must implement your EntityFramework DbContext and you must implement the INServiceBusDbContextFactory interface that this library provides you.

INServiceBusDbContextFactory

The internal persisters in this library depend on an interface of type INServiceBusDbContextFactory that you must implement in your client code.

Implementation

The definition of this interface is very simple.

public interface INServiceBusDbContextFactory
{
    ISagaDbContext CreateSagaDbContext();

    ISubscriptionDbContext CreateSubscriptionDbContext();

    ITimeoutDbContext CreateTimeoutDbContext();
}

Each method is intended to return an instance of an EntityFramework DbContext that defines access to the database in which you want to store Saga data, subscriptions and timeouts.

Each interface defines the methods or properties that your DbContext must implement.

Container Registration

You must also register your implementation of INServiceBusDbContextFactory with the dependency injection framework that you have configured for NServiceBus.

If you are using the default container with NServiceBus, your registration may look something like this.

public class EndpointConfig
{
    public void Customize(BusConfiguration configuration)
    {
        configuration.RegisterComponents(c => c.ConfigureComponent<MyNServiceBusDbContextFactory>(DependencyLifecycle.SingleInstance));
		
        configuration.UsePersistence<EntityFrameworkPersistence>();
    }
}

DbContext

You can have three different DbContexts (one for each interface that the INServiceBusDbContextFactory requires) or have one DbContext implement all three interfaces. Here is an example of a DbContext that implements all three interfaces.

public class ExampleDbContext : DbContext,
    ITimeoutDbContext,
    ISubscriptionDbContext,
    ISagaDbContext
{
    public ExampleDbContext()
        : base("ExampleDbContext")
    {
    }

    public bool HasSet(Type entityType)
    {
        return Set(entityType) != null;
    }

    public DbSet<SubscriptionEntity> Subscriptions { get; set; }
    public DbSet<TimeoutDataEntity> Timeouts { get; set; }

    public DbSet<Example1SagaData> Example1Sagas { get; set; }
    public DbSet<Example2SagaData> Example2Sagas { get; set; }
}

In this example, I have two Saga data classes defined: Example1Sagas and Example2Sagas. The HasSet method is defined in ISagaDbContext and should return true if you have a DbSet<> property defined on your DbContext for the type provided.

Notice that the SubscriptionEntity and TimeoutDataEntity classes are defined in this library.

An Easier Way to Define Your DbContext

A good portion of the three interfaces and what they make you implement is boilerplate, unless you have very specific use-cases. They're also useful to mock in testing, of course.

If you don't have some abnormal EntityFramework setup, you can have your custom DbContext inherit from the abstract NServiceBusDbContext class in the GoodlyFere.NServiceBus.EntityFramework.SharedDbContext namespace. This abstract class is simple in definition and takes care of everything except defining your custom saga data DbSet<> properties.

public abstract class NServiceBusDbContext : DbContext, ISubscriptionDbContext, ITimeoutDbContext, ISagaDbContext
{
    protected NServiceBusDbContext(string nameOrConnectionString)
        : base(nameOrConnectionString)
    {
    }

    public virtual bool HasSet(Type entityType)
    {
        return Set(entityType) != null;
    }

    public virtual DbSet<SubscriptionEntity> Subscriptions { get; set; }
    public virtual DbSet<TimeoutDataEntity> Timeouts { get; set; }
}

Version History

• 1.4: Fix TryRemove in timeouts persister to actually try to remove timeouts (duh!!)
• 1.3: Implement TimeoutV2 interface
• 1.2: Corrections to implementation of Saga concurrency and use of DbContext in saving, deleting and updated entities.
• 1.1: Saga concurrency updates, use of pipeline to create and dispose saga DbContexts.
• 1.0: Initial release to NuGet. Stable use in production for timeout, subscription and saga data storage.