and reconnection functionality if the connection to the database is lost

handlers/db_helpers.go

@@ -1,13 +1,25 @@
 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()
@@ -40,7 +52,6 @@ func (app *App) getDB(ctx context.Context) (*sql.DB, error) {
 		return nil, err
 	}
 
-	// Optional ping (InitMSSQL already pings, but this keeps semantics explicit)
 	pingCtx, cancel2 := context.WithTimeout(dialCtx, 1*time.Second)
 	defer cancel2()
 
@@ -52,3 +63,144 @@ func (app *App) getDB(ctx context.Context) (*sql.DB, error) {
 	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

@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"bytes"
+	"context"
 	"database/sql"
 	"encoding/json"
 	"encoding/xml"
@@ -15,7 +16,6 @@ import (
 
 	"gitea.futuresens.co.uk/futuresens/cmstypes"
 	"gitea.futuresens.co.uk/futuresens/hardlink/config"
-	"gitea.futuresens.co.uk/futuresens/hardlink/db"
 	"gitea.futuresens.co.uk/futuresens/hardlink/dispenser"
 	"gitea.futuresens.co.uk/futuresens/hardlink/errorhandlers"
 	"gitea.futuresens.co.uk/futuresens/hardlink/lockserver"
@@ -137,14 +137,7 @@ func (app *App) takePreauthorization(w http.ResponseWriter, r *http.Request) {
 	theResponse.Status = result.Status
 	theResponse.Data, save = payment.BuildPreauthRedirectURL(result.Fields)
 	if save {
-		dbConn, err := app.getDB(r.Context())
-		if err != nil {
-			log.WithError(err).Warn("DB unavailable; preauth not stored")
-		} else {
-			if err := db.InsertPreauth(r.Context(), dbConn, result.Fields, theRequest.CheckoutDate); err != nil {
-				log.WithError(err).Warn("Failed to store preauth in DB")
-			}
-		}
+		go app.persistPreauth(context.Background(), result.Fields, theRequest.CheckoutDate)
 	}
 
 	writeTransactionResult(w, http.StatusOK, theResponse)

release notes.md

@@ -2,6 +2,14 @@
 
 builtVersion is a const in main.go
 
+#### 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
+
 #### 1.0.30 - 09 January 2026
 improved logging for preauth releaser