added logging for unknown dispenser status positions

config/config.go

@@ -5,7 +5,7 @@ import (
 	"os"
 	"strings"
 
-	"gitea.futuresens.co.uk/futuresens/hardlink/handlers"
+	"gitea.futuresens.co.uk/futuresens/hardlink/errorhandlers"
 	log "github.com/sirupsen/logrus"
 	yaml "gopkg.in/yaml.v3"
 )
@@ -49,7 +49,7 @@ func ReadHardlinkConfig() ConfigRec {
 
 	if cfg.LockType == "" {
 		err = fmt.Errorf("LockType is required in %s", configName)
-		handlers.FatalError(err)
+		errorhandlers.FatalError(err)
 	}
 	cfg.LockType = strings.ToLower(cfg.LockType)
 
@@ -81,7 +81,7 @@ func ReadPreauthReleaserConfig() ConfigRec {
 
 	if cfg.Dbport <= 0 || cfg.Dbuser == "" || cfg.Dbname == "" || cfg.Dbpassword == "" {
 		err = fmt.Errorf("Database config (dbport, dbuser, dbname, dbpassword) are required in %s", configName)
-		handlers.FatalError(err)
+		errorhandlers.FatalError(err)
 	}
 
 	if cfg.LogDir == "" {

db/db.go

@@ -198,3 +198,4 @@ WHERE TxnReference = @TxnReference AND Released = 0;
 	log.Infof("Marked preauth %s released at %s", txnReference, releasedAt.Format(time.RFC3339))
 	return nil
 }
+

dispenser/dispenser.go

@@ -1,9 +1,8 @@
 package dispenser
 
 import (
-	// "encoding/hex"
 	"fmt"
-	// "log"
+	"strings"
 	"time"
 
 	log "github.com/sirupsen/logrus"
@@ -20,29 +19,25 @@ const (
 	space    = 0x00                   // Space character
 	baudRate = 9600                   // Baud rate for serial communication
 	delay    = 500 * time.Millisecond // Delay for processing commands
-)
 
-// type (
-// 	configRec struct {
-// 		SerialPort string `yaml:"port"`
-// 		Address    string `yaml:"addr"`
-// 	}
-// )
+	// cache freshness for "continuous status" reads (tune as you wish)
+	defaultStatusTTL = 1500 * time.Millisecond
+)
 
 var (
 	SerialPort string
 	Address    []byte
-	commandFC7 = []byte{ETX, 0x46, 0x43, 0x37} // "FC7" command dispense card at read card position
-	commandFC0 = []byte{ETX, 0x46, 0x43, 0x30} // "FC0" command dispense card out of card mouth command
+
+	commandFC7 = []byte{ETX, 0x46, 0x43, 0x37} // "FC7"
+	commandFC0 = []byte{ETX, 0x46, 0x43, 0x30} // "FC0"
 
 	statusPos0 = map[byte]string{
 		0x38: "Keep",
 		0x34: "Command cannot execute",
 		0x32: "Preparing card fails",
 		0x31: "Preparing card",
-		0x30: "Normal", // Default if none of the above
+		0x30: "Normal",
 	}
-
 	statusPos1 = map[byte]string{
 		0x38: "Dispensing card",
 		0x34: "Capturing card",
@@ -50,7 +45,6 @@ var (
 		0x31: "Capture card error",
 		0x30: "Normal",
 	}
-
 	statusPos2 = map[byte]string{
 		0x38: "No captured card",
 		0x34: "Card overlapped",
@@ -58,7 +52,6 @@ var (
 		0x31: "Card pre-empty",
 		0x30: "Normal",
 	}
-
 	statusPos3 = map[byte]string{
 		0x38: "Card empty",
 		0x34: "Card ready position",
@@ -69,48 +62,77 @@ var (
 	}
 )
 
-func checkStatus(statusResp []byte) (string, error) {
-	if len(statusResp) > 3 {
-		statusBytes := statusResp[7:11] // Extract the relevant bytes from the response
-		// For each position, get the ASCII character, hex value, and mapped meaning.
-		posStatus := []struct {
-			pos    int
-			value  byte
-			mapper map[byte]string
-		}{
-			{pos: 1, value: statusBytes[0], mapper: statusPos0},
-			{pos: 2, value: statusBytes[1], mapper: statusPos1},
-			{pos: 3, value: statusBytes[2], mapper: statusPos2},
-			{pos: 4, value: statusBytes[3], mapper: statusPos3},
-		}
+// --------------------
+// Status helpers
+// --------------------
 
-		result := ""
-		for _, p := range posStatus {
-			statusMsg, exists := p.mapper[p.value]
-			if !exists {
-				statusMsg = "Unknown status"
-			}
-			if p.value != 0x30 {
-				result += fmt.Sprintf("Status: %s; ", statusMsg)
-			}
-			if p.pos == 4 && p.value == 0x38 {
-				return result, fmt.Errorf("Card well empty")
-			}
-		}
-		return result, nil
+func logStatus(statusBytes []byte) {
+	if len(statusBytes) < 4 {
+		log.Infof("Dispenser status: <invalid len=%d>", len(statusBytes))
+		return
+	}
 
-	} else {
-		if len(statusResp) == 3 && statusResp[0] == ACK && statusResp[1] == Address[0] && statusResp[2] == Address[1] {
-			return "active;", nil
-		} else if len(statusResp) > 0 && statusResp[0] == NAK {
-			return "", fmt.Errorf("negative response from dispenser")
-		} else {
-			return "", fmt.Errorf("unexpected response status: % X", statusResp)
+	posStatus := []struct {
+		pos    int
+		value  byte
+		mapper map[byte]string
+	}{
+		{pos: 1, value: statusBytes[0], mapper: statusPos0},
+		{pos: 2, value: statusBytes[1], mapper: statusPos1},
+		{pos: 3, value: statusBytes[2], mapper: statusPos2},
+		{pos: 4, value: statusBytes[3], mapper: statusPos3},
+	}
+
+	var result strings.Builder
+	for _, p := range posStatus {
+		statusMsg, exists := p.mapper[p.value]
+		if !exists {
+			statusMsg = fmt.Sprintf("Unknown status 0x%X at position %d", p.value, p.pos)
+		}
+		if p.value != 0x30 {
+			result.WriteString(statusMsg + "; ")
 		}
 	}
+	log.Infof("Dispenser status: %s", result.String())
 }
 
-// calculateBCC computes the Block Check Character (BCC) as the XOR of all bytes from STX to ETX.
+func isAtEncoderPosition(statusBytes []byte) bool {
+	return len(statusBytes) >= 4 && statusBytes[3] == 0x33
+}
+
+func stockTake(statusBytes []byte) string {
+	if len(statusBytes) < 4 {
+		return ""
+	}
+	status := ""
+	if statusBytes[2] != 0x30 {
+		status = statusPos2[statusBytes[2]]
+	}
+	if statusBytes[3] == 0x38 {
+		status = statusPos3[statusBytes[3]]
+	}
+	return status
+}
+
+func isCardWellEmpty(statusBytes []byte) bool {
+	return len(statusBytes) >= 4 && statusBytes[3] == 0x38
+}
+
+func checkACK(statusResp []byte) error {
+	if len(statusResp) == 3 &&
+		statusResp[0] == ACK &&
+		len(Address) >= 2 &&
+		statusResp[1] == Address[0] &&
+		statusResp[2] == Address[1] {
+		return nil
+	}
+	if len(statusResp) > 0 && statusResp[0] == NAK {
+		return fmt.Errorf("negative response from dispenser")
+	}
+	return fmt.Errorf("unexpected response status: % X", statusResp)
+}
+
+// calculateBCC computes BCC as XOR of all bytes from STX to ETX.
 func calculateBCC(data []byte) byte {
 	var bcc byte
 	for _, b := range data {
@@ -121,8 +143,8 @@ func calculateBCC(data []byte) byte {
 
 func createPacket(address []byte, command []byte) []byte {
 	packet := []byte{STX}
-	packet = append(packet, address...) // Address bytes
-	packet = append(packet, space)      // Space character
+	packet = append(packet, address...)
+	packet = append(packet, space)
 	packet = append(packet, command...)
 	packet = append(packet, ETX)
 	bcc := calculateBCC(packet)
@@ -130,165 +152,134 @@ func createPacket(address []byte, command []byte) []byte {
 	return packet
 }
 
-func buildCheckRF(address []byte) []byte {
-	return createPacket(address, []byte{STX, 0x52, 0x46})
-}
-
-func buildCheckAP(address []byte) []byte {
-	return createPacket(address, []byte{STX, 0x41, 0x50})
-}
+func buildCheckAP(address []byte) []byte { return createPacket(address, []byte{STX, 0x41, 0x50}) }
 
 func sendAndReceive(port *serial.Port, packet []byte, delay time.Duration) ([]byte, error) {
-	n, err := port.Write(packet)
+	_, err := port.Write(packet)
 	if err != nil {
 		return nil, fmt.Errorf("error writing to port: %w", err)
 	}
-	// log.Printf("TX %d bytes: % X", n, packet[:n])
 
-	time.Sleep(delay) // Wait for the dispenser to process the command
+	time.Sleep(delay)
 
 	buf := make([]byte, 128)
-	n, err = port.Read(buf)
+	n, err := port.Read(buf)
 	if err != nil {
 		return nil, fmt.Errorf("error reading from port: %w", err)
 	}
-	resp := buf[:n]
-	// log.Printf("RX %d bytes: % X", n, buf[:n])
-	return resp, nil
+	return buf[:n], nil
 }
 
+// --------------------
+// Serial init (3 attempts)
+// --------------------
+
 func InitializeDispenser() (*serial.Port, error) {
-	const funcName = "initializeDispenser"
+	const (
+		funcName   = "InitializeDispenser"
+		maxRetries = 3
+		retryDelay = 2 * time.Second
+	)
+
+	if SerialPort == "" {
+		return nil, fmt.Errorf("%s: SerialPort is empty", funcName)
+	}
+	if len(Address) < 2 {
+		return nil, fmt.Errorf("%s: Address must be at least 2 bytes", funcName)
+	}
+
 	serialConfig := &serial.Config{
 		Name:        SerialPort,
 		Baud:        baudRate,
-		ReadTimeout: time.Second * 2,
+		ReadTimeout: 2 * time.Second,
 	}
-	port, err := serial.OpenPort(serialConfig)
-	if err != nil {
-		return nil, fmt.Errorf("error opening dispenser COM port: %w", err)
+
+	var lastErr error
+	for attempt := 1; attempt <= maxRetries; attempt++ {
+		port, err := serial.OpenPort(serialConfig)
+		if err == nil {
+			log.Infof("%s: dispenser opened on %s (attempt %d/%d)", funcName, SerialPort, attempt, maxRetries)
+			return port, nil
+		}
+
+		lastErr = err
+		log.Warnf("%s: failed to open dispenser on %s (attempt %d/%d): %v", funcName, SerialPort, attempt, maxRetries, err)
+		if attempt < maxRetries {
+			time.Sleep(retryDelay)
+		}
 	}
-	return port, nil
+
+	return nil, fmt.Errorf("%s: failed to open dispenser on %s after %d attempts: %w", funcName, SerialPort, maxRetries, lastErr)
 }
 
-func DispenserSequence(port *serial.Port) (string, error) {
-	const funcName = "dispenserSequence"
-	var result string
+// --------------------
+// Internal (port-owner only) operations
+// --------------------
 
-	// Check dispenser status
-	status, err := CheckDispenserStatus(port)
-	if err != nil {
-		return status, fmt.Errorf("[%s] error checking dispenser status: %v", funcName, err)
-	}
-	result += status
-
-	// Send card to encoder position
-	status, err = CardToEncoderPosition(port)
-	if err != nil {
-		return status, fmt.Errorf("[%s] error sending card to encoder position: %v", funcName, err)
-	}
-	result += "; " + status
-
-	return result, nil
-}
-
-// if dispenser is not responding, I should repeat the command
-func CheckDispenserStatus(port *serial.Port) (string, error) {
-	const funcName = "checkDispenserStatus"
-	var result string
+// checkDispenserStatus talks to the device and returns the 4 status bytes [pos0..pos3].
+func checkDispenserStatus(port *serial.Port) ([]byte, error) {
 	checkCmd := buildCheckAP(Address)
 	enq := append([]byte{ENQ}, Address...)
 
-	// Send check command (AP)
 	statusResp, err := sendAndReceive(port, checkCmd, delay)
 	if err != nil {
-		return "", fmt.Errorf("error sending check command: %v", err)
+		return nil, fmt.Errorf("error sending check command: %w", err)
 	}
 	if len(statusResp) == 0 {
-		return "", fmt.Errorf("no response from dispenser")
+		return nil, fmt.Errorf("no response from dispenser")
 	}
-	status, err := checkStatus(statusResp)
-	if err != nil {
-		return status, err
+	if err := checkACK(statusResp); err != nil {
+		return nil, err
 	}
-	result += "; " + status
 
-	// Send ENQ+ADDR to prompt device to execute the command.
 	statusResp, err = sendAndReceive(port, enq, delay)
 	if err != nil {
-		log.Errorf("error sending ENQ: %v", err)
+		return nil, fmt.Errorf("error sending ENQ: %w", err)
 	}
-	if len(statusResp) == 0 {
-		return "", fmt.Errorf("no response from dispenser")
+	if len(statusResp) < 13 {
+		return nil, fmt.Errorf("incomplete status response from dispenser: % X", statusResp)
 	}
-	status, err = checkStatus(statusResp)
-	if err != nil {
-		return status, err
-	}
-	result += status
-	return result, nil
+	return statusResp[7:11], nil
 }
 
-func CardToEncoderPosition(port *serial.Port) (string, error) {
-	const funcName = "cartToEncoderPosition"
+func cardToEncoderPosition(port *serial.Port) error {
 	enq := append([]byte{ENQ}, Address...)
 
-	//Send Dispense card to encoder position (FC7) ---
 	dispenseCmd := createPacket(Address, commandFC7)
 	log.Println("Send card to encoder position")
+
 	statusResp, err := sendAndReceive(port, dispenseCmd, delay)
 	if err != nil {
-		return "", fmt.Errorf("error sending card to encoder position: %v", err)
+		return fmt.Errorf("error sending card to encoder position: %w", err)
 	}
-	_, err = checkStatus(statusResp)
-	if err != nil {
-		return "", err
+	if err := checkACK(statusResp); err != nil {
+		return err
 	}
 
-	//Send ENQ to prompt device ---
 	_, err = port.Write(enq)
 	if err != nil {
-		return "", fmt.Errorf("error sending ENQ to prompt device: %v", err)
+		return fmt.Errorf("error sending ENQ to prompt device: %w", err)
 	}
-
-	time.Sleep(delay)
-
-	//Check card position status
-	status, err := CheckDispenserStatus(port)
-	if err != nil {
-		return "", err
-	}
-	return status, nil
+	return nil
 }
 
-func CardOutOfMouth(port *serial.Port) (string, error) {
-	const funcName = "CardOutOfMouth"
+func cardOutOfMouth(port *serial.Port) error {
 	enq := append([]byte{ENQ}, Address...)
 
-	// Send  card out of card mouth (FC0) ---
 	dispenseCmd := createPacket(Address, commandFC0)
 	log.Println("Send card to out mouth position")
+
 	statusResp, err := sendAndReceive(port, dispenseCmd, delay)
 	if err != nil {
-		return "", fmt.Errorf("error sending out of mouth command: %v", err)
+		return fmt.Errorf("error sending out of mouth command: %w", err)
 	}
-	_, err = checkStatus(statusResp)
-	if err != nil {
-		return "", err
+	if err := checkACK(statusResp); err != nil {
+		return err
 	}
 
-	//Send ENQ to prompt device ---
 	_, err = port.Write(enq)
 	if err != nil {
-		return "", fmt.Errorf("error sending ENQ to prompt device: %v", err)
+		return fmt.Errorf("error sending ENQ to prompt device: %w", err)
 	}
-
-	time.Sleep(delay)
-
-	//Check card position status
-	status, err := CheckDispenserStatus(port)
-	if err != nil {
-		return "", err
-	}
-	return status, nil
+	return nil
 }

dispenser/dispenserclient.go

@@ -0,0 +1,341 @@
+// --------------------
+// Queue-based client (single owner of port)
+// --------------------
+package dispenser
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/tarm/serial"
+)
+
+type cmdType int
+
+const (
+	cmdStatus cmdType = iota
+	cmdToEncoder
+	cmdOutOfMouth
+)
+
+type cmdReq struct {
+	typ    cmdType
+	ctx    context.Context
+	respCh chan cmdResp
+}
+
+type cmdResp struct {
+	status []byte
+	err    error
+}
+
+type Client struct {
+	port *serial.Port
+
+	reqCh chan cmdReq
+	done  chan struct{}
+
+	// status cache
+	mu          sync.RWMutex
+	lastStatus  []byte
+	lastStatusT time.Time
+	statusTTL   time.Duration
+
+	// published "stock/cardwell" cache + callback
+	lastStockMu sync.RWMutex
+	lastStock   string
+	onStock     func(string)
+}
+
+// NewClient starts the worker that owns the serial port.
+func NewClient(port *serial.Port, queueSize int) *Client {
+	if queueSize <= 0 {
+		queueSize = 16
+	}
+	c := &Client{
+		port:      port,
+		reqCh:     make(chan cmdReq, queueSize),
+		done:      make(chan struct{}),
+		statusTTL: defaultStatusTTL,
+	}
+	go c.loop()
+	return c
+}
+
+func (c *Client) Close() {
+	select {
+	case <-c.done:
+		return
+	default:
+		close(c.done)
+	}
+}
+
+// Optional: tune cache TTL (how "fresh" cached status must be)
+func (c *Client) SetStatusTTL(d time.Duration) {
+	c.mu.Lock()
+	c.statusTTL = d
+	c.mu.Unlock()
+}
+
+// OnStockUpdate registers a callback called whenever polling (or status reads) produce a stock status string.
+func (c *Client) OnStockUpdate(fn func(string)) {
+	c.lastStockMu.Lock()
+	c.onStock = fn
+	c.lastStockMu.Unlock()
+}
+
+// LastStock returns the most recently computed stock/card-well status string.
+func (c *Client) LastStock() string {
+	c.lastStockMu.RLock()
+	defer c.lastStockMu.RUnlock()
+	return c.lastStock
+}
+
+func (c *Client) setStock(statusBytes []byte) {
+	stock := stockTake(statusBytes)
+
+	c.lastStockMu.Lock()
+	c.lastStock = stock
+	fn := c.onStock
+	c.lastStockMu.Unlock()
+
+	// call outside lock
+	if fn != nil {
+		fn(stock)
+	}
+}
+
+// StartPolling performs a periodic status refresh.
+// It will NOT interrupt commands: it enqueues only when queue is idle.
+func (c *Client) StartPolling(interval time.Duration) {
+	if interval <= 0 {
+		return
+	}
+	go func() {
+		t := time.NewTicker(interval)
+		defer t.Stop()
+
+		for {
+			select {
+			case <-c.done:
+				return
+			case <-t.C:
+				// enqueue only if idle to avoid delaying real commands
+				if len(c.reqCh) != 0 {
+					continue
+				}
+				ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+				_, err := c.CheckStatus(ctx)
+				if err != nil {
+					log.Debugf("dispenser polling: %v", err)
+				}
+				cancel()
+			}
+		}
+	}()
+}
+
+func (c *Client) loop() {
+	for {
+		select {
+		case <-c.done:
+			return
+		case req := <-c.reqCh:
+			c.handle(req)
+		}
+	}
+}
+
+func (c *Client) handle(req cmdReq) {
+	select {
+	case <-req.ctx.Done():
+		req.respCh <- cmdResp{err: req.ctx.Err()}
+		return
+	default:
+	}
+
+	switch req.typ {
+	case cmdStatus:
+		st, err := checkDispenserStatus(c.port)
+		if err == nil && len(st) == 4 {
+			c.mu.Lock()
+			c.lastStatus = append([]byte(nil), st...)
+			c.lastStatusT = time.Now()
+			c.mu.Unlock()
+
+			// publish stock/cardwell
+			c.setStock(st)
+		}
+		req.respCh <- cmdResp{status: st, err: err}
+
+	case cmdToEncoder:
+		err := cardToEncoderPosition(c.port)
+		req.respCh <- cmdResp{err: err}
+
+	case cmdOutOfMouth:
+		err := cardOutOfMouth(c.port)
+		req.respCh <- cmdResp{err: err}
+
+	default:
+		req.respCh <- cmdResp{err: fmt.Errorf("unknown command")}
+	}
+}
+
+func (c *Client) do(ctx context.Context, typ cmdType) ([]byte, error) {
+	rch := make(chan cmdResp, 1)
+	req := cmdReq{typ: typ, ctx: ctx, respCh: rch}
+
+	select {
+	case c.reqCh <- req:
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+
+	select {
+	case r := <-rch:
+		return r.status, r.err
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+}
+
+// CheckStatus returns cached status if fresh, otherwise enqueues a device status read.
+func (c *Client) CheckStatus(ctx context.Context) ([]byte, error) {
+	c.mu.RLock()
+	ttl := c.statusTTL
+	st := append([]byte(nil), c.lastStatus...)
+	ts := c.lastStatusT
+	c.mu.RUnlock()
+
+	if len(st) == 4 && time.Since(ts) <= ttl {
+		// even when returning cached, keep stock in sync
+		c.setStock(st)
+		return st, nil
+	}
+	return c.do(ctx, cmdStatus)
+}
+
+func (c *Client) ToEncoder(ctx context.Context) error {
+	_, err := c.do(ctx, cmdToEncoder)
+	return err
+}
+
+func (c *Client) OutOfMouth(ctx context.Context) error {
+	_, err := c.do(ctx, cmdOutOfMouth)
+	return err
+}
+
+// --------------------
+// Public sequences updated to use Client (queue)
+// --------------------
+
+// DispenserPrepare: check status; if empty => ok; else ensure at encoder.
+func (c *Client) DispenserPrepare(ctx context.Context) (string, error) {
+	const funcName = "DispenserPrepare"
+	stockStatus := ""
+
+	status, err := c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] check status: %w", funcName, err)
+	}
+
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	if isCardWellEmpty(status) {
+		return stockStatus, nil
+	}
+	if isAtEncoderPosition(status) {
+		return stockStatus, nil
+	}
+
+	if err := c.ToEncoder(ctx); err != nil {
+		return stockStatus, fmt.Errorf("[%s] to encoder: %w", funcName, err)
+	}
+
+	time.Sleep(delay)
+	status, err = c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] re-check status: %w", funcName, err)
+	}
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	return stockStatus, nil
+}
+
+func (c *Client) DispenserStart(ctx context.Context) (string, error) {
+	const funcName = "DispenserStart"
+	stockStatus := ""
+
+	status, err := c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] check status: %w", funcName, err)
+	}
+
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	if isCardWellEmpty(status) {
+		return stockStatus, fmt.Errorf(stockStatus)
+	}
+	if isAtEncoderPosition(status) {
+		return stockStatus, nil
+	}
+
+	if err := c.ToEncoder(ctx); err != nil {
+		return stockStatus, fmt.Errorf("[%s] to encoder: %w", funcName, err)
+	}
+
+	time.Sleep(delay)
+	status, err = c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] re-check status: %w", funcName, err)
+	}
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	return stockStatus, nil
+}
+
+func (c *Client) DispenserFinal(ctx context.Context) (string, error) {
+	const funcName = "DispenserFinal"
+	stockStatus := ""
+
+	if err := c.OutOfMouth(ctx); err != nil {
+		return stockStatus, fmt.Errorf("[%s] out of mouth: %w", funcName, err)
+	}
+
+	time.Sleep(delay)
+	status, err := c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] check status: %w", funcName, err)
+	}
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	time.Sleep(delay)
+	if err := c.ToEncoder(ctx); err != nil {
+		return stockStatus, fmt.Errorf("[%s] to encoder: %w", funcName, err)
+	}
+
+	time.Sleep(delay)
+	status, err = c.CheckStatus(ctx)
+	if err != nil {
+		return stockStatus, fmt.Errorf("[%s] re-check status: %w", funcName, err)
+	}
+	logStatus(status)
+	stockStatus = stockTake(status)
+	c.setStock(status)
+
+	return stockStatus, nil
+}

errorhandlers/errorhandlers.go

@@ -0,0 +1,32 @@
+package errorhandlers
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+
+	"gitea.futuresens.co.uk/futuresens/cmstypes"
+	log "github.com/sirupsen/logrus"
+)
+
+const serviceName = "hardlink"
+
+// writeError is a helper to send a JSON error and HTTP status in one go.
+func WriteError(w http.ResponseWriter, status int, msg string) {
+	theResponse := cmstypes.StatusRec{
+		Code:    status,
+		Message: msg,
+	}
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(status)
+	json.NewEncoder(w).Encode(theResponse)
+}
+
+func FatalError(err error) {
+	fmt.Println(err.Error())
+	log.Errorf(err.Error())
+	fmt.Println(". Press Enter to exit...")
+	fmt.Scanln()
+	os.Exit(1)
+}

handlers/db_helpers.go

@@ -0,0 +1,206 @@
+package handlers
+
+import (
+	"bufio"
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"gitea.futuresens.co.uk/futuresens/hardlink/db"
+	log "github.com/sirupsen/logrus"
+)
+
+type preauthSpoolRecord struct {
+	CreatedAt    time.Time         `json:"createdAt"`
+	CheckoutDate string            `json:"checkoutDate"` // keep as received
+	Fields       map[string]string `json:"fields"`       // ChipDNA result.Fields
+}
+
+func (app *App) getDB(ctx context.Context) (*sql.DB, error) {
+	app.dbMu.Lock()
+	defer app.dbMu.Unlock()
+
+	// Fast path: db exists and is alive
+	if app.db != nil {
+		pingCtx, cancel := context.WithTimeout(ctx, 1*time.Second)
+		defer cancel()
+
+		if err := app.db.PingContext(pingCtx); err == nil {
+			return app.db, nil
+		}
+
+		// stale handle
+		_ = app.db.Close()
+		app.db = nil
+	}
+
+	// Reconnect once, bounded
+	dialCtx, cancel := context.WithTimeout(ctx, 3*time.Second)
+	defer cancel()
+
+	dbConn, err := db.InitMSSQL(
+		app.cfg.Dbport,
+		app.cfg.Dbuser,
+		app.cfg.Dbpassword,
+		app.cfg.Dbname,
+	)
+	if err != nil {
+		return nil, err
+	}
+
+	pingCtx, cancel2 := context.WithTimeout(dialCtx, 1*time.Second)
+	defer cancel2()
+
+	if err := dbConn.PingContext(pingCtx); err != nil {
+		_ = dbConn.Close()
+		return nil, err
+	}
+
+	app.db = dbConn
+	return app.db, nil
+}
+
+func (app *App) spoolPath() string {
+	// keep it near logs; adjust if you prefer a dedicated dir
+	// ensure LogDir ends with separator in your config loader
+	return filepath.Join(app.cfg.LogDir, "preauth_spool.ndjson")
+}
+
+// persistPreauth tries DB first; if DB is down or insert fails, it spools to file.
+// It never returns an error to the caller (so your HTTP flow stays simple),
+// but it logs failures.
+func (app *App) persistPreauth(ctx context.Context, fields map[string]string, checkoutDate string) {
+	// First, try DB (with your reconnect logic inside getDB)
+	dbConn, err := app.getDB(ctx)
+	if err == nil && dbConn != nil {
+		if err := db.InsertPreauth(ctx, dbConn, fields, checkoutDate); err == nil {
+			// opportunistic drain once DB is alive
+			go app.drainPreauthSpool(context.Background())
+			return
+		} else {
+			log.WithError(err).Warn("DB insert failed; will spool preauth")
+		}
+	} else {
+		log.WithError(err).Warn("DB unavailable; will spool preauth")
+	}
+
+	// Fallback: spool to file
+	rec := preauthSpoolRecord{
+		CreatedAt:    time.Now().UTC(),
+		CheckoutDate: checkoutDate,
+		Fields:       fields,
+	}
+	if spErr := app.spoolPreauth(rec); spErr != nil {
+		log.WithError(spErr).Error("failed to spool preauth")
+	}
+}
+
+// append one line JSON (NDJSON)
+func (app *App) spoolPreauth(rec preauthSpoolRecord) error {
+	p := app.spoolPath()
+
+	f, err := os.OpenFile(p, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
+	if err != nil {
+		return fmt.Errorf("open spool file: %w", err)
+	}
+	defer f.Close()
+
+	b, err := json.Marshal(rec)
+	if err != nil {
+		return fmt.Errorf("marshal spool record: %w", err)
+	}
+
+	if _, err := f.Write(append(b, '\n')); err != nil {
+		return fmt.Errorf("write spool record: %w", err)
+	}
+
+	return f.Sync() // ensure it's on disk
+}
+
+// Drain spool into DB.
+// Strategy: read all lines, insert each; keep failures in a temp file; then replace original.
+func (app *App) drainPreauthSpool(ctx context.Context) {
+	dbConn, err := app.getDB(ctx)
+	if err != nil {
+		return // still down, nothing to do
+	}
+
+	spool := app.spoolPath()
+	in, err := os.Open(spool)
+	if err != nil {
+		// no spool is fine
+		return
+	}
+	defer in.Close()
+
+	tmp := spool + ".tmp"
+	out, err := os.OpenFile(tmp, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0666)
+	if err != nil {
+		log.WithError(err).Warn("drain spool: open tmp failed")
+		return
+	}
+	defer out.Close()
+
+	sc := bufio.NewScanner(in)
+	// allow long lines if receipts ever sneak in (shouldn't, but safe)
+	buf := make([]byte, 0, 64*1024)
+	sc.Buffer(buf, 2*1024*1024)
+
+	var (
+		okCount   int
+		failCount int
+	)
+
+	for sc.Scan() {
+		line := sc.Bytes()
+		if len(line) == 0 {
+			continue
+		}
+
+		var rec preauthSpoolRecord
+		if err := json.Unmarshal(line, &rec); err != nil {
+			// malformed line: keep it so we don't lose evidence
+			_, _ = out.Write(append(line, '\n'))
+			failCount++
+			continue
+		}
+
+		// attempt insert
+		if err := db.InsertPreauth(ctx, dbConn, rec.Fields, rec.CheckoutDate); err != nil {
+			// DB still flaky or data issue: keep it for later retry
+			_, _ = out.Write(append(line, '\n'))
+			failCount++
+			continue
+		}
+
+		okCount++
+	}
+
+	if err := sc.Err(); err != nil {
+		log.WithError(err).Warn("drain spool: scanner error")
+		// best effort; do not replace spool
+		return
+	}
+
+	_ = out.Sync()
+
+	// Replace original spool with temp (atomic on Windows is best-effort; still OK here)
+	_ = in.Close()
+	_ = out.Close()
+
+	if err := os.Rename(tmp, spool); err != nil {
+		log.WithError(err).Warn("drain spool: rename failed")
+		return
+	}
+
+	if okCount > 0 || failCount > 0 {
+		log.WithFields(log.Fields{
+			"inserted":  okCount,
+			"remaining": failCount,
+		}).Info("preauth spool drained")
+	}
+}

handlers/handlers.go

@@ -2,19 +2,20 @@ package handlers
 
 import (
 	"bytes"
+	"context"
 	"database/sql"
 	"encoding/json"
 	"encoding/xml"
 	"io"
 	"net/http"
 	"strings"
+	"sync"
 	"time"
 
-	"github.com/tarm/serial"
-
 	"gitea.futuresens.co.uk/futuresens/cmstypes"
-	"gitea.futuresens.co.uk/futuresens/hardlink/db"
+	"gitea.futuresens.co.uk/futuresens/hardlink/config"
 	"gitea.futuresens.co.uk/futuresens/hardlink/dispenser"
+	"gitea.futuresens.co.uk/futuresens/hardlink/errorhandlers"
 	"gitea.futuresens.co.uk/futuresens/hardlink/lockserver"
 	"gitea.futuresens.co.uk/futuresens/hardlink/payment"
 	"gitea.futuresens.co.uk/futuresens/hardlink/printer"
@@ -24,19 +25,26 @@ import (
 )
 
 type App struct {
-	dispPort   *serial.Port
-	lockserver lockserver.LockServer
-	isPayment  bool
-	db         *sql.DB
+	disp           *dispenser.Client
+	lockserver     lockserver.LockServer
+	isPayment      bool
+	db             *sql.DB
+	cfg            *config.ConfigRec
+	dbMu           sync.Mutex
+	cardWellMu     sync.RWMutex
+	cardWellStatus string
 }
 
-func NewApp(dispPort *serial.Port, lockType, encoderAddress string, db *sql.DB, isPayment bool) *App {
-	return &App{
-		isPayment:  isPayment,
-		dispPort:   dispPort,
-		lockserver: lockserver.NewLockServer(lockType, encoderAddress, FatalError),
+func NewApp(disp *dispenser.Client, lockType, encoderAddress, cardWellStatus string, db *sql.DB, cfg *config.ConfigRec) *App {
+	app := &App{
+		isPayment:  cfg.IsPayment,
+		disp:       disp,
+		lockserver: lockserver.NewLockServer(lockType, encoderAddress, errorhandlers.FatalError),
 		db:         db,
+		cfg:        cfg,
 	}
+	app.SetCardWellStatus(cardWellStatus)
+	return app
 }
 
 func (app *App) RegisterRoutes(mux *http.ServeMux) {
@@ -44,6 +52,7 @@ func (app *App) RegisterRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("/printroomticket", app.printRoomTicket)
 	mux.HandleFunc("/takepreauth", app.takePreauthorization)
 	mux.HandleFunc("/takepayment", app.takePayment)
+	mux.HandleFunc("/dispenserstatus", app.reportDispenserStatus)
 }
 
 func (app *App) takePreauthorization(w http.ResponseWriter, r *http.Request) {
@@ -131,8 +140,9 @@ func (app *App) takePreauthorization(w http.ResponseWriter, r *http.Request) {
 	theResponse.Status = result.Status
 	theResponse.Data, save = payment.BuildPreauthRedirectURL(result.Fields)
 	if save {
-		db.InsertPreauth(r.Context(), app.db, result.Fields, theRequest.CheckoutDate)
+		go app.persistPreauth(context.Background(), result.Fields, theRequest.CheckoutDate)
 	}
+
 	writeTransactionResult(w, http.StatusOK, theResponse)
 }
 
@@ -241,19 +251,19 @@ func (app *App) issueDoorCard(w http.ResponseWriter, r *http.Request) {
 
 	log.Println("issueDoorCard called")
 	if r.Method != http.MethodPost {
-		writeError(w, http.StatusMethodNotAllowed, "Method not allowed; use POST")
+		errorhandlers.WriteError(w, http.StatusMethodNotAllowed, "Method not allowed; use POST")
 		return
 	}
 	defer r.Body.Close()
 
 	if ct := r.Header.Get("Content-Type"); ct != "application/json" {
-		writeError(w, http.StatusUnsupportedMediaType, "Content-Type must be application/json")
+		errorhandlers.WriteError(w, http.StatusUnsupportedMediaType, "Content-Type must be application/json")
 		return
 	}
 
 	if err := json.NewDecoder(r.Body).Decode(&doorReq); err != nil {
 		logging.Error(serviceName, err.Error(), "ReadJSON", string(op), "", "", 0)
-		writeError(w, http.StatusBadRequest, "Invalid JSON payload: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusBadRequest, "Invalid JSON payload: "+err.Error())
 		return
 	}
 
@@ -261,57 +271,61 @@ func (app *App) issueDoorCard(w http.ResponseWriter, r *http.Request) {
 	checkIn, err := time.Parse(types.CustomLayout, doorReq.CheckinTime)
 	if err != nil {
 		logging.Error(serviceName, err.Error(), "Invalid checkinTime format", string(op), "", "", 0)
-		writeError(w, http.StatusBadRequest, "Invalid checkinTime format: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusBadRequest, "Invalid checkinTime format: "+err.Error())
 		return
 	}
 	checkOut, err := time.Parse(types.CustomLayout, doorReq.CheckoutTime)
 	if err != nil {
 		logging.Error(serviceName, err.Error(), "Invalid checkoutTime format", string(op), "", "", 0)
-		writeError(w, http.StatusBadRequest, "Invalid checkoutTime format: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusBadRequest, "Invalid checkoutTime format: "+err.Error())
 		return
 	}
 
-	// dispenser sequence
-	if status, err := dispenser.DispenserSequence(app.dispPort); err != nil {
-		if status != "" {
-			logging.Error(serviceName, status, "Dispense error", string(op), "", "", 0)
-			writeError(w, http.StatusServiceUnavailable, "Dispense error: "+err.Error())
-		} else {
-			logging.Error(serviceName, err.Error(), "Dispense error", string(op), "", "", 0)
-			writeError(w, http.StatusServiceUnavailable, "Dispense error: "+err.Error()+"; check card stock")
-		}
+	// Ensure dispenser ready (card at encoder) BEFORE we attempt encoding.
+	// With queued dispenser ops, this will not clash with polling.
+	status, err := app.disp.DispenserStart(r.Context())
+	app.SetCardWellStatus(status)
+	if err != nil {
+		logging.Error(serviceName, err.Error(), "Dispense error", string(op), "", "", 0)
+		errorhandlers.WriteError(w, http.StatusServiceUnavailable, "Dispense error: "+err.Error())
 		return
-	} else {
-		log.Info(status)
+	}
+
+	// Always attempt to finalize after we have moved a card / started an issuance flow.
+	// This guarantees we eject and prepare the next card even on lock failures.
+	finalize := func() {
+		if app.disp == nil {
+			return
+		}
+		ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+		defer cancel()
+
+		status, ferr := app.disp.DispenserFinal(ctx)
+		if ferr != nil {
+			logging.Error(serviceName, ferr.Error(), "Dispenser final error", string(op), "", "", 0)
+			return
+		}
+		app.SetCardWellStatus(status)
 	}
 
 	// build lock server command
 	app.lockserver.BuildCommand(doorReq, checkIn, checkOut)
 
 	// lock server sequence
-	err = app.lockserver.LockSequence()
-	if err != nil {
+	if err := app.lockserver.LockSequence(); err != nil {
 		logging.Error(serviceName, err.Error(), "Key encoding", string(op), "", "", 0)
-		writeError(w, http.StatusBadGateway, err.Error())
-		dispenser.CardOutOfMouth(app.dispPort)
+		finalize()
+		errorhandlers.WriteError(w, http.StatusBadGateway, err.Error())
 		return
 	}
 
 	// final dispenser steps
-	if status, err := dispenser.CardOutOfMouth(app.dispPort); err != nil {
-		logging.Error(serviceName, err.Error(), "Dispenser eject error", string(op), "", "", 0)
-		writeError(w, http.StatusServiceUnavailable, "Dispenser eject error: "+err.Error())
-		return
-	} else {
-		log.Info(status)
-	}
+	finalize()
 
 	theResponse.Code = http.StatusOK
 	theResponse.Message = "Card issued successfully"
-	// success! return 200 and any data you like
-	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusOK)
-	json.NewEncoder(w).Encode(theResponse)
+	_ = json.NewEncoder(w).Encode(theResponse)
 }
 
 func (app *App) printRoomTicket(w http.ResponseWriter, r *http.Request) {
@@ -328,32 +342,32 @@ func (app *App) printRoomTicket(w http.ResponseWriter, r *http.Request) {
 	}
 	log.Println("printRoomTicket called")
 	if r.Method != http.MethodPost {
-		writeError(w, http.StatusMethodNotAllowed, "Method not allowed; use POST")
+		errorhandlers.WriteError(w, http.StatusMethodNotAllowed, "Method not allowed; use POST")
 		return
 	}
 	if ct := r.Header.Get("Content-Type"); !strings.Contains(ct, "xml") {
-		writeError(w, http.StatusUnsupportedMediaType, "Content-Type must be application/xml")
+		errorhandlers.WriteError(w, http.StatusUnsupportedMediaType, "Content-Type must be application/xml")
 		return
 	}
 
 	defer r.Body.Close()
 	if err := xml.NewDecoder(r.Body).Decode(&roomDetails); err != nil {
 		logging.Error(serviceName, err.Error(), "ReadXML", string(op), "", "", 0)
-		writeError(w, http.StatusBadRequest, "Invalid XML payload: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusBadRequest, "Invalid XML payload: "+err.Error())
 		return
 	}
 
 	data, err := printer.BuildRoomTicket(roomDetails)
 	if err != nil {
 		logging.Error(serviceName, err.Error(), "BuildRoomTicket", string(op), "", "", 0)
-		writeError(w, http.StatusInternalServerError, "BuildRoomTicket failed: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusInternalServerError, "BuildRoomTicket failed: "+err.Error())
 		return
 	}
 
 	// Send to the Windows Epson TM-T82II via the printer package
 	if err := printer.SendToPrinter(data); err != nil {
 		logging.Error(serviceName, err.Error(), "printRoomTicket", "printRoomTicket", "", "", 0)
-		writeError(w, http.StatusInternalServerError, "Print failed: "+err.Error())
+		errorhandlers.WriteError(w, http.StatusInternalServerError, "Print failed: "+err.Error())
 		return
 	}
 
@@ -365,3 +379,24 @@ func (app *App) printRoomTicket(w http.ResponseWriter, r *http.Request) {
 		Message: "Print job sent successfully",
 	})
 }
+
+func (app *App) reportDispenserStatus(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(http.StatusOK)
+	_ = json.NewEncoder(w).Encode(cmstypes.StatusRec{
+		Code:    http.StatusOK,
+		Message: app.CardWellStatus(),
+	})
+}
+
+func (app *App) SetCardWellStatus(s string) {
+	app.cardWellMu.Lock()
+	app.cardWellStatus = s
+	app.cardWellMu.Unlock()
+}
+
+func (app *App) CardWellStatus() string {
+	app.cardWellMu.RLock()
+	defer app.cardWellMu.RUnlock()
+	return app.cardWellStatus
+}

handlers/http_helpers.go

@@ -2,28 +2,14 @@ package handlers
 
 import (
 	"encoding/json"
-	"fmt"
 	"net/http"
-	"os"
 
 	"gitea.futuresens.co.uk/futuresens/cmstypes"
 	"gitea.futuresens.co.uk/futuresens/logging"
-	log "github.com/sirupsen/logrus"
 )
 
 const serviceName = "hardlink"
 
-// writeError is a helper to send a JSON error and HTTP status in one go.
-func writeError(w http.ResponseWriter, status int, msg string) {
-	theResponse := cmstypes.StatusRec{
-		Code:    status,
-		Message: msg,
-	}
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(status)
-	json.NewEncoder(w).Encode(theResponse)
-}
-
 func writeTransactionResult(w http.ResponseWriter, status int, theResponse cmstypes.ResponseRec) {
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(status)
@@ -32,10 +18,3 @@ func writeTransactionResult(w http.ResponseWriter, status int, theResponse cmsty
 	}
 }
 
-func FatalError(err error) {
-	fmt.Println(err.Error())
-	log.Errorf(err.Error())
-	fmt.Println(". Press Enter to exit...")
-	fmt.Scanln()
-	os.Exit(1)
-}

hardlink-preauth-release/main.go

@@ -14,7 +14,7 @@ import (
 )
 
 const (
-	buildVersion = "1.0.1"
+	buildVersion = "1.0.2"
 	serviceName  = "preauth-release"
 )
 
@@ -33,12 +33,15 @@ func main() {
 	defer database.Close()
 
 	if err := payment.ReleasePreauthorizations(database); err != nil {
-		log.WithError(err).Fatal("Preauth release failed")
+		log.Error(err)
+		fmt.Println(err)
+	} else {
+		log.Info("Task completed successfully")
+		fmt.Println("Task completed successfully")
 	}
 
-	log.Info("Task completed successfully")
 	for i := 20; i > 0; i-- {
-		fmt.Printf("\rExiting in %2d seconds...", i)
+		fmt.Printf("\rExiting in %2d seconds...   ", i)
 		time.Sleep(time.Second)
 	}
 	fmt.Println("\rExiting now.            ")

lockserver/saltolockserver.go

@@ -155,7 +155,7 @@ func (lock *SaltoLockServer) LockSequence() error {
 	reader := bufio.NewReader(conn)
 
 	// 1. Send ENQ
-	log.Infof("Sending ENQ")
+	log.Infof("LockSequence: sending ENQ")
 	if _, e := conn.Write([]byte{ENQ}); e != nil {
 		return fmt.Errorf("failed to send ENQ: %w", e)
 	}
@@ -166,7 +166,7 @@ func (lock *SaltoLockServer) LockSequence() error {
 	}
 
 	// 3. Send command frame
-	log.Infof("Sending encoding command: %q", string(lock.command))
+	log.Infof("LockSequence: sending encoding command: %q", string(lock.command))
 	if _, e := conn.Write(lock.command); e != nil {
 		return fmt.Errorf("failed to send command frame: %w", e)
 	}

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"encoding/xml"
 	"fmt"
 	"net/http"
@@ -18,6 +19,7 @@ import (
 	"gitea.futuresens.co.uk/futuresens/hardlink/bootstrap"
 	"gitea.futuresens.co.uk/futuresens/hardlink/config"
 	"gitea.futuresens.co.uk/futuresens/hardlink/dispenser"
+	"gitea.futuresens.co.uk/futuresens/hardlink/errorhandlers"
 	"gitea.futuresens.co.uk/futuresens/hardlink/handlers"
 	"gitea.futuresens.co.uk/futuresens/hardlink/lockserver"
 	"gitea.futuresens.co.uk/futuresens/hardlink/logging"
@@ -25,72 +27,82 @@ import (
 )
 
 const (
-	buildVersion = "1.0.29"
-	serviceName  = "hardlink"
+	buildVersion     = "1.1.2"
+	serviceName      = "hardlink"
+	pollingFrequency = 8 * time.Second
 )
 
 func main() {
 	// Load config
-	config := config.ReadHardlinkConfig()
+	cfg := config.ReadHardlinkConfig()
 	printer.Layout = readTicketLayout()
-	printer.PrinterName = config.PrinterName
-	lockserver.Cert = config.Cert
-	lockserver.LockServerURL = config.LockserverUrl
-	dispHandle := &serial.Port{}
+	printer.PrinterName = cfg.PrinterName
+	lockserver.Cert = cfg.Cert
+	lockserver.LockServerURL = cfg.LockserverUrl
+
+	var (
+		dispPort       *serial.Port
+		disp           *dispenser.Client
+		cardWellStatus string
+	)
 
 	// Setup logging and get file handle
-	logFile, err := logging.SetupLogging(config.LogDir, serviceName, buildVersion)
+	logFile, err := logging.SetupLogging(cfg.LogDir, serviceName, buildVersion)
 	if err != nil {
 		log.Printf("Failed to set up logging: %v\n", err)
 	}
 	defer logFile.Close()
 
 	// Initialize dispenser
-	if !config.TestMode {
-		dispenser.SerialPort = config.DispenserPort
-		dispenser.Address = []byte(config.DispenserAdrr)
-		dispHandle, err = dispenser.InitializeDispenser()
-		if err != nil {
-			handlers.FatalError(err)
-		}
-		defer dispHandle.Close()
+	if !cfg.TestMode {
+		dispenser.SerialPort = cfg.DispenserPort
+		dispenser.Address = []byte(cfg.DispenserAdrr)
 
-		status, err := dispenser.CheckDispenserStatus(dispHandle)
+		dispPort, err = dispenser.InitializeDispenser()
 		if err != nil {
-			if len(status) == 0 {
-				err = fmt.Errorf("%s; wrong dispenser address: %s", err, config.DispenserAdrr)
-				handlers.FatalError(err)
-			} else {
-				fmt.Println(status)
-				fmt.Println(err.Error())
-			}
+			errorhandlers.FatalError(err)
 		}
-		log.Infof("Dispenser initialized on port %s, %s", config.DispenserPort, status)
+		defer dispPort.Close()
+
+		// Start queued dispenser client (single goroutine owns the serial port)
+		disp = dispenser.NewClient(dispPort, 32)
+		defer disp.Close()
+
+		// Prepare dispenser (ensures card at encoder position unless empty)
+		ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+		defer cancel()
+
+		cardWellStatus, err = disp.DispenserPrepare(ctx)
+		if err != nil {
+			err = fmt.Errorf("%s; wrong dispenser address: %s", err, cfg.DispenserAdrr)
+			errorhandlers.FatalError(err)
+		}
+		fmt.Println(cardWellStatus)
 	}
 
 	// Test lock-server connection
-	switch strings.ToLower(config.LockType) {
+	switch strings.ToLower(cfg.LockType) {
 	case lockserver.TLJ:
-
+		// TLJ uses HTTP - skip TCP probe here (as you did before)
 	default:
-		lockConn, err := lockserver.InitializeServerConnection(config.LockserverUrl)
+		lockConn, err := lockserver.InitializeServerConnection(cfg.LockserverUrl)
 		if err != nil {
 			fmt.Println(err.Error())
 			log.Errorf(err.Error())
 		} else {
-			fmt.Printf("Connected to the lock server successfuly at %s\n", config.LockserverUrl)
-			log.Infof("Connected to the lock server successfuly at %s", config.LockserverUrl)
+			fmt.Printf("Connected to the lock server successfuly at %s\n", cfg.LockserverUrl)
+			log.Infof("Connected to the lock server successfuly at %s", cfg.LockserverUrl)
 			lockConn.Close()
 		}
 	}
 
-	database, err := bootstrap.OpenDB(&config)
+	database, err := bootstrap.OpenDB(&cfg)
 	if err != nil {
 		log.Warnf("DB init failed: %v", err)
 	}
 	defer database.Close()
 
-	if config.IsPayment {
+	if cfg.IsPayment {
 		fmt.Println("Payment processing is enabled")
 		log.Info("Payment processing is enabled")
 		startChipDnaClient()
@@ -100,16 +112,32 @@ func main() {
 	}
 
 	// Create App and wire routes
-	app := handlers.NewApp(dispHandle, config.LockType, config.EncoderAddress, database, config.IsPayment)
+	// NOTE: change handlers.NewApp signature to accept *dispenser.Client instead of *serial.Port
+	app := handlers.NewApp(disp, cfg.LockType, cfg.EncoderAddress, cardWellStatus, database, &cfg)
+
+	// Update cardWellStatus when dispenser status changes
+	if !cfg.TestMode {
+		// Set initial cardWellStatus
+		app.SetCardWellStatus(cardWellStatus)
+
+		// Set up callback to update cardWellStatus when dispenser status changes
+		disp.OnStockUpdate(func(stock string) {
+			app.SetCardWellStatus(stock)
+		})
+
+		// Start polling for dispenser status every 10 seconds
+		disp.StartPolling(pollingFrequency)
+	}
 
 	mux := http.NewServeMux()
 	app.RegisterRoutes(mux)
 
-	addr := fmt.Sprintf(":%d", config.Port)
+	addr := fmt.Sprintf(":%d", cfg.Port)
 	log.Infof("Starting HTTP server on http://localhost%s", addr)
 	fmt.Printf("Starting HTTP server on http://localhost%s", addr)
+
 	if err := http.ListenAndServe(addr, mux); err != nil {
-		handlers.FatalError(err)
+		errorhandlers.FatalError(err)
 	}
 }
 
@@ -120,12 +148,12 @@ func readTicketLayout() printer.LayoutOptions {
 	// 1) Read the file
 	data, err := os.ReadFile(layoutName)
 	if err != nil {
-		handlers.FatalError(fmt.Errorf("failed to read %s: %v", layoutName, err))
+		errorhandlers.FatalError(fmt.Errorf("failed to read %s: %v", layoutName, err))
 	}
 
 	// 2) Unmarshal into your struct
 	if err := xml.Unmarshal(data, &layout); err != nil {
-		handlers.FatalError(fmt.Errorf("failed to parse %s: %v", layoutName, err))
+		errorhandlers.FatalError(fmt.Errorf("failed to parse %s: %v", layoutName, err))
 	}
 
 	return layout
@@ -144,7 +172,7 @@ func startChipDnaClient() {
 
 	cmd, err := startClient()
 	if err != nil {
-		handlers.FatalError(err)
+		errorhandlers.FatalError(err)
 	}
 
 	// Restart loop

payment/preauthReleaser.go

@@ -21,7 +21,7 @@ const (
 )
 
 /* ==============================
-   Public Entry Point (LEGACY)
+   Public Entry Point
    ============================== */
 
 func ReleasePreauthorizations(database *sql.DB) error {
@@ -78,6 +78,7 @@ func handlePreauthRelease(
 	if err != nil {
 		return err
 	}
+	log.Infof("res=%s state=%s", info.transactionRes, info.transactionState)
 
 	// If already voided or declined → mark released
 	if isAlreadyReleased(info) {
@@ -86,8 +87,7 @@ func handlePreauthRelease(
 
 	// Only void approved + uncommitted
 	if !isVoidable(info) {
-		log.Infof("Preauth %s not eligible for void (res=%s state=%s)",
-			ref, info.transactionRes, info.transactionState)
+		log.Infof("Preauth %s not eligible for void (res=%s state=%s)", ref, info.transactionRes, info.transactionState)
 		return nil
 	}
 

release notes.md

@@ -2,6 +2,25 @@
 
 builtVersion is a const in main.go
 
+#### 1.1.2 - 02 February 2026
+added logging for unknown dispenser status positions
+
+#### 1.1.1 - 02 February 2026
+added contionuous polling of the dispenser status every 8 seconds to update the card well status
+
+#### 1.1.0 - 26 January 2026
+divided `/starttransaction` endpoint into two separate endpoints:
+  `/takepreauth` to request preauthorization payment
+  `/takepayment` to request taking payment
+added preauth releaser functionality to release preauthorization payments after a defined time period
+added db connection check before adding a transaction to the database
+and reconnection functionality if the connection to the database is lost
+added `/dispenserstatus` endpoint
+key card always stays at encoder position
+
+#### 1.0.30 - 09 January 2026
+improved logging for preauth releaser
+
 #### 1.0.29 - 08 January 2026
 added count down before exiting the preauth releaser 20 seconds