void AppendEntries(RaftMessage message)
{
//Ignore if message.term < term
if (message.Term < currentTerm)
{
Console.Out.WriteLine("Old term detected. Discarding append entries.");
return;
}
if (string.IsNullOrEmpty(message.Data))
{
Console.Out.WriteLine("FOLLOWING ORDERS");
leader = message.Sender;
state = RaftState.Follower;
votedFor = null;
electionTimeout = DateTime.UtcNow.AddMilliseconds(electionWaitPeriod);
}
else
{
var data = message.Data.Split('-');
var prevLogIndex = Int32.Parse(data[0]);
var prevLogTerm = Int32.Parse(data[1]);
var leaderCommitIndex = Int32.Parse(data[2]);
//ignore if log doesn't contain an entry at prevLogIndex whos term is equal to prevLogTerm
if (log[prevLogIndex] != null)
{
if (log[prevLogIndex].Term != prevLogTerm)
{
Console.Out.WriteLine("Incorrect term for previous log entry detected. Discarding append entries.");
return;
}
}
Console.Out.WriteLine("DOING WORK");
//If entry conflicts, delete entry and following entries
/*
* if (log[RaftLogEntry.Index] != null && log[RaftLogEntry.Index].Term != RaftLogEntry.Term)
* {
* var toBeDeleted = log.Where(x => x.Index >= RaftLogEntry.Index).Select(x => x.Index).ToList();
* foreach(var index in toBeDeleted)
* {
* log[index] = null;
* }
* }
*/
//Append all new entries to log
/*
* if(leaderCommitIndex > commitIndex)
* {
* commitIndex = Math.Min(leaderCommitIndex, lastNewEntry);
* }
*/
}
}
public BlockingCollection <RaftMessage> StartIncoming()
{
if (inStarted)
{
throw new Exception("You can only start the comms package input once.");
}
LocalHost = LocalIPAddress().ToString() + ":" + listenport;
Task.Factory.StartNew(() =>
{
string message;
try
{
IPEndPoint localEndpoint = new IPEndPoint(LocalIPAddress(), listenport);
IPEndPoint remoteEndpoint = new IPEndPoint(IPAddress.Any, 0);
UdpClient server = new UdpClient(localEndpoint);
Console.Out.WriteLine("I'm listening on " + LocalHost);
while (true)
{
message = Encoding.UTF8.GetString(server.Receive(ref remoteEndpoint));
Console.WriteLine("COM: Got message {0}", message);
var dataParts = message.Split('|');
if (dataParts.Count() < 3)
{
continue;
}
var type = (RaftMessageType)Int32.Parse(dataParts[0]);
var sender = dataParts[1];
var term = Int32.Parse(dataParts[2]);
var data = (dataParts.Count() > 3 ? dataParts[3] : "");
var msg = new RaftMessage
{
Type = type,
Term = term,
Sender = sender,
Data = data
};
incoming.Add(msg);
}
}
catch (Exception ex)
{
Console.Out.Write(ex);
}
}, TaskCreationOptions.LongRunning);
inStarted = true;
return(incoming);
}
public void StartIncoming()
{
// ZMQ Context, server socket
context = ZmqContext.Create();
LocalHost = LocalIPAddress() + ":" + listenport;
Task.Factory.StartNew(() =>
{
string message;
try
{
ZmqSocket server = context.CreateSocket(ZeroMQ.SocketType.REP);
server.Bind("tcp://" + LocalHost);
Console.Out.WriteLine("I'm listening on " + LocalHost);
while (true)
{
message = server.Receive(Encoding.Unicode);
if (message.Equals("OVER"))
{
continue;
}
Console.WriteLine("COM: Got message {0}", message);
var dataParts = message.Split('|');
if (dataParts.Count() < 2)
{
continue;
}
var type = (RaftMessageType)Int32.Parse(dataParts[0]);
var sender = dataParts[1];
var data = (dataParts.Count() > 2 ? dataParts[2] : "");
var msg = new RaftMessage
{
Type = type,
Sender = sender,
Data = data
};
incoming.Add(msg);
server.Send("OVER", Encoding.UTF8);
}
}
catch (Exception ex)
{
Console.Out.Write(ex);
}
}, TaskCreationOptions.LongRunning);
}
private void Send(RaftMessageType type, string destination, string data)
{
var msg = new RaftMessage
{
Type = type,
Term = currentTerm,
Destination = destination,
Data = data
};
outputQueue.Add(msg);
}
void Vote(RaftMessage message)
{
var requester = message.Sender;
if (message.Term < currentTerm)
{
Send(RaftMessageType.Vote, requester, "0");
return;
}
var logData = message.Data.Split('-');
var lastLogIndex = Int32.Parse(logData[0]);
var lastLogTerm = Int32.Parse(logData[1]);
if (votedFor == null || (lastLogIndex >= lastApplied && (lastApplied == 0 ? true : log[lastApplied].Term >= lastLogTerm)))
{
Console.Out.WriteLine("I voted for " + requester);
votedFor = requester;
electionTimeout = DateTime.UtcNow.AddMilliseconds(electionWaitPeriod);
Send(RaftMessageType.Vote, requester, "1");
}
}
private void VoteReceived(RaftMessage message)
{
if (message.Data == "1")
{
if (state != RaftState.Leader)
{
var from = message.Sender;
Console.Out.WriteLine("Got vote from " + from);
remoteNodes[from].VoteGranted = true;
//me + others = total / 2 + 1 = quora
var votesForMe = 1 + remoteNodes.Values.Where(x => x.VoteGranted).Count();
var votesNeeded = Math.Floor((double)((1 + remoteNodes.Keys.Count())) / 2) + 1;
Console.Out.WriteLine("I need " + votesNeeded + " votes. I have " + votesForMe + " votes");
if (votesForMe >= votesNeeded)
{
BecomeLeader();
}
}
}
}
private void ProcessMessage(RaftMessage message)
{
//If any message has a bigger term, set term = message.term and become follower
if (message.Term > currentTerm)
{
state = RaftState.Follower;
currentTerm = message.Term;
}
switch (message.Type)
{
case RaftMessageType.Vote:
VoteReceived(message);
break;
case RaftMessageType.RequestVote:
Vote(message);
break;
case RaftMessageType.AppendEntries:
AppendEntries(message);
break;
}
}