syncthing/lib/config/wrapper.go

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// Copyright (C) 2014 The Syncthing Authors.
//
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// 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 config
import (
"os"
"path/filepath"
"sync/atomic"
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"github.com/syncthing/syncthing/lib/events"
"github.com/syncthing/syncthing/lib/fs"
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"github.com/syncthing/syncthing/lib/osutil"
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"github.com/syncthing/syncthing/lib/protocol"
"github.com/syncthing/syncthing/lib/rand"
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"github.com/syncthing/syncthing/lib/sync"
"github.com/syncthing/syncthing/lib/util"
)
// The Committer interface is implemented by objects that need to know about
// or have a say in configuration changes.
//
// When the configuration is about to be changed, VerifyConfiguration() is
// called for each subscribing object, with the old and new configuration. A
// nil error is returned if the new configuration is acceptable (i.e. does not
// contain any errors that would prevent it from being a valid config).
// Otherwise an error describing the problem is returned.
//
// If any subscriber returns an error from VerifyConfiguration(), the
// configuration change is not committed and an error is returned to whoever
// tried to commit the broken config.
//
// If all verification calls returns nil, CommitConfiguration() is called for
// each subscribing object. The callee returns true if the new configuration
// has been successfully applied, otherwise false. Any Commit() call returning
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// false will result in a "restart needed" response to the API/user. Note that
// the new configuration will still have been applied by those who were
// capable of doing so.
type Committer interface {
VerifyConfiguration(from, to Configuration) error
CommitConfiguration(from, to Configuration) (handled bool)
String() string
}
// A wrapper around a Configuration that manages loads, saves and published
// notifications of changes to registered Handlers
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type Wrapper struct {
cfg Configuration
path string
deviceMap map[protocol.DeviceID]DeviceConfiguration
folderMap map[string]FolderConfiguration
replaces chan Configuration
subs []Committer
mut sync.Mutex
requiresRestart uint32 // an atomic bool
}
// Wrap wraps an existing Configuration structure and ties it to a file on
// disk.
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func Wrap(path string, cfg Configuration) *Wrapper {
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w := &Wrapper{
cfg: cfg,
path: path,
mut: sync.NewMutex(),
}
w.replaces = make(chan Configuration)
return w
}
// Load loads an existing file on disk and returns a new configuration
// wrapper.
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func Load(path string, myID protocol.DeviceID) (*Wrapper, error) {
fd, err := os.Open(path)
if err != nil {
return nil, err
}
defer fd.Close()
cfg, err := ReadXML(fd, myID)
if err != nil {
return nil, err
}
return Wrap(path, cfg), nil
}
func (w *Wrapper) ConfigPath() string {
return w.path
}
// Stop stops the Serve() loop. Set and Replace operations will panic after a
// Stop.
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func (w *Wrapper) Stop() {
close(w.replaces)
}
// Subscribe registers the given handler to be called on any future
// configuration changes.
func (w *Wrapper) Subscribe(c Committer) {
w.mut.Lock()
w.subs = append(w.subs, c)
w.mut.Unlock()
}
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// Unsubscribe de-registers the given handler from any future calls to
// configuration changes
func (w *Wrapper) Unsubscribe(c Committer) {
w.mut.Lock()
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for i := range w.subs {
if w.subs[i] == c {
copy(w.subs[i:], w.subs[i+1:])
w.subs[len(w.subs)-1] = nil
w.subs = w.subs[:len(w.subs)-1]
break
}
}
w.mut.Unlock()
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}
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// RawCopy returns a copy of the currently wrapped Configuration object.
func (w *Wrapper) RawCopy() Configuration {
w.mut.Lock()
defer w.mut.Unlock()
return w.cfg.Copy()
}
// ReplaceBlocking swaps the current configuration object for the given one,
// and waits for subscribers to be notified.
func (w *Wrapper) ReplaceBlocking(cfg Configuration) error {
w.mut.Lock()
wg := sync.NewWaitGroup()
err := w.replaceLocked(cfg, wg)
w.mut.Unlock()
wg.Wait()
return err
}
// Replace swaps the current configuration object for the given one.
func (w *Wrapper) Replace(cfg Configuration) error {
w.mut.Lock()
defer w.mut.Unlock()
return w.replaceLocked(cfg, nil)
}
func (w *Wrapper) replaceLocked(to Configuration, wg sync.WaitGroup) error {
from := w.cfg
if err := to.clean(); err != nil {
return err
}
for _, sub := range w.subs {
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.
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l.Debugln(sub, "verifying configuration")
if err := sub.VerifyConfiguration(from, to); err != nil {
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.
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l.Debugln(sub, "rejected config:", err)
return err
}
}
w.cfg = to
w.deviceMap = nil
w.folderMap = nil
w.notifyListeners(from, to, wg)
return nil
}
func (w *Wrapper) notifyListeners(from, to Configuration, wg sync.WaitGroup) {
if wg != nil {
wg.Add(len(w.subs))
}
for _, sub := range w.subs {
go func(commiter Committer) {
w.notifyListener(commiter, from.Copy(), to.Copy())
if wg != nil {
wg.Done()
}
}(sub)
}
}
func (w *Wrapper) notifyListener(sub Committer, from, to Configuration) {
l.Debugln(sub, "committing configuration")
if !sub.CommitConfiguration(from, to) {
l.Debugln(sub, "requires restart")
w.setRequiresRestart()
}
}
// Devices returns a map of devices. Device structures should not be changed,
// other than for the purpose of updating via SetDevice().
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func (w *Wrapper) Devices() map[protocol.DeviceID]DeviceConfiguration {
w.mut.Lock()
defer w.mut.Unlock()
if w.deviceMap == nil {
w.deviceMap = make(map[protocol.DeviceID]DeviceConfiguration, len(w.cfg.Devices))
for _, dev := range w.cfg.Devices {
w.deviceMap[dev.DeviceID] = dev
}
}
return w.deviceMap
}
// SetDevices adds new devices to the configuration, or overwrites existing
// devices with the same ID.
func (w *Wrapper) SetDevices(devs []DeviceConfiguration) error {
w.mut.Lock()
defer w.mut.Unlock()
newCfg := w.cfg.Copy()
var replaced bool
for oldIndex := range devs {
replaced = false
for newIndex := range newCfg.Devices {
if newCfg.Devices[newIndex].DeviceID == devs[oldIndex].DeviceID {
newCfg.Devices[newIndex] = devs[oldIndex]
replaced = true
break
}
}
if !replaced {
newCfg.Devices = append(newCfg.Devices, devs[oldIndex])
}
}
return w.replaceLocked(newCfg, nil)
}
// SetDevice adds a new device to the configuration, or overwrites an existing
// device with the same ID.
func (w *Wrapper) SetDevice(dev DeviceConfiguration) error {
return w.SetDevices([]DeviceConfiguration{dev})
}
// RemoveDevice removes the device from the configuration
func (w *Wrapper) RemoveDevice(id protocol.DeviceID) error {
w.mut.Lock()
defer w.mut.Unlock()
newCfg := w.cfg.Copy()
removed := false
for i := range newCfg.Devices {
if newCfg.Devices[i].DeviceID == id {
newCfg.Devices = append(newCfg.Devices[:i], newCfg.Devices[i+1:]...)
removed = true
break
}
}
if !removed {
return nil
}
return w.replaceLocked(newCfg, nil)
}
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// Folders returns a map of folders. Folder structures should not be changed,
// other than for the purpose of updating via SetFolder().
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func (w *Wrapper) Folders() map[string]FolderConfiguration {
w.mut.Lock()
defer w.mut.Unlock()
if w.folderMap == nil {
w.folderMap = make(map[string]FolderConfiguration, len(w.cfg.Folders))
for _, fld := range w.cfg.Folders {
w.folderMap[fld.ID] = fld
}
}
return w.folderMap
}
// SetFolder adds a new folder to the configuration, or overwrites an existing
// folder with the same ID.
func (w *Wrapper) SetFolder(fld FolderConfiguration) error {
w.mut.Lock()
defer w.mut.Unlock()
newCfg := w.cfg.Copy()
replaced := false
for i := range newCfg.Folders {
if newCfg.Folders[i].ID == fld.ID {
newCfg.Folders[i] = fld
replaced = true
break
}
}
if !replaced {
newCfg.Folders = append(w.cfg.Folders, fld)
}
return w.replaceLocked(newCfg, nil)
}
// Options returns the current options configuration object.
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func (w *Wrapper) Options() OptionsConfiguration {
w.mut.Lock()
defer w.mut.Unlock()
return w.cfg.Options
}
// SetOptions replaces the current options configuration object.
func (w *Wrapper) SetOptions(opts OptionsConfiguration) error {
w.mut.Lock()
defer w.mut.Unlock()
newCfg := w.cfg.Copy()
newCfg.Options = opts
return w.replaceLocked(newCfg, nil)
}
// GUI returns the current GUI configuration object.
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func (w *Wrapper) GUI() GUIConfiguration {
w.mut.Lock()
defer w.mut.Unlock()
return w.cfg.GUI
}
// SetGUI replaces the current GUI configuration object.
func (w *Wrapper) SetGUI(gui GUIConfiguration) error {
w.mut.Lock()
defer w.mut.Unlock()
newCfg := w.cfg.Copy()
newCfg.GUI = gui
return w.replaceLocked(newCfg, nil)
}
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// IgnoredDevice returns whether or not connection attempts from the given
// device should be silently ignored.
func (w *Wrapper) IgnoredDevice(id protocol.DeviceID) bool {
w.mut.Lock()
defer w.mut.Unlock()
for _, device := range w.cfg.IgnoredDevices {
if device == id {
return true
}
}
return false
}
// IgnoredFolder returns whether or not share attempts for the given
// folder should be silently ignored.
func (w *Wrapper) IgnoredFolder(folder string) bool {
w.mut.Lock()
defer w.mut.Unlock()
for _, nfolder := range w.cfg.IgnoredFolders {
if folder == nfolder {
return true
}
}
return false
}
// Device returns the configuration for the given device and an "ok" bool.
func (w *Wrapper) Device(id protocol.DeviceID) (DeviceConfiguration, bool) {
w.mut.Lock()
defer w.mut.Unlock()
for _, device := range w.cfg.Devices {
if device.DeviceID == id {
return device, true
}
}
return DeviceConfiguration{}, false
}
// Folder returns the configuration for the given folder and an "ok" bool.
func (w *Wrapper) Folder(id string) (FolderConfiguration, bool) {
w.mut.Lock()
defer w.mut.Unlock()
for _, folder := range w.cfg.Folders {
if folder.ID == id {
return folder, true
}
}
return FolderConfiguration{}, false
}
// Save writes the configuration to disk, and generates a ConfigSaved event.
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func (w *Wrapper) Save() error {
fd, err := osutil.CreateAtomic(w.path)
if err != nil {
l.Debugln("CreateAtomic:", err)
return err
}
if err := w.cfg.WriteXML(fd); err != nil {
l.Debugln("WriteXML:", err)
fd.Close()
return err
}
if err := fd.Close(); err != nil {
l.Debugln("Close:", err)
return err
}
events.Default.Log(events.ConfigSaved, w.cfg)
return nil
}
func (w *Wrapper) GlobalDiscoveryServers() []string {
var servers []string
for _, srv := range w.cfg.Options.GlobalAnnServers {
switch srv {
case "default":
servers = append(servers, DefaultDiscoveryServers...)
case "default-v4":
servers = append(servers, DefaultDiscoveryServersV4...)
case "default-v6":
servers = append(servers, DefaultDiscoveryServersV6...)
default:
servers = append(servers, srv)
}
}
return util.UniqueStrings(servers)
}
func (w *Wrapper) ListenAddresses() []string {
var addresses []string
for _, addr := range w.cfg.Options.ListenAddresses {
switch addr {
case "default":
addresses = append(addresses, DefaultListenAddresses...)
default:
addresses = append(addresses, addr)
}
}
return util.UniqueStrings(addresses)
}
func (w *Wrapper) RequiresRestart() bool {
return atomic.LoadUint32(&w.requiresRestart) != 0
}
func (w *Wrapper) setRequiresRestart() {
atomic.StoreUint32(&w.requiresRestart, 1)
}
func (w *Wrapper) StunServers() []string {
var addresses []string
for _, addr := range w.cfg.Options.StunServers {
switch addr {
case "default":
addresses = append(addresses, DefaultStunServers...)
default:
addresses = append(addresses, addr)
}
}
addresses = util.UniqueStrings(addresses)
// Shuffle
l := len(addresses)
for i := range addresses {
r := rand.Intn(l)
addresses[i], addresses[r] = addresses[r], addresses[i]
}
return addresses
}
func (w *Wrapper) MyName() string {
w.mut.Lock()
myID := w.cfg.MyID
w.mut.Unlock()
cfg, _ := w.Device(myID)
return cfg.Name
}
// CheckHomeFreeSpace returns nil if the home disk has the required amount of
// free space, or if home disk free space checking is disabled.
func (w *Wrapper) CheckHomeFreeSpace() error {
return checkFreeSpace(w.Options().MinHomeDiskFree, fs.NewFilesystem(fs.FilesystemTypeBasic, filepath.Dir(w.ConfigPath())))
}