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Refactor config commit stuff to support restartless updates better

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Includes restartless updates of the GUI settings (listening port etc) as
a proof of concept.
This commit is contained in:
Jakob Borg
2015-06-03 09:47:39 +02:00
parent ef6f52f688
commit 76ad925842
13 changed files with 412 additions and 116 deletions
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160
internal/config/wrapper.go
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@@ -17,17 +17,39 @@ import (
"github.com/syncthing/syncthing/internal/sync"
)
// An interface to handle configuration changes, and a wrapper type á la
// http.Handler
type Handler interface {
Changed(Configuration) error
// 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
// false will result in a "restart needed" respone 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
}
type HandlerFunc func(Configuration) error
type CommitResponse struct {
ValidationError error
RequiresRestart bool
}
func (fn HandlerFunc) Changed(cfg Configuration) error {
return fn(cfg)
var ResponseNoRestart = CommitResponse{
ValidationError: nil,
RequiresRestart: false,
}
// A wrapper around a Configuration that manages loads, saves and published
@@ -42,7 +64,7 @@ type Wrapper struct {
replaces chan Configuration
mut sync.Mutex
subs []Handler
subs []Committer
sMut sync.Mutex
}
@@ -56,7 +78,6 @@ func Wrap(path string, cfg Configuration) *Wrapper {
sMut: sync.NewMutex(),
}
w.replaces = make(chan Configuration)
go w.Serve()
return w
}
@@ -77,21 +98,6 @@ func Load(path string, myID protocol.DeviceID) (*Wrapper, error) {
return Wrap(path, cfg), nil
}
// Serve handles configuration replace events and calls any interested
// handlers. It is started automatically by Wrap() and Load() and should not
// be run manually.
func (w *Wrapper) Serve() {
for cfg := range w.replaces {
w.sMut.Lock()
subs := w.subs
w.sMut.Unlock()
for _, h := range subs {
h.Changed(cfg)
}
}
}
// Stop stops the Serve() loop. Set and Replace operations will panic after a
// Stop.
func (w *Wrapper) Stop() {
@@ -100,9 +106,9 @@ func (w *Wrapper) Stop() {
// Subscribe registers the given handler to be called on any future
// configuration changes.
func (w *Wrapper) Subscribe(h Handler) {
func (w *Wrapper) Subscribe(c Committer) {
w.sMut.Lock()
w.subs = append(w.subs, h)
w.subs = append(w.subs, c)
w.sMut.Unlock()
}
@@ -112,14 +118,50 @@ func (w *Wrapper) Raw() Configuration {
}
// Replace swaps the current configuration object for the given one.
func (w *Wrapper) Replace(cfg Configuration) {
func (w *Wrapper) Replace(cfg Configuration) CommitResponse {
w.mut.Lock()
defer w.mut.Unlock()
return w.replaceLocked(cfg)
}
w.cfg = cfg
func (w *Wrapper) replaceLocked(to Configuration) CommitResponse {
from := w.cfg
for _, sub := range w.subs {
if debug {
l.Debugln(sub, "verifying configuration")
}
if err := sub.VerifyConfiguration(from, to); err != nil {
if debug {
l.Debugln(sub, "rejected config:", err)
}
return CommitResponse{
ValidationError: err,
}
}
}
allOk := true
for _, sub := range w.subs {
if debug {
l.Debugln(sub, "committing configuration")
}
ok := sub.CommitConfiguration(from, to)
if !ok {
if debug {
l.Debugln(sub, "requires restart")
}
allOk = false
}
}
w.cfg = to
w.deviceMap = nil
w.folderMap = nil
w.replaces <- cfg.Copy()
return CommitResponse{
RequiresRestart: !allOk,
}
}
// Devices returns a map of devices. Device structures should not be changed,
@@ -138,22 +180,24 @@ func (w *Wrapper) Devices() map[protocol.DeviceID]DeviceConfiguration {
// SetDevice adds a new device to the configuration, or overwrites an existing
// device with the same ID.
func (w *Wrapper) SetDevice(dev DeviceConfiguration) {
func (w *Wrapper) SetDevice(dev DeviceConfiguration) CommitResponse {
w.mut.Lock()
defer w.mut.Unlock()
w.deviceMap = nil
for i := range w.cfg.Devices {
if w.cfg.Devices[i].DeviceID == dev.DeviceID {
w.cfg.Devices[i] = dev
w.replaces <- w.cfg.Copy()
return
newCfg := w.cfg.Copy()
replaced := false
for i := range newCfg.Devices {
if newCfg.Devices[i].DeviceID == dev.DeviceID {
newCfg.Devices[i] = dev
replaced = true
break
}
}
if !replaced {
newCfg.Devices = append(w.cfg.Devices, dev)
}
w.cfg.Devices = append(w.cfg.Devices, dev)
w.replaces <- w.cfg.Copy()
return w.replaceLocked(newCfg)
}
// Folders returns a map of folders. Folder structures should not be changed,
@@ -172,22 +216,24 @@ func (w *Wrapper) Folders() map[string]FolderConfiguration {
// SetFolder adds a new folder to the configuration, or overwrites an existing
// folder with the same ID.
func (w *Wrapper) SetFolder(fld FolderConfiguration) {
func (w *Wrapper) SetFolder(fld FolderConfiguration) CommitResponse {
w.mut.Lock()
defer w.mut.Unlock()
w.folderMap = nil
for i := range w.cfg.Folders {
if w.cfg.Folders[i].ID == fld.ID {
w.cfg.Folders[i] = fld
w.replaces <- w.cfg.Copy()
return
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)
}
w.cfg.Folders = append(w.cfg.Folders, fld)
w.replaces <- w.cfg.Copy()
return w.replaceLocked(newCfg)
}
// Options returns the current options configuration object.
@@ -198,11 +244,12 @@ func (w *Wrapper) Options() OptionsConfiguration {
}
// SetOptions replaces the current options configuration object.
func (w *Wrapper) SetOptions(opts OptionsConfiguration) {
func (w *Wrapper) SetOptions(opts OptionsConfiguration) CommitResponse {
w.mut.Lock()
defer w.mut.Unlock()
w.cfg.Options = opts
w.replaces <- w.cfg.Copy()
newCfg := w.cfg.Copy()
newCfg.Options = opts
return w.replaceLocked(newCfg)
}
// GUI returns the current GUI configuration object.
@@ -213,11 +260,12 @@ func (w *Wrapper) GUI() GUIConfiguration {
}
// SetGUI replaces the current GUI configuration object.
func (w *Wrapper) SetGUI(gui GUIConfiguration) {
func (w *Wrapper) SetGUI(gui GUIConfiguration) CommitResponse {
w.mut.Lock()
defer w.mut.Unlock()
w.cfg.GUI = gui
w.replaces <- w.cfg.Copy()
newCfg := w.cfg.Copy()
newCfg.GUI = gui
return w.replaceLocked(newCfg)
}
// IgnoredDevice returns whether or not connection attempts from the given