private void MulticastStartViewChange()
{
IMessage message = new StartViewChange(this.replicaState.ServerId, this.viewNumber, this.configuration);
Uri[] currentConfiguration = this.replicaState.ReplicasUrl.ToArray();
IResponses responses = this.messageServiceClient.RequestMulticast(
message,
currentConfiguration,
this.replicaState.Configuration.Count / 2,
(int)(Timeout.TIMEOUT_VIEW_CHANGE),
true);
IResponse[] responsesVector = responses.ToArray();
// There was no quorum to accept the view change
if (responsesVector.Length < this.numberToWait)
{
Log.Debug($"There was no quorum for view change. " +
$"Just received {responsesVector.Length} from at least {this.numberToWait}");
this.replicaState.ChangeToNormalState();
return;
}
// In case I'm the leader, wait for f DoViewChange
if (this.imTheLeader)
{
this.CheckNumberAndSetNewConfiguration();
}
else
{
// Else, send DoViewChange to leader
Uri leader = this.configuration.Values.ToArray()[0];
IMessage doViewMessage = new DoViewChange(
this.replicaState.ServerId,
this.viewNumber,
this.replicaState.ViewNumber,
this.configuration,
this.replicaState.Logger,
this.replicaState.OpNumber,
this.replicaState.CommitNumber);
this.messageServiceClient.Request(doViewMessage, leader, -1);
}
}
public ClientHandShakeResponse DoHandShake()
{
// Do the handshake
Uri[] servers = System.IO.File.ReadAllLines(SERVERS_LIST).ToList()
.ConvertAll <Uri>(server => new Uri(server))
.ToArray();
IResponses responses = this.MessageServiceClient.RequestMulticast(
new ClientHandShakeRequest(this.Id),
servers,
1,
-1,
true);
ClientHandShakeResponse response = (ClientHandShakeResponse)responses.ToArray()[0];
this.ViewNumber = response.ViewNumber;
this.ViewServers = response.ViewConfiguration;
this.Leader = response.Leader;
return(response);
}
private void InitProtocol()
{
Uri[] servers = System.IO.File.ReadAllLines(SERVERS_LIST).ToList()
.ConvertAll <Uri>(server => new Uri(server))
.Where(server => !server.Equals(this.replicaState.MyUrl))
.ToArray();
IMessage message = new ServerHandShakeRequest(this.replicaState.ServerId, Protocol.StateMachineReplication);
IResponses responses =
this.messageServiceClient.RequestMulticast(message, servers, 1, Timeout.TIMEOUT_SERVER_HANDSHAKE, true);
IResponse[] filteredResponses = responses.ToArray();
// I'm the first server
if (filteredResponses.Length == 0)
{
Log.Info("No servers found for handshake.");
this.replicaState.SetNewConfiguration(
new SortedDictionary <string, Uri> {
{ this.replicaState.ServerId, this.replicaState.MyUrl }
},
new Uri[] { },
this.replicaState.ViewNumber + 1);
this.replicaState.ChangeToNormalState();
return;
}
// Else multicast joinView to everyone
Uri[] configuration = ((ServerHandShakeResponse)filteredResponses[0]).ViewConfiguration;
IMessage joinViewMessage = new JoinView(this.replicaState.ServerId, this.replicaState.MyUrl);
this.messageServiceClient.RequestMulticast(
joinViewMessage,
configuration,
configuration.Length,
Timeout.TIMEOUT_INIT,
false);
}
private void RecoveryProtocol()
{
// Multicast recovery message
IMessage message = new Recovery(
this.replicaState.ServerId,
this.replicaState.ViewNumber,
this.replicaState.OpNumber,
this.replicaState.CommitNumber);
IResponses responses = this.messageServiceClient.RequestMulticast(
message,
this.replicaState.ReplicasUrl.ToArray(),
this.replicaState.Configuration.Count / 2,
-1,
true);
Log.Debug($"Recovery Protocol: got {responses.Count()} responses.");
if (responses.Count() == 0)
{
this.replicaState.ChangeToInitializationState();
return;
}
RecoveryResponse betterResponse = null;
foreach (IResponse response in responses.ToArray())
{
RecoveryResponse recoveryResponse = (RecoveryResponse)response;
if (recoveryResponse.ViewNumber > this.replicaState.ViewNumber)
{
this.replicaState.ChangeToInitializationState();
return;
}
if (recoveryResponse.ViewNumber == this.replicaState.ViewNumber)
{
if (betterResponse == null)
{
betterResponse = recoveryResponse;
continue;
}
if (recoveryResponse.OpNumber > betterResponse.OpNumber)
{
betterResponse = recoveryResponse;
}
}
}
if (betterResponse != null &&
betterResponse.OpNumber > this.replicaState.OpNumber)
{
Log.Debug($"Better Response: OpNumber = {betterResponse.OpNumber}, " +
$"CommitNumber = {betterResponse.CommitNumber} ({this.replicaState.CommitNumber})");
this.replicaState.Logger.AddRange(betterResponse.SuffixLogger);
this.replicaState.UpdateOpNumber();
this.replicaState.ExecuteFromUntil(this.replicaState.CommitNumber, betterResponse.CommitNumber);
}
Log.Debug($"Recovery Protocol: Changing to Normal State.");
this.replicaState.ChangeToNormalState();
}
public ReplicaState(MessageServiceClient messageServiceClient, Uri url, string serverId)
{
this.MessageServiceClient = messageServiceClient;
this.ServerId = serverId;
this.MyUrl = url;
this.Configuration = new SortedDictionary <string, Uri> {
{ this.ServerId, url }
};
this.ReplicasUrl = new List <Uri>();
this.ClientTable = new Dictionary <string, Tuple <int, ClientResponse> >();
this.State = new InitializationStateMessageProcessor(this, this.MessageServiceClient);
this.ViewNumber = 0;
this.TupleSpace = new TupleSpace.TupleSpace();
this.HeartBeats = new SortedDictionary <string, DateTime>();
this.RequestsExecutor = new RequestsExecutor(this);
// Handlers
this.HandlerStateChanged = new EventWaitHandle(false, EventResetMode.ManualReset);
this.HandlersClient = new ConcurrentDictionary <string, EventWaitHandle>();
// Task that checks HeartBeats
Task.Factory.StartNew(() => {
while (true)
{
Thread.Sleep(Timeout.TIMEOUT_VIEW_CHANGE);
foreach (KeyValuePair <string, DateTime> entry in this.HeartBeats)
{
if (entry.Value < DateTime.Now.AddMilliseconds(-Timeout.TIMEOUT_HEART_BEAT_XL * 1.1))
{
int newViewNumber = this.ViewNumber + 1;
SortedDictionary <string, Uri> newConfiguration = new SortedDictionary <string, Uri>(
this.Configuration
.Where(kvp => !kvp.Key.Equals(entry.Key))
.ToDictionary(kvp => kvp.Key, kvp => kvp.Value));
Log.Debug($"Server {entry.Key} is presumably dead as the HeartBeat timeout expired.");
this.ChangeToViewChange(newViewNumber, newConfiguration);
break;
}
}
}
});
// Task that sends the HeartBeats
Task.Factory.StartNew(() => {
while (true)
{
Thread.Sleep(Timeout.TIMEOUT_HEART_BEAT_XL);
if (!(this.State is NormalStateMessageProcessor))
{
continue;
}
Task.Factory.StartNew(() => {
IResponses responses = this.MessageServiceClient.RequestMulticast(
new HeartBeat(this.ServerId),
this.ReplicasUrl.ToArray(),
this.ReplicasUrl.Count,
-1,
false);
IResponse[] filteredResponses = responses.ToArray()
.Where(response => ((HeartBeatResponse)response).ViewNumber > ViewNumber)
.ToArray();
if (filteredResponses.Length > 0)
{
this.ChangeToInitializationState();
}
});
}
});
}