Files
db-mysql/errors.go
Rene Nochebuena d64fd5403d feat(db-mysql): initial implementation — database/sql MySQL with lifecycle and UnitOfWork (v1.0.0)
Introduces code.nochebuena.dev/einherjar/db-mysql — the MySQL database starter
for the Einherjar framework. Absorbs the mysql package from micro-lib using the
go-sql-driver/mysql driver, replacing fmt.Errorf wrapping with core/xerrors.

Interfaces (CT-6: one TypeSpec per file):
- Executor — ExecContext, QueryContext, QueryRowContext (database/sql types)
- Tx — Executor + Commit(), Rollback() — no ctx; honest database/sql contract
- Provider — GetExecutor, Begin, BeginTx, Ping, HandleError
- Component — lifecycle.Component + observability.Checkable + Provider + Stats()
- UnitOfWork — Do(ctx, fn)

Implementation:
- New(logger, cfg) Component — pool not created until OnInit
- OnInit: sql.Open + SetMaxOpenConns/SetMaxIdleConns/SetConnMaxLifetime/SetConnMaxIdleTime
- OnStart: Ping with 5s timeout; logs "mysql: connected"
- OnStop: db.Close(); logs "mysql: closing pool"
- GetExecutor: returns active Tx from context (ctxTxKey) or *sql.DB; explicit
  nil return when db uninitialized to avoid typed-nil interface pitfall
- Begin/BeginTx: wraps db.BeginTx(*sql.TxOptions); wrapped in xerrors on error
- HealthCheck: delegates to Ping; Priority LevelCritical
- Stats() sql.DBStats — zero value when pool uninitialized
- NewUnitOfWork(logger, provider) UnitOfWork — Begin+inject+commit/rollback;
  no write mutex (MySQL is a server DB with internal concurrency control)
- HandleError: 1062→ErrAlreadyExists, 1216/1217/1451/1452→ErrInvalidInput,
  sql.ErrNoRows→ErrNotFound, all others→ErrInternal
- Driver imported as mysqldrv alias in errors.go to avoid package-name collision;
  registered via blank import in new.go

Config (EINHERJAR_MYSQL_* env vars):
  Host, Port(3306), User, Password, Name,
  MaxConns(5), MinConns(2), MaxConnLifetime(1h), MaxConnIdleTime(30m),
  Charset(utf8mb4), Loc(UTC), ParseTime(true)

- Component interface embeds observability.Identifiable; identifiable.go implements
  ModulePath and ModuleVersion via runtime/debug.ReadBuildInfo() — prints in launcher banner
2026-05-29 15:51:53 +00:00

38 lines
1.1 KiB
Go

package mysql
import (
"database/sql"
"errors"
mysqldrv "github.com/go-sql-driver/mysql"
"code.nochebuena.dev/einherjar/core/xerrors"
)
// HandleError maps MySQL driver and database/sql errors to typed [xerrors] values.
// Returns nil when err is nil. Also available as [Provider.HandleError].
//
// Mapped codes:
// - 1062 (ER_DUP_ENTRY) → ErrAlreadyExists
// - 1216, 1217, 1451, 1452 (FK errors) → ErrInvalidInput
// - sql.ErrNoRows → ErrNotFound
// - all others → ErrInternal
func HandleError(err error) error {
if err == nil {
return nil
}
var mysqlErr *mysqldrv.MySQLError
if errors.As(err, &mysqlErr) {
switch mysqlErr.Number {
case 1062:
return xerrors.New(xerrors.ErrAlreadyExists, "record already exists").WithError(err)
case 1216, 1217, 1451, 1452:
return xerrors.New(xerrors.ErrInvalidInput, "data integrity violation").WithError(err)
}
}
if errors.Is(err, sql.ErrNoRows) {
return xerrors.New(xerrors.ErrNotFound, "record not found").WithError(err)
}
return xerrors.New(xerrors.ErrInternal, "unexpected database error").WithError(err)
}