Documently is a single bounded context with a single domain model and multiple autonymous services. The SAAS that is Documently is exposed by sending command to the
Documently.Domain.Service and listening to corresponding events domain events.
A higher-level description of the architecture is available at the Jayway Architecture site.
First with git:
git clone https://github.com/haf/Documently.git git submodule init
Start the event-store and view-store - RavenDB.Server, in this case. It can be found in
src\packages\RavenDB.1.x.x\server. Once this is done, install RabbitMQ
There are two sample clients: one WPF Client with a nice UI and one console application for a quick start. Before using them, you need to compile the solution and start the
Documently.Domain.Service console application. This is the domain service that handles the domain logic and broadcasts the (domain) events.
Once both RavenDB and the Domain Service are started without error messages, start one of the clients, or both and try it out!
Note: When starting Domain Service the first time you will need to run it as admin to avoid getting error messages from MassTransit's Performance Counters - or you can run it and just ignore those messages.
TODO for v2
- StateBox-like for union and ordinary event stream merging when eventually consistent event store (different from the often spoken about eventual consistency of read models) - this would allow you to use Riak and other master-master type events stores and also handle for example event-stores in different countries/data centers in which case net-splits between stores may occurr.
- Document upload in user interface
- Document listing in user interface
- Document details in user interface
- Document search in user interface
All messages interfaces + proper infrastructure Do away with complex unit testing procedures Better cohesion in code base by avoiding inheritance and using value objects to a greater extent and having infrastructure that is only used with command handlers in that specific assembly (that may take a couple of dependencies on infrastructure) Better naming of commands and events based on experience with too-long-names Better documentation for each folder Using dynamic instead of CommonDomain
- Proper Saga example with Automatonymous and MassTransit (and EventStore?)
- Properly handling de-duplication of events on the read-side
- Properly handling replaying of the event store from the last received point forward on the read-side
- Finishing implementing the Document-part of the App and WpfClient
- Running a WPF, a iOS phone and console application side-by-side and having the system work as a whole.
- Implement the indexing logic for the Document-part of the domain using SVMs.
- Bump up the domain model complexity a notch to warrant DDD in the first place!
Some of the concepts you can learn include:
- Creating a Caliburn Micro WPF client with a ribbon, which uses the EventAggregator pattern for its reactive UI and wires itself up with Castle Windsor.
- How to configure MassTransit with RabbitMQ
- How to write unit-tests for aggregate roots based on simple invoke-method, read resulting events.
- How to use CommonDomain to publish committed events
- Getting started with RavenDB
- Getting started with RabbitMQ
- Doing application validation logic (non-emptyness, etc) with FluentValidation
- How to use TopShelf with the DomainService (in daemon/Windows Service mode, not hosted).
The sample is based on code by:
- Greg Young: http://github.com/gregoryyoung/m-r
- and uses Jonathan Oliver's EventStore libraries.
- The WPF Client uses Caliburn.Micro: http://caliburnmicro.codeplex.com/
- The wiki is in parts based on a presentation 2011-07-23 by Greg Young
You can find more information about CQRS in the wiki: https://github.com/haf/Documently/wiki