Improve client serial robustness

client/cli.go

@@ -282,6 +282,7 @@ func (this *Cli) drawAxis(name string, x, y, width, height int) {
 	textWidth := width - 3
 	ls.Items = []string{
 		padApart("VAL:", this.vars["placement"][name].ValueString(), textWidth),
+		padApart("VEL:", this.vars["placement"][name+"Vel"].ValueString(), textWidth),
 		padApart("OUT:", this.vars["controllerOut"][name].ValueString(), textWidth),
 		padApart("EN:", conf["enabled"].ValueString(), textWidth),
 	}

client/sender.go

@@ -37,6 +37,7 @@ func (this *Sender) Start() {
 
 	go func() {
 		var handheldConnected, droneConnected bool
+		//var handheldConnected bool
 
 		for {
 			select {
@@ -123,7 +124,7 @@ func (this *Sender) read(encodedInChan chan chan []byte) {
 				}
 				if proto.Unmarshal(encodedVar[1:encodedVar[0]+1], shmMsg) != nil {
 					this.status <- "Unable to unmarshal remote message"
-					continue
+					break
 				}
 
 				var outValue interface{}
@@ -136,13 +137,13 @@ func (this *Sender) read(encodedInChan chan chan []byte) {
 					outValue = inValue.BoolValue
 				default:
 					this.status <- "Unknown remote var type"
-					continue
+					break
 				}
 
 				v, err := BindVarTag(int(*shmMsg.Tag), outValue)
 				if err != nil {
 					this.status <- fmt.Sprint("Failed to bind remote var:", err)
-					continue
+					break
 				}
 				this.varsOut <- v
 				encodedVar = encodedVar[encodedVar[0]+1:]

client/serial.go

@@ -7,7 +7,10 @@ import (
 	"github.com/tarm/serial"
 )
 
-const handheldRetryPeriod = time.Millisecond * 250
+const (
+	serialRetryPeriod = time.Second / 4
+	serialTimeout     = time.Second / 10
+)
 
 type Serial struct {
 	In        chan [][]byte
@@ -38,13 +41,17 @@ func (this *Serial) Start() {
 	go func() {
 		for {
 			this.startSession(portChan)
-			time.Sleep(handheldRetryPeriod)
+			time.Sleep(serialRetryPeriod)
 		}
 	}()
 }
 
 func (this *Serial) startSession(portChan chan *serial.Port) {
-	config := serial.Config{Name: this.portName, Baud: this.baud}
+	config := serial.Config{
+		Name:        this.portName,
+		Baud:        this.baud,
+		ReadTimeout: serialTimeout,
+	}
 	port, err := serial.OpenPort(&config)
 	if err != nil {
 		return
@@ -55,18 +62,37 @@ func (this *Serial) startSession(portChan chan *serial.Port) {
 
 	portChan <- port
 
+	disconnect := func() {
+		this.Connected <- false
+		this.status <- fmt.Sprint("Serial disconnected on", this.portName)
+	}
+
 	buf := make([]byte, 256)
 	for {
-		n, err := port.Read(buf)
-		if err != nil {
-			this.Connected <- false
-			this.status <- fmt.Sprint("Serial disconnected on", this.portName)
-			return
+		t := time.Now()
+		n, _ := port.Read(buf[:1])
+		if n == 0 {
+			if time.Since(t) < serialTimeout/2 {
+				disconnect()
+				return
+			}
+			continue
+		}
+
+		msgTarget := buf[1 : buf[0]+1]
+		t = time.Now()
+		n, _ = port.Read(msgTarget)
+		if n < len(msgTarget) {
+			if time.Since(t) < serialTimeout/2 {
+				disconnect()
+				return
+			}
+			continue
 		}
 
-		// Assume we get the whole message(s) at once
-		outBuf := make([]byte, n)
-		copy(outBuf, buf[:n])
+		// Assume we've received the entire message at this point
+		outBuf := make([]byte, len(msgTarget)+1)
+		copy(outBuf, buf[:len(msgTarget)+1])
 		this.Out <- outBuf
 	}
 }