/// <summary>
/// This is expected to run for a long time, and it cannot leak exceptions
/// </summary>
private void Run()
{
try
{
var handles = new WaitHandle[]
{
_newEntry,
_voterResponded,
_promotableUpdated,
_shutdownRequested
};
var noopCmd = new DynamicJsonValue
{
["Command"] = "noop"
};
using (_engine.ContextPool.AllocateOperationContext(out TransactionOperationContext context))
using (var tx = context.OpenWriteTransaction())
using (var cmd = context.ReadObject(noopCmd, "noop-cmd"))
{
_engine.InsertToLeaderLog(context, Term, cmd, RachisEntryFlags.Noop);
tx.Commit();
}
_newEntry.Set(); //This is so the noop would register right away
while (_running)
{
switch (WaitHandle.WaitAny(handles, _engine.ElectionTimeout))
{
case 0: // new entry
_newEntry.Reset();
// release any waiting ambassadors to send immediately
TaskExecutor.CompleteAndReplace(ref _newEntriesArrived);
if (_voters.Count == 0)
{
goto case 1;
}
break;
case 1: // voter responded
_voterResponded.Reset();
OnVoterConfirmation();
break;
case 2: // promotable updated
_promotableUpdated.Reset();
CheckPromotables();
break;
case WaitHandle.WaitTimeout:
break;
case 3: // shutdown requested
if (_engine.Log.IsInfoEnabled && _voters.Count != 0)
{
_engine.Log.Info($"{ToString()}: shutting down");
}
_running.Lower();
return;
}
EnsureThatWeHaveLeadership(VotersMajority);
_engine.ReportLeaderTime(LeaderShipDuration);
// don't trancate if we are disposing an old peer
// otherwise he would not recieve notification that he was
// kick out of the cluster
if (_previousPeersWereDisposed > 0) // Not Interlocked, because the race here is not interesting.
{
continue;
}
var lowestIndexInEntireCluster = GetLowestIndexInEntireCluster();
if (lowestIndexInEntireCluster != LowestIndexInEntireCluster)
{
using (_engine.ContextPool.AllocateOperationContext(out TransactionOperationContext context))
using (context.OpenWriteTransaction())
{
_engine.TruncateLogBefore(context, lowestIndexInEntireCluster);
LowestIndexInEntireCluster = lowestIndexInEntireCluster;
context.Transaction.Commit();
}
}
}
}
catch (Exception e)
{
if (_engine.Log.IsInfoEnabled)
{
_engine.Log.Info("Error when running leader behavior", e);
}
if (e is VoronErrorException)
{
_engine.Notify(AlertRaised.Create(
null,
"Error when running leader behavior",
e.Message,
AlertType.ClusterTopologyWarning,
NotificationSeverity.Error, details: new ExceptionDetails(e)));
}
try
{
_engine.SwitchToCandidateState("An error occurred during our leadership." + Environment.NewLine + e);
}
catch (Exception e2)
{
if (_engine.Log.IsOperationsEnabled)
{
_engine.Log.Operations("After leadership failure, could not setup switch to candidate state", e2);
}
}
}
}
