public Task <Event> GetLastEventAsync(Guid aggregateId) => storage.GetLastEventAsync(aggregateId);
public async Task CommitAsync()
{
try
{
foreach (var aggregate in trackedAggregates.Values)
{
if (!aggregate.HasEventSourcing())
{
throw new AggregateFeatureNotFoundException($"Aggregate '{aggregate.GetType().Name}:{aggregate.Id}' must has '{nameof(EventSourcingAggregateFeature)}' to uses '{nameof(EventSourcingRepository<TAggregate>)}'.");
}
var expectedVersion = aggregate.GetLastCommittedVersion();
var lastEvent = await eventStorage.GetLastEventAsync(aggregate.Id);
if ((lastEvent != null) && (expectedVersion == 0))
{
throw new AggregateCreationException($"Aggregate '{aggregate.Id}' can't be created as it already exists with version {lastEvent.EventSourcing().TargetVersion + 1}");
}
else if ((lastEvent != null) && ((lastEvent.EventSourcing().TargetVersion + 1) != expectedVersion))
{
throw new ConcurrencyException($"Aggregate '{aggregate.Id}' has been modified externally and has an updated state. Can't commit changes.");
}
var changesToCommit = aggregate.GetPendingEvents();
//perform pre commit actions
foreach (var e in changesToCommit)
{
e.EventSourcing().EventCommittedTimestamp = DateTime.UtcNow;
}
//CommitAsync events to storage provider
await eventStorage.CommitAsync(aggregate.Id, changesToCommit);
aggregate.EventSourcing().LastCommittedVersion = aggregate.GetCurrentVersion();
// If the Aggregate is snapshottable
if (aggregate.IsSnapshottable())
{
if (aggregate.GetCurrentVersion() - aggregate.GetSnapshotVersion() > aggregate.GetSnapshotFrequency())
{
await snapshotStorage.SaveSnapshotAsync(aggregate.GetSnapshot());
aggregate.EventSourcing().SnapshotVersion = aggregate.GetCurrentVersion();
}
}
// Dispatch events asynchronously
foreach (var e in changesToCommit)
{
await eventDispatcher.DispatchAsync(e);
}
aggregate.ClearPendingEvents();
}
trackedAggregates.Clear();
}
catch (Exception ex)
{
log.Error($"Error '{ex.GetType().Name}' in '{nameof(EventSourcingRepository<TAggregate>)}.{nameof(CommitAsync)}': {ex.Message}", ex);
throw;
}
}