syncthing/versioner/staggered.go
2014-08-28 21:35:55 +02:00

310 lines
7.0 KiB
Go

// Copyright (C) 2014 Jakob Borg and Contributors (see the CONTRIBUTORS file).
// All rights reserved. Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.
package versioner
import (
"fmt"
"os"
"path/filepath"
"sort"
"strconv"
"strings"
"sync"
"time"
"github.com/syncthing/syncthing/osutil"
)
func init() {
// Register the constructor for this type of versioner with the name "staggered"
Factories["staggered"] = NewStaggered
}
type Interval struct {
step int64
end int64
}
// The type holds our configuration
type Staggered struct {
versionsPath string
cleanInterval int64
repoPath string
interval [4]Interval
mutex *sync.Mutex
}
// Check if file or dir
func isFile(path string) bool {
fileInfo, err := os.Stat(path)
if err != nil {
l.Infoln("versioner isFile:", err)
return false
}
return fileInfo.Mode().IsRegular()
}
// The constructor function takes a map of parameters and creates the type.
func NewStaggered(repoID, repoPath string, 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
}
// Use custom path if set, otherwise .stversions in repoPath
var versionsDir string
if params["versionsPath"] == "" {
if debug {
l.Debugln("using default dir .stversions")
}
versionsDir = filepath.Join(repoPath, ".stversions")
} else {
if debug {
l.Debugln("using dir", params["versionsPath"])
}
versionsDir = params["versionsPath"]
}
var mutex sync.Mutex
s := Staggered{
versionsPath: versionsDir,
cleanInterval: cleanInterval,
repoPath: repoPath,
interval: [4]Interval{
Interval{30, 3600}, // first hour -> 30 sec between versions
Interval{3600, 86400}, // next day -> 1 h between versions
Interval{86400, 592000}, // next 30 days -> 1 day between versions
Interval{604800, maxAge * 86400}, // next year -> 1 week between versions
},
mutex: &mutex,
}
if debug {
l.Debugf("instantiated %#v", s)
}
go func() {
s.clean()
for _ = range time.Tick(time.Duration(cleanInterval) * time.Second) {
s.clean()
}
}()
return s
}
func (v Staggered) clean() {
if debug {
l.Debugln("Versioner clean: Waiting for lock on", v.versionsPath)
}
v.mutex.Lock()
defer v.mutex.Unlock()
if debug {
l.Debugln("Versioner clean: Cleaning", v.versionsPath)
}
_, err := os.Stat(v.versionsPath)
if err != nil {
if os.IsNotExist(err) {
if debug {
l.Debugln("creating versions dir", v.versionsPath)
}
os.MkdirAll(v.versionsPath, 0755)
osutil.HideFile(v.versionsPath)
} else {
l.Warnln("Versioner: can't create versions dir", err)
}
}
versionsPerFile := make(map[string][]string)
filesPerDir := make(map[string]int)
err = filepath.Walk(v.versionsPath, func(path string, f os.FileInfo, err error) error {
switch mode := f.Mode(); {
case mode.IsDir():
filesPerDir[path] = 0
case mode.IsRegular():
extension := filepath.Ext(path)
dir := filepath.Dir(path)
name := path[:len(path)-len(extension)]
filesPerDir[dir]++
versionsPerFile[name] = append(versionsPerFile[name], path)
}
return nil
})
if err != nil {
l.Warnln("Versioner: error scanning versions dir", err)
return
}
for _, versionList := range versionsPerFile {
// List from filepath.Walk is sorted
v.expire(versionList)
}
for path, numFiles := range filesPerDir {
if path == v.versionsPath {
if debug {
l.Debugln("Cleaner: versions dir is empty, don't delete", path)
}
continue
}
if numFiles > 0 {
continue
}
if debug {
l.Debugln("Cleaner: deleting empty directory", path)
}
err = os.Remove(path)
if err != nil {
l.Warnln("Versioner: can't remove directory", path, err)
}
}
if debug {
l.Debugln("Cleaner: Finished cleaning", v.versionsPath)
}
}
func (v Staggered) expire(versions []string) {
if debug {
l.Debugln("Versioner: Expiring versions", versions)
}
now := time.Now().Unix()
var prevAge int64
firstFile := true
for _, file := range versions {
if isFile(file) {
versiondate, err := strconv.ParseInt(strings.Replace(filepath.Ext(file), ".v", "", 1), 10, 0)
if err != nil {
l.Infof("Versioner: file name %q is invalid: %v", file, err)
continue
}
age := now - versiondate
// 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 {
if debug {
l.Debugln("Versioner: File over maximum age -> delete ", file)
}
err = os.Remove(file)
if err != nil {
l.Warnf("Versioner: can't remove %q: %v", file, err)
}
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 {
if debug {
l.Debugln("too many files in step -> delete", file)
}
err = os.Remove(file)
if err != nil {
l.Warnf("Versioner: can't remove %q: %v", file, err)
}
continue
}
prevAge = age
} else {
l.Infof("non-file %q is named like a file version", file)
}
}
}
// Move away the named file 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 {
if debug {
l.Debugln("Waiting for lock on ", v.versionsPath)
}
v.mutex.Lock()
defer v.mutex.Unlock()
_, err := os.Stat(filePath)
if err != nil {
if os.IsNotExist(err) {
if debug {
l.Debugln("not archiving nonexistent file", filePath)
}
return nil
} else {
return err
}
}
_, err = os.Stat(v.versionsPath)
if err != nil {
if os.IsNotExist(err) {
if debug {
l.Debugln("creating versions dir", v.versionsPath)
}
os.MkdirAll(v.versionsPath, 0755)
osutil.HideFile(v.versionsPath)
} else {
return err
}
}
if debug {
l.Debugln("archiving", filePath)
}
file := filepath.Base(filePath)
inRepoPath, err := filepath.Rel(v.repoPath, filepath.Dir(filePath))
if err != nil {
return err
}
dir := filepath.Join(v.versionsPath, inRepoPath)
err = os.MkdirAll(dir, 0755)
if err != nil && !os.IsExist(err) {
return err
}
ver := file + ".v" + fmt.Sprintf("%010d", time.Now().Unix())
dst := filepath.Join(dir, ver)
if debug {
l.Debugln("moving to", dst)
}
err = osutil.Rename(filePath, dst)
if err != nil {
return err
}
versions, err := filepath.Glob(filepath.Join(dir, file+".v[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]"))
if err != nil {
l.Warnln("Versioner: error finding versions for", file, err)
return nil
}
sort.Strings(versions)
v.expire(versions)
return nil
}