81 lines
2.1 KiB
Go
81 lines
2.1 KiB
Go
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package raft
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import (
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"fmt"
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"os"
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"path/filepath"
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)
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// dataBackupHelper helps making and rotating backups from a folder.
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// it will name them <folderName>.old.0, .old.1... and so on.
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// when a new backup is made, the old.0 is renamed to old.1 and so on.
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// when the "keep" number is reached, the oldest is always
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// discarded.
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type dataBackupHelper struct {
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baseDir string
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folderName string
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keep int
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}
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func newDataBackupHelper(dataFolder string, keep int) *dataBackupHelper {
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return &dataBackupHelper{
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baseDir: filepath.Dir(dataFolder),
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folderName: filepath.Base(dataFolder),
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keep: keep,
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}
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}
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func (dbh *dataBackupHelper) makeName(i int) string {
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return filepath.Join(dbh.baseDir, fmt.Sprintf("%s.old.%d", dbh.folderName, i))
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}
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func (dbh *dataBackupHelper) listBackups() []string {
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backups := []string{}
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for i := 0; i < dbh.keep; i++ {
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name := dbh.makeName(i)
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if _, err := os.Stat(name); os.IsNotExist(err) {
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return backups
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}
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backups = append(backups, name)
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}
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return backups
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}
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func (dbh *dataBackupHelper) makeBackup() error {
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folder := filepath.Join(dbh.baseDir, dbh.folderName)
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if _, err := os.Stat(folder); os.IsNotExist(err) {
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// nothing to backup
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logger.Debug("nothing to backup")
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return nil
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}
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// make sure config folder exists
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err := os.MkdirAll(dbh.baseDir, 0700)
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if err != nil {
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return err
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}
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// list all backups in it
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backups := dbh.listBackups()
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// remove last / oldest. Ex. if max is five, remove name.old.4
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if len(backups) >= dbh.keep {
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os.RemoveAll(backups[len(backups)-1])
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} else { // append new backup folder. Ex, if 2 exist: add name.old.2
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backups = append(backups, dbh.makeName(len(backups)))
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}
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// increase number for all backups folders.
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// If there are 3: 1->2, 0->1.
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// Note in all cases the last backup in the list does not exist
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// (either removed or not created, just added to this list)
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for i := len(backups) - 1; i > 0; i-- {
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err := os.Rename(backups[i-1], backups[i])
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if err != nil {
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return err
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}
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}
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// save new as name.old.0
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return os.Rename(filepath.Join(dbh.baseDir, dbh.folderName), dbh.makeName(0))
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}
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