docs/server/storage/database.go

121 lines
3.5 KiB
Go

package storage
import (
"database/sql"
"github.com/go-sql-driver/mysql"
)
// MySQLStorage implements a versioned store using a relational database.
// The database table must look like:
// CREATE TABLE `tuf_files` (
// `id` INT AUTO_INCREMENT,
// `gun` VARCHAR(255) NOT NULL
// `role` VARCHAR(255) NOT NULL
// `version` INT
// `data` LONGBLOB
// PRIMARY KEY (`id`)
// UNIQUE INDEX (`gun`, `role`, `version`)
// ) DEFAULT CHARSET=utf8;
//
// CREATE TABLE `timestamp_keys` (
// `gun` VARCHAR(255),
// `cipher` VARCHAR(30),
// `public` BLOB NOT NULL,
// ) DEFAULT CHARSET=utf8;
type MySQLStorage struct {
sql.DB
}
// NewMySQLStorage is a convenience method to create a MySQLStorage
func NewMySQLStorage(db *sql.DB) *MySQLStorage {
return &MySQLStorage{
DB: *db,
}
}
// UpdateCurrent updates multiple TUF records in a single transaction.
// Always insert a new row. The unique constraint will ensure there is only ever
func (db *MySQLStorage) UpdateCurrent(gun, role string, version int, data []byte) error {
checkStmt := "SELECT count(*) FROM `tuf_files` WHERE `gun`=? AND `role`=? AND `version`>=?;"
insertStmt := "INSERT INTO `tuf_files` (`gun`, `role`, `version`, `data`) VALUES (?,?,?,?) ;"
// ensure immediately previous version exists
row := db.QueryRow(checkStmt, gun, role, version)
var exists int
err := row.Scan(&exists)
if err != nil {
return err
}
if exists != 0 {
return &ErrOldVersion{}
}
// attempt to insert. Due to race conditions with the check this could fail.
// That's OK, we're doing first write wins. The client will be messaged it
// needs to rebase.
_, err = db.Exec(insertStmt, gun, role, version, data)
if err != nil {
// need to check error type for duplicate key exception
// and return ErrOldVersion if duplicate
return err
}
return nil
}
// GetCurrent gets a specific TUF record
func (db *MySQLStorage) GetCurrent(gun, tufRole string) (data []byte, err error) {
stmt := "SELECT `data` FROM `tuf_files` WHERE `gun`=? AND `role`=? ORDER BY `version` DESC LIMIT 1;"
rows, err := db.Query(stmt, gun, tufRole) // this should be a QueryRow()
if err != nil {
return nil, err
}
defer rows.Close()
// unique constraint on (gun, role) will ensure only one row is returned (or none if no match is found)
if !rows.Next() {
return nil, &ErrNotFound{}
}
err = rows.Scan(&data)
if err != nil {
return nil, err
}
return data, nil
}
// Delete deletes all the records for a specific GUN
func (db *MySQLStorage) Delete(gun string) error {
stmt := "DELETE FROM `tuf_files` WHERE `gun`=?;"
_, err := db.Exec(stmt, gun)
return err
}
// GetTimestampKey returns the timestamps Public Key data
func (db *MySQLStorage) GetTimestampKey(gun string) (cipher string, public []byte, err error) {
stmt := "SELECT `cipher`, `public` FROM `timestamp_keys` WHERE `gun`=?;"
row := db.QueryRow(stmt, gun)
err = row.Scan(&cipher, &public)
if err == sql.ErrNoRows {
return "", nil, ErrNoKey{gun: gun}
} else if err != nil {
return "", nil, err
}
return cipher, public, err
}
// SetTimestampKey attempts to write a TimeStamp key and returns an error if it already exists
func (db *MySQLStorage) SetTimestampKey(gun, cipher string, public []byte) error {
stmt := "INSERT INTO `timestamp_keys` (`gun`, `cipher`, `public`) VALUES (?,?,?);"
_, err := db.Exec(stmt, gun, cipher, public)
if err, ok := err.(*mysql.MySQLError); ok {
if err.Number == 1022 { // duplicate key error
return &ErrTimestampKeyExists{gun: gun}
}
} else if err != nil {
return err
}
return nil
}