private Func <CancellationToken, Task> PeerAppendLog(Peer peer)
{
return((CancellationToken c) =>
{
long nextIndex;
long matchIndex;
var hasMatch = _volatileLeaderState.TryGetMatchIndex(peer.Id, out matchIndex);
var hasNext = _volatileLeaderState.TryGetNextIndex(peer.Id, out nextIndex);
var myLastIndex = _logPersister.LastIndex;
if (!hasMatch)
{
TheTrace.TraceWarning($"[{_meAsAPeer.ShortName}] Could not find peer with id {peer.Id} and address {peer.Address} in matchIndex dic.");
return Task.CompletedTask;
}
if (!hasNext)
{
TheTrace.TraceWarning($"[{_meAsAPeer.ShortName}] Could not find peer with id {peer.Id} and address {peer.Address} in nextIndex dic.");
return Task.CompletedTask;
}
if (nextIndex > myLastIndex)
{
TheTrace.TraceVerbose($"[{_meAsAPeer.ShortName}] PeerAppendLog - Nothing to do for peer {peer.ShortName} since myIndex is {myLastIndex} and nextIndex is {nextIndex}.");
return Task.CompletedTask; // nothing to do
}
var count = (int)Math.Min(_settings.MaxNumberLogEntriesToAskToBeAppended, myLastIndex + 1 - nextIndex);
var proxy = _peerManager.GetProxy(peer.Address);
var retry = TheTrace.LogPolicy(_meAsAPeer.ShortName).WaitAndRetryAsync(2, (i) => TimeSpan.FromMilliseconds(20));
var policy = Policy.TimeoutAsync(_settings.CandidacyTimeout).WrapAsync(retry); // TODO: create its own timeout
if (nextIndex >= _logPersister.LogOffset)
{
TheTrace.TraceVerbose($"[{_meAsAPeer.ShortName}] Intending to do SendLog for peer {peer.Address} with nextIndex {nextIndex} and count {count}.");
return SendLogs(proxy, policy, peer, nextIndex, matchIndex, count);
}
else
{
TheTrace.TraceVerbose($"[{_meAsAPeer.ShortName}] Intending to do SendSnapshot for peer {peer.Address}.");
return SendSnapshot(proxy, policy, peer, nextIndex, matchIndex);
}
});
}
/// <inheritdocs/>
public void Append(LogEntry[] entries, long?startingOffset = null)
{
if (startingOffset.HasValue && startingOffset.Value != LastIndex + 1)
{
throw new InvalidOperationException($"Starting index is {startingOffset} but LastIndex is {LastIndex}");
}
if (entries.Length == 0)
{
throw new InvalidOperationException("Entries is empty.");
}
TheTrace.TraceVerbose($"[{Name}] LmdbPersister.Append - Before Lock");
lock (_lock)
{
startingOffset = LastIndex + 1;
TheTrace.TraceVerbose($"[{Name}] LmdbPersister.Append - Inside Lock. Entries: {entries.Length}. startingOffset: {startingOffset}");
var indices = Enumerable.Range(0, entries.Length).Select(x => x + startingOffset);
TheTrace.TraceVerbose($"[{Name}] LmdbPersister.Append - Before tx");
using (var tx = _env.BeginTransaction())
{
TheTrace.TraceVerbose($"[{Name}] LmdbPersister.Append - After tx");
foreach (var e in entries.Zip(indices, (l, i) => (i, l)).Select(x => new Bufferable(x.l.Body).PrefixWithIndexAndTerm(x.i.Value, x.l.Term)))
{
TheTrace.TraceVerbose($"[{Name}] LmdbPersister.Append - Before put");
tx.Put(_logDb, LogKey, e, TransactionPutOptions.AppendDuplicateData);
TheTrace.TraceVerbose($"[{Name}] LmdbPersister.Append - After Put");
}
tx.Commit();
}
TheTrace.TraceVerbose($"[{Name}] LmdbPersister.Append - Before LoadLastTermAndIndex");
LoadLastTermAndIndex();
TheTrace.TraceVerbose($"[{Name}] LmdbPersister.Append - After LoadLastTermAndIndex");
if (LastIndex != startingOffset + entries.Length - 1)
{
throw new InvalidOperationException($"THIS IS BAD!! expected {startingOffset} + {entries.Length} but found {LastIndex}.");
}
if (LastEntryTerm != entries.Last().Term)
{
throw new InvalidOperationException($"THIS IS BAD!! expected last term {entries.Last().Term} but found {LastEntryTerm}.");
}
}
}
private Task ProcessCommandsQueue(CancellationToken c)
{
if (_isSnapshotting)
{
return(Task.CompletedTask);
}
if (Role == Role.Leader)
{
TheTrace.TraceVerbose($"[{_meAsAPeer.ShortName}] ProcessCommandsQueue with {_commands.Count} items.");
}
var entries = new List <LogEntry>();
StateMachineCommandRequest command;
TheTrace.TraceVerbose($"[{_meAsAPeer.ShortName}] ProcessCommandsQueue - Before with trying to take.");
while (_commands.TryTake(out command, 10)) // we can set up a maximum but really we should accept all
{
TheTrace.TraceVerbose($"[{_meAsAPeer.ShortName}] ProcessCommandsQueue - Got an item.");
entries.Add(new LogEntry()
{
Body = command.Command,
Term = State.CurrentTerm
});
}
if (entries.Any())
{
TheTrace.TraceVerbose($"[{_meAsAPeer.ShortName}] ProcessCommandsQueue - Before applying {entries.Count} entries.");
_logPersister.Append(entries.ToArray());
TheTrace.TraceVerbose($"[{_meAsAPeer.ShortName}] ProcessCommandsQueue - His Majesty appended {entries.Count} entries.");
}
return(Task.CompletedTask);
}
