go/uc_sensor_node_zmq/main.go

   1 // (c) Bernhard Tittelbach, 2013
   2
   3 package main
   4
   5 import (
   6         "flag"
   7         "time"
   8
   9         zmq "github.com/vaughan0/go-zmq"
  10 )
  11
  12 // ---------- Main Code -------------
  13
  14 var (
  15         tty_dev_      string
  16         pub_addr      string
  17         use_syslog_   bool
  18         enable_debug_ bool
  19         serial_speed_ uint
  20 )
  21
  22 const exponential_backof_activation_threshold int64 = 4
  23
  24 func init() {
  25         flag.StringVar(&pub_addr, "brokeraddr", "tcp://torwaechter.realraum.at:4243", "zmq address to send stuff to")
  26         flag.StringVar(&tty_dev_, "ttydev", "/dev/ttyACM0", "path do tty uc device")
  27         flag.UintVar(&serial_speed_, "serspeed", 0, "tty baudrate (0 to disable setting a baudrate e.g. in case of ttyACM)")
  28         flag.BoolVar(&use_syslog_, "syslog", false, "log to syslog local1 facility")
  29         flag.BoolVar(&enable_debug_, "debug", false, "debugging messages on")
  30         flag.Parse()
  31 }
  32
  33 func ConnectSerialToZMQ(pub_sock *zmq.Socket, timeout time.Duration) {
  34         defer func() {
  35                 if x := recover(); x != nil {
  36                         Syslog_.Println(x)
  37                 }
  38         }()
  39
  40         serial_wr, serial_rd, err := OpenAndHandleSerial(tty_dev_, serial_speed_)
  41         if err != nil {
  42                 panic(err)
  43         }
  44         defer close(serial_wr)
  45
  46         t := time.NewTimer(timeout)
  47         for {
  48                 select {
  49                 case incoming_ser_line, seropen := <-serial_rd:
  50                         if !seropen {
  51                                 return
  52                         }
  53                         t.Reset(timeout)
  54                         Syslog_.Printf("%s", incoming_ser_line)
  55                         if err := pub_sock.Send(incoming_ser_line); err != nil {
  56                                 Syslog_.Println(err.Error())
  57                         }
  58
  59                 case <-t.C:
  60                         Syslog_.Print("Timeout, no message for 120 seconds")
  61                 }
  62         }
  63 }
  64
  65 func main() {
  66         zmqctx, pub_sock := ZmqsInit(pub_addr)
  67         if pub_sock == nil {
  68                 panic("zmq socket creation failed")
  69         }
  70         defer zmqctx.Close()
  71         defer pub_sock.Close()
  72
  73         if enable_debug_ {
  74                 LogEnableDebuglog()
  75         } else if use_syslog_ {
  76                 LogEnableSyslog()
  77                 Syslog_.Print("started")
  78         }
  79
  80         var backoff_exp uint32 = 0
  81         for {
  82                 start_time := time.Now().Unix()
  83                 ConnectSerialToZMQ(pub_sock, time.Second*120)
  84                 run_time := time.Now().Unix() - start_time
  85                 if run_time > exponential_backof_activation_threshold {
  86                         backoff_exp = 0
  87                 }
  88                 time.Sleep(150 * (1 << backoff_exp) * time.Millisecond)
  89                 if backoff_exp < 12 {
  90                         backoff_exp++
  91                 }
  92         }
  93 }