public async Task <ISnapshot> GetSnapshot <T>(string bucket, Id streamId, Id[] parents) where T : IEntity
{
var streamName = _streamGen(_registrar.GetVersionedName(typeof(T)), StreamTypes.Snapshot, bucket, streamId, parents);
Logger.DebugEvent("Get", "[{Stream:l}]", streamName);
if (_snapshots != null)
{
var snapshot = await _snapshots.Retrieve(streamName).ConfigureAwait(false);
if (snapshot != null)
{
_metrics.Mark("Snapshot Cache Hits", Unit.Items);
Logger.DebugEvent("Cached", "[{Stream:l}] version {Version}", streamName, snapshot.Version);
return(snapshot);
}
}
_metrics.Mark("Snapshot Cache Misses", Unit.Items);
// Check store directly (this might be a new instance which hasn't caught up to snapshot stream yet
var read = await _store.GetEventsBackwards(streamName, StreamPosition.End, 1).ConfigureAwait(false);
if (read != null && read.Any())
{
var @event = read.Single();
var snapshot = new Snapshot
{
EntityType = @event.Descriptor.EntityType,
Bucket = bucket,
StreamId = streamId,
Timestamp = @event.Descriptor.Timestamp,
Version = @event.Descriptor.Version,
Payload = @event.Event as IState
};
Logger.DebugEvent("Read", "[{Stream:l}] version {Version}", streamName, snapshot.Version);
return(snapshot);
}
Logger.DebugEvent("NotFound", "[{Stream:l}]", streamName);
return(null);
}
