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forgejo/models/db/collation.go
wxiaoguang 2df7563f31
Recommend/convert to use case-sensitive collation for MySQL/MSSQL (#28662)
Mainly for MySQL/MSSQL.

It is important for Gitea to use case-sensitive database charset
collation. If the database is using a case-insensitive collation, Gitea
will show startup error/warning messages, and show the errors/warnings
on the admin panel's Self-Check page.

Make `gitea doctor convert` work for MySQL to convert the collations of
database & tables & columns.

* Fix #28131

## ⚠️ BREAKING ⚠️

It is not quite breaking, but it's highly recommended to convert the
database&table&column to a consistent and case-sensitive collation.
2024-01-10 11:03:23 +00:00

191 lines
7 KiB
Go

// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package db
import (
"errors"
"fmt"
"strings"
"code.gitea.io/gitea/modules/container"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"xorm.io/xorm"
"xorm.io/xorm/schemas"
)
type CheckCollationsResult struct {
ExpectedCollation string
AvailableCollation container.Set[string]
DatabaseCollation string
IsCollationCaseSensitive func(s string) bool
CollationEquals func(a, b string) bool
ExistingTableNumber int
InconsistentCollationColumns []string
}
func findAvailableCollationsMySQL(x *xorm.Engine) (ret container.Set[string], err error) {
var res []struct {
Collation string
}
if err = x.SQL("SHOW COLLATION WHERE (Collation = 'utf8mb4_bin') OR (Collation LIKE '%\\_as\\_cs%')").Find(&res); err != nil {
return nil, err
}
ret = make(container.Set[string], len(res))
for _, r := range res {
ret.Add(r.Collation)
}
return ret, nil
}
func findAvailableCollationsMSSQL(x *xorm.Engine) (ret container.Set[string], err error) {
var res []struct {
Name string
}
if err = x.SQL("SELECT * FROM sys.fn_helpcollations() WHERE name LIKE '%[_]CS[_]AS%'").Find(&res); err != nil {
return nil, err
}
ret = make(container.Set[string], len(res))
for _, r := range res {
ret.Add(r.Name)
}
return ret, nil
}
func CheckCollations(x *xorm.Engine) (*CheckCollationsResult, error) {
dbTables, err := x.DBMetas()
if err != nil {
return nil, err
}
res := &CheckCollationsResult{
ExistingTableNumber: len(dbTables),
CollationEquals: func(a, b string) bool { return a == b },
}
var candidateCollations []string
if x.Dialect().URI().DBType == schemas.MYSQL {
if _, err = x.SQL("SELECT @@collation_database").Get(&res.DatabaseCollation); err != nil {
return nil, err
}
res.IsCollationCaseSensitive = func(s string) bool {
return s == "utf8mb4_bin" || strings.HasSuffix(s, "_as_cs")
}
candidateCollations = []string{"utf8mb4_0900_as_cs", "uca1400_as_cs", "utf8mb4_bin"}
res.AvailableCollation, err = findAvailableCollationsMySQL(x)
if err != nil {
return nil, err
}
res.CollationEquals = func(a, b string) bool {
// MariaDB adds the "utf8mb4_" prefix, eg: "utf8mb4_uca1400_as_cs", but not the name "uca1400_as_cs" in "SHOW COLLATION"
// At the moment, it's safe to ignore the database difference, just trim the prefix and compare. It could be fixed easily if there is any problem in the future.
return a == b || strings.TrimPrefix(a, "utf8mb4_") == strings.TrimPrefix(b, "utf8mb4_")
}
} else if x.Dialect().URI().DBType == schemas.MSSQL {
if _, err = x.SQL("SELECT DATABASEPROPERTYEX(DB_NAME(), 'Collation')").Get(&res.DatabaseCollation); err != nil {
return nil, err
}
res.IsCollationCaseSensitive = func(s string) bool {
return strings.HasSuffix(s, "_CS_AS")
}
candidateCollations = []string{"Latin1_General_CS_AS"}
res.AvailableCollation, err = findAvailableCollationsMSSQL(x)
if err != nil {
return nil, err
}
} else {
return nil, nil
}
if res.DatabaseCollation == "" {
return nil, errors.New("unable to get collation for current database")
}
res.ExpectedCollation = setting.Database.CharsetCollation
if res.ExpectedCollation == "" {
for _, collation := range candidateCollations {
if res.AvailableCollation.Contains(collation) {
res.ExpectedCollation = collation
break
}
}
}
if res.ExpectedCollation == "" {
return nil, errors.New("unable to find a suitable collation for current database")
}
allColumnsMatchExpected := true
allColumnsMatchDatabase := true
for _, table := range dbTables {
for _, col := range table.Columns() {
if col.Collation != "" {
allColumnsMatchExpected = allColumnsMatchExpected && res.CollationEquals(col.Collation, res.ExpectedCollation)
allColumnsMatchDatabase = allColumnsMatchDatabase && res.CollationEquals(col.Collation, res.DatabaseCollation)
if !res.IsCollationCaseSensitive(col.Collation) || !res.CollationEquals(col.Collation, res.DatabaseCollation) {
res.InconsistentCollationColumns = append(res.InconsistentCollationColumns, fmt.Sprintf("%s.%s", table.Name, col.Name))
}
}
}
}
// if all columns match expected collation or all match database collation, then it could also be considered as "consistent"
if allColumnsMatchExpected || allColumnsMatchDatabase {
res.InconsistentCollationColumns = nil
}
return res, nil
}
func CheckCollationsDefaultEngine() (*CheckCollationsResult, error) {
return CheckCollations(x)
}
func alterDatabaseCollation(x *xorm.Engine, collation string) error {
if x.Dialect().URI().DBType == schemas.MYSQL {
_, err := x.Exec("ALTER DATABASE CHARACTER SET utf8mb4 COLLATE " + collation)
return err
} else if x.Dialect().URI().DBType == schemas.MSSQL {
// TODO: MSSQL has many limitations on changing database collation, it could fail in many cases.
_, err := x.Exec("ALTER DATABASE CURRENT COLLATE " + collation)
return err
}
return errors.New("unsupported database type")
}
// preprocessDatabaseCollation checks database & table column collation, and alter the database collation if needed
func preprocessDatabaseCollation(x *xorm.Engine) {
r, err := CheckCollations(x)
if err != nil {
log.Error("Failed to check database collation: %v", err)
}
if r == nil {
return // no check result means the database doesn't need to do such check/process (at the moment ....)
}
// try to alter database collation to expected if the database is empty, it might fail in some cases (and it isn't necessary to succeed)
// at the moment, there is no "altering" solution for MSSQL, site admin should manually change the database collation
// and there is a bug https://github.com/go-testfixtures/testfixtures/pull/182 mssql: Invalid object name 'information_schema.tables'.
if !r.CollationEquals(r.DatabaseCollation, r.ExpectedCollation) && r.ExistingTableNumber == 0 && x.Dialect().URI().DBType == schemas.MYSQL {
if err = alterDatabaseCollation(x, r.ExpectedCollation); err != nil {
log.Error("Failed to change database collation to %q: %v", r.ExpectedCollation, err)
} else {
_, _ = x.Exec("SELECT 1") // after "altering", MSSQL's session becomes invalid, so make a simple query to "refresh" the session
if r, err = CheckCollations(x); err != nil {
log.Error("Failed to check database collation again after altering: %v", err) // impossible case
return
}
log.Warn("Current database has been altered to use collation %q", r.DatabaseCollation)
}
}
// check column collation, and show warning/error to end users -- no need to fatal, do not block the startup
if !r.IsCollationCaseSensitive(r.DatabaseCollation) {
log.Warn("Current database is using a case-insensitive collation %q, although Gitea could work with it, there might be some rare cases which don't work as expected.", r.DatabaseCollation)
}
if len(r.InconsistentCollationColumns) > 0 {
log.Error("There are %d table columns using inconsistent collation, they should use %q. Please go to admin panel Self Check page", len(r.InconsistentCollationColumns), r.DatabaseCollation)
}
}