private async Task <MongoDbRecord> LockRecord(byte[] lockToken, Record r)
{
var key = r.Key.ToByteArray();
var version = r.Version.ToByteArray();
if (version.Length != 0)
{
var res = await RecordCollection.FindOneAndUpdateAsync(
x => x.Key.Equals(key) && x.Version.Equals(version) && (x.TransactionLock == null || x.TransactionLock.Equals(lockToken)),
Builders <MongoDbRecord> .Update
.Set(x => x.TransactionLock, lockToken)
);
if (res == null)
{
var e = new ConcurrentMutationException(r);
e.Data["ExceptionType"] = "LockRecord";
throw e;
}
#if DEBUG
Logger.LogDebug($"Locked token {new ByteString(lockToken)} {r.Key.ToString()}");
#endif
return(res);
}
return(null);
}
private async Task RollbackTransaction(byte[] hash)
{
// Rollback is idempotent && reentrant : may be call twice even at the same time
try
{
#if DEBUG
Logger.LogDebug($"Rollbacking transaction {new ByteString(hash)}");
#endif
// get affected records
var trn = await PendingTransactionCollection.Find(x => x.TransactionHash.Equals(hash)).SingleOrDefaultAsync();
if (trn != null)
{
// revert records values & version
foreach (var r in trn.InitialRecords)
{
await RecordCollection.FindOneAndUpdateAsync(
x => x.Key.Equals(r.Key) && x.TransactionLock.Equals(trn.LockToken),
Builders <MongoDbRecord> .Update.Set(x => x.Value, r.Value).Set(x => x.Version, r.Version).Unset(x => x.TransactionLock)
);
}
foreach (var r in trn.AddedRecords)
{
await RecordCollection.FindOneAndDeleteAsync(
x => x.Key.Equals(r) && x.TransactionLock.Equals(trn.LockToken)
);
}
// remove transaction
await TransactionCollection.DeleteOneAsync(x => x.TransactionHash.Equals(hash));
await RecordCollection.UpdateOneAsync(
x => x.TransactionLock == trn.LockToken,
Builders <MongoDbRecord> .Update
.Unset(x => x.TransactionLock)
);
// remove pending transaction
await PendingTransactionCollection.DeleteOneAsync(x => x.TransactionHash.Equals(hash));
Logger.LogInformation($"Transaction {new ByteString(hash)} rollbacked");
}
}
catch (Exception ex)
{
var msg = "Error rollbacking transaction : " + new ByteString(hash).ToString();
Logger.LogCritical(msg, ex);
throw new Exception(msg, ex);
}
}
private async Task <MongoDbRecord> LockRecord(byte[] lockToken, Record r)
{
var key = r.Key.ToByteArray();
var version = r.Version.ToByteArray();
if (version.Length != 0)
{
var res = await RecordCollection.FindOneAndUpdateAsync(
x => x.Key.Equals(key) && x.Version.Equals(version) && (x.TransactionLock == null || x.TransactionLock.Equals(lockToken)),
Builders <MongoDbRecord> .Update
.Set(x => x.TransactionLock, lockToken)
);
if (res == null)
{
throw new ConcurrentMutationException(r);
}
return(res);
}
return(null);
}
