Transaction implementation (#2)

Reviewed-on: #2
2026-05-24 16:40:04 +00:00
parent e98dbe3338
commit a6ff01d694
7 changed files with 597 additions and 207 deletions
@@ -10,6 +10,7 @@ import (
 	log "gitlab.com/gdulai/simpleloglvl"
 )

+// Created and executes the DDL created by [simpleorm.ORM]
 func ExecuteDDL(conn *simpleorm.DBConnection, orm *simpleorm.ORM) {
 	schema, err := orm.CreateSchema()
 	if err != nil {
@@ -24,14 +25,143 @@ func ExecuteDDL(conn *simpleorm.DBConnection, orm *simpleorm.ORM) {
 	}
 }

+// Wraps and represents a DB transaction.
+// Allows for all at once or separate execution of [exec.Exec] implementations.
+type Transaction struct {
+	conn       *simpleorm.DBConnection
+	executions []*Exec[any]
+	tx         *sql.Tx
+	finished   bool
+}
+
+// Creates a new [exec.Transaction].
+// Can be initialized with a set of [exec.Exec]s.
+func NewTransaction(conn *simpleorm.DBConnection, executions ...*Exec[any]) *Transaction {
+	return &Transaction{conn: conn, executions: executions, finished: false}
+}
+
+// The executions assigned to this transaction.
+func (t *Transaction) Executions() []*Exec[any] {
+	return t.executions
+}
+
+// Executes all the [exec.Exec] implementations assigned to this transactions.
+// Begins, commits or rollbacks the transaction.
+// This is a terminal operation, the [exec.Transaction] is considered finished after calling this.
+func (t *Transaction) ExecuteAtOnce() error {
+	if t.finished {
+		return errors.New("Transaction already finished.")
+	}
+
+	if t.tx == nil {
+		tx, err := t.conn.Begin()
+		t.tx = tx
+		if err != nil {
+			t.finished = true
+			return err
+		}
+	}
+
+	for _, exec := range t.executions {
+		err := (*exec).execute(nil, t.tx)
+		if err != nil {
+			rollbackErr := t.Rollback()
+			if rollbackErr != nil {
+				return rollbackErr
+			}
+			return err
+		}
+
+	}
+
+	err := t.tx.Commit()
+	if err != nil {
+		return err
+	}
+
+	t.finished = true
+	return nil
+}
+
+// Executes and assigns the passed [exec.Exec]s to the Transaction.
+// Calls rollback in case of an error.
+// This is NOT a terminal operation, transactions still has to be committed.
+func (t *Transaction) Execute(execs ...Exec[any]) error {
+	if t.finished {
+		return errors.New("Transaction already finished.")
+	}
+
+	for _, exec := range execs {
+		execPtr := &exec
+		t.executions = append(t.executions, execPtr)
+		if t.tx == nil {
+			tx, err := t.conn.Begin()
+			t.tx = tx
+			if err != nil {
+				t.finished = true
+				return err
+			}
+		}
+
+		err := (*execPtr).execute(nil, t.tx)
+		if err != nil {
+			rollbackErr := t.Rollback()
+			if rollbackErr != nil {
+				return rollbackErr
+			}
+			return err
+		}
+
+	}
+
+	return nil
+}
+
+// Finishes the transaction, commits the changes.
+// This is terminal operation.
+func (t *Transaction) Finish() error {
+	if t.finished {
+		return errors.New("Transaction already finished.")
+	}
+
+	if t.tx == nil {
+		return errors.New("Transaction is nil.")
+	}
+
+	t.tx.Commit()
+	t.finished = true
+	return nil
+}
+
+// Rollbacks and aborts the transaction.
+// This is a terminal operation.
+func (t *Transaction) Rollback() error {
+	if t.finished {
+		return errors.New("Transaction already finished.")
+	}
+
+	if t.tx == nil {
+		return errors.New("Transaction is nil.")
+	}
+
+	rollbackErr := t.tx.Rollback()
+	if rollbackErr != nil {
+		return rollbackErr
+	}
+	t.finished = true
+	return nil
+}
+
 type Exec[T any] interface {
-	Execute(conn *simpleorm.DBConnection) ([]T, error)
+	Execute(conn *simpleorm.DBConnection) error
+	execute(conn *simpleorm.DBConnection, tx *sql.Tx) error
 }

 type Select[T any] struct {
 	target    schema.Table
 	whereStmt string
 	args      []any
+	results   []T
 }

 func CreateSelect[T any](orm *simpleorm.ORM, whereStmt string, args ...any) (Select[T], error) {
@@ -43,10 +173,20 @@ func CreateSelect[T any](orm *simpleorm.ORM, whereStmt string, args ...any) (Sel
 	return Select[T]{target: *table, whereStmt: whereStmt, args: args}, nil
 }

-func (s Select[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {
+func (s *Select[T]) Results() []T {
+	return s.results
+}
+
+func (s *Select[T]) Execute(conn *simpleorm.DBConnection) error {
+	return s.execute(conn, nil)
+}
+
+func (s *Select[T]) execute(conn *simpleorm.DBConnection, tx *sql.Tx) error {
+	// Reinit the results, new execution
+	s.results = []T{}
 	dml, err := s.target.GetSelectDML()
 	if err != nil {
-		return []T{}, err
+		return err
 	}

 	if s.whereStmt != "" {
@@ -55,9 +195,15 @@ func (s Select[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {

 	log.LogDebug("Preparing sql: %s, with args: %s", dml, s.args)

-	stmt, err := conn.Prepare(dml)
+	var stmt *sql.Stmt
+	if tx != nil {
+		stmt, err = tx.Prepare(dml)
+	} else {
+		stmt, err = conn.Prepare(dml)
+	}
+
 	if err != nil {
-		return nil, err
+		return err
 	}
 	defer stmt.Close()

@@ -81,40 +227,21 @@ func (s Select[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {
 	}

 	if err != nil {
-		return nil, err
+		return err
 	}

-	rowContainer := createSelectResultContainer(s.target)
-
-	var results []T
-
-	for rows.Next() {
-		err = rows.Scan(rowContainer...)
-		if err != nil {
-			return nil, err
-		}
-
-		targetType := s.target.Type
-		parsedResult := reflect.New(targetType)
-		for i, fieldVal := range rowContainer {
-			col := s.target.Columns[i]
-			targetField := parsedResult.Elem().Field(i)
-
-			rawValue := reflect.Indirect(reflect.ValueOf(fieldVal))
-			decoded := reflect.ValueOf(col.Decode(targetField.Type().Name(), rawValue))
-
-			targetField.Set(decoded)
-		}
-		parsedObj := reflect.Indirect(parsedResult).Interface().(T)
-		results = append(results, parsedObj)
+	s.results, err = readRows[T](s.target, rows)
+	if err != nil {
+		return err
 	}

-	return results, nil
+	return nil
 }

 type Insert[T any] struct {
 	target   schema.Table
 	toInsert []T
+	results  []T
 }

 func NewInsert[T any](orm *simpleorm.ORM, toInsert ...T) (Insert[T], error) {
@@ -126,10 +253,18 @@ func NewInsert[T any](orm *simpleorm.ORM, toInsert ...T) (Insert[T], error) {
 	return Insert[T]{target: *table, toInsert: toInsert}, nil
 }

-func (ins Insert[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {
+func (ins *Insert[T]) Results() []T {
+	return ins.results
+}
+
+func (ins *Insert[T]) Execute(conn *simpleorm.DBConnection) error {
+	return ins.execute(conn, nil)
+}
+
+func (ins *Insert[T]) execute(conn *simpleorm.DBConnection, tx *sql.Tx) error {
 	dml, err := ins.target.GetInsertDML(len(ins.toInsert))
 	if err != nil {
-		return []T{}, err
+		return err
 	}

 	var params []any
@@ -145,21 +280,26 @@ func (ins Insert[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {

 	log.LogInfo("%s [%s]", dml, params)

-	stmt, err := conn.Prepare(dml)
-	if err != nil {
-		return []T{}, err
+	var stmt *sql.Stmt
+	if tx != nil {
+		stmt, err = tx.Prepare(dml)
+	} else {
+		stmt, err = conn.Prepare(dml)
 	}
 	defer stmt.Close()

-	result, err := stmt.Exec(params...)
+	rows, err := stmt.Query(params...)
+
 	if err != nil {
-	} else {
-		rowsAffected, _ := result.RowsAffected()
-		log.LogInfo("Inserted %s row", rowsAffected)
-		lastInsertId, _ := result.LastInsertId()
-		log.LogInfo("Last ID: %s", lastInsertId)
+		return err
 	}
-	return []T{}, nil
+
+	ins.results, err = readRows[T](ins.target, rows)
+	if err != nil {
+		return err
+	}
+
+	return nil
 }

 type Update[T any] struct {
@@ -176,17 +316,21 @@ func NewUpdate[T any](orm *simpleorm.ORM, toUpdate T) (Update[T], error) {
 	return Update[T]{target: *table, toUpdate: toUpdate}, nil
 }

-func (u Update[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {
+func (u Update[T]) Execute(conn *simpleorm.DBConnection) error {
+	return u.execute(conn, nil)
+}
+
+func (u Update[T]) execute(conn *simpleorm.DBConnection, tx *sql.Tx) error {
 	dml, err := u.target.GetUpdateDML()
 	if err != nil {
-		return []T{}, err
+		return err
 	}

 	params := prepareParams(u.toUpdate, u.target)

 	pkCols, err := getPk(u.toUpdate, u.target)
 	if err != nil {
-		return []T{}, err
+		return err
 	}
 	// Put the pks back at the end
 	for _, pk := range pkCols {
@@ -195,20 +339,22 @@ func (u Update[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {

 	log.LogInfo("%s [%s]", dml, params)

-	stmt, err := conn.Prepare(dml)
-	if err != nil {
-		return []T{}, err
+	var stmt *sql.Stmt
+	if tx != nil {
+		stmt, err = tx.Prepare(dml)
+	} else {
+		stmt, err = conn.Prepare(dml)
 	}
 	defer stmt.Close()

 	result, err := stmt.Exec(params...)
 	if err != nil {
-		return []T{}, err
+		return err
 	} else {
 		rowsAffected, _ := result.RowsAffected()
 		log.LogInfo("Updated %s row", rowsAffected)
 	}
-	return []T{u.toUpdate}, nil
+	return nil
 }

 type Delete[T any] struct {
@@ -225,11 +371,15 @@ func NewDelete[T any](orm *simpleorm.ORM, toDelete []T) (Delete[T], error) {
 	return Delete[T]{target: *table, toDelete: toDelete}, nil
 }

-func (d Delete[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {
+func (d *Delete[T]) Execute(conn *simpleorm.DBConnection) error {
+	return d.execute(conn, nil)
+}
+
+func (d *Delete[T]) execute(conn *simpleorm.DBConnection, tx *sql.Tx) error {
 	count := len(d.toDelete)
 	dml, err := d.target.GetDeleteDML(count)
 	if err != nil {
-		return []T{}, err
+		return err
 	}

 	var params []any
@@ -237,7 +387,7 @@ func (d Delete[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {
 	for _, del := range d.toDelete {
 		pkCols, err := getPk(del, d.target)
 		if err != nil {
-			return []T{}, err
+			return err
 		}

 		for _, pk := range pkCols {
@@ -247,21 +397,23 @@ func (d Delete[T]) Execute(conn *simpleorm.DBConnection) ([]T, error) {

 	log.LogInfo("%s [%s]", dml, params)

-	stmt, err := conn.Prepare(dml)
-	if err != nil {
-		return []T{}, err
+	var stmt *sql.Stmt
+	if tx != nil {
+		stmt, err = tx.Prepare(dml)
+	} else {
+		stmt, err = conn.Prepare(dml)
 	}
 	defer stmt.Close()

 	result, err := stmt.Exec(params...)
 	if err != nil {
-		return []T{}, err
+		return err
 	} else {
 		rowsAffected, _ := result.RowsAffected()
 		log.LogInfo("Deleted %s row", rowsAffected)
 	}

-	return d.toDelete, nil
+	return nil

 }

@@ -322,3 +474,31 @@ func getPk(src any, t schema.Table) ([]any, error) {

 	return values, nil
 }
+
+func readRows[T any](table schema.Table, rows *sql.Rows) ([]T, error) {
+	rowContainer := createSelectResultContainer(table)
+
+	var results []T
+
+	for rows.Next() {
+		err := rows.Scan(rowContainer...)
+		if err != nil {
+			return nil, err
+		}
+
+		targetType := table.Type
+		parsedResult := reflect.New(targetType)
+		for i, fieldVal := range rowContainer {
+			col := table.Columns[i]
+			targetField := parsedResult.Elem().Field(i)
+
+			rawValue := reflect.Indirect(reflect.ValueOf(fieldVal))
+			decoded := reflect.ValueOf(col.Decode(targetField.Type().Name(), rawValue))
+
+			targetField.Set(decoded)
+		}
+		parsedObj := reflect.Indirect(parsedResult).Interface().(T)
+		results = append(results, parsedObj)
+	}
+	return results, nil
+}