public void Execute(IList<IAggregateCommand> commands, int expectedVersion)
{
if (commands.Count == 0)
{
return;
}
// readModelBuilderBus will publish events to a bus that will build read models and then pass events off to
// the real eventBus
var readModelBuilderBus = new ReadModelBuildingEventBus(this.registration.ImmediateReadModels(this.scope), this.eventBus);
// holds the events that were raised from the aggregate and will push them to the read model building bus
var aggregateEvents = new UnitOfWorkEventBus(readModelBuilderBus);
// subscribe to the changes in the aggregate and publish them to aggregateEvents
var aggregateRepo = new AggregateRepository(registration.New, this.scope.GetRegisteredObject<IEventStore>(), scope.GetRegisteredObject<ISnapshotRepository>());
var subscription = aggregateRepo.Changes.Subscribe(aggregateEvents.Publish);
this.scope.Add(new UnitOfWorkDisposable(subscription));
// add them in this order so that aggregateEvents >> readModelBuilderBus >> read model builder >> eventBus
this.scope.Add(aggregateEvents);
this.scope.Add(readModelBuilderBus);
var cmd = new CommandExecutor(aggregateRepo);
cmd.Execute(commands.ToList(), expectedVersion);
// enqueue pending commands
this.EnqueueCommands(this.scope.GetRegisteredObject<IPendingCommandRepository>(), commands);
// enqueue read models to be built - for non-immediate read models
var typeName = AggregateRootBase.GetAggregateTypeDescriptor(registration.AggregateType);
this.EnqueueReadModels(this.scope.GetRegisteredObject<IReadModelQueueProducer>(), typeName, aggregateEvents.GetEvents().Select(x => x.Event).OfType<IAggregateEvent>().ToList());
}
protected virtual void InternalExecute <T>(IList <IAggregateCommand> commands, int expectedVersion) where T : IAggregateRoot
{
var registration = this.registrations.FirstOrDefault(x => x.AggregateType == typeof(T));
if (registration == null)
{
throw new InvalidOperationException(string.Format("Unregistered aggregate type {0}", typeof(T)));
}
// create a unit of work eventbus to capture aggregate events and read model events and publish in one go
using (var busBuffer = new UnitOfWorkEventBus(this.EventBus))
{
using (var scope = this.BeginUnitOfWork())
{
var exec = new DomainCommandExecutor(scope, registration, busBuffer);
exec.Execute(commands, expectedVersion);
scope.Commit();
}
// get events in the buffer, bundle them up and send them in one go to the background read model builder
// finally, publish the events to the real event bus
busBuffer.Commit();
}
}
private void DoProcessQueue()
{
// begin read model transaction scope
// get events for workitem.AggregateId
// pass events to read model
// commit
// we might see a work item for an aggregate twice in a row
// especially if we poke the queue when we receive events on
// the event bus
// in fact we can subscibe to events on the event bus and do our own poking
var doMore = true;
while (doMore)
{
var scope = this.scopeFactory();
using (scope)
{
var queue = this.queueFactory(scope);
var workItems = queue.Peek(this.maxItems);
var bus = new UnitOfWorkEventBus(this.context.EventBus);
scope.Add(bus);
foreach (var workItem in workItems)
{
if (this.cancel.IsCancellationRequested)
{
return;
}
var registration = this.registrations.FirstOrDefault(x => AggregateRootBase.GetAggregateTypeDescriptor(x.AggregateType) == workItem.AggregateType);
if (registration != null)
{
try
{
this.ProcessWorkItem(scope, registration, bus, workItem);
queue.Dequeue(workItem);
}
catch (Exception ex)
{
// TODO: handle sqlite busy exceptions
var topic = new DomainTopic(registration.AggregateType, workItem.Identity);
this.context.EventBus.Publish(new DomainNotification(topic, new ReadModelBuilderFaultedEvent(workItem.Identity, ex)));
throw;
}
}
}
scope.Commit();
doMore = workItems.Count == this.maxItems;
}
}
}
public void Execute(IList <IAggregateCommand> commands, int expectedVersion)
{
if (commands.Count == 0)
{
return;
}
// readModelBuilderBus will publish events to a bus that will build read models and then pass events off to
// the real eventBus
var readModelBuilderBus = new ReadModelBuildingEventBus(this.registration.ImmediateReadModels(this.scope), this.eventBus);
// holds the events that were raised from the aggregate and will push them to the read model building bus
var aggregateEvents = new UnitOfWorkEventBus(readModelBuilderBus);
// subscribe to the changes in the aggregate and publish them to aggregateEvents
var aggregateRepo = new AggregateRepository(registration.New, this.scope.GetRegisteredObject <IEventStore>(), scope.GetRegisteredObject <ISnapshotRepository>());
var subscription = aggregateRepo.Changes.Subscribe(aggregateEvents.Publish);
this.scope.Add(new UnitOfWorkDisposable(subscription));
// add them in this order so that aggregateEvents >> readModelBuilderBus >> read model builder >> eventBus
this.scope.Add(aggregateEvents);
this.scope.Add(readModelBuilderBus);
var cmd = new CommandExecutor(aggregateRepo);
cmd.Execute(commands.ToList(), expectedVersion);
// enqueue pending commands
this.EnqueueCommands(this.scope.GetRegisteredObject <IPendingCommandRepository>(), commands);
// enqueue read models to be built - for non-immediate read models
var typeName = AggregateRootBase.GetAggregateTypeDescriptor(registration.AggregateType);
this.EnqueueReadModels(this.scope.GetRegisteredObject <IReadModelQueueProducer>(), typeName, aggregateEvents.GetEvents().Select(x => x.Event).OfType <IAggregateEvent>().ToList());
}
private void DoProcessQueue()
{
// begin read model transaction scope
// get events for workitem.AggregateId
// pass events to read model
// commit
// we might see a work item for an aggregate twice in a row
// especially if we poke the queue when we receive events on
// the event bus
// in fact we can subscibe to events on the event bus and do our own poking
var doMore = true;
while (doMore)
{
var scope = this.scopeFactory();
using (scope)
{
var queue = this.queueFactory(scope);
var workItems = queue.Peek(this.maxItems);
var bus = new UnitOfWorkEventBus(this.context.EventBus);
scope.Add(bus);
foreach (var workItem in workItems)
{
if (this.cancel.IsCancellationRequested)
{
return;
}
var registration = this.registrations.FirstOrDefault(x => AggregateRootBase.GetAggregateTypeDescriptor(x.AggregateType) == workItem.AggregateType);
if (registration != null)
{
try
{
this.ProcessWorkItem(scope, registration, bus, workItem);
queue.Dequeue(workItem);
}
catch (Exception ex)
{
// TODO: handle sqlite busy exceptions
var topic = new DomainTopic(registration.AggregateType, workItem.Identity);
this.context.EventBus.Publish(new DomainNotification(topic, new ReadModelBuilderFaultedEvent(workItem.Identity, ex)));
throw;
}
}
}
scope.Commit();
doMore = workItems.Count == this.maxItems;
}
}
}
