// .split broker client_msg method
// Process a request coming from a client. We implement MMI requests
// directly here (at present, we implement only the mmi.service request):
public void ClientMsg(ZFrame sender, ZMessage msg)
{
// service & body
if (msg.Count < 2)
{
throw new InvalidOperationException();
}
using (ZFrame serviceFrame = msg.Pop())
{
Service service = RequireService(serviceFrame);
// Set reply return identity to client sender
msg.Wrap(sender.Duplicate());
//if we got a MMI Service request, process that internally
if (serviceFrame.Length >= 4 &&
serviceFrame.ToString().StartsWith("mmi."))
{
string returnCode;
if (serviceFrame.ToString().Equals("mmi.service"))
{
string name = msg.Last().ToString();
returnCode = Services.ContainsKey(name) &&
Services[name].Workers > 0
? "200"
: "404";
}
else
{
returnCode = "501";
}
var client = msg.Unwrap();
msg.Clear();
msg.Add(new ZFrame(returnCode));
msg.Prepend(serviceFrame);
msg.Prepend(new ZFrame(MdpCommon.MDPC_CLIENT));
msg.Wrap(client);
Socket.Send(msg);
}
else
{
// Else dispatch the message to the requested Service
service.Dispatch(msg);
}
}
}
// .split service methods
// Here is the implementation of the methods that work on a service:
// Lazy constructor that locates a service by name or creates a new
// service if there is no service already with that name.
public Service RequireService(ZFrame serviceFrame)
{
if (serviceFrame == null)
{
throw new InvalidOperationException();
}
string name = serviceFrame.ToString();
Service service;
if (Services.ContainsKey(name))
{
service = Services[name];
}
else
{
service = new Service(this, name);
Services[name] = service;
//zhash_freefn(self->workers, id_string, s_worker_destroy);
if (Verbose)
{
"I: added service: '{0}'".DumpString(name);
}
}
return(service);
}
// .skip
// The recv method waits for a reply message and returns that to the
// caller.
// ---------------------------------------------------------------------
// Returns the reply message or NULL if there was no reply. Does not
// attempt to recover from a broker failure, this is not possible
// without storing all unanswered requests and resending them all...
public ZMessage Recv(CancellationTokenSource cancellor)
{
// Poll socket for a reply, with timeout
var p = ZPollItem.CreateReceiver();
ZMessage msg;
ZError error;
// .split body of send
// On any blocking call, {{libzmq}} will return -1 if there was
// an error; we could in theory check for different error codes,
// but in practice it's OK to assume it was {{EINTR}} (Ctrl-C):
// Poll the client Message
if (Client.PollIn(p, out msg, out error, Timeout))
{
// If we got a reply, process it
if (Verbose)
{
msg.DumpZmsg("I: received reply");
}
// Don't try to handle errors, just assert noisily
if (msg.Count < 4)
{
throw new InvalidOperationException();
}
using (ZFrame empty = msg.Pop())
if (!empty.ToString().Equals(string.Empty))
{
throw new InvalidOperationException();
}
using (ZFrame header = msg.Pop())
if (!header.ToString().Equals(MdpCommon.MDPC_CLIENT))
{
throw new InvalidOperationException();
}
using (ZFrame replyService = msg.Pop())
{}
return(msg);
}
else if (Equals(error, ZError.ETERM))
{
"W: interrupt received, killing client...\n".DumpString();
cancellor.Cancel();
}
else
{
if (Verbose)
{
"W: permanent error, abandoning Error: {0}".DumpString(error);
}
}
return(null);
}
static void Main(string[] args)
{
using (ZSocket request = new ZSocket(ZSocketType.REQ))
{
request.Connect("tcp://localhost:50000");
Console.WriteLine($"Connect to server: tcp://localhost:50000");
for (int i = 0; i < 10; i++)
{
string postStr = $"Lynn {i}";
request.Send(new ZFrame(postStr));
Console.WriteLine($"Post {postStr} to server....");
using (ZFrame reply = request.ReceiveFrame())
{
Console.WriteLine($"Receive reply: {reply.ToString()}");
}
}
}
Console.Read();
}
static void Main(string[] args)
{
string url = "tcp://*:50000";
using (ZSocket receiver = new ZSocket(ZSocketType.REP))
{
receiver.Bind(url);
Console.WriteLine($"Server is binding to {url}");
while (true)
{
using (ZFrame message = receiver.ReceiveFrame())
{
Console.WriteLine($"Receive message {message.ToString()}");
var reply = new ZFrame("Lynn");
Console.WriteLine($"Send reply: {reply.ToString()}");
receiver.Send(reply);
};
}
};
}
// .split service methods
// Here is the implementation of the methods that work on a service:
// Lazy constructor that locates a service by name or creates a new
// service if there is no service already with that name.
public Service RequireService(ZFrame serviceFrame)
{
if(serviceFrame == null)
throw new InvalidOperationException();
string name = serviceFrame.ToString();
Service service;
if (Services.ContainsKey(name))
{
service = Services[name];
}
else
{
service = new Service(this, name);
Services[name] = service;
//zhash_freefn(self->workers, id_string, s_worker_destroy);
if (Verbose)
"I: added service: '{0}'".DumpString(name);
}
return service;
}
// .split send request and wait for reply
// Here is the {{send}} method. It sends a request to the broker and gets
// a reply even if it has to retry several times. It takes ownership of
// the request message, and destroys it when sent. It returns the reply
// message, or NULL if there was no reply after multiple attempts:
public ZMessage Send(string service, ZMessage request, CancellationTokenSource cancellor)
{
if (request == null)
{
throw new InvalidOperationException();
}
// Prefix request with protocol frames
// Frame 1: "MDPCxy" (six bytes, MDP/Client x.y)
// Frame 2: Service name (printable string)
request.Prepend(new ZFrame(service));
request.Prepend(new ZFrame(MdpCommon.MDPC_CLIENT));
if (Verbose)
{
request.DumpZmsg("I: send request to '{0}' service:", service);
}
int retriesLeft = Retries;
while (retriesLeft > 0 && !cancellor.IsCancellationRequested)
{
if (cancellor.IsCancellationRequested ||
(Console.KeyAvailable && Console.ReadKey(true).Key == ConsoleKey.Escape))
{
_context.Shutdown();
}
// Copy the Request and send on Client
ZMessage msgreq = request.Duplicate();
ZError error;
if (!Client.Send(msgreq, out error))
{
if (Equals(error, ZError.ETERM))
{
cancellor.Cancel();
break; // Interrupted
}
}
var p = ZPollItem.CreateReceiver();
ZMessage msg;
// .split body of send
// On any blocking call, {{libzmq}} will return -1 if there was
// an error; we could in theory check for different error codes,
// but in practice it's OK to assume it was {{EINTR}} (Ctrl-C):
// Poll the client Message
if (Client.PollIn(p, out msg, out error, Timeout))
{
// If we got a reply, process it
if (Verbose)
{
msg.DumpZmsg("I: received reply");
}
if (msg.Count < 3)
{
throw new InvalidOperationException();
}
using (ZFrame header = msg.Pop())
if (!header.ToString().Equals(MdpCommon.MDPC_CLIENT))
{
throw new InvalidOperationException();
}
using (ZFrame replyService = msg.Pop())
if (!replyService.ToString().Equals(service))
{
throw new InvalidOperationException();
}
request.Dispose();
return(msg);
}
else if (Equals(error, ZError.ETERM))
{
cancellor.Cancel();
break; // Interrupted
}
else if (Equals(error, ZError.EAGAIN))
{
if (--retriesLeft > 0)
{
if (Verbose)
{
"W: no reply, reconnecting...".DumpString();
}
ConnectToBroker();
}
else
{
if (Verbose)
{
"W: permanent error, abandoning".DumpString();
}
break; // Give up
}
}
}
if (cancellor.IsCancellationRequested)
{
"W: interrupt received, killing client...\n".DumpString();
}
request.Dispose();
return(null);
}
// .split recv method
// This is the {{recv}} method; it's a little misnamed because it first sends
// any reply and then waits for a new request. If you have a better name
// for this, let me know.
// Send reply, if any, to broker and wait for next request.
public ZMessage Recv(ZMessage reply, CancellationTokenSource cancellor)
{
if (reply == null &&
_expectReply)
{
throw new InvalidOperationException();
}
if (reply != null)
{
if (_replyTo == null)
{
throw new InvalidOperationException();
}
reply.Wrap(_replyTo);
SendToBroker(MdpCommon.MdpwCmd.REPLY.ToHexString(), string.Empty, reply);
}
_expectReply = true;
while (true)
{
if (cancellor.IsCancellationRequested ||
(Console.KeyAvailable && Console.ReadKey(true).Key == ConsoleKey.Escape))
{
_context.Shutdown();
}
var p = ZPollItem.CreateReceiver();
ZMessage msg;
ZError error;
if (Worker.PollIn(p, out msg, out error, Heartbeat))
{
using (msg)
{
// If we got a reply
if (Verbose)
{
msg.DumpZmsg("I: received message from broker:");
}
Liveness = MdpCommon.HEARTBEAT_LIVENESS;
// Don't try to handle errors, just assert noisily
if (msg.Count < 3)
{
throw new InvalidOperationException();
}
using (ZFrame empty = msg.Pop())
{
if (!empty.ToString().Equals(""))
{
throw new InvalidOperationException();
}
}
using (ZFrame header = msg.Pop())
{
if (!header.ToString().Equals(MdpCommon.MDPW_WORKER))
{
throw new InvalidOperationException();
}
}
//header.ReadString().Equals(MDPW_WORKER);
using (ZFrame command = msg.Pop())
{
if (command.StrHexEq(MdpCommon.MdpwCmd.REQUEST))
{
// We should pop and save as many addresses as there are
// up to a null part, but for now, just save one...
_replyTo = msg.Unwrap();
// .split process message
// Here is where we actually have a message to process; we
// return it to the caller application:
return(msg.Duplicate());
}
else if (command.StrHexEq(MdpCommon.MdpwCmd.HEARTBEAT))
{
// Do nothing for heartbeats
}
else if (command.StrHexEq(MdpCommon.MdpwCmd.DISCONNECT))
{
ConnectToBroker();
}
else
{
"E: invalid input message: '{0}'".DumpString(command.ToString());
}
}
}
}
else if (Equals(error, ZError.ETERM))
{
cancellor.Cancel();
break; // Interrupted
}
else if (Equals(error, ZError.EAGAIN) &&
--Liveness == 0)
{
if (Verbose)
{
"W: disconnected from broker - retrying...".DumpString();
}
Thread.Sleep(Reconnect);
ConnectToBroker();
}
// Send HEARTBEAT if it's time
if (DateTime.UtcNow > HeartbeatAt)
{
SendToBroker(MdpCommon.MdpwCmd.HEARTBEAT.ToHexString(), null, null);
HeartbeatAt = DateTime.UtcNow + Heartbeat;
}
}
if (cancellor.IsCancellationRequested)
{
"W: interrupt received, killing worker...\n".DumpString();
}
return(null);
}
public static bool StrHexEq(this ZFrame zfrm, MdpCommon.MdpwCmd cmd)
{
return(zfrm.ToString().ToMdCmd().Equals(cmd));
}
// .split main task
// Finally, here is the main task. We create a new broker instance and
// then process messages on the broker Socket:
public static void MDBroker(string[] args)
{
CancellationTokenSource cancellor = new CancellationTokenSource();
Console.CancelKeyPress += (s, ea) =>
{
ea.Cancel = true;
cancellor.Cancel();
};
using (Broker broker = new Broker(Verbose))
{
broker.Bind("tcp://*:5555");
// Get and process messages forever or until interrupted
while (true)
{
if (cancellor.IsCancellationRequested ||
(Console.KeyAvailable && Console.ReadKey(true).Key == ConsoleKey.Escape))
{
broker.ShutdownContext();
}
var p = ZPollItem.CreateReceiver();
ZMessage msg;
ZError error;
if (broker.Socket.PollIn(p, out msg, out error, MdpCommon.HEARTBEAT_INTERVAL))
{
if (Verbose)
{
msg.DumpZmsg("I: received message:");
}
using (ZFrame sender = msg.Pop())
using (ZFrame empty = msg.Pop())
using (ZFrame header = msg.Pop())
{
if (header.ToString().Equals(MdpCommon.MDPC_CLIENT))
{
broker.ClientMsg(sender, msg);
}
else if (header.ToString().Equals(MdpCommon.MDPW_WORKER))
{
broker.WorkerMsg(sender, msg);
}
else
{
msg.DumpZmsg("E: invalid message:");
msg.Dispose();
}
}
}
else
{
if (Equals(error, ZError.ETERM))
{
"W: interrupt received, shutting down...".DumpString();
break; // Interrupted
}
if (!Equals(error, ZError.EAGAIN))
{
throw new ZException(error);
}
}
// Disconnect and delete any expired workers
// Send heartbeats to idle workes if needed
if (DateTime.UtcNow > broker.HeartbeatAt)
{
broker.Purge();
foreach (var waitingworker in broker.Waiting)
{
waitingworker.Send(MdpCommon.MdpwCmd.HEARTBEAT.ToHexString(), null, null);
}
broker.HeartbeatAt = DateTime.UtcNow + MdpCommon.HEARTBEAT_INTERVAL;
}
}
}
}
// .split broker worker_msg method
// This method processes one READY, REPLY, HEARTBEAT, or
// DISCONNECT message sent to the broker by a worker:
public void WorkerMsg(ZFrame sender, ZMessage msg)
{
if (msg.Count < 1) // At least, command
{
throw new InvalidOperationException();
}
ZFrame command = msg.Pop();
//string id_string = sender.ReadString();
bool isWorkerReady;
//string id_string;
using (var sfrm = sender.Duplicate())
{
var idString = sfrm.Read().ToHexString();
isWorkerReady = Workers.ContainsKey(idString);
}
Worker worker = RequireWorker(sender);
using (msg)
using (command)
{
if (command.StrHexEq(MdpCommon.MdpwCmd.READY))
{
if (isWorkerReady)
{
// Not first command in session
worker.Delete(true);
}
else if (command.Length >= 4 &&
command.ToString().StartsWith("mmi."))
{
// Reserd servicee name
worker.Delete(true);
}
else
{
// Attach worker to service and mark as idle
using (ZFrame serviceFrame = msg.Pop())
{
worker.Service = RequireService(serviceFrame);
worker.Service.Workers++;
worker.Waiting();
}
}
}
else if (command.StrHexEq(MdpCommon.MdpwCmd.REPLY))
{
if (isWorkerReady)
{
// Remove and save client return envelope and insert the
// protocol header and service name, then rewrap envelope.
ZFrame client = msg.Unwrap();
msg.Prepend(new ZFrame(worker.Service.Name));
msg.Prepend(new ZFrame(MdpCommon.MDPC_CLIENT));
msg.Wrap(client);
Socket.Send(msg);
worker.Waiting();
}
else
{
worker.Delete(true);
}
}
else if (command.StrHexEq(MdpCommon.MdpwCmd.HEARTBEAT))
{
if (isWorkerReady)
{
worker.Expiry = DateTime.UtcNow + MdpCommon.HEARTBEAT_EXPIRY;
}
else
{
worker.Delete(true);
}
}
else if (command.StrHexEq(MdpCommon.MdpwCmd.DISCONNECT))
{
worker.Delete(false);
}
else
{
msg.DumpZmsg("E: invalid input message");
}
}
}
private void UpdateLoop(object sender, DoWorkEventArgs e)
{
loopActive = true;
int loopInterval = 50;
// Loop to get and assign elements, then update UI
while (loopActive)
{
AsyncFormUpdate(new Action(() =>
{
lblStatus.Text = "Update Loop Running";
}));
// Check to see if thread cancellation is pending
// If true, stop the loop
if (bwUpdateLoop.CancellationPending)
{
requester.Close();
context.Shutdown();
context.Dispose();
requester.Dispose();
loopActive = false;
AsyncFormUpdate(new Action(() =>
{
lblStatus.Text = "Update Loop Stopped";
}));
break;
}
/// Socket Code
// Send
requester.Send(new ZFrame(_autoMode));
try
{
// Receive
using (ZFrame reply = requester.ReceiveFrame())
{
returnedData = JObject.Parse(reply.ToString());
}
}
catch (ZException ex)
{
requester.Close();
context.Shutdown();
context.Dispose();
requester.Dispose();
loopActive = false;
AsyncFormUpdate(new Action(() =>
{
lblMode.Text = "Loop Stopped";
lblStatus.Text = "Update Loop Stopped";
}));
break;
}
// ======================================================
// Take all elements from the Dictionary and update the UI with them
AsyncFormUpdate(new Action(() => ShowUI(returnedData)));
// Stall the thread for a given interval to save on bandwidth
Thread.Sleep(loopInterval);
}
/// update the UI with this status
AsyncFormUpdate(new Action(() => {
lblMode.Text = "Not Connected";
}));
}
