oktaykir/eventflow.example

DDD+CQRS+Event-sourcing examples using EventFlow following CQRS-ES architecture. It is configured with RabbitMQ, MongoDB(Snapshot store), PostgreSQL(Read store), EventStore(GES). It's targeted to .Net Core 2.2 and include docker compose file.

EventFlow.Example

DDD+CQRS+Event-sourcing examples using EventFlow following CQRS-ES architecture. It is configured with RabbitMQ, MongoDB(Snapshot store), PostgreSQL(Read store), EventStore(GES). It's targeted to .Net Core 2.2 and include docker compose file.

Event Sourcing/CQRS Architecture

The most common CQRS/ES architecture would look like following diagram

The example consists of the following concepts, each shown below

• Aggregates
• Command bus and commands
• Synchronous subscriber
• Event store (GES)
• In-memory read model.
• Snapshots (MongoDb)
• Sagas
• Event publising (In-memory, RabbitMq)
• Metadata
• Command bus decorator, custom value object, custom execution result, ...

Configuration

var resolver = EventFlowOptions.New
    .UseAutofacContainerBuilder(new ContainerBuilder())
    .Configure(c => c.ThrowSubscriberExceptions = true)
    .AddEvents(typeof(ExampleEvent))
    .AddEvents(typeof(ResetEvent))
    .AddCommands(typeof(ExampleCommand))
    .AddCommands(typeof(ResetCommand))
    .AddCommandHandlers(typeof(ExampleCommandHandler))
    .AddCommandHandlers(typeof(ResetCommandHandler))
    .ConfigureEventStore()
    .ConfigureMongoDb(client, SNAPSHOT_CONTAINER_NAME)
    .AddSnapshots(typeof(ExampleSnaphost))
    .UseMongoDbSnapshotStore()
    .RegisterServices(sr => sr.Register(i => SnapshotEveryFewVersionsStrategy.Default))
    .RegisterServices(DecorateCommandBus)
    .PublishToRabbitMq(RabbitMqConfiguration.With(new Uri(@"amqp://test:test@localhost:5672"), true, 4, "eventflow"))
    .UseInMemoryReadStoreFor<Aggregates.ReadModels.ExampleReadModel>()
    .AddJobs(typeof(ExampleJob))
    .CreateResolver());

📦 Stack

• EventFlow
• EventStore
• RabbitMQ
• MongoDB
• PostgreSQL
• Docker

🤝 Contributing

1. Fork it ( https://github.com/OKTAYKIR/EventFlow.Example/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

✨ Contributors

Show your support

Please ⭐️ this repository if this project helped you!

📝 License

Apache-2.0 © Oktay Kır

eventflow.example's Issues

Upgrading some stuff

@suadev, I get the following error after running the application:

12:17:48:558 [Debug]: Execution of command 'ExampleCommand' with ID 'command-a478d189-d908-4bb9-918f-c7507b1eb9ee' on aggregate 'EventFlowExample.Aggregates.ExampleAggregate' failed due to exception 'TypeInitializationException' with message: The type initializer for 'MongoDB.Bson.Serialization.BsonClassMap' threw an exception. - System.TypeInitializationException: The type initializer for 'MongoDB.Bson.Serialization.BsonClassMap' threw an exception.
 ---> System.ArgumentNullException: Value cannot be null. (Parameter 'type')
   at System.Reflection.IntrospectionExtensions.GetTypeInfo(Type type)
   at MongoDB.Bson.Serialization.BsonClassMap..cctor()
   --- End of inner exception stack trace ---
   at MongoDB.Bson.Serialization.BsonClassMap.LookupClassMap(Type classType)
   at MongoDB.Bson.Serialization.BsonClassMapSerializationProvider.GetSerializer(Type type, IBsonSerializerRegistry serializerRegistry)
   at MongoDB.Bson.Serialization.BsonSerializerRegistry.CreateSerializer(Type type)
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at MongoDB.Bson.Serialization.BsonSerializerRegistry.GetSerializer(Type type)
   at MongoDB.Bson.Serialization.BsonSerializerRegistry.GetSerializer[T]()
   at MongoDB.Driver.MongoCollectionImpl`1..ctor(IMongoDatabase database, CollectionNamespace collectionNamespace, MongoCollectionSettings settings, ICluster cluster, IOperationExecutor operationExecutor)
   at MongoDB.Driver.MongoDatabaseImpl.GetCollection[TDocument](String name, MongoCollectionSettings settings)
   at EventFlow.MongoDB.SnapshotStores.MongoDbSnapshotPersistence.GetSnapshotAsync(Type aggregateType, IIdentity identity, CancellationToken cancellationToken)
   at EventFlow.Snapshots.SnapshotStore.LoadSnapshotAsync[TAggregate,TIdentity,TSnapshot](TIdentity identity, CancellationToken cancellationToken)
   at EventFlow.Snapshots.SnapshotAggregateRoot`3.LoadAsync(IEventStore eventStore, ISnapshotStore snapshotStore, CancellationToken cancellationToken)
   at EventFlow.Aggregates.AggregateStore.LoadAsync[TAggregate,TIdentity](TIdentity id, CancellationToken cancellationToken)
   at EventFlow.Aggregates.AggregateStore.<>c__DisplayClass11_0`3.<<UpdateAsync>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at EventFlow.Core.TransientFaultHandler`1.TryAsync[T](Func`2 action, Label label, CancellationToken cancellationToken)
   at EventFlow.Aggregates.AggregateStore.UpdateAsync[TAggregate,TIdentity,TExecutionResult](TIdentity id, ISourceId sourceId, Func`3 updateAggregate, CancellationToken cancellationToken)
   at EventFlow.CommandBus.ExecuteCommandAsync[TAggregate,TIdentity,TResult](ICommand`3 command, CancellationToken cancellationToken)
   at EventFlow.CommandBus.PublishAsync[TAggregate,TIdentity,TResult](ICommand`3 command, CancellationToken cancellationToken)

I reverted your commit, you can create a new pull request.

Originally posted by @OKTAYKIR in #4 (comment)

Writing Integration Tests