private void PollerThread()
{
while (true)
{
try
{
if (poller == null || !poller.IsStarted)
{
SignalService.Logger.Info("Start NetMQ Poller");
poller = new Poller();
poller.AddSocket(router);
poller.Start();
}
}
catch (Exception e)
{
SignalService.Logger.Error("NetMQ Poller Thread Exception.\n{0}", e.StackTrace);
if (poller != null)
{
poller.Stop();
poller.Dispose();
}
}
}
}
/// <summary>
/// Release any contained resources.
/// </summary>
/// <param name="disposing">set this to true if releasing managed resources</param>
protected virtual void Dispose(bool disposing)
{
if (!disposing)
{
return;
}
if (!m_ownPoller && !m_poller.IsStarted)
{
DisposeSynced();
return;
}
// disposing on the scheduler thread
var task = new Task(DisposeSynced);
task.Start(this);
task.Wait();
// poller cannot be stopped from poller thread
if (m_ownPoller)
{
m_poller.CancelAndJoin();
m_poller.Dispose();
}
m_isSchedulerThread.Dispose();
}
public void Run()
{
Console.WriteLine("[CLIENT {0}] Starting", m_id);
var rnd = new Random(m_id);
// each request shall have an unique id in order to recognize an reply for a request
var messageId = new byte[5];
// create clientId for messages
var clientId = new[] { m_id };
// a flag to signal that an answer has arrived
bool messageAnswered = false;
// we use a poller because we have a socket and a timer to monitor
var clientPoller = new Poller();
using (var context = NetMQContext.Create())
using (var client = context.CreateRequestSocket())
using (var monitor = context.CreatePushSocket())
{
client.Connect(m_localFrontendAddress);
monitor.Connect(m_monitorAddress);
client.Options.Identity = new[] { m_id };
var timer = new NetMQTimer((int)TimeSpan.FromSeconds(10).TotalMilliseconds);
// use as flag to indicate exit
var exit = false;
// every 10 s check if message has been received, if not then send error message and ext
// and restart timer otherwise
timer.Elapsed += (s, e) =>
{
if (messageAnswered)
{
e.Timer.Enable = true;
}
else
{
var msg = string.Format("[CLIENT {0}] ERR - EXIT - lost message {1}", m_id, messageId);
// send an error message
monitor.Send(msg);
// if poller is started than stop it
if (clientPoller.IsStarted)
clientPoller.CancelAndJoin();
// mark the required exit
exit = true;
}
};
// process arriving answers
client.ReceiveReady += (s, e) =>
{
// mark the arrival of an answer
messageAnswered = true;
// worker is supposed to answer with our request id
var reply = e.Socket.ReceiveMessage();
if (reply.FrameCount == 0)
{
// something went wrong
monitor.Send(string.Format("[CLIENT {0}] Received an empty message!", m_id));
// mark the exit flag to ensure the exit
exit = true;
}
else
{
var sb = new StringBuilder();
// create success message
foreach (var frame in reply)
sb.Append("[" + frame.ConvertToString() + "]");
// send the success message
monitor.Send(string.Format("[CLIENT {0}] Received answer {1}",
m_id,
sb.ToString()));
}
};
// add socket & timer to poller
clientPoller.AddSocket(client);
clientPoller.AddTimer(timer);
// start poller in extra task in order to allow the continued processing
// clientPoller.Start() -> blocking call
var pollTask = Task.Factory.StartNew(clientPoller.PollTillCancelled);
// if true the message has been answered
// the 0th message is always answered
messageAnswered = true;
while (!exit)
{
// simulate sporadic activity by randomly delaying
Thread.Sleep((int)TimeSpan.FromSeconds(rnd.Next(5)).TotalMilliseconds);
// only send next message if the previous one has been replied to
if (messageAnswered)
{
// generate random 5 byte as identity for for the message
rnd.NextBytes(messageId);
messageAnswered = false;
// create message [client adr][empty][message id] and send it
var msg = new NetMQMessage();
msg.Push(messageId);
msg.Push(NetMQFrame.Empty);
msg.Push(clientId);
client.SendMessage(msg);
}
}
}
// stop poller if needed
if (clientPoller.IsStarted)
clientPoller.CancelAndJoin();
clientPoller.Dispose();
}
/// <summary>
/// the broker setting up the cluster
///
///
/// State 2 ---+ +--- State n
/// | |
/// +----+----+
/// client 1 ---| | |--- worker 1
/// client 2 ---+---- BROKER 1 ----+--- worker 2
/// : | | | :
/// client n ---+ +----+----+ +--- worker n
/// | |
/// BROKER 2 BROKER n
///
/// BROKER 2 and n are not included and must be setup separately
///
/// A minimum of two address must be supplied
/// </summary>
/// <param name="args">[0] = this broker's address
/// [1] = 1st peer's address
/// :
/// [n] = nth peer address</param>
/// <remarks>
/// since "inproc://" is not working in NetMQ we use "tcp://"
/// for each broker we need 5 ports which for this example are
/// assigned as follows (in true life it should be configurable whether
/// they are ports or tcp/ip addresses)
///
/// this brokers address => local frontend binds to tcp://127.0.0.1:5555
/// cloud frontend binds to :5556
/// local backend binds to :5557
/// state backend binds to :5558
/// monitor PULL binds to :5559
///
/// the sockets are connected as follows
///
/// this broker's monitor PUSH connects to tcp://127.0.0.1:5559
///
/// (if peer's address and port is tcp://127.0.0.1:5575)
///
/// this broker's cloud backend connects to :5576
/// this broker's state frontend connects to :5578
///
/// this scheme is fix in this example
/// </remarks>
public static void Main(string[] args)
{
Console.Title = "NetMQ Inter-Broker Router";
const string baseAddress = "tcp://127.0.0.1:";
if (args.Length < 2)
{
Console.WriteLine("usage: program me peer1 [peer]*");
Console.WriteLine("each broker needs 5 port for his sockets!");
Console.WriteLine("place enough distance between multiple broker addresses!");
Environment.Exit(-1);
}
// trapping Ctrl+C as exit signal!
Console.CancelKeyPress += (s, e) =>
{
e.Cancel = true;
s_keepRunning = false;
};
// get random generator for later use
var rnd = new Random();
// get list for registering the clients
var clients = new List<byte[]>(NbrClients);
// get a list of peer addresses
var peers = new List<byte[]>();
// get all peer addresses - first is this broker!
for (var i = 1; i < args.Length; i++)
peers.Add(Encoding.UTF8.GetBytes(args[i]));
// build this broker's address
var me = baseAddress + args[0];
// get the port as integer for later use
var myPort = int.Parse(args[0]);
Console.WriteLine("[BROKER] The broker can be stopped by using CTRL+C!");
Console.WriteLine("[BROKER] setting up sockets ...");
// set up all the addresses needed in the due course
var localFrontendAddress = me;
var cloudFrontendAddress = baseAddress + (myPort + 1);
var localBackendAddress = baseAddress + (myPort + 2);
var stateBackendAddress = baseAddress + (myPort + 3);
var monitorAddress = baseAddress + (myPort + 4);
// create the context and all the sockets
using (var context = NetMQContext.Create())
using (var localFrontend = context.CreateRouterSocket())
using (var localBackend = context.CreateRouterSocket())
using (var cloudFrontend = context.CreateRouterSocket())
using (var cloudBackend = context.CreateRouterSocket())
using (var stateBackend = context.CreatePublisherSocket())
using (var stateFrontend = context.CreateSubscriberSocket())
using (var monitor = context.CreatePullSocket())
{
// give every socket an unique identity, e.g. LocalFrontend[Port]
SetIdentities(myPort,
localFrontend,
cloudFrontend,
localBackend,
stateBackend,
monitor,
cloudBackend, stateFrontend);
// subscribe to any message on the stateFrontend socket!
stateFrontend.Subscribe("");
// bind the serving sockets
localFrontend.Bind(localFrontendAddress);
cloudFrontend.Bind(cloudFrontendAddress);
localBackend.Bind(localBackendAddress);
stateBackend.Bind(stateBackendAddress);
monitor.Bind(monitorAddress);
// connect sockets to peers
for (var i = 1; i < args.Length; i++)
{
// build the cloud back end address
var peerPort = int.Parse(args[i]);
var address = baseAddress + (peerPort + 1);
Console.WriteLine("[BROKER] connect to cloud peer {0}", address);
// this cloudBackend connects to all peer cloudFrontends
cloudBackend.Connect(address);
// build the state front end address
address = baseAddress + (peerPort + 3);
Console.WriteLine("[BROKER] subscribe to state peer {0}", address);
// this stateFrontend to all peer stateBackends
stateFrontend.Connect(address);
}
// setup the local worker queue for LRU and monitor cloud capacity
var workerQueue = new Queue<byte[]>();
int previousLocalCapacity = 0;
// receive the capacity available from other peer(s)
stateFrontend.ReceiveReady += (s, e) =>
{
// the message should contain the available cloud capacity
var capacity = e.Socket.ReceiveFrameString();
Debug.Assert(string.IsNullOrWhiteSpace(capacity), "StateFrontend: message was empty!");
int couldCapacity;
Debug.Assert(int.TryParse(capacity, out couldCapacity), "StateFrontend: message did not contain a number!");
};
// get the status message and print it
monitor.ReceiveReady += (s, e) =>
{
var msg = e.Socket.ReceiveFrameString();
Console.WriteLine("[MONITOR] {0}", msg);
};
// all local clients are connecting to this socket
// they send a REQ and get a REPLY
localFrontend.ReceiveReady += (s, e) =>
{
// [client adr][empty][message id]
var request = e.Socket.ReceiveMultipartMessage();
// register the local client for later identification if not known
if (!clients.Any(n => AreSame(n, request[0])))
clients.Add(request[0].Buffer);
// if we have local capacity send worker else send to cloud
if (workerQueue.Count > 0)
{
// get the LRU worker adr
var worker = workerQueue.Dequeue();
// wrap message with workers address
var msg = Wrap(worker, request);
// send message to the worker
// [worker adr][empty][client adr][empty][data]
localBackend.SendMessage(msg);
}
else
{
// get an random index for peers
var peerIdx = rnd.Next(peers.Count - 2) + 2;
// get peers address
var peer = peers[peerIdx];
// wrap message with peer's address
var msg = Wrap(peer, request);
// [peer adr][empty][client adr][empty][data]
cloudBackend.SendMessage(msg);
}
};
// the workers are connected to this socket
// we get a REPLY either for a cloud client [worker adr][empty][peer adr][empty][peer client adr][empty][data]
// or local client [worker adr][empty][client adr][empty][data]
// or a READY message [worker adr][empty][WORKER_READY]
localBackend.ReceiveReady += (s, e) =>
{
// a worker can send "READY" or a request
// or an REPLAY
var msg = e.Socket.ReceiveMultipartMessage();
// just to make sure we received a proper message
Debug.Assert(msg != null && msg.FrameCount > 0, "[LocalBackend] message was empty or frame count == 0!");
// get the workers identity
var id = Unwrap(msg);
// this worker done in either way so add it to available workers
workerQueue.Enqueue(id);
// if it is NOT a ready message we need to route the message
// it could be a reply to a peer or a local client
// [WORKER_READY] or [client adr][empty][data] or [peer adr][empty][peer client adr][empty][data]
if (msg[0].Buffer[0] != WorkerReady)
{
Debug.Assert(msg.FrameCount > 2, "[LocalBackend] None READY message malformed");
// if the adr (first frame) is any of the clients send the REPLY there
// and send it to the peer otherwise
if (clients.Any(n => AreSame(n, msg.First)))
localFrontend.SendMessage(msg);
else
cloudFrontend.SendMessage(msg);
}
};
// this socket is connected to all peers
// we receive either a REQ or a REPLY form a peer
// REQ [peer adr][empty][peer client adr][empty][message id] -> send to peer for processing
// REP [peer adr][empty][client adr][empty][message id] -> send to local client
cloudBackend.ReceiveReady += (s, e) =>
{
var msg = e.Socket.ReceiveMultipartMessage();
// just to make sure we received a message
Debug.Assert(msg != null && msg.FrameCount > 0, "[CloudBackend] message was empty or frame count == 0!");
// we need the peers address for proper addressing
var peerAdr = Unwrap(msg);
// the remaining message must be at least 3 frames!
Debug.Assert(msg.FrameCount > 2, "[CloudBackend] message malformed");
// if the id is any of the local clients it is a REPLY
// and a REQ otherwise
if (clients.Any(n => AreSame(n, msg.First)))
{
// [client adr][empty][message id]
localFrontend.SendMessage(msg);
}
else
{
// add the peers address to the request
var request = Wrap(peerAdr, msg);
// [peer adr][empty][peer client adr][empty][message id]
cloudFrontend.SendMessage(request);
}
};
// all peers are binding to this socket
// we receive REPLY or REQ from peers
// REQ [peer adr][empty][peer client adr][empty][data] -> send to local worker for processing
// REP [peer adr][empty][client adr][empty][data] -> send to local client
cloudFrontend.ReceiveReady += (s, e) =>
{
var msg = e.Socket.ReceiveMultipartMessage();
// just to make sure we received a message
Debug.Assert(msg != null && msg.FrameCount > 0, "[CloudFrontend] message was empty or frame count == 0!");
// we may need need the peers address for proper addressing
var peerAdr = Unwrap(msg);
// the remaining message must be at least 3 frames!
Debug.Assert(msg.FrameCount > 2, "[CloudFrontend] message malformed");
// if the address is any of the local clients it is a REPLY
// and a REQ otherwise
if (clients.Any(n => AreSame(n, msg.First)))
localFrontend.SendMessage(msg);
else
{
// in order to know which per to send back the peers adr must be added again
var original = Wrap(peerAdr, msg);
// reduce the capacity to reflect the use of a worker by a cloud request
previousLocalCapacity = workerQueue.Count;
// get the LRU worker
var workerAdr = workerQueue.Dequeue();
// wrap the message with the worker address and send
var request = Wrap(workerAdr, original);
localBackend.SendMessage(request);
}
};
// in order to reduce chatter we only check to see if we have local capacity to provide to cloud
// periodically every 2 seconds with a timer
var timer = new NetMQTimer((int)TimeSpan.FromSeconds(2).TotalMilliseconds);
timer.Elapsed += (t, e) =>
{
// send message only if the previous send information changed
if (previousLocalCapacity != workerQueue.Count)
{
// set the information
previousLocalCapacity = workerQueue.Count;
// generate the message
var msg = new NetMQMessage();
var data = new NetMQFrame(previousLocalCapacity.ToString());
msg.Append(data);
var stateMessage = Wrap(Encoding.UTF8.GetBytes(me), msg);
// publish info
stateBackend.SendMessage(stateMessage);
}
// restart the timer
e.Timer.Enable = true;
};
// start all clients and workers as threads
var clientTasks = new Thread[NbrClients];
var workerTasks = new Thread[NbrWorker];
for (var i = 0; i < NbrClients; i++)
{
var client = new Client(localFrontendAddress, monitorAddress, (byte)i);
clientTasks[i] = new Thread(client.Run) { Name = string.Format("Client_{0}", i) };
clientTasks[i].Start();
}
for (var i = 0; i < NbrWorker; i++)
{
var worker = new Worker(localBackendAddress, (byte)i);
workerTasks[i] = new Thread(worker.Run) { Name = string.Format("Worker_{0}", i) };
workerTasks[i].Start();
}
var sockets = new NetMQSocket[]
{
localFrontend,
localBackend,
cloudFrontend,
cloudBackend,
stateFrontend,
stateBackend,
monitor
};
// create poller and add sockets & timer
var poller = new Poller(sockets);
poller.AddTimer(timer);
// start monitoring the sockets
Task.Factory.StartNew(poller.PollTillCancelled);
// we wait for a CTRL+C to exit
while (s_keepRunning)
{}
Console.WriteLine("Ctrl-C encountered! Exiting the program!");
if (poller.IsStarted)
poller.CancelAndJoin();
poller.Dispose();
}
}
