feat: add support sql

sql.go

@@ -0,0 +1,77 @@
+package uow
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/pkg/errors"
+)
+
+// SqlTx implements the Runner interface for SQL database transactions. It manages
+// the lifecycle of SQL database connections and transactions for any database
+// that supports the standard database/sql interface (PostgreSQL, MySQL, SQLite, MariaDB, etc.).
+//
+// Note: You must import your preferred database driver in your main package, e.g.:
+//
+//	_ "github.com/lib/pq"           // PostgreSQL
+//	_ "github.com/go-sql-driver/mysql"  // MySQL/MariaDB
+//	_ "github.com/mattn/go-sqlite3"     // SQLite
+//	_ "github.com/jackc/pgx/v5/stdlib"   // PostgreSQL (alternative)
+var _ Runner = &SqlTx{}
+
+// SqlTx struct holds the SQL database connection pool.
+type SqlTx struct {
+	db *sql.DB
+}
+
+// NewSqlTx creates a new SqlTx instance. It takes a SQL database
+// connection pool as an argument. This function should be called to initialize
+// a new transaction with any SQL database.
+func NewSqlTx(db *sql.DB) *SqlTx {
+	return &SqlTx{
+		db: db,
+	}
+}
+
+// Ctx starts a new SQL transaction. It uses the provided context and
+// starts a new transaction with default isolation level. If any errors
+// occur during this process, they are wrapped and returned. This function
+// is crucial for initiating transactions in the context.
+func (s *SqlTx) Ctx(ctx context.Context) (context.Context, error) {
+	tx, err := s.db.BeginTx(ctx, nil)
+	if err != nil {
+		return nil, errors.Wrap(err, "error in starting transaction")
+	}
+	return context.WithValue(ctx, "tx", tx), nil
+}
+
+// Get retrieves the SQL transaction. It checks if a transaction is present
+// in the context. If a transaction exists, it returns the transaction. Otherwise,
+// it returns the database connection pool. This function provides access to the
+// database within the transaction's context.
+func (s *SqlTx) Get(ctx context.Context) any {
+	if tx, ok := ctx.Value("tx").(*sql.Tx); ok {
+		return tx
+	}
+	return s.db
+}
+
+// Rollback aborts the current transaction. It checks for the presence of a
+// transaction in the context and rolls it back if one exists. This function
+// is essential for handling transaction failures.
+func (s *SqlTx) Rollback(ctx context.Context) error {
+	if tx, ok := ctx.Value("tx").(*sql.Tx); ok {
+		return tx.Rollback()
+	}
+	return nil
+}
+
+// Commit commits the current transaction. It checks for the presence of a
+// transaction in the context and commits it if one exists. This function
+// is crucial for saving changes made within a transaction.
+func (s *SqlTx) Commit(ctx context.Context) error {
+	if tx, ok := ctx.Value("tx").(*sql.Tx); ok {
+		return tx.Commit()
+	}
+	return nil
+}