private void ProcessClientReq()
{
Console.WriteLine("[Server-{0} :: {1}] is processing a client request ...\n",
this.Id, this.CurrentTerm);
this.Client = ((Tuple <Machine, Command>) this.Payload).Item1;
var newEntry = new Entry();
newEntry.Command = ((Tuple <Machine, Command>) this.Payload).Item2;
newEntry.Index = this.Log.Count;
newEntry.Term = this.CurrentTerm;
this.Log.Clear();
this.Log.Add(newEntry);
var appendEntries = new AppendEntriesMessage();
appendEntries.Term = this.CurrentTerm;
appendEntries.LeaderId = this.Id;
appendEntries.LeaderCommit = this.CommitIndex;
if (this.Servers != null)
{
for (int idx = 0; idx < this.Servers.Count; idx++)
{
if (idx == this.Id)
{
continue;
}
appendEntries.Entries = new List <Entry>();
var nextIndex = this.NextIndex[idx];
if (this.Log.Count - 1 >= nextIndex && nextIndex >= 0)
{
for (int i = nextIndex; i < this.Log.Count; i++)
{
appendEntries.Entries.Add(this.Log[i]);
}
}
else
{
appendEntries.Entries.Add(newEntry);
}
this.Send(this.Servers[idx], new eAppendEntries(appendEntries));
}
}
this.Acks.Add(true);
}
private void ProcessHeartBeat()
{
Console.WriteLine("[Server-{0} :: {1}] is sending heartbeats ...\n",
this.Id, this.CurrentTerm);
if (this.Servers != null)
{
for (int idx = 0; idx < this.Servers.Count; idx++)
{
if (idx != this.Id)
{
var appendEntries = new AppendEntriesMessage();
appendEntries.Term = this.CurrentTerm;
appendEntries.LeaderId = this.Id;
appendEntries.Entries = new List <Entry>();
this.Send(this.Servers[idx], new eAppendEntries(appendEntries));
}
}
}
}
private void ProcessAppendEntriesAck()
{
var appendEntriesAck = (AppendEntriesAckMessage)this.Payload;
if (appendEntriesAck.Success)
{
Console.WriteLine("[Server-{0} :: {1}] received a successful append entries ack from " +
"server {2} with term {3} ...\n", this.Id, this.CurrentTerm,
appendEntriesAck.SenderId, appendEntriesAck.Term);
this.NextIndex[appendEntriesAck.SenderId] = this.Log.Count - 1;
this.MatchIndex[appendEntriesAck.SenderId] = this.Log.Count - 1;
}
else
{
Console.WriteLine("[Server-{0} :: {1}] received an un-successful append entries ack from " +
"server {2} with term {3} ...\n", this.Id, this.CurrentTerm,
appendEntriesAck.SenderId, appendEntriesAck.Term);
this.NextIndex[appendEntriesAck.SenderId] = this.NextIndex[appendEntriesAck.SenderId] - 1;
if (this.NextIndex[appendEntriesAck.SenderId] < 0)
{
this.NextIndex[appendEntriesAck.SenderId] = 0;
}
if (this.Servers != null && this.Log.Count > 0)
{
var appendEntries = new AppendEntriesMessage();
appendEntries.Term = this.CurrentTerm;
appendEntries.LeaderId = this.Id;
appendEntries.LeaderCommit = this.CommitIndex;
appendEntries.Entries = new List <Entry>();
var nextIndex = this.NextIndex[appendEntriesAck.SenderId];
if (this.Log.Count - 1 >= nextIndex)
{
for (int i = nextIndex; i < this.Log.Count; i++)
{
appendEntries.Entries.Add(this.Log[i]);
}
}
else
{
appendEntries.Entries.Add(this.Log[this.Log.Count - 1]);
}
if (nextIndex > 0)
{
appendEntries.PrevLogIndex = nextIndex - 1;
appendEntries.PrevLogTerm = this.Log[nextIndex - 1].Term;
}
this.Send(this.Servers[appendEntriesAck.SenderId], new eAppendEntries(appendEntries));
}
}
if (appendEntriesAck.Term > this.CurrentTerm)
{
this.CurrentTerm = appendEntriesAck.Term;
}
this.Acks.Add(appendEntriesAck.Success);
int ackCounter = 0;
foreach (var ack in this.Acks)
{
if (ack)
{
ackCounter = ackCounter + 1;
}
}
var majority = (this.Votes.Length / 2) + 1;
if (this.Acks.Count == this.Votes.Length &&
this.Log.Count > 0 && this.Client != null)
{
if (ackCounter >= majority)
{
var latestCommand = this.Log[this.Log.Count - 1].Command;
if (latestCommand.CommandType == CommandTypes.Add)
{
this.State = this.State + latestCommand.Value;
}
else
{
this.State = this.State - latestCommand.Value;
}
this.CommitIndex = this.Log.Count - 1;
this.Send(this.Client, new eClientReqAck(this.State));
}
else
{
this.Send(this.Client, new eClientReqAck(null));
}
}
}