syncthing/lib/versioner/trashcan.go
Jakob Borg 76af9ba53d 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 18:09:53 +02:00

176 lines
4.0 KiB
Go

// 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 http://mozilla.org/MPL/2.0/.
package versioner
import (
"fmt"
"os"
"path/filepath"
"strconv"
"time"
"github.com/syncthing/syncthing/lib/osutil"
)
func init() {
// Register the constructor for this type of versioner
Factories["trashcan"] = NewTrashcan
}
type Trashcan struct {
folderPath string
cleanoutDays int
stop chan struct{}
}
func NewTrashcan(folderID, folderPath string, params map[string]string) Versioner {
cleanoutDays, _ := strconv.Atoi(params["cleanoutDays"])
// On error we default to 0, "do not clean out the trash can"
s := &Trashcan{
folderPath: folderPath,
cleanoutDays: cleanoutDays,
stop: make(chan struct{}),
}
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 {
_, err := osutil.Lstat(filePath)
if os.IsNotExist(err) {
l.Debugln("not archiving nonexistent file", filePath)
return nil
} else if err != nil {
return err
}
versionsDir := filepath.Join(t.folderPath, ".stversions")
if _, err := os.Stat(versionsDir); err != nil {
if !os.IsNotExist(err) {
return err
}
l.Debugln("creating versions dir", versionsDir)
if err := osutil.MkdirAll(versionsDir, 0777); err != nil {
return err
}
osutil.HideFile(versionsDir)
}
l.Debugln("archiving", filePath)
relativePath, err := filepath.Rel(t.folderPath, filePath)
if err != nil {
return err
}
archivedPath := filepath.Join(versionsDir, relativePath)
if err := osutil.MkdirAll(filepath.Dir(archivedPath), 0777); err != nil && !os.IsExist(err) {
return err
}
l.Debugln("moving to", archivedPath)
if err := osutil.Rename(filePath, archivedPath); err != nil {
return err
}
// Set the mtime to the time the file was deleted. This is used by the
// cleanout routine. If this fails things won't work optimally but there's
// not much we can do about it so we ignore the error.
os.Chtimes(archivedPath, time.Now(), time.Now())
return nil
}
func (t *Trashcan) Serve() {
l.Debugln(t, "starting")
defer l.Debugln(t, "stopping")
// Do the first cleanup one minute after startup.
timer := time.NewTimer(time.Minute)
defer timer.Stop()
for {
select {
case <-t.stop:
return
case <-timer.C:
if t.cleanoutDays > 0 {
if err := t.cleanoutArchive(); err != nil {
l.Infoln("Cleaning trashcan:", err)
}
}
// Cleanups once a day should be enough.
timer.Reset(24 * time.Hour)
}
}
}
func (t *Trashcan) Stop() {
close(t.stop)
}
func (t *Trashcan) String() string {
return fmt.Sprintf("trashcan@%p", t)
}
func (t *Trashcan) cleanoutArchive() error {
versionsDir := filepath.Join(t.folderPath, ".stversions")
if _, err := osutil.Lstat(versionsDir); os.IsNotExist(err) {
return nil
}
cutoff := time.Now().Add(time.Duration(-24*t.cleanoutDays) * time.Hour)
currentDir := ""
filesInDir := 0
walkFn := func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.IsDir() {
// We have entered a new directory. Lets check if the previous
// directory was empty and try to remove it. We ignore failure for
// the time being.
if currentDir != "" && filesInDir == 0 {
osutil.Remove(currentDir)
}
currentDir = path
filesInDir = 0
return nil
}
if info.ModTime().Before(cutoff) {
// The file is too old; remove it.
osutil.Remove(path)
} else {
// Keep this file, and remember it so we don't unnecessarily try
// to remove this directory.
filesInDir++
}
return nil
}
if err := filepath.Walk(versionsDir, walkFn); err != nil {
return err
}
// The last directory seen by the walkFn may not have been removed as it
// should be.
if currentDir != "" && filesInDir == 0 {
osutil.Remove(currentDir)
}
return nil
}