From 9573e06a09323121fe7cb79779c81e0640ea051c Mon Sep 17 00:00:00 2001
From: Roman Dmitrienko <roman@dmitrienko.com>
Date: Tue, 24 Dec 2024 11:59:21 +0300
Subject: [PATCH] fix: serialize concurrent transactions when running tests
 with txdb

---
 db/db.go                             | 14 ++++++++++++++
 tests/db/test_db.go                  |  4 ++++
 transactions/transactions_service.go | 10 +++++-----
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/db/db.go b/db/db.go
index 97b106cb..2dd03728 100644
--- a/db/db.go
+++ b/db/db.go
@@ -13,6 +13,8 @@ import (
 	"github.com/getAlby/hub/logger"
 )
 
+var SerializeTransactions = false
+
 type Config struct {
 	URI        string
 	LogQueries bool
@@ -156,3 +158,15 @@ func Stop(db *gorm.DB) error {
 func IsPostgresURI(uri string) bool {
 	return strings.HasPrefix(uri, "postgresql://")
 }
+
+var txSerializer = make(chan struct{}, 1)
+
+func RunTransaction(db *gorm.DB, txFunc func(tx *gorm.DB) error) error {
+	if SerializeTransactions {
+		txSerializer <- struct{}{}
+		defer func() {
+			<-txSerializer
+		}()
+	}
+	return db.Transaction(txFunc)
+}
diff --git a/tests/db/test_db.go b/tests/db/test_db.go
index 70c6a814..e6c79d44 100644
--- a/tests/db/test_db.go
+++ b/tests/db/test_db.go
@@ -18,6 +18,10 @@ func init() {
 		uri := GetTestDatabaseURI()
 		if db.IsPostgresURI(uri) {
 			txdb.Register(testDriver, "pgx", uri)
+
+			// txdb fails when transactions are run concurrently in goroutines
+			// (concurrent begins/commits/rollback confuse its checkpoints logic).
+			db.SerializeTransactions = true
 		}
 	}
 }
diff --git a/transactions/transactions_service.go b/transactions/transactions_service.go
index ec087908..e1d4d6cc 100644
--- a/transactions/transactions_service.go
+++ b/transactions/transactions_service.go
@@ -225,7 +225,7 @@ func (svc *transactionsService) SendPaymentSync(ctx context.Context, payReq stri
 		paymentAmount = *amountMsat
 	}
 
-	err = svc.db.Transaction(func(tx *gorm.DB) error {
+	err = db.RunTransaction(svc.db, func(tx *gorm.DB) error {
 		var existingSettledTransaction db.Transaction
 		if tx.Limit(1).Find(&existingSettledTransaction, &db.Transaction{
 			Type:        constants.TRANSACTION_TYPE_OUTGOING,
@@ -294,7 +294,7 @@ func (svc *transactionsService) SendPaymentSync(ctx context.Context, payReq stri
 		}
 
 		// As the LNClient did not return a timeout error, we assume the payment definitely failed
-		svc.db.Transaction(func(tx *gorm.DB) error {
+		db.RunTransaction(svc.db, func(tx *gorm.DB) error {
 			return svc.markPaymentFailed(tx, &dbTransaction, err.Error())
 		})
 
@@ -303,7 +303,7 @@ func (svc *transactionsService) SendPaymentSync(ctx context.Context, payReq stri
 
 	// the payment definitely succeeded
 	var settledTransaction *db.Transaction
-	err = svc.db.Transaction(func(tx *gorm.DB) error {
+	err = db.RunTransaction(svc.db, func(tx *gorm.DB) error {
 		settledTransaction, err = svc.markTransactionSettled(tx, &dbTransaction, response.Preimage, response.Fee, selfPayment)
 		return err
 	})
@@ -352,7 +352,7 @@ func (svc *transactionsService) SendKeysend(ctx context.Context, amount uint64,
 
 	selfPayment := destination == lnClient.GetPubkey()
 
-	err = svc.db.Transaction(func(tx *gorm.DB) error {
+	err = db.RunTransaction(svc.db, func(tx *gorm.DB) error {
 		err := svc.validateCanPay(tx, appId, amount, "")
 		if err != nil {
 			return err
@@ -464,7 +464,7 @@ func (svc *transactionsService) SendKeysend(ctx context.Context, amount uint64,
 
 	// the payment definitely succeeded
 	var settledTransaction *db.Transaction
-	err = svc.db.Transaction(func(tx *gorm.DB) error {
+	err = db.RunTransaction(svc.db, func(tx *gorm.DB) error {
 		settledTransaction, err = svc.markTransactionSettled(tx, &dbTransaction, preimage, payKeysendResponse.Fee, selfPayment)
 		return err
 	})