func (server *Server) monitor(ctx *zmq.Context, addr string) {
sock, err := ctx.NewSocket(zmq.PAIR)
if err != nil {
glog.Fatal(err)
}
if err := sock.Connect(addr); err != nil {
glog.Fatal(err)
}
defer sock.Close()
var lock sync.Mutex
var numClients int
for {
evtType, _, _, err := sock.RecvEvent(0)
if err != nil {
glog.Error(err)
break
}
switch zmq.Event(evtType) {
case zmq.EVENT_ACCEPTED:
lock.Lock()
numClients++
glog.Infof("Client #%d connected", numClients)
lock.Unlock()
case zmq.EVENT_DISCONNECTED:
lock.Lock()
glog.Infof("Client #%d disconnected", numClients)
numClients--
lock.Unlock()
}
}
}
//
// MonitorSocket creates a monitoring socket using given context and connects
// to a given socket to be monitored. Returns a channel to receive monitoring
// events. See event definitions here: http://api.zeromq.org/3-2:zmq-socket-monitor
//
func MonitorSocket(socket *zmq.Socket, name string) (<-chan zmq.Event, error) {
endpoint := fmt.Sprintf("inproc://%v.%v.%v", name, os.Getpid(), time.Now().UnixNano())
monCh := make(chan zmq.Event, 512) // make a buffered channel in case of heavy network activity
go func() {
monSock, err := zmq.NewSocket(zmq.PAIR)
if err != nil {
log.Println("Failed to start monitoring socket:", err.Error())
return
}
monSock.Connect(endpoint)
for {
data, err := monSock.RecvMessageBytes(0)
if err != nil {
return
}
eventID := zmq.Event(binary.LittleEndian.Uint16(data[0][:2]))
/*
switch eventID {
case zmq.EVENT_CONNECTED:
log.Println("MonitorSocket: EVENT_CONNECTED", string(data[1]))
case zmq.EVENT_CONNECT_DELAYED:
log.Println("MonitorSocket: EVENT_CONNECT_DELAYED", string(data[1]))
case zmq.EVENT_CONNECT_RETRIED:
log.Println("MonitorSocket: EVENT_CONNECT_RETRIED", string(data[1]))
case zmq.EVENT_LISTENING:
log.Println("MonitorSocket: EVENT_LISTENING", string(data[1]))
case zmq.EVENT_BIND_FAILED:
log.Println("MonitorSocket: EVENT_BIND_FAILED", string(data[1]))
case zmq.EVENT_ACCEPTED:
log.Println("MonitorSocket: EVENT_ACCEPTED", string(data[1]))
case zmq.EVENT_ACCEPT_FAILED:
log.Println("MonitorSocket: EVENT_ACCEPT_FAILED", string(data[1]))
case zmq.EVENT_CLOSED:
log.Println("MonitorSocket: EVENT_CLOSED", string(data[1]))
case zmq.EVENT_CLOSE_FAILED:
log.Println("MonitorSocket: EVENT_CLOSE_FAILED", string(data[1]))
case zmq.EVENT_DISCONNECTED:
log.Println("MonitorSocket: EVENT_DISCONNECTED", string(data[1]))
default:
log.Printf("MonitorSocket: Unsupported event id: %#v - Message: %#v", eventID, data)
}
*/
monCh <- zmq.Event(eventID)
}
}()
return monCh, socket.Monitor(endpoint, MonitorEvents)
}