public static MasterConfiguration FromMessage(Message msg)
{
if (!msg.Header.StartsWith("master", StringComparison.OrdinalIgnoreCase))
{
throw new ArgumentException("Message is not a 'master' message");
}
var ret = new MasterConfiguration();
using (var reader = msg.GetContentReader())
{
string line;
while((line = reader.ReadLine()) != null)
{
var nvp = line.Split(':');
if (nvp.Length == 2)
{
switch (nvp[0].ToLowerInvariant())
{
case "writequorum":
ret.WriteQuorum = Int32.Parse(nvp[1]);
break;
}
}
}
}
return ret;
}
public override Message AsMessage()
{
const string header = "spu";
var args = String.Join(" ", StoreId, JobId, PrevTxnId);
var msg = new Message(header, args);
using(var writer = msg.GetContentWriter())
{
if (!String.IsNullOrEmpty(Expression))
{
writer.WriteLine(Expression);
}
}
return msg;
}
public static ClusterSparqlTransaction FromMessage(Message msg)
{
var args = msg.Args.Split(' ');
var txn = new ClusterSparqlTransaction
{
StoreId = args[0],
JobId = Guid.Parse(args[1]),
PrevTxnId = Guid.Parse(args[2]),
};
using(var reader = msg.GetContentReader())
{
txn.Expression = ReadSection(reader);
}
return txn;
}
private bool SendMasterMessage(NodeConfiguration master)
{
var socket = AssertConnection(master);
if (socket == null) return false;
var msg = new Message("master", String.Empty);
using(var writer = msg.GetContentWriter())
{
_config.MasterConfiguration.WriteTo(writer);
}
bool masterIsSet = SendMessageAndWaitForAck(socket,msg);
if (masterIsSet)
{
_master = master;
}
return masterIsSet;
}
public static ClusterUpdateTransaction FromMessage(Message msg)
{
var args = msg.Args.Split(' ');
var txn = new ClusterUpdateTransaction
{
StoreId = args[0],
JobId = Guid.Parse(args[1]),
PrevTxnId = Guid.Parse(args[2]),
};
using(var reader = msg.GetContentReader())
{
txn.Preconditions = ReadSection(reader);
txn.Deletes = ReadSection(reader);
txn.Inserts = ReadSection(reader);
}
return txn;
}
public override Message AsMessage()
{
const string header = "txn";
var args = String.Join(" ", StoreId, JobId, PrevTxnId);
var msg = new Message(header, args);
using(var writer = msg.GetContentWriter())
{
if (!String.IsNullOrEmpty(Preconditions))
{
writer.WriteLine(Preconditions);
}
writer.WriteLine("||");
if (!String.IsNullOrEmpty(Deletes))
{
writer.WriteLine(Deletes);
}
writer.WriteLine("||");
if (!String.IsNullOrEmpty(Inserts))
{
writer.WriteLine(Inserts);
}
}
return msg;
}
private void HandleClientRequest(object client)
{
var tcpClient = (TcpClient)client;
var clientStream = tcpClient.GetStream();
// all message have a single line header and then data.
var msg = Message.Read(clientStream);
switch (msg.Header.ToLowerInvariant())
{
case "ping":
SendMessage(clientStream, new Message("pong", String.Empty));
break;
case "master":
{
var configuration = MasterConfiguration.FromMessage(msg);
bool handledOk = _requestHandler.SetMaster(configuration);
SendMessage(clientStream, handledOk ? Message.ACK : Message.NAK);
break;
}
case "slaveof":
{
var args = msg.Args.Split(' ');
bool handledOk = _requestHandler.SlaveOf(args[0], Int32.Parse(args[1]));
SendMessage(clientStream, handledOk ? Message.ACK : Message.NAK);
break;
}
case "sync":
{
var dict = new Dictionary<string, string>();
using (var reader = msg.GetContentReader())
{
string line;
while ((line = reader.ReadLine()) != null)
{
var args = line.Split('|');
var storeName = args[0];
var txnId = args[1];
dict.Add(storeName, txnId);
}
}
var syncOk = _requestHandler.SyncSlave(
dict,
new SyncContext {Connection = tcpClient},
(context, message) => SendMessageAndWaitForAck(context.Connection, message));
// Send endsync message
var endsync = new Message("endsync", new[] { syncOk ? "OK" : "FAIL" }); // TODO: Body could provide some check - e.g. # messages sent in sync ?
SendMessage(clientStream, endsync);
break;
}
case "listen":
{
AddSlave(tcpClient);
break;
}
}
}
private Response HandleTransactionMessage(Message txnMessage)
{
bool handledOk = false;
switch (txnMessage.Header.ToLowerInvariant())
{
case "txn":
var updateTransaction = ClusterUpdateTransaction.FromMessage(txnMessage);
handledOk = _requestHandler.ProcessSlaveTransaction(updateTransaction);
break;
case "spu":
var sparqlTransaction = ClusterSparqlTransaction.FromMessage(txnMessage);
handledOk = _requestHandler.ProcessSlaveTransaction(sparqlTransaction);
break;
case "+store":
handledOk = _requestHandler.CreateStore(txnMessage.Args);
break;
case "-store":
handledOk = _requestHandler.DeleteStore(txnMessage.Args);
break;
}
return new Response(handledOk ? Message.ACK : Message.NAK);
}
/// <summary>
/// Create a channel to the master for receiving new transactions
/// </summary>
/// <param name="masterAddress"></param>
public void OpenTransactionChannel(EndpointAddress masterAddress)
{
var tcpClient = new TcpClient(masterAddress.Uri.Host, masterAddress.Uri.Port);
var msg = new Message("listen", String.Empty);
var stream = tcpClient.GetStream();
msg.WriteTo(stream);
stream.Flush();
_transactionMessageReader = new MessageReader(tcpClient, HandleTransactionMessage);
_transactionMessageReader.Start();
}
/// <summary>
/// Handler function for messages that can be received by the slave
/// through the initial sync connection with the master
/// </summary>
/// <param name="msg">The message received</param>
/// <returns>The response to send to the message</returns>
private Response HandleSyncMessage(Message msg)
{
bool handledOk = false;
switch (msg.Header.ToLowerInvariant())
{
case "txn":
var txn = ClusterUpdateTransaction.FromMessage(msg);
handledOk = _requestHandler.ProcessSyncTransaction(txn);
break;
case "+store":
handledOk = _requestHandler.CreateStore(msg.Args);
break;
case "-store":
handledOk = _requestHandler.DeleteStore(msg.Args);
break;
case "endsync":
var syncStatus = msg.Args.Split(' ')[0];
_requestHandler.SlaveSyncCompleted(syncStatus);
handledOk = true;
break;
}
if (handledOk)
{
return new Response(Message.ACK);
}
return new Response(Message.NAK, true);
}
/// <summary>
/// Construct a sync message that lists all the stores we have and the last commited transaction id for each one
/// then start a reader to process the updates the master will send to us
/// </summary>
/// <param name="masterAddress"></param>
/// <param name="lastTxn"></param>
public void SendSyncToMaster(EndpointAddress masterAddress, Dictionary<string, string> lastTxn)
{
var msg = new Message("sync", String.Empty);
using(var writer = msg.GetContentWriter())
{
foreach (var entry in lastTxn)
{
writer.WriteLine("{0}|{1}", entry.Key, entry.Value);
}
}
var socket = new TcpClient(masterAddress.Uri.Host, masterAddress.Uri.Port);
var socketStream = socket.GetStream();
msg.WriteTo(socketStream);
socketStream.Flush();
var messageReader = new MessageReader(socket, HandleSyncMessage);
messageReader.Start();
}
private bool SendMessageAndWaitForAck(TcpClient socket, Message messageToSend)
{
var stream = socket.GetStream();
messageToSend.WriteTo(stream);
stream.Flush();
var message = Message.Read(stream);
return message.Header.Equals("ACK", StringComparison.OrdinalIgnoreCase);
}
private void SendMessage(Stream networkStream, Message messageToSend)
{
messageToSend.WriteTo(networkStream);
networkStream.Flush();
}
public bool SyncSlave(Dictionary<string, string> lastTxn, SyncContext context, Func<SyncContext, Message, bool> messageSink )
{
bool syncOk = true;
// Push existing transactions down the pipe
foreach(var storeId in _stores)
{
IEnumerable<ITransactionInfo> transactionsToSend;
if (lastTxn.ContainsKey(storeId))
{
Guid lastJobId = Guid.Parse(lastTxn[storeId]);
transactionsToSend = _serverCore.GetTransactions(storeId).SkipWhile(t => !t.JobId.Equals(lastJobId)).Skip(1);
syncOk &= SendTransactions(context, messageSink, transactionsToSend, storeId, lastJobId);
}
else
{
// For all stores that aren't listed in the lastTxn dictionary
// Send a create store message followed byt all transactions
var createMessage = new Message("+store", storeId);
if (messageSink(context, createMessage))
{
syncOk &= SendTransactions(context, messageSink, _serverCore.GetTransactions(storeId), storeId,
Guid.Empty);
}
else
{
syncOk = false;
}
}
}
// For all stores that are listed in lastTxn dictionary and not in our store list
// send a delete store message
foreach (var storeId in lastTxn.Keys.Where(s=>!_stores.Contains(s)))
{
var deleteMessage = new Message("-store", storeId);
messageSink(context, deleteMessage);
}
return syncOk;
}
