error.go

/*
This file is tailored for postgres using the github.com/lib/pq library.
If you want to use mysql, check out the commented lines.
*/

package modeldb

import (
	"errors"
	"regexp"

	// github.com/go-sql-driver/mysql
	"github.com/lib/pq"
)

var (
	ERR_DUPLICATE_ENTRY = errors.New("ERR_DUPLICATE_ENTRY")
	ERR_SERIAL_TX       = errors.New("ERR_SERIAL_TX")
	ERR_OTHER           = errors.New("ERR_OTHER")

	RE_MYSQL_DUPLICATE_KEY = regexp.MustCompile("Duplicate entry.*for key '(.+)'")
)

// Golang's sql returns an opaque error type.
// We translate these into known error types.
func GetErrorType(err error) error {
	if err == nil {
		return nil
	}

	// dbErr, ok := err.(*mysql.MySQLError)
	dbErr, ok := err.(*pq.Error)

	if ok {

		// MYSQL
		// http://dev.mysql.com/doc/refman/5.5/en/error-messages-server.html#error_er_dup_entry
		/*
		   switch dbErr.Number {
		   case 1062: return ERR_DUPLICATE_ENTRY
		   default:   return ERR_OTHER
		   }
		*/

		// POSTGRESQL
		// https://github.com/lib/pq/blob/master/error.go
		switch dbErr.Code {
		case "23505":
			return ERR_DUPLICATE_ENTRY
		case "40001":
			return ERR_SERIAL_TX
		default:
			return ERR_OTHER
		}

	}
	return err
}

func GetErrorMessage(err error) string {
	if err == nil {
		return ""
	}
	// dbErr, ok := err.(*mysql.MySQLError)
	dbErr, ok := err.(*pq.Error)
	if ok {
		return dbErr.Message
	}
	panic("Message unknown for err")
}

func GetDuplicateKey(err error) string {
	// dbErr, ok := err.(*mysql.MySQLError)
	dbErr, ok := err.(*pq.Error)
	if ok {
		// MYSQL
		/*
		   message := dbErr.Message
		   match := RE_MYSQL_DUPLICATE_KEY.FindStringSubmatch(message)
		   if match == nil {
		       panic("Not a duplicate key error")
		   }
		   return match[1]
		*/

		// POSTGRESQL
		return dbErr.Constraint
	}
	panic("Message unknown for err")
}