private AppendEntriesResponse AppendEntries(string address, IHost host, ulong nextIndex)
{
AppendEntriesRequest request = new AppendEntriesRequest
{
LeaderId = Id,
Term = _stateController.PersistentState.CurrentTerm,
PrevLogIndex = _stateController.PersistentState.LastLogIndex,
PrevLogTerm = _stateController.PersistentState.LastLogTerm,
LeaderCommit = _stateController.VolatileState.CommitIndex
};
if (_stateController.PersistentState.LastLogIndex >= nextIndex)
{
List <LogEntry> logEntries = _uncommittiedLogs.FindAll(w => w.Index >= nextIndex);
if (logEntries != null && logEntries.Any())
{
request.Entries = logEntries;
}
}
AppendEntriesResponse response = host.AppendEntriesInvoke(request);
if (!response.IsSuccess && _leaderVolatileStates[address].NextIndex != 0)
{
_leaderVolatileStates[address].NextIndex -= 1;
response = AppendEntries(address, host, _leaderVolatileStates[address].NextIndex);
}
return(response);
}
private void Heartbeat()
{
bool committedLog = false;
int replicatedCount = 1;
foreach (Peer peer in _node.Peers)
{
Task.Run(() =>
{
try
{
DebugConsole.WriteLine($"Sync to follower({peer.Address})... term {_stateController.PersistentState.CurrentTerm}...");
AppendEntriesResponse response = AppendEntries(peer.Address, peer.RemoteClient, _leaderVolatileStates[peer.Address].NextIndex);
if (_node.EnsureExistGreaterTermAndChangeRole(response.Term))
{
return;
}
if (response.IsSuccess)
{
lock (_appliedLogLockObj)
{
_leaderVolatileStates[peer.Address].NextIndex = _stateController.PersistentState.LastLogIndex + 1;
_leaderVolatileStates[peer.Address].MatchIndex += 1;
replicatedCount += 1;
int majorityCount = _node.Peers.Count;
if (!committedLog && replicatedCount > majorityCount / 2 + 1)
{
committedLog = true;
CommitLogs();
}
}
}
}
catch (Exception ex)
{
DebugConsole.WriteLine(ex.Message);
//todo
}
});
}
}
public AppendEntriesResponse AppendEntries(AppendEntriesRequest request)
{
if (string.IsNullOrEmpty(LeaderId))
{
LeaderId = request.LeaderId;
}
if (request.Term == _stateController.PersistentState.CurrentTerm)
{
lock (this)
{
_isFromLegalLeaderRequest = true;
}
}
AppendEntriesResponse response = new AppendEntriesResponse();
if (_stateController.PersistentState.Logs.Any())
{
LogEntry logEntry = _stateController.PersistentState.Logs.SingleOrDefault(w => w.Index == request.PrevLogIndex && w.Term == request.PrevLogTerm);
if (logEntry == null)
{
response.IsSuccess = false;
response.Term = _stateController.PersistentState.CurrentTerm;
return(response);
}
LogEntry diffTermLogEntry = _stateController.PersistentState.Logs.SingleOrDefault(w => request.Entries.Exists(e => e.Index == w.Index && w.Term != e.Term));
if (diffTermLogEntry != null)
{
_stateController.PersistentState.Logs.RemoveRange((int)diffTermLogEntry.Index, _stateController.PersistentState.Logs.Count - (int)diffTermLogEntry.Index);
}
_stateController.PersistentState.Logs.AddRange(request.Entries);
}
if (request.LeaderCommit > _stateController.VolatileState.CommitIndex)
{
_stateController.UpdateTerm(request.Term);
_stateController.UpdateCommitIndex(Math.Min(request.LeaderCommit, request.PrevLogIndex));
}
response.IsSuccess = true;
response.Term = _stateController.PersistentState.CurrentTerm;
return(response);
}