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upgrades.go
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upgrades.go
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package upgrades
import (
"database/sql"
"fmt"
"strings"
log "maunium.net/go/maulogger/v2"
)
type Dialect int
const (
Postgres Dialect = iota
SQLite
)
func (dialect Dialect) String() string {
switch dialect {
case Postgres:
return "postgres"
case SQLite:
return "sqlite3"
default:
return ""
}
}
type upgradeFunc func(*sql.Tx, context) error
type context struct {
dialect Dialect
db *sql.DB
log log.Logger
}
type upgrade struct {
message string
fn upgradeFunc
}
const NumberOfUpgrades = 21
var upgrades [NumberOfUpgrades]upgrade
var UnsupportedDatabaseVersion = fmt.Errorf("unsupported database version")
func GetVersion(db *sql.DB) (int, error) {
_, err := db.Exec("CREATE TABLE IF NOT EXISTS version (version INTEGER)")
if err != nil {
return -1, err
}
version := 0
row := db.QueryRow("SELECT version FROM version LIMIT 1")
if row != nil {
_ = row.Scan(&version)
}
return version, nil
}
func SetVersion(tx *sql.Tx, version int) error {
_, err := tx.Exec("DELETE FROM version")
if err != nil {
return err
}
_, err = tx.Exec("INSERT INTO version (version) VALUES ($1)", version)
return err
}
func Run(log log.Logger, dialectName string, db *sql.DB) error {
var dialect Dialect
switch strings.ToLower(dialectName) {
case "postgres":
dialect = Postgres
case "sqlite3":
dialect = SQLite
default:
return fmt.Errorf("unknown dialect %s", dialectName)
}
version, err := GetVersion(db)
if err != nil {
return err
}
if version > NumberOfUpgrades {
return UnsupportedDatabaseVersion
}
log.Infofln("Database currently on v%d, latest: v%d", version, NumberOfUpgrades)
for i, upgrade := range upgrades[version:] {
log.Infofln("Upgrading database to v%d: %s", version+i+1, upgrade.message)
tx, err := db.Begin()
if err != nil {
return err
}
err = upgrade.fn(tx, context{dialect, db, log})
if err != nil {
return err
}
err = SetVersion(tx, version+i+1)
if err != nil {
return err
}
err = tx.Commit()
if err != nil {
return err
}
}
return nil
}