public async Task WriteStateAsync(string grainType, GrainReference grainReference, IGrainState grainState)
{
EnsureNotClosed();
var meta = grainState.ToGrainMeta(grainReference, grainType, _serviceId);
try
{
var collectionName = Naming.CollectionNameForGrain(grainType, _options.CollectionNamePrefix);
var collection = _database.GetCollection <MongoGrain>(collectionName);
LogVerbose3($"Writing data: {meta}", MongoStorageLogCode.TraceWriting);
if (string.IsNullOrEmpty(grainState.ETag))
{
var grain = grainState.ToGrain(grainReference, grainType, _serviceId);
grain.Meta.Timestamp = DateTime.UtcNow.Ticks;
await collection.InsertOneAsync(grain);
grainState.ETag = grain.Meta.ETag;
}
else
{
var id = Naming.PrimaryKeyForGrain(_serviceId, grainReference);
// Update data and generate new timestamp
var update = Builders <MongoGrain> .Update
.Set(x => x.Data, grainState.State)
.Set(x => x.Meta.Timestamp, DateTime.UtcNow.Ticks);
var options = new FindOneAndUpdateOptions <MongoGrain>
{
IsUpsert = false,
ReturnDocument = ReturnDocument.After,
Projection = Builders <MongoGrain> .Projection.Include(x => x.Meta)
};
var updatedGrain = await collection.FindOneAndUpdateAsync <MongoGrain>(
x => x.Id == id && x.Meta.Timestamp == meta.Timestamp,
update,
options);
if (updatedGrain == null)
{
var message =
$"Inconsistent state for grain: {meta}. ETag has changed or document has already been deleted.";
throw new InconsistentStateException(message);
}
grainState.ETag = updatedGrain.Meta.ETag;
}
LogVerbose3($"Wrote data: {meta}", MongoStorageLogCode.TraceWrite);
}
catch (Exception ex)
{
LogError($"Error while writing. {meta} Error={ex.Message}", MongoStorageLogCode.ErrorWrite, ex);
throw;
}
}