public async Task Persist(string streamtype, string id, IEnumerable<ISourcedEvent> pendingEvents)
{
Trace.TraceInformation("Preparing batch for stream {0}.", streamtype);
var batch = new TableBatchOperation();
foreach (var @event in pendingEvents)
{
var entity = new DictionaryTableEntity
{
PartitionKey = streamtype,
RowKey = id + "_" + @event.Version.ToString(VersionKeyFormat)
};
var compressed = false;
var body = Json.Encode(@event);
if (body.Length > 32*1024)
{
body = new GzipCompression().Compress(body);
compressed = true;
}
entity.Add("EventType", @event.GetType().FullName);
entity.Add("SourceId", @event.SourceId);
entity.Add("Version", @event.Version);
entity.Add("Body", body);
entity.Add("Compressed", compressed);
batch.Add(TableOperation.Insert(entity));
}
Trace.TraceInformation("Executing batch on stream {0}.", streamtype);
await _table.ExecuteBatchAsync(batch).ContinueWith(r =>
{
Trace.TraceInformation("Batch on stream {0} complete {1} exceptions.", streamtype, r.Exception != null ? "with" : "without");
if (r.Exception != null)
{
r.Exception.Handle(exception =>
{
Trace.TraceError(exception.ToString());
return true;
});
}
});
}
private async Task<IEnumerable<ISourcedEvent>> LoadEvents(TableQuery<DictionaryTableEntity> query)
{
var events = new List<ISourcedEvent>();
TableQuerySegment<DictionaryTableEntity> querySegment = null;
var entities = new List<DictionaryTableEntity>();
while (querySegment == null || querySegment.ContinuationToken != null)
{
querySegment =
await _table.ExecuteQuerySegmentedAsync(query, querySegment != null ? querySegment.ContinuationToken : null);
entities.AddRange(querySegment);
}
foreach (var entity in entities)
{
var eventType = GetType(entity["EventType"].StringValue);
if (eventType == null) continue;
var body = entity["Body"].StringValue;
if (entity.ContainsKey("Compressed") && entity["Compressed"].BooleanValue.HasValue &&
entity["Compressed"].BooleanValue.Value)
{
body = new GzipCompression().Uncompress(body);
}
var @event = Json.Decode(body, eventType) as ISourcedEvent;
if (@event != null)
{
events.Add(@event);
}
}
return events;
}