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/*
* Copyright (c) 2013 IBM Corp.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Seth Hoenig
* Allan Stockdill-Mander
* Mike Robertson
*/
package mqtt
import (
"io/ioutil"
"os"
"path"
"sort"
"sync"
"github.com/eclipse/paho.mqtt.golang/packets"
)
const (
msgExt = ".msg"
tmpExt = ".tmp"
corruptExt = ".CORRUPT"
)
// FileStore implements the store interface using the filesystem to provide
// true persistence, even across client failure. This is designed to use a
// single directory per running client. If you are running multiple clients
// on the same filesystem, you will need to be careful to specify unique
// store directories for each.
type FileStore struct {
sync.RWMutex
directory string
opened bool
}
// NewFileStore will create a new FileStore which stores its messages in the
// directory provided.
func NewFileStore(directory string) *FileStore {
store := &FileStore{
directory: directory,
opened: false,
}
return store
}
// Open will allow the FileStore to be used.
func (store *FileStore) Open() {
store.Lock()
defer store.Unlock()
// if no store directory was specified in ClientOpts, by default use the
// current working directory
if store.directory == "" {
store.directory, _ = os.Getwd()
}
// if store dir exists, great, otherwise, create it
if !exists(store.directory) {
perms := os.FileMode(0770)
merr := os.MkdirAll(store.directory, perms)
chkerr(merr)
}
store.opened = true
DEBUG.Println(STR, "store is opened at", store.directory)
}
// Close will disallow the FileStore from being used.
func (store *FileStore) Close() {
store.Lock()
defer store.Unlock()
store.opened = false
DEBUG.Println(STR, "store is closed")
}
// Put will put a message into the store, associated with the provided
// key value.
func (store *FileStore) Put(key string, m packets.ControlPacket) {
store.Lock()
defer store.Unlock()
if !store.opened {
ERROR.Println(STR, "Trying to use file store, but not open")
return
}
full := fullpath(store.directory, key)
write(store.directory, key, m)
if !exists(full) {
ERROR.Println(STR, "file not created:", full)
}
}
// Get will retrieve a message from the store, the one associated with
// the provided key value.
func (store *FileStore) Get(key string) packets.ControlPacket {
store.RLock()
defer store.RUnlock()
if !store.opened {
ERROR.Println(STR, "Trying to use file store, but not open")
return nil
}
filepath := fullpath(store.directory, key)
if !exists(filepath) {
return nil
}
mfile, oerr := os.Open(filepath)
chkerr(oerr)
msg, rerr := packets.ReadPacket(mfile)
chkerr(mfile.Close())
// Message was unreadable, return nil
if rerr != nil {
newpath := corruptpath(store.directory, key)
WARN.Println(STR, "corrupted file detected:", rerr.Error(), "archived at:", newpath)
os.Rename(filepath, newpath)
return nil
}
return msg
}
// All will provide a list of all of the keys associated with messages
// currently residing in the FileStore.
func (store *FileStore) All() []string {
store.RLock()
defer store.RUnlock()
return store.all()
}
// Del will remove the persisted message associated with the provided
// key from the FileStore.
func (store *FileStore) Del(key string) {
store.Lock()
defer store.Unlock()
store.del(key)
}
// Reset will remove all persisted messages from the FileStore.
func (store *FileStore) Reset() {
store.Lock()
defer store.Unlock()
WARN.Println(STR, "FileStore Reset")
for _, key := range store.all() {
store.del(key)
}
}
// lockless
func (store *FileStore) all() []string {
var err error
var keys []string
var files fileInfos
if !store.opened {
ERROR.Println(STR, "Trying to use file store, but not open")
return nil
}
files, err = ioutil.ReadDir(store.directory)
chkerr(err)
sort.Sort(files)
for _, f := range files {
DEBUG.Println(STR, "file in All():", f.Name())
name := f.Name()
if name[len(name)-4:] != msgExt {
DEBUG.Println(STR, "skipping file, doesn't have right extension: ", name)
continue
}
key := name[0 : len(name)-4] // remove file extension
keys = append(keys, key)
}
return keys
}
// lockless
func (store *FileStore) del(key string) {
if !store.opened {
ERROR.Println(STR, "Trying to use file store, but not open")
return
}
DEBUG.Println(STR, "store del filepath:", store.directory)
DEBUG.Println(STR, "store delete key:", key)
filepath := fullpath(store.directory, key)
DEBUG.Println(STR, "path of deletion:", filepath)
if !exists(filepath) {
WARN.Println(STR, "store could not delete key:", key)
return
}
rerr := os.Remove(filepath)
chkerr(rerr)
DEBUG.Println(STR, "del msg:", key)
if exists(filepath) {
ERROR.Println(STR, "file not deleted:", filepath)
}
}
func fullpath(store string, key string) string {
p := path.Join(store, key+msgExt)
return p
}
func tmppath(store string, key string) string {
p := path.Join(store, key+tmpExt)
return p
}
func corruptpath(store string, key string) string {
p := path.Join(store, key+corruptExt)
return p
}
// create file called "X.[messageid].tmp" located in the store
// the contents of the file is the bytes of the message, then
// rename it to "X.[messageid].msg", overwriting any existing
// message with the same id
// X will be 'i' for inbound messages, and O for outbound messages
func write(store, key string, m packets.ControlPacket) {
temppath := tmppath(store, key)
f, err := os.Create(temppath)
chkerr(err)
werr := m.Write(f)
chkerr(werr)
cerr := f.Close()
chkerr(cerr)
rerr := os.Rename(temppath, fullpath(store, key))
chkerr(rerr)
}
func exists(file string) bool {
if _, err := os.Stat(file); err != nil {
if os.IsNotExist(err) {
return false
}
chkerr(err)
}
return true
}
type fileInfos []os.FileInfo
func (f fileInfos) Len() int {
return len(f)
}
func (f fileInfos) Swap(i, j int) {
f[i], f[j] = f[j], f[i]
}
func (f fileInfos) Less(i, j int) bool {
return f[i].ModTime().Before(f[j].ModTime())
}
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