add serial client module

serial-client.go

@@ -0,0 +1,181 @@
+//go:build cgo
+
+package showbridge
+
+import (
+	"fmt"
+	"log/slog"
+	"time"
+
+	"github.com/jwetzell/showbridge-go/internal/framing"
+	"go.bug.st/serial"
+)
+
+type SerialClient struct {
+	config ModuleConfig
+	router *Router
+	Port   string
+	Framer framing.Framer
+	Mode   *serial.Mode
+	port   serial.Port
+}
+
+func init() {
+	RegisterModule(ModuleRegistration{
+		//TODO(jwetzell): find a better namespace than "misc"
+		Type: "misc.serial.client",
+		New: func(config ModuleConfig) (Module, error) {
+			params := config.Params
+			port, ok := params["port"]
+
+			if !ok {
+				return nil, fmt.Errorf("misc.serial.client requires a port parameter")
+			}
+
+			portString, ok := port.(string)
+
+			if !ok {
+				return nil, fmt.Errorf("misc.serial.client port must be a string")
+			}
+
+			framingMethod, ok := params["framing"]
+			if !ok {
+				return nil, fmt.Errorf("misc.serial.client requires a framing method")
+			}
+
+			framingMethodString, ok := framingMethod.(string)
+
+			if !ok {
+				return nil, fmt.Errorf("misc.serial.client framing method must be a string")
+			}
+
+			var framer framing.Framer
+
+			switch framingMethodString {
+			case "CR":
+				framer = framing.NewByteSeparatorFramer([]byte{'\r'})
+			case "LF":
+				framer = framing.NewByteSeparatorFramer([]byte{'\n'})
+			case "CRLF":
+				framer = framing.NewByteSeparatorFramer([]byte{'\r', '\n'})
+			case "SLIP":
+				framer = framing.NewSlipFramer()
+			default:
+				return nil, fmt.Errorf("unknown framing method: %s", framingMethodString)
+			}
+
+			buadRate, ok := params["baudRate"]
+			if !ok {
+				return nil, fmt.Errorf("misc.serial.client requires a baudRate parameter")
+			}
+
+			baudRateNum, ok := buadRate.(float64)
+			if !ok {
+				return nil, fmt.Errorf("misc.serial.client baudRate must be a number")
+			}
+
+			mode := serial.Mode{
+				BaudRate: int(baudRateNum),
+			}
+
+			return &SerialClient{config: config, Port: portString, Framer: framer, Mode: &mode}, nil
+		},
+	})
+}
+
+func (mc *SerialClient) Id() string {
+	return mc.config.Id
+}
+
+func (mc *SerialClient) Type() string {
+	return mc.config.Type
+}
+
+func (mc *SerialClient) RegisterRouter(router *Router) {
+	mc.router = router
+}
+
+func (mc *SerialClient) SetupPort() error {
+
+	port, err := serial.Open(mc.Port, mc.Mode)
+	if err != nil {
+		return fmt.Errorf("misc.serial.client can't open input port: %s", mc.Port)
+	}
+
+	mc.port = port
+
+	return nil
+}
+
+func (mc *SerialClient) Run() error {
+
+	// TODO(jwetzell): shutdown with router.Context properly
+	go func() {
+		<-mc.router.Context.Done()
+		slog.Debug("router context done in module", "id", mc.config.Id)
+		if mc.port != nil {
+			mc.port.Close()
+		}
+	}()
+
+	for {
+		err := mc.SetupPort()
+		if err != nil {
+			if mc.router.Context.Err() != nil {
+				slog.Debug("router context done in module", "id", mc.config.Id)
+				return nil
+			}
+			slog.Error("misc.serial.client", "id", mc.config.Id, "error", err.Error())
+			time.Sleep(time.Second * 2)
+			continue
+		}
+
+		buffer := make([]byte, 1024)
+		select {
+		case <-mc.router.Context.Done():
+			slog.Debug("router context done in module", "id", mc.config.Id)
+			return nil
+		default:
+		READ:
+			for {
+				select {
+				case <-mc.router.Context.Done():
+					slog.Debug("router context done in module", "id", mc.config.Id)
+					return nil
+				default:
+					byteCount, err := mc.port.Read(buffer)
+
+					if err != nil {
+						mc.Framer.Clear()
+						break READ
+					}
+
+					if mc.Framer != nil {
+						if byteCount > 0 {
+							messages := mc.Framer.Decode(buffer[0:byteCount])
+							for _, message := range messages {
+								if mc.router != nil {
+									mc.router.HandleInput(mc.config.Id, message)
+								} else {
+									slog.Error("misc.serial.client has no router", "id", mc.config.Id)
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+}
+
+func (mc *SerialClient) Output(payload any) error {
+
+	payloadBytes, ok := payload.([]byte)
+
+	if !ok {
+		return fmt.Errorf("misc.serial.client can only ouptut bytes")
+	}
+
+	_, err := mc.port.Write(mc.Framer.Encode(payloadBytes))
+	return err
+}