syncthing/lib/versioner/trashcan.go

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// Copyright (C) 2015 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package versioner
import (
"context"
"fmt"
"strconv"
"time"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/fs"
)
func init() {
// Register the constructor for this type of versioner
factories["trashcan"] = newTrashcan
}
type trashcan struct {
folderFs fs.Filesystem
versionsFs fs.Filesystem
cleanoutDays int
copyRangeMethod fs.CopyRangeMethod
}
func newTrashcan(cfg config.FolderConfiguration) Versioner {
cleanoutDays, _ := strconv.Atoi(cfg.Versioning.Params["cleanoutDays"])
// On error we default to 0, "do not clean out the trash can"
s := &trashcan{
folderFs: cfg.Filesystem(nil),
versionsFs: versionerFsFromFolderCfg(cfg),
cleanoutDays: cleanoutDays,
copyRangeMethod: cfg.CopyRangeMethod,
}
Implement facility based logger, debugging via REST API This implements a new debug/trace infrastructure based on a slightly hacked up logger. Instead of the traditional "if debug { ... }" I've rewritten the logger to have no-op Debugln and Debugf, unless debugging has been enabled for a given "facility". The "facility" is just a string, typically a package name. This will be slightly slower than before; but not that much as it's mostly a function call that returns immediately. For the cases where it matters (the Debugln takes a hex.Dump() of something for example, and it's not in a very occasional "if err != nil" branch) there is an l.ShouldDebug(facility) that is fast enough to be used like the old "if debug". The point of all this is that we can now toggle debugging for the various packages on and off at runtime. There's a new method /rest/system/debug that can be POSTed a set of facilities to enable and disable debug for, or GET from to get a list of facilities with descriptions and their current debug status. Similarly a /rest/system/log?since=... can grab the latest log entries, up to 250 of them (hardcoded constant in main.go) plus the initial few. Not implemented in this commit (but planned) is a simple debug GUI available on /debug that shows the current log in an easily pasteable format and has checkboxes to enable the various debug facilities. The debug instructions to a user then becomes "visit this URL, check these boxes, reproduce your problem, copy and paste the log". The actual log viewer on the hypothetical /debug URL can poll regularly for new log entries and this bypass the 250 line limit. The existing STTRACE=foo variable is still obeyed and just sets the start state of the system.
2015-10-03 15:25:21 +00:00
l.Debugf("instantiated %#v", s)
return s
}
// Archive moves the named file away to a version archive. If this function
// returns nil, the named file does not exist any more (has been archived).
func (t *trashcan) Archive(filePath string) error {
return archiveFile(t.copyRangeMethod, t.folderFs, t.versionsFs, filePath, func(name, tag string) string {
return name
})
}
func (t *trashcan) String() string {
return fmt.Sprintf("trashcan@%p", t)
}
func (t *trashcan) Clean(ctx context.Context) error {
if t.cleanoutDays <= 0 {
return nil
}
if _, err := t.versionsFs.Lstat("."); fs.IsNotExist(err) {
return nil
}
cutoff := time.Now().Add(time.Duration(-24*t.cleanoutDays) * time.Hour)
dirTracker := make(emptyDirTracker)
walkFn := func(path string, info fs.FileInfo, err error) error {
if err != nil {
return err
}
select {
case <-ctx.Done():
return ctx.Err()
default:
}
if info.IsDir() && !info.IsSymlink() {
dirTracker.addDir(path)
return nil
}
if info.ModTime().Before(cutoff) {
// The file is too old; remove it.
err = t.versionsFs.Remove(path)
} else {
// Keep this file, and remember it so we don't unnecessarily try
// to remove this directory.
dirTracker.addFile(path)
}
return err
}
if err := t.versionsFs.Walk(".", walkFn); err != nil {
return err
}
dirTracker.deleteEmptyDirs(t.versionsFs)
return nil
}
func (t *trashcan) GetVersions() (map[string][]FileVersion, error) {
return retrieveVersions(t.versionsFs)
}
func (t *trashcan) Restore(filepath string, versionTime time.Time) error {
// If we have an untagged file A and want to restore it on top of existing file A, we can't first archive the
// existing A as we'd overwrite the old A version, therefore when we archive existing file, we archive it with a
// tag but when the restoration is finished, we rename it (untag it). This is only important if when restoring A,
// there already exists a file at the same location
// If we restore a deleted file, there won't be a conflict and archiving won't happen thus there won't be anything
// in the archive to rename afterwards. Log whether the file exists prior to restoring.
_, dstPathErr := t.folderFs.Lstat(filepath)
taggedName := ""
tagger := func(name, tag string) string {
// We also abuse the fact that tagger gets called twice, once for tagging the restoration version, which
// should just return the plain name, and second time by archive which archives existing file in the folder.
// We can't use TagFilename here, as restoreFile would discover that as a valid version and restore that instead.
if taggedName != "" {
return taggedName
}
taggedName = fs.TempName(name)
return name
}
if err := restoreFile(t.copyRangeMethod, t.versionsFs, t.folderFs, filepath, versionTime, tagger); taggedName == "" {
return err
}
// If a deleted file was restored, even though the RenameOrCopy method is robust, check if the file exists and
// skip the renaming function if this is the case.
if fs.IsNotExist(dstPathErr) {
if _, err := t.folderFs.Lstat(filepath); err != nil {
return err
}
return nil
}
return t.versionsFs.Rename(taggedName, filepath)
}