Implemented periodic ping to keep connection of transaction alive

main.go

@@ -36,7 +36,9 @@ type DB struct {
 //	func main() {
 //	  db, err := gorm.Open("mysql", "user:password@/dbname?charset=utf8&parseTime=True&loc=Local")
 //	}
+//
 // GORM has wrapped some drivers, for easier to remember driver's import path, so you could import the mysql driver with
+//
 //	import _ "github.com/jinzhu/gorm/dialects/mysql"
 //	// import _ "github.com/jinzhu/gorm/dialects/postgres"
 //	// import _ "github.com/jinzhu/gorm/dialects/sqlite"
@@ -121,7 +123,9 @@ func (s *DB) Dialect() Dialect {
 }
 
 // Callback return `Callbacks` container, you could add/change/delete callbacks with it
+//
 //	db.Callback().Create().Register("update_created_at", updateCreated)
+//
 // Refer https://jinzhu.github.io/gorm/development.html#callbacks
 func (s *DB) Callback() *Callback {
 	s.parent.callbacks = s.parent.callbacks.clone()
@@ -224,6 +228,7 @@ func (s *DB) Offset(offset interface{}) *DB {
 }
 
 // Order specify order when retrieve records from database, set reorder to `true` to overwrite defined conditions
+//
 //	db.Order("name DESC")
 //	db.Order("name DESC", true) // reorder
 //	db.Order(gorm.Expr("name = ? DESC", "first")) // sql expression
@@ -253,12 +258,14 @@ func (s *DB) Having(query interface{}, values ...interface{}) *DB {
 }
 
 // Joins specify Joins conditions
+//
 //	db.Joins("JOIN emails ON emails.user_id = users.id AND emails.email = ?", "jinzhu@example.org").Find(&user)
 func (s *DB) Joins(query interface{}, args ...interface{}) *DB {
 	return s.clone().search.Joins(query, args...).db
 }
 
 // Scopes pass current database connection to arguments `func(*DB) *DB`, which could be used to add conditions dynamically
+//
 //	func AmountGreaterThan1000(db *gorm.DB) *gorm.DB {
 //	    return db.Where("amount > ?", 1000)
 //	}
@@ -270,6 +277,7 @@ func (s *DB) Joins(query interface{}, args ...interface{}) *DB {
 //	}
 //
 //	db.Scopes(AmountGreaterThan1000, OrderStatus([]string{"paid", "shipped"})).Find(&orders)
+//
 // Refer https://jinzhu.github.io/gorm/crud.html#scopes
 func (s *DB) Scopes(funcs ...func(*DB) *DB) *DB {
 	for _, f := range funcs {
@@ -356,6 +364,7 @@ func (s *DB) ScanRows(rows *sql.Rows, result interface{}) error {
 }
 
 // Pluck used to query single column from a model as a map
+//
 //	var ages []int64
 //	db.Find(&users).Pluck("age", &ages)
 func (s *DB) Pluck(column string, value interface{}) *DB {
@@ -454,6 +463,7 @@ func (s *DB) Delete(value interface{}, where ...interface{}) *DB {
 }
 
 // Raw use raw sql as conditions, won't run it unless invoked by other methods
+//
 //	db.Raw("SELECT name, age FROM users WHERE name = ?", 3).Scan(&result)
 func (s *DB) Raw(sql string, values ...interface{}) *DB {
 	return s.clone().search.Raw(true).Where(sql, values...).db
@@ -469,6 +479,7 @@ func (s *DB) Exec(sql string, values ...interface{}) *DB {
 }
 
 // Model specify the model you would like to run db operations
+//
 //	// update all users's name to `hello`
 //	db.Model(&User{}).Update("name", "hello")
 //	// if user's primary key is non-blank, will use it as condition, then will only update the user's name to `hello`
@@ -530,13 +541,42 @@ func (s *DB) WrapInTx(f func(tx *DB) error) (err error) {
 	if _, ok := s.db.(*sql.Tx); ok {
 		// Already in a transaction
 		return f(s)
-	} else {
+	}
+
 	// Lets start a new transaction
 	tx := s.Begin()
 	if err = tx.Error; err != nil {
+		return err
+	}
+
+	// Create a channel to stop the ping goroutine.
+	stopTxPing := make(chan bool)
+	// Start a goroutine that pings the database connection for a keep-alive.
+	go func() {
+		for {
+			select {
+			// Stop the goroutine when the stop channel receives a value ..
+			case <-stopTxPing:
+				return
+			// .. otherwise ping the database connection every 10 seconds.
+			case <-time.After(10 * time.Second):
+				err := tx.DB().Ping()
+				if err != nil {
+					tx.AddError(
+						fmt.Errorf(
+							"Could not ping database connection for transaction: %w",
+							err,
+						),
+					)
+
 					return
 				}
+			}
+		}
+	}()
+
 	panicked := true
+
 	defer func() {
 		if panicked || err != nil {
 			rollbackErr := tx.Rollback().Error
@@ -549,13 +589,22 @@ func (s *DB) WrapInTx(f func(tx *DB) error) (err error) {
 			}
 		}
 	}()
+
 	err = f(tx)
+
+	// As soon as the inner stack has returned, stop the ping goroutine. As the transaction will be
+	// only committed after this point, the ping would fail and the goroutine will exit.
+	stopTxPing <- true
+	// Last but not least, close the stop ping channel.
+	close(stopTxPing)
+
 	if err == nil {
 		err = tx.Commit().Error
 	}
+
 	panicked = false
-		return
+
-	}
+	return err
 }
 
 // SkipAssocSave disables saving of associations
@@ -674,6 +723,7 @@ func (s *DB) RemoveIndex(indexName string) *DB {
 }
 
 // AddForeignKey Add foreign key to the given scope, e.g:
+//
 //	db.Model(&User{}).AddForeignKey("city_id", "cities(id)", "RESTRICT", "RESTRICT")
 func (s *DB) AddForeignKey(field string, dest string, onDelete string, onUpdate string) *DB {
 	scope := s.NewScope(s.Value)
@@ -682,6 +732,7 @@ func (s *DB) AddForeignKey(field string, dest string, onDelete string, onUpdate
 }
 
 // RemoveForeignKey Remove foreign key from the given scope, e.g:
+//
 //	db.Model(&User{}).RemoveForeignKey("city_id", "cities(id)")
 func (s *DB) RemoveForeignKey(field string, dest string) *DB {
 	scope := s.clone().NewScope(s.Value)
@@ -712,6 +763,7 @@ func (s *DB) Association(column string) *Association {
 }
 
 // Preload preload associations with given conditions
+//
 //	db.Preload("Orders", "state NOT IN (?)", "cancelled").Find(&users)
 func (s *DB) Preload(column string, conditions ...interface{}) *DB {
 	return s.clone().search.Preload(column, conditions...).db