syncthing/lib/versioner/staggered.go

233 lines
5.6 KiB
Go

// Copyright (C) 2014 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 (
"sort"
"strconv"
"time"
"github.com/thejerf/suture"
"github.com/syncthing/syncthing/lib/fs"
"github.com/syncthing/syncthing/lib/sync"
"github.com/syncthing/syncthing/lib/util"
)
func init() {
// Register the constructor for this type of versioner with the name "staggered"
Factories["staggered"] = NewStaggered
}
type Interval struct {
step int64
end int64
}
type Staggered struct {
suture.Service
cleanInterval int64
folderFs fs.Filesystem
versionsFs fs.Filesystem
interval [4]Interval
mutex sync.Mutex
testCleanDone chan struct{}
}
func NewStaggered(folderID string, folderFs fs.Filesystem, params map[string]string) Versioner {
maxAge, err := strconv.ParseInt(params["maxAge"], 10, 0)
if err != nil {
maxAge = 31536000 // Default: ~1 year
}
cleanInterval, err := strconv.ParseInt(params["cleanInterval"], 10, 0)
if err != nil {
cleanInterval = 3600 // Default: clean once per hour
}
// Backwards compatibility
params["fsPath"] = params["versionsPath"]
versionsFs := fsFromParams(folderFs, params)
s := &Staggered{
cleanInterval: cleanInterval,
folderFs: folderFs,
versionsFs: versionsFs,
interval: [4]Interval{
{30, 3600}, // first hour -> 30 sec between versions
{3600, 86400}, // next day -> 1 h between versions
{86400, 592000}, // next 30 days -> 1 day between versions
{604800, maxAge}, // next year -> 1 week between versions
},
mutex: sync.NewMutex(),
}
s.Service = util.AsService(s.serve)
l.Debugf("instantiated %#v", s)
return s
}
func (v *Staggered) serve(stop chan struct{}) {
v.clean()
if v.testCleanDone != nil {
close(v.testCleanDone)
}
tck := time.NewTicker(time.Duration(v.cleanInterval) * time.Second)
defer tck.Stop()
for {
select {
case <-tck.C:
v.clean()
case <-stop:
return
}
}
}
func (v *Staggered) clean() {
l.Debugln("Versioner clean: Waiting for lock on", v.versionsFs)
v.mutex.Lock()
defer v.mutex.Unlock()
l.Debugln("Versioner clean: Cleaning", v.versionsFs)
if _, err := v.versionsFs.Stat("."); fs.IsNotExist(err) {
// There is no need to clean a nonexistent dir.
return
}
versionsPerFile := make(map[string][]string)
dirTracker := make(emptyDirTracker)
walkFn := func(path string, f fs.FileInfo, err error) error {
if err != nil {
return err
}
if f.IsDir() && !f.IsSymlink() {
dirTracker.addDir(path)
return nil
}
// Regular file, or possibly a symlink.
dirTracker.addFile(path)
name, _ := UntagFilename(path)
if name == "" {
return nil
}
versionsPerFile[name] = append(versionsPerFile[name], path)
return nil
}
if err := v.versionsFs.Walk(".", walkFn); err != nil {
l.Warnln("Versioner: error scanning versions dir", err)
return
}
for _, versionList := range versionsPerFile {
v.expire(versionList)
}
dirTracker.deleteEmptyDirs(v.versionsFs)
l.Debugln("Cleaner: Finished cleaning", v.versionsFs)
}
func (v *Staggered) expire(versions []string) {
l.Debugln("Versioner: Expiring versions", versions)
for _, file := range v.toRemove(versions, time.Now()) {
if fi, err := v.versionsFs.Lstat(file); err != nil {
l.Warnln("versioner:", err)
continue
} else if fi.IsDir() {
l.Infof("non-file %q is named like a file version", file)
continue
}
if err := v.versionsFs.Remove(file); err != nil {
l.Warnf("Versioner: can't remove %q: %v", file, err)
}
}
}
func (v *Staggered) toRemove(versions []string, now time.Time) []string {
var prevAge int64
firstFile := true
var remove []string
// The list of versions may or may not be properly sorted.
sort.Strings(versions)
for _, version := range versions {
versionTime, err := time.ParseInLocation(TimeFormat, ExtractTag(version), time.Local)
if err != nil {
l.Debugf("Versioner: file name %q is invalid: %v", version, err)
continue
}
age := int64(now.Sub(versionTime).Seconds())
// If the file is older than the max age of the last interval, remove it
if lastIntv := v.interval[len(v.interval)-1]; lastIntv.end > 0 && age > lastIntv.end {
l.Debugln("Versioner: File over maximum age -> delete ", version)
remove = append(remove, version)
continue
}
// If it's the first (oldest) file in the list we can skip the interval checks
if firstFile {
prevAge = age
firstFile = false
continue
}
// Find the interval the file fits in
var usedInterval Interval
for _, usedInterval = range v.interval {
if age < usedInterval.end {
break
}
}
if prevAge-age < usedInterval.step {
l.Debugln("too many files in step -> delete", version)
remove = append(remove, version)
continue
}
prevAge = age
}
return remove
}
// 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 (v *Staggered) Archive(filePath string) error {
l.Debugln("Waiting for lock on ", v.versionsFs)
v.mutex.Lock()
defer v.mutex.Unlock()
if err := archiveFile(v.folderFs, v.versionsFs, filePath, TagFilename); err != nil {
return err
}
v.expire(findAllVersions(v.versionsFs, filePath))
return nil
}
func (v *Staggered) GetVersions() (map[string][]FileVersion, error) {
return retrieveVersions(v.versionsFs)
}
func (v *Staggered) Restore(filepath string, versionTime time.Time) error {
return restoreFile(v.versionsFs, v.folderFs, filepath, versionTime, TagFilename)
}