refac: decouple persistence and image storage behind driver registries

internal/infrastructure/persistence/database/sqliteBackup.go

@@ -0,0 +1,87 @@
+package database
+
+import (
+	domain "RenewCMS/internal/domain/update"
+	"errors"
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+
+	"gorm.io/gorm"
+)
+
+var errBackupExists = errors.New("a backup with this name already exists")
+
+const (
+	backupsToKeep       = 3
+	backupFileExtension = ".db"
+	backupFilePrefix    = "renewcms-"
+	backupTimeLayout    = "20060102T150405.000000000Z"
+)
+
+type SQLiteBackup struct {
+	db        *gorm.DB
+	directory string
+	now       func() time.Time
+}
+
+var _ domain.DatabaseBackup = &SQLiteBackup{}
+
+func NewSQLiteBackup(db *gorm.DB, directory string, now func() time.Time) *SQLiteBackup {
+	return &SQLiteBackup{db: db, directory: directory, now: now}
+}
+
+func (b *SQLiteBackup) Backup() (string, error) {
+	if err := os.MkdirAll(b.directory, os.ModePerm); 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 {
+		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
+}