/// <summary>
/// Create a poller, start the poller and return starting position of the poller.
/// </summary>
/// <param name="poller"></param>
/// <param name="pollerId"></param>
/// <returns></returns>
private Int64 CreatePollerAndStart(ref PollingClient poller, Int32 pollerId, Func <AtomicDispatchChunk, Task <Boolean> > dispatchToTplFunction)
{
if (poller != null)
{
poller.Stop();
}
var startingPosition = TryGetStartingPoint(pollerId);
Logger.InfoFormat("AtomicProjectionEngine: Starting poller id {0} from position {1}", pollerId, startingPosition);
var subscription = new JarvisFrameworkLambdaSubscription(c => dispatchToTplFunction(new AtomicDispatchChunk(pollerId, c)));
poller = new PollingClient(_persistence, startingPosition, subscription, _nStoreLoggerFactory);
poller.Start();
return(startingPosition);
}
/// <summary>
/// Create a poller, start the poller and return starting position of the poller.
/// </summary>
/// <param name="poller"></param>
/// <param name="pollerId"></param>
/// <returns></returns>
private Int64 CreatePollerAndStart(ref PollingClient poller, Int32 pollerId, Func <AtomicDispatchChunk, Task <Boolean> > dispatchToTplFunction)
{
if (poller != null)
{
poller.Stop();
}
//The default value to start is zero, it is a situation that should never happen, if it happens this poller has no projection to dispatch.
var startingPosition = TryGetStartingPoint(pollerId, 0);
Logger.InfoFormat("AtomicProjectionEngine: Starting poller id {0} from position {1}", pollerId, startingPosition);
var subscription = new JarvisFrameworkLambdaSubscription(c => dispatchToTplFunction(new AtomicDispatchChunk(pollerId, c)));
poller = new PollingClient(_persistence, startingPosition, subscription, _nStoreLoggerFactory);
poller.Start();
return(startingPosition);
}
public void Configure(
Int64 checkpointTokenFrom,
Int32 bufferSize)
{
_logger.InfoFormat("CommitPollingClient {0}: Configured starting from {1} buffer {2}", _id, checkpointTokenFrom, bufferSize);
_bufferSize = bufferSize;
_lastDispatchedPosition = checkpointTokenFrom - 1;
LastException = null;
//prepare single poller thread.
CreateTplChain();
_innerSubscription = new JarvisFrameworkLambdaSubscription(DispatchChunk);
_innerClient = new PollingClient(
_persistence,
checkpointTokenFrom,
_innerSubscription,
_factory);
RegisterHealthChecks(_id);
}
public async Task UnwindAsync()
{
var lastEvent = _unwindedEventCollection
.Find(Builders <UnwindedDomainEvent> .Filter.Empty)
.Sort(Builders <UnwindedDomainEvent> .Sort.Descending(e => e.CheckpointToken))
.Limit(1)
.SingleOrDefault();
Int64 startToken = 1; //remember with NStore is inclusive
if (lastEvent != null)
{
startToken = lastEvent.CheckpointToken;
}
//we want to avoid holes up to the maximum committed tokens, holes are only when we are
//in high concurrency.
var lastCommittedToken = await _persistence.ReadLastPositionAsync().ConfigureAwait(false);
lastCommittedToken = Math.Max(0, lastCommittedToken - 10); //we choose an arbitrary offset to avoid problem in high concurrency
_logger.InfoFormat("Unwind events starting from commit {0}", startToken);
//Since we could have crashed during unwind of last commit, we want to reunwind again last commit
Int64 checkpointToken = startToken;
_unwindedEventCollection.DeleteMany(Builders <UnwindedDomainEvent> .Filter.Gte(e => e.CheckpointToken, startToken));
Int64 count = 0;
List <UnwindedDomainEvent> batchEventUnwind = new List <UnwindedDomainEvent>(550);
var subscription = new JarvisFrameworkLambdaSubscription(async data =>
{
foreach (var evt in UnwindChunk(data))
{
batchEventUnwind.Add(evt);
if (batchEventUnwind.Count > 500)
{
await _unwindedEventCollection.InsertManyAsync(batchEventUnwind).ConfigureAwait(false);
batchEventUnwind.Clear();
}
}
checkpointToken = data.Position;
if (++count % 10000 == 0)
{
_logger.InfoFormat("Unwinded block of 10000 commit, now we are at checkpoint {0}", checkpointToken);
}
return(true);
}, "unwinder");
var sequencer = new NStoreSequencer(
startToken - 1,
subscription,
timeToWaitInMilliseconds: 0,
maximumWaitCountForSingleHole: 5,
safePosition: lastCommittedToken,
logger: _logger);
//Need to cycle until the sequencer skipped an hole, to be sure to unwind all events.
do
{
//Reload from the last position where the sequencer stopped.
await _persistence.ReadAllAsync(sequencer.Position + 1, sequencer).ConfigureAwait(false);
} while (sequencer.RetriesOnHole > 0);
if (subscription.Failed)
{
throw new JarvisFrameworkEngineException("Error unwinding commits", subscription.LastException);
}
//Flush last batch.
if (batchEventUnwind.Count > 0)
{
_unwindedEventCollection.InsertMany(batchEventUnwind);
}
_logger.InfoFormat("Unwind events ends, started from commit {0} and ended with commit {1}", startToken, checkpointToken);
}