added error returns to the SendData method on the peripheral interface

devices/cdashdisplay/display.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	helper "esdi/helpers"
+	"esdi/peripheral"
 	"esdi/peripheral/communication"
 	"esdi/peripheral/communication/packets"
 	"esdi/peripheral/types"
@@ -107,10 +108,12 @@ func NewCDashState() *CDashState {
 }
 
 type CDashDisplay struct {
-	WT             *communication.WalkieTalkie
-	State          *CDashState
-	fieldToWindows map[telemetry.FieldID][]int16
-	bufPool        sync.Pool
+	WT                          *communication.WalkieTalkie
+	State                       *CDashState
+	fieldToWindows              map[telemetry.FieldID][]int16
+	bufPool                     sync.Pool
+	failedSends                 int
+	FailedSendsConsecutiveLimit int
 }
 
 // Connect will try to find and connect to the CDashDisplay
@@ -118,7 +121,7 @@ func NewCDashDisplay() (*CDashDisplay, error) {
 	// Look for the port
 	p, err := findDisplayPort()
 	if err != nil {
-		slog.Info("failed to find cdashdisplay port: %s", err.Error())
+		slog.Info("failed to find cdashdisplay port", "reason", err.Error())
 		return nil, err
 	}
 
@@ -132,6 +135,8 @@ func NewCDashDisplay() (*CDashDisplay, error) {
 				return &b
 			},
 		},
+		failedSends:                 0,
+		FailedSendsConsecutiveLimit: 5,
 	}, nil
 }
 
@@ -393,12 +398,12 @@ func (d *CDashDisplay) UnloadLayout() error {
 	return nil
 }
 
-func (d *CDashDisplay) SendData(data *telemetry.TelemetryData) {
+func (d *CDashDisplay) SendData(data *telemetry.TelemetryData) error {
 	packet := d.encodePacket(data)
 
 	bytes, err := helper.StructToBytes(packet)
 	if err != nil {
-		return
+		return peripheral.ErrFailureToPackData
 	}
 
 	curStr := ""
@@ -408,7 +413,6 @@ func (d *CDashDisplay) SendData(data *telemetry.TelemetryData) {
 		curStr += fmt.Sprintf("%02x ", byte)
 
 		if byteCount == 8 {
-			// slog.Debug(curStr)
 			curStr = ""
 			byteCount = 0
 		}
@@ -417,6 +421,11 @@ func (d *CDashDisplay) SendData(data *telemetry.TelemetryData) {
 	// var ack packets.AckPacket
 	err = d.WT.SendCommand(sendDataCMDID, bytes, nil)
 	if err != nil && err != io.EOF {
-		return
+		if d.failedSends == d.FailedSendsConsecutiveLimit {
+			return peripheral.ErrDeviceTimedOut
+		}
+		d.failedSends++
 	}
+
+	return nil
 }

devices/uidevice/device.go

@@ -17,9 +17,9 @@ func NewUIDevice() (peripheral.Peripheral, error) {
 	}, nil
 }
 
-func (uid *UIDevice) SendData(data *telemetry.TelemetryData) {
+func (uid *UIDevice) SendData(data *telemetry.TelemetryData) error {
 	if data == nil {
-		return
+		return peripheral.ErrInvalidData
 	}
 
 	select {
@@ -27,6 +27,8 @@ func (uid *UIDevice) SendData(data *telemetry.TelemetryData) {
 	default:
 		// Drop frame if buffer is full
 	}
+
+	return nil
 }
 
 func (uid *UIDevice) Name() string {

peripheral/errors.go

@@ -0,0 +1,9 @@
+package peripheral
+
+import "errors"
+
+var (
+	ErrInvalidData       = errors.New("invalid data")
+	ErrDeviceTimedOut    = errors.New("device timed out")
+	ErrFailureToPackData = errors.New("failed to pack received data")
+)

peripheral/peripheral.go

@@ -17,7 +17,7 @@ const (
 
 type Peripheral interface {
 	Name() string
-	SendData(*telemetry.TelemetryData)
+	SendData(*telemetry.TelemetryData) error
 	RequiredFields() []telemetry.FieldID
 }
 

services/devices.go

@@ -159,7 +159,11 @@ func (ds *DeviceService) transmit(ctx context.Context) {
 			// the data locked
 			ds.mu.RLock()
 			for _, dev := range ds.Devices {
-				dev.SendData(&data)
+				err := dev.SendData(&data)
+				if err == peripheral.ErrDeviceTimedOut {
+					// What do we do here?
+					// TODO: somehow we need to handle reconnection
+				}
 			}
 			ds.mu.RUnlock()