EventFlow is a basic CQRS+ES framework designed to be easy to use.

Have a look at our getting started guide, the dos and don'ts and the FAQ.

• CQRS+ES framework
• Async/await first: Every part of EventFlow is written using async/await. In some places EventFlow exposes sync methods like e.g. the ICommandBus, but these merely try to do the right thing using an async bridge
• Highly configurable and extendable
• Easy to use
• No use of threads or background workers making it "web friendly"
• Cancellation: All methods that does IO work or might delay execution, takes a CancellationToken argument to allow you to cancel the operation

Here is a list of the EventFlow concepts. Use the links to navigate to the documentation.

• Aggregates: Domains object that guarantees the consistency of changes being made within each aggregate
• Command bus: Entry point for all command execution.
• Event store: Storage of the event stream for aggregates. Currently there is support for these storage types.
• In-memory - only for test
• Files - only for test
• Microsoft SQL Server
• EventStore - only for test (for now) home page
• Read models: Denormalized representation of aggregate events optimized for reading fast. Currently there is support for these read model storage types.
  • In-memory - only for test
  • Microsoft SQL Server
• Queries:: Value objects that represent a query without specifying how its executed, that is let to a query handler
• Event upgrade:: As events committed to the event store is never changed, EventFlow uses the concept of event upgraders to deprecate events and replace them with new during aggregate load.
• Event publishing: Sometimes you want other applications or services to consume and act on domains. For this EventFlow supports event publishing.
• RabbitMQ
• Metadata: Additional information for each aggregate event, e.g. the IP of the user behind the event being emitted. EventFlow ships with several providers ready to use used.
• Value objects: Data containing classes used to validate and hold domain data, e.g. a username or e-mail.
• Customize: Almost every single part of EventFlow can be swapped with a custom implementation through the embedded IoC container.

Here's an example on how to use the in-memory event store (default) and a in-memory read model store.

using (var resolver = EventFlowOptions.New
    .AddEvents(typeof (TestAggregate).Assembly)
    .AddCommandHandlers(typeof (TestAggregate).Assembly)
    .UseInMemoryReadStoreFor<TestAggregate, TestReadModel>()
    .CreateResolver())
{
  var commandBus = resolver.Resolve<ICommandBus>();
  var eventStore = resolver.Resolve<IEventStore>();
  var readModelStore = resolver.Resolve<IInMemoryReadModelStore<
    TestAggregate,
    TestReadModel>>();
  var id = TestId.New;

  // Publish a command
  await commandBus.PublishAsync(new PingCommand(id));

  // Load aggregate
  var testAggregate = await eventStore.LoadAggregateAsync<TestAggregate>(id);

  // Get read model from in-memory read store
  var testReadModel = await readModelStore.GetAsync(id);
}

Note: .ConfigureAwait(false) omitted in above example.

EventFlow is still under development, especially the parts regarding how read models are re-populated.

EventFlow is currently used in production environments and performs very well, but it need to mature before key APIs are stable.

EventFlow is greatly opinionated, but its possible to create new implementations for almost every part of EventFlow by registering a different implementation of a a interface.

• CQRS Journey by Microsoft

The MIT License (MIT)

Copyright (c) 2015 Rasmus Mikkelsen
https://github.com/rasmus/EventFlow

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