func (postgre *PostgreClient) read(query string) (pgx.Row, error) {
client, err := postgre.client.Acquire(context.TODO())
transaction, err := client.BeginTx(context.TODO(), pgx.TxOptions{})
if err != nil {
return nil, err
}
defer transaction.Rollback(context.TODO())
rows := transaction.QueryRow(context.TODO(), query)
if err != nil {
return nil, err
}
err = transaction.Commit(context.TODO())
return rows, err
}
Thanks in advance.
You have to scan the row before you commit the transaction.
If you want the handling of the transaction to remain within the function you can pass an interface that does the scanning also inside the function.
For example:
// implemented by *sql.Row & *sql.Rows
type Row interface {
Scan(dst ...interface{}) error
}
// implemented by your "models"
type RowScanner interface {
ScanRow(r Row) error
}
type User struct {
Id int
Email string
}
func (u *User) ScanRow(r Row) error {
return r.Scan(
&u.Id,
&u.Email,
)
}
func (postgre *PostgreClient) read(query string, rs RowScanner) (err error) {
conn, err := postgre.client.Acquire(context.TODO())
if err != nil {
return err
}
defer conn.Release()
tx, err := conn.BeginTx(context.TODO(), pgx.TxOptions{})
if err != nil {
return err
}
defer func() {
if err != nil {
tx.Rollback(context.TODO())
} else {
tx.Commit(context.TODO())
}
}()
row := tx.QueryRow(context.TODO(), query)
if err != nil {
return nil, err
}
return rs.ScanRow(row)
}
u := new(User)
if err := pg.read("select id, email from users limit 1", u); err != nil {
panic(err)
}
For scanning a list of models:
type UserList []*User
func (ul *UserList) ScanRow(r Row) error {
u := new(User)
if err := u.ScanRow(r); err != nil {
return err
}
*ul = append(*ul, u)
return nil
}
func (postgre *PostgreClient) list(query string, rs RowScanner) (err error) {
conn, err := postgre.client.Acquire(context.TODO())
if err != nil {
return err
}
defer conn.Release()
tx, err := conn.BeginTx(context.TODO(), pgx.TxOptions{})
if err != nil {
return err
}
defer func() {
if err != nil {
tx.Rollback(context.TODO())
} else {
tx.Commit(context.TODO())
}
}()
rows, err := tx.Query(context.TODO(), query)
if err != nil {
return err
}
defer rows.Close()
for rows.Next() {
if err := rs.ScanRow(rows); err != nil {
return err
}
}
return rows.Err()
}
ul := new(UserList)
if err := pg.list("select id, email from users", ul); err != nil {
panic(err)
}