feat: optional MySQL/MariaDB database driver for deployments that cannot use local SQLite

internal/infrastructure/persistence/database/backupRetention.go

@@ -0,0 +1,55 @@
+package database
+
+import (
+	"os"
+	"path/filepath"
+	"slices"
+	"strings"
+	"time"
+)
+
+type backupFile struct {
+	path     string
+	modified time.Time
+}
+
+func newBackupTarget(directory string, now time.Time, extension string) (string, error) {
+	if err := os.MkdirAll(directory, os.ModePerm); err != nil {
+		return "", err
+	}
+	target := filepath.Join(directory, backupFilePrefix+now.UTC().Format(backupTimeLayout)+extension)
+	if _, err := os.Stat(target); err == nil {
+		return "", errBackupExists
+	}
+	return target, nil
+}
+
+func pruneBackups(directory string, extension string) error {
+	entries, err := os.ReadDir(directory)
+	if err != nil {
+		return err
+	}
+	files := make([]backupFile, 0, len(entries))
+	for _, entry := range entries {
+		if entry.IsDir() || !strings.HasSuffix(entry.Name(), extension) {
+			continue
+		}
+		info, err := entry.Info()
+		if err != nil {
+			return err
+		}
+		files = append(files, backupFile{path: filepath.Join(directory, entry.Name()), modified: info.ModTime()})
+	}
+	slices.SortFunc(files, func(a, b backupFile) int {
+		if byTime := b.modified.Compare(a.modified); byTime != 0 {
+			return byTime
+		}
+		return strings.Compare(b.path, a.path)
+	})
+	for _, stale := range files[min(backupsToKeep, len(files)):] {
+		if err := os.Remove(stale.path); err != nil {
+			return err
+		}
+	}
+	return nil
+}

internal/infrastructure/persistence/database/driver.go

@@ -8,9 +8,16 @@ import (
 	"gorm.io/gorm"
 )
 
+type PoolSettings struct {
+	MaxOpenConns    int
+	MaxIdleConns    int
+	ConnMaxLifetime time.Duration
+}
+
 type Config struct {
 	Driver string
 	Source string
+	Pool   *PoolSettings
 }
 
 type Driver interface {
@@ -20,6 +27,7 @@ type Driver interface {
 
 var drivers = map[string]Driver{
 	DriverSQLite: sqliteDriver{},
+	DriverMySQL:  mysqlDriver{},
 }
 
 type Connection struct {
@@ -36,9 +44,25 @@ func Connect(config Config) (*Connection, error) {
 	if err != nil {
 		return nil, err
 	}
+	if config.Pool != nil {
+		if err := applyPool(db, *config.Pool); err != nil {
+			return nil, err
+		}
+	}
 	return &Connection{DB: db, driver: driver}, nil
 }
 
+func applyPool(db *gorm.DB, pool PoolSettings) error {
+	sqlDb, err := db.DB()
+	if err != nil {
+		return err
+	}
+	sqlDb.SetMaxOpenConns(pool.MaxOpenConns)
+	sqlDb.SetMaxIdleConns(pool.MaxIdleConns)
+	sqlDb.SetConnMaxLifetime(pool.ConnMaxLifetime)
+	return nil
+}
+
 func (c *Connection) NewBackup(directory string, now func() time.Time) domainUpdate.DatabaseBackup {
 	return c.driver.NewBackup(c.DB, directory, now)
 }

internal/infrastructure/persistence/database/dumpBackup.go

@@ -0,0 +1,79 @@
+package database
+
+import (
+	domain "RenewCMS/internal/domain/update"
+	"bufio"
+	"os"
+	"time"
+)
+
+const (
+	dumpFileExtension        = ".sql"
+	dumpPartialFileExtension = ".partial"
+)
+
+type DumpBackup struct {
+	open      func() (DumpSource, error)
+	directory string
+	now       func() time.Time
+}
+
+var _ domain.DatabaseBackup = &DumpBackup{}
+
+func NewDumpBackup(open func() (DumpSource, error), directory string, now func() time.Time) *DumpBackup {
+	return &DumpBackup{open: open, directory: directory, now: now}
+}
+
+func (b *DumpBackup) Backup() (string, error) {
+	target, err := newBackupTarget(b.directory, b.now(), dumpFileExtension)
+	if err != nil {
+		return "", err
+	}
+	if err := b.writeAtomically(target); err != nil {
+		return "", err
+	}
+	if err := pruneBackups(b.directory, dumpFileExtension); err != nil {
+		return "", err
+	}
+	return target, nil
+}
+
+func (b *DumpBackup) writeAtomically(target string) error {
+	partial := target + dumpPartialFileExtension
+	if err := b.writePartial(partial); err != nil {
+		_ = os.Remove(partial)
+		return err
+	}
+	if err := os.Rename(partial, target); err != nil {
+		_ = os.Remove(partial)
+		return err
+	}
+	return nil
+}
+
+func (b *DumpBackup) writePartial(partial string) error {
+	source, err := b.open()
+	if err != nil {
+		return err
+	}
+	defer source.Close()
+
+	file, err := os.OpenFile(partial, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o600)
+	if err != nil {
+		return err
+	}
+	buffered := bufio.NewWriter(file)
+	if err := WriteDump(buffered, source); err != nil {
+		_ = file.Close()
+		return err
+	}
+	if err := buffered.Flush(); err != nil {
+		_ = file.Close()
+		return err
+	}
+	if err := file.Sync(); err != nil {
+		_ = file.Close()
+		return err
+	}
+	return file.Close()
+}

internal/infrastructure/persistence/database/migrate.go

@@ -7,7 +7,7 @@ import (
 )
 
 func Migrate(db *gorm.DB) error {
-	err := db.AutoMigrate(&models.Article{}, &models.Image{}, &models.User{}, &models.Invite{}, &models.APIKey{}, &models.PurgeSettings{})
+	err := tableOptionsFor(db).AutoMigrate(&models.Article{}, &models.Image{}, &models.User{}, &models.Invite{}, &models.APIKey{}, &models.PurgeSettings{})
 	if err != nil {
 		return err
 	}

internal/infrastructure/persistence/database/mysql.go

@@ -0,0 +1,86 @@
+package database
+
+import (
+	domainUpdate "RenewCMS/internal/domain/update"
+	"fmt"
+	"net"
+	"strings"
+	"time"
+
+	mysqldriver "github.com/go-sql-driver/mysql"
+	"gorm.io/driver/mysql"
+	"gorm.io/gorm"
+)
+
+const (
+	DriverMySQL = "mysql"
+
+	mysqlCharset         = "utf8mb4"
+	mysqlLocation        = "UTC"
+	mysqlCollation       = "utf8mb4_bin"
+	mysqlConnectTimeout  = 5 * time.Second
+	mysqlSessionSQLMode  = "'ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION'"
+	mysqlTableOptionsKey = "gorm:table_options"
+	redactedPassword     = "***"
+)
+
+type mysqlDriver struct{}
+
+type MySQLConfig struct {
+	Host     string
+	Port     string
+	User     string
+	Password string
+	Name     string
+	TLS      string
+}
+
+func MySQLDSN(config MySQLConfig) string {
+	dsn := mysqldriver.NewConfig()
+	dsn.User = config.User
+	dsn.Passwd = config.Password
+	dsn.Net = "tcp"
+	dsn.Addr = net.JoinHostPort(config.Host, config.Port)
+	dsn.DBName = config.Name
+	dsn.TLSConfig = config.TLS
+	dsn.ParseTime = true
+	dsn.ClientFoundRows = true
+	dsn.Collation = mysqlCollation
+	dsn.Timeout = mysqlConnectTimeout
+	dsn.Params = map[string]string{
+		"charset":  mysqlCharset,
+		"loc":      mysqlLocation,
+		"sql_mode": mysqlSessionSQLMode,
+	}
+	return dsn.FormatDSN()
+}
+
+func (mysqlDriver) Open(source string) (*gorm.DB, error) {
+	parsed, err := mysqldriver.ParseDSN(source)
+	if err != nil {
+		return nil, fmt.Errorf("the mysql connection settings are invalid")
+	}
+	db, err := gorm.Open(mysql.Open(source), &gorm.Config{})
+	if err != nil {
+		return nil, fmt.Errorf("cannot use the mysql server at %s: %s", parsed.Addr, redact(err.Error(), parsed.Passwd))
+	}
+	return db, nil
+}
+
+func (mysqlDriver) NewBackup(db *gorm.DB, directory string, now func() time.Time) domainUpdate.DatabaseBackup {
+	return NewMySQLBackup(db, directory, now)
+}
+
+func redact(message string, secret string) string {
+	if secret == "" {
+		return message
+	}
+	return strings.ReplaceAll(message, secret, redactedPassword)
+}
+
+func tableOptionsFor(db *gorm.DB) *gorm.DB {
+	if db.Dialector.Name() == DriverMySQL {
+		return db.Set(mysqlTableOptionsKey, "DEFAULT CHARSET="+mysqlCharset+" COLLATE="+mysqlCollation)
+	}
+	return db
+}

internal/infrastructure/persistence/database/mysqlBackup.go

@@ -0,0 +1,131 @@
+package database
+
+import (
+	"database/sql"
+	"fmt"
+	"time"
+
+	"gorm.io/gorm"
+)
+
+const (
+	dumpTimeLayout = "2006-01-02 15:04:05.000000"
+	zeroDumpTime   = "0000-00-00 00:00:00"
+)
+
+func NewMySQLBackup(db *gorm.DB, directory string, now func() time.Time) *DumpBackup {
+	return NewDumpBackup(func() (DumpSource, error) { return openMySQLDumpSource(db) }, directory, now)
+}
+
+type mysqlDumpSource struct {
+	tx *gorm.DB
+}
+
+var _ DumpSource = &mysqlDumpSource{}
+
+func openMySQLDumpSource(db *gorm.DB) (*mysqlDumpSource, error) {
+	tx := db.Begin(&sql.TxOptions{Isolation: sql.LevelRepeatableRead, ReadOnly: true})
+	if tx.Error != nil {
+		return nil, tx.Error
+	}
+	return &mysqlDumpSource{tx: tx}, nil
+}
+
+func (s *mysqlDumpSource) Tables() ([]string, error) {
+	var tables []string
+	err := s.tx.Raw("SELECT table_name FROM information_schema.tables WHERE table_schema = DATABASE() AND table_type = 'BASE TABLE' ORDER BY table_name").Scan(&tables).Error
+	return tables, err
+}
+
+func (s *mysqlDumpSource) CreateStatement(table string) (string, error) {
+	var name, statement string
+	row := s.tx.Raw("SHOW CREATE TABLE " + quoteIdentifier(table)).Row()
+	if err := row.Scan(&name, &statement); err != nil {
+		return "", err
+	}
+	return statement, nil
+}
+
+func (s *mysqlDumpSource) Rows(table string) (DumpRows, error) {
+	rows, err := s.tx.Raw("SELECT * FROM " + quoteIdentifier(table)).Rows()
+	if err != nil {
+		return nil, err
+	}
+	return &mysqlDumpRows{rows: rows}, nil
+}
+
+func (s *mysqlDumpSource) Close() error {
+	return s.tx.Rollback().Error
+}
+
+type mysqlDumpRows struct {
+	rows *sql.Rows
+}
+
+var _ DumpRows = &mysqlDumpRows{}
+
+func (r *mysqlDumpRows) Columns() ([]DumpColumn, error) {
+	types, err := r.rows.ColumnTypes()
+	if err != nil {
+		return nil, err
+	}
+	columns := make([]DumpColumn, len(types))
+	for index, columnType := range types {
+		columns[index] = DumpColumn{Name: columnType.Name(), Type: columnType.DatabaseTypeName()}
+	}
+	return columns, nil
+}
+
+func (r *mysqlDumpRows) Next() bool {
+	return r.rows.Next()
+}
+
+func (r *mysqlDumpRows) Values() ([][]byte, error) {
+	columnCount, err := r.rows.Columns()
+	if err != nil {
+		return nil, err
+	}
+	scanned := make([]any, len(columnCount))
+	targets := make([]any, len(columnCount))
+	for index := range scanned {
+		targets[index] = &scanned[index]
+	}
+	if err := r.rows.Scan(targets...); err != nil {
+		return nil, err
+	}
+	values := make([][]byte, len(scanned))
+	for index, value := range scanned {
+		values[index] = dumpBytes(value)
+	}
+	return values, nil
+}
+
+func (r *mysqlDumpRows) Err() error {
+	return r.rows.Err()
+}
+
+func (r *mysqlDumpRows) Close() error {
+	return r.rows.Close()
+}
+
+func dumpBytes(value any) []byte {
+	switch typed := value.(type) {
+	case nil:
+		return nil
+	case []byte:
+		return append([]byte{}, typed...)
+	case string:
+		return []byte(typed)
+	case time.Time:
+		return []byte(formatDumpTime(typed))
+	default:
+		return []byte(fmt.Sprint(typed))
+	}
+}
+
+func formatDumpTime(value time.Time) string {
+	if value.IsZero() {
+		return zeroDumpTime
+	}
+	return value.UTC().Format(dumpTimeLayout)
+}

internal/infrastructure/persistence/database/sqlDump.go

@@ -0,0 +1,170 @@
+package database
+
+import (
+	"encoding/hex"
+	"fmt"
+	"io"
+	"regexp"
+	"strings"
+)
+
+type DumpColumn struct {
+	Name string
+	Type string
+}
+
+type DumpRows interface {
+	Columns() ([]DumpColumn, error)
+	Next() bool
+	Values() ([][]byte, error)
+	Err() error
+	Close() error
+}
+
+type DumpSource interface {
+	Tables() ([]string, error)
+	CreateStatement(table string) (string, error)
+	Rows(table string) (DumpRows, error)
+	Close() error
+}
+
+var dumpPreamble = []string{
+	"SET NAMES utf8mb4;",
+	"SET sql_mode = 'NO_AUTO_VALUE_ON_ZERO';",
+	"SET foreign_key_checks = 0;",
+}
+
+var dumpPostamble = []string{
+	"SET foreign_key_checks = 1;",
+}
+
+var plainNumber = regexp.MustCompile(`^-?[0-9]+(\.[0-9]+)?([eE][+-]?[0-9]+)?$`)
+
+var textEscapes = strings.NewReplacer(
+	`\`, `\\`,
+	`'`, `\'`,
+	"\x00", `\0`,
+	"\n", `\n`,
+	"\r", `\r`,
+	"\x1a", `\Z`,
+)
+
+func WriteDump(output io.Writer, source DumpSource) error {
+	if err := writeStatements(output, dumpPreamble); err != nil {
+		return err
+	}
+	tables, err := source.Tables()
+	if err != nil {
+		return err
+	}
+	for _, table := range tables {
+		if err := writeTable(output, source, table); err != nil {
+			return err
+		}
+	}
+	return writeStatements(output, dumpPostamble)
+}
+
+func writeStatements(output io.Writer, statements []string) error {
+	for _, statement := range statements {
+		if _, err := fmt.Fprintln(output, statement); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func writeTable(output io.Writer, source DumpSource, table string) error {
+	create, err := source.CreateStatement(table)
+	if err != nil {
+		return err
+	}
+	if _, err := fmt.Fprintf(output, "%s;\n", create); err != nil {
+		return err
+	}
+	rows, err := source.Rows(table)
+	if err != nil {
+		return err
+	}
+	defer rows.Close()
+	return writeRows(output, table, rows)
+}
+
+func writeRows(output io.Writer, table string, rows DumpRows) error {
+	columns, err := rows.Columns()
+	if err != nil {
+		return err
+	}
+	insertPrefix := insertStatementPrefix(table, columns)
+	for rows.Next() {
+		values, err := rows.Values()
+		if err != nil {
+			return err
+		}
+		if _, err := fmt.Fprintf(output, "%s%s);\n", insertPrefix, joinLiterals(columns, values)); err != nil {
+			return err
+		}
+	}
+	return rows.Err()
+}
+
+func insertStatementPrefix(table string, columns []DumpColumn) string {
+	names := make([]string, len(columns))
+	for index, column := range columns {
+		names[index] = quoteIdentifier(column.Name)
+	}
+	return fmt.Sprintf("INSERT INTO %s (%s) VALUES (", quoteIdentifier(table), strings.Join(names, ","))
+}
+
+func joinLiterals(columns []DumpColumn, values [][]byte) string {
+	literals := make([]string, len(columns))
+	for index, column := range columns {
+		literals[index] = sqlLiteral(column.Type, values[index])
+	}
+	return strings.Join(literals, ",")
+}
+
+func quoteIdentifier(name string) string {
+	return "`" + strings.ReplaceAll(name, "`", "``") + "`"
+}
+
+func sqlLiteral(databaseType string, value []byte) string {
+	if value == nil {
+		return "NULL"
+	}
+	switch {
+	case isNumericType(databaseType) && plainNumber.Match(value):
+		return string(value)
+	case isBinaryType(databaseType):
+		return hexLiteral(value)
+	default:
+		return "'" + textEscapes.Replace(string(value)) + "'"
+	}
+}
+
+func hexLiteral(value []byte) string {
+	if len(value) == 0 {
+		return "''"
+	}
+	return "0x" + hex.EncodeToString(value)
+}
+
+func isNumericType(databaseType string) bool {
+	upper := strings.ToUpper(databaseType)
+	for _, suffix := range []string{"INT", "DECIMAL", "NUMERIC", "FLOAT", "DOUBLE", "YEAR"} {
+		if strings.HasSuffix(upper, suffix) {
+			return true
+		}
+	}
+	return false
+}
+
+func isBinaryType(databaseType string) bool {
+	upper := strings.ToUpper(databaseType)
+	for _, suffix := range []string{"BLOB", "BINARY", "BIT", "GEOMETRY"} {
+		if strings.HasSuffix(upper, suffix) {
+			return true
+		}
+	}
+	return false
+}

internal/infrastructure/persistence/database/sqliteBackup.go

@@ -4,9 +4,6 @@ import (
 	domain "RenewCMS/internal/domain/update"
 	"errors"
 	"os"
-	"path/filepath"
-	"sort"
-	"strings"
 	"time"
 
 	"gorm.io/gorm"
@@ -34,54 +31,16 @@ func NewSQLiteBackup(db *gorm.DB, directory string, now func() time.Time) *SQLit
 }
 
 func (b *SQLiteBackup) Backup() (string, error) {
-	if err := os.MkdirAll(b.directory, os.ModePerm); err != nil {
+	target, err := newBackupTarget(b.directory, b.now(), backupFileExtension)
+	if err != nil {
 		return "", err
 	}
-	target := filepath.Join(b.directory, backupFilePrefix+b.now().UTC().Format(backupTimeLayout)+backupFileExtension)
-	if _, err := os.Stat(target); err == nil {
-		return "", errBackupExists
-	}
 	if err := b.db.Exec("VACUUM INTO ?", target).Error; err != nil {
 		_ = os.Remove(target)
 		return "", err
 	}
-	if err := b.prune(); err != nil {
+	if err := pruneBackups(b.directory, backupFileExtension); err != nil {
 		return "", err
 	}
 	return target, nil
 }
-
-type backupFile struct {
-	path     string
-	modified time.Time
-}
-
-func (b *SQLiteBackup) prune() error {
-	entries, err := os.ReadDir(b.directory)
-	if err != nil {
-		return err
-	}
-	files := make([]backupFile, 0, len(entries))
-	for _, entry := range entries {
-		if entry.IsDir() || !strings.HasSuffix(entry.Name(), backupFileExtension) {
-			continue
-		}
-		info, err := entry.Info()
-		if err != nil {
-			return err
-		}
-		files = append(files, backupFile{path: filepath.Join(b.directory, entry.Name()), modified: info.ModTime()})
-	}
-	sort.Slice(files, func(i, j int) bool {
-		if files[i].modified.Equal(files[j].modified) {
-			return files[i].path > files[j].path
-		}
-		return files[i].modified.After(files[j].modified)
-	})
-	for _, stale := range files[min(backupsToKeep, len(files)):] {
-		if err := os.Remove(stale.path); err != nil {
-			return err
-		}
-	}
-	return nil
-}