rclone/backend/union/union.go

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package union
import (
"fmt"
"io"
"path"
"path/filepath"
"strings"
"time"
"github.com/ncw/rclone/fs"
"github.com/ncw/rclone/fs/config/configmap"
"github.com/ncw/rclone/fs/config/configstruct"
"github.com/ncw/rclone/fs/hash"
"github.com/pkg/errors"
)
// Register with Fs
func init() {
fsi := &fs.RegInfo{
Name: "union",
Description: "A stackable unification remote, which can appear to merge the contents of several remotes",
NewFs: NewFs,
Options: []fs.Option{{
Name: "remotes",
Help: "List of space separated remotes.\nCan be 'remotea:test/dir remoteb:', '\"remotea:test/space dir\" remoteb:', etc.\nThe last remote is used to write to.",
Required: true,
}},
}
fs.Register(fsi)
}
// Options defines the configuration for this backend
type Options struct {
Remotes fs.SpaceSepList `config:"remotes"`
}
// Fs represents a union of remotes
type Fs struct {
name string // name of this remote
features *fs.Features // optional features
opt Options // options for this Fs
root string // the path we are working on
remotes []fs.Fs // slice of remotes
wr fs.Fs // writable remote
hashSet hash.Set // intersection of hash types
}
// Object describes a union Object
//
// This is a wrapped object which returns the Union Fs as its parent
type Object struct {
fs.Object
fs *Fs // what this object is part of
}
// Wrap an existing object in the union Object
func (f *Fs) wrapObject(o fs.Object) *Object {
return &Object{
Object: o,
fs: f,
}
}
// Fs returns the union Fs as the parent
func (o *Object) Fs() fs.Info {
return o.fs
}
// Name of the remote (as passed into NewFs)
func (f *Fs) Name() string {
return f.name
}
// Root of the remote (as passed into NewFs)
func (f *Fs) Root() string {
return f.root
}
// String converts this Fs to a string
func (f *Fs) String() string {
return fmt.Sprintf("union root '%s'", f.root)
}
// Features returns the optional features of this Fs
func (f *Fs) Features() *fs.Features {
return f.features
}
// Rmdir removes the root directory of the Fs object
func (f *Fs) Rmdir(dir string) error {
return f.wr.Rmdir(dir)
}
// Hashes returns hash.HashNone to indicate remote hashing is unavailable
func (f *Fs) Hashes() hash.Set {
return f.hashSet
}
// Mkdir makes the root directory of the Fs object
func (f *Fs) Mkdir(dir string) error {
return f.wr.Mkdir(dir)
}
// Purge all files in the root and the root directory
//
// Implement this if you have a way of deleting all the files
// quicker than just running Remove() on the result of List()
//
// Return an error if it doesn't exist
func (f *Fs) Purge() error {
return f.wr.Features().Purge()
}
// Copy src to this remote using server side copy operations.
//
// This is stored with the remote path given
//
// It returns the destination Object and a possible error
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantCopy
func (f *Fs) Copy(src fs.Object, remote string) (fs.Object, error) {
if src.Fs() != f.wr {
fs.Debugf(src, "Can't copy - not same remote type")
return nil, fs.ErrorCantCopy
}
o, err := f.wr.Features().Copy(src, remote)
if err != nil {
return nil, err
}
return f.wrapObject(o), nil
}
// Move src to this remote using server side move operations.
//
// This is stored with the remote path given
//
// It returns the destination Object and a possible error
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantMove
func (f *Fs) Move(src fs.Object, remote string) (fs.Object, error) {
if src.Fs() != f.wr {
fs.Debugf(src, "Can't move - not same remote type")
return nil, fs.ErrorCantMove
}
o, err := f.wr.Features().Move(src, remote)
if err != nil {
return nil, err
}
return f.wrapObject(o), err
}
// DirMove moves src, srcRemote to this remote at dstRemote
// using server side move operations.
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantDirMove
//
// If destination exists then return fs.ErrorDirExists
func (f *Fs) DirMove(src fs.Fs, srcRemote, dstRemote string) error {
srcFs, ok := src.(*Fs)
if !ok {
fs.Debugf(srcFs, "Can't move directory - not same remote type")
return fs.ErrorCantDirMove
}
return f.wr.Features().DirMove(srcFs.wr, srcRemote, dstRemote)
}
// ChangeNotify calls the passed function with a path
// that has had changes. If the implementation
// uses polling, it should adhere to the given interval.
// At least one value will be written to the channel,
// specifying the initial value and updated values might
// follow. A 0 Duration should pause the polling.
2019-02-07 18:41:17 +01:00
// The ChangeNotify implementation must empty the channel
// regularly. When the channel gets closed, the implementation
// should stop polling and release resources.
func (f *Fs) ChangeNotify(fn func(string, fs.EntryType), ch <-chan time.Duration) {
var remoteChans []chan time.Duration
for _, remote := range f.remotes {
if ChangeNotify := remote.Features().ChangeNotify; ChangeNotify != nil {
ch := make(chan time.Duration)
remoteChans = append(remoteChans, ch)
ChangeNotify(fn, ch)
}
}
go func() {
for i := range ch {
for _, c := range remoteChans {
c <- i
}
}
for _, c := range remoteChans {
close(c)
}
}()
}
// DirCacheFlush resets the directory cache - used in testing
// as an optional interface
func (f *Fs) DirCacheFlush() {
for _, remote := range f.remotes {
if DirCacheFlush := remote.Features().DirCacheFlush; DirCacheFlush != nil {
DirCacheFlush()
}
}
}
// PutStream uploads to the remote path with the modTime given of indeterminate size
//
// May create the object even if it returns an error - if so
// will return the object and the error, otherwise will return
// nil and the error
func (f *Fs) PutStream(in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
o, err := f.wr.Features().PutStream(in, src, options...)
if err != nil {
return nil, err
}
return f.wrapObject(o), err
}
// About gets quota information from the Fs
func (f *Fs) About() (*fs.Usage, error) {
return f.wr.Features().About()
}
// Put in to the remote path with the modTime given of the given size
//
// May create the object even if it returns an error - if so
// will return the object and the error, otherwise will return
// nil and the error
func (f *Fs) Put(in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
o, err := f.wr.Put(in, src, options...)
if err != nil {
return nil, err
}
return f.wrapObject(o), err
}
// List the objects and directories in dir into entries. The
// entries can be returned in any order but should be for a
// complete directory.
//
// dir should be "" to list the root, and should not have
// trailing slashes.
//
// This should return ErrDirNotFound if the directory isn't
// found.
func (f *Fs) List(dir string) (entries fs.DirEntries, err error) {
set := make(map[string]fs.DirEntry)
found := false
for _, remote := range f.remotes {
var remoteEntries, err = remote.List(dir)
if err == fs.ErrorDirNotFound {
continue
}
if err != nil {
return nil, errors.Wrapf(err, "List failed on %v", remote)
}
found = true
for _, remoteEntry := range remoteEntries {
set[remoteEntry.Remote()] = remoteEntry
}
}
if !found {
return nil, fs.ErrorDirNotFound
}
for _, entry := range set {
if o, ok := entry.(fs.Object); ok {
entry = f.wrapObject(o)
}
entries = append(entries, entry)
}
return entries, nil
}
// NewObject creates a new remote union file object based on the first Object it finds (reverse remote order)
func (f *Fs) NewObject(path string) (fs.Object, error) {
for i := range f.remotes {
var remote = f.remotes[len(f.remotes)-i-1]
var obj, err = remote.NewObject(path)
if err == fs.ErrorObjectNotFound {
continue
}
if err != nil {
return nil, errors.Wrapf(err, "NewObject failed on %v", remote)
}
return f.wrapObject(obj), nil
}
return nil, fs.ErrorObjectNotFound
}
// Precision is the greatest Precision of all remotes
func (f *Fs) Precision() time.Duration {
var greatestPrecision time.Duration
for _, remote := range f.remotes {
if remote.Precision() > greatestPrecision {
greatestPrecision = remote.Precision()
}
}
return greatestPrecision
}
// NewFs constructs an Fs from the path.
//
// The returned Fs is the actual Fs, referenced by remote in the config
func NewFs(name, root string, m configmap.Mapper) (fs.Fs, error) {
// Parse config into Options struct
opt := new(Options)
err := configstruct.Set(m, opt)
if err != nil {
return nil, err
}
if len(opt.Remotes) == 0 {
return nil, errors.New("union can't point to an empty remote - check the value of the remotes setting")
}
if len(opt.Remotes) == 1 {
return nil, errors.New("union can't point to a single remote - check the value of the remotes setting")
}
for _, remote := range opt.Remotes {
if strings.HasPrefix(remote, name+":") {
return nil, errors.New("can't point union remote at itself - check the value of the remote setting")
}
}
var remotes []fs.Fs
for i := range opt.Remotes {
// Last remote first so we return the correct (last) matching fs in case of fs.ErrorIsFile
var remote = opt.Remotes[len(opt.Remotes)-i-1]
_, configName, fsPath, err := fs.ParseRemote(remote)
if err != nil {
return nil, err
}
var rootString = path.Join(fsPath, filepath.ToSlash(root))
if configName != "local" {
rootString = configName + ":" + rootString
}
myFs, err := fs.NewFs(rootString)
if err != nil {
if err == fs.ErrorIsFile {
return myFs, err
}
return nil, err
}
remotes = append(remotes, myFs)
}
// Reverse the remotes again so they are in the order as before
for i, j := 0, len(remotes)-1; i < j; i, j = i+1, j-1 {
remotes[i], remotes[j] = remotes[j], remotes[i]
}
f := &Fs{
name: name,
root: root,
opt: *opt,
remotes: remotes,
wr: remotes[len(remotes)-1],
}
var features = (&fs.Features{
CaseInsensitive: true,
DuplicateFiles: false,
ReadMimeType: true,
WriteMimeType: true,
CanHaveEmptyDirectories: true,
BucketBased: true,
SetTier: true,
GetTier: true,
}).Fill(f)
features = features.Mask(f.wr) // mask the features just on the writable fs
// Really need the union of all remotes for these, so
// re-instate and calculate separately.
features.ChangeNotify = f.ChangeNotify
features.DirCacheFlush = f.DirCacheFlush
// FIXME maybe should be masking the bools here?
// Clear ChangeNotify and DirCacheFlush if all are nil
clearChangeNotify := true
clearDirCacheFlush := true
for _, remote := range f.remotes {
remoteFeatures := remote.Features()
if remoteFeatures.ChangeNotify != nil {
clearChangeNotify = false
}
if remoteFeatures.DirCacheFlush != nil {
clearDirCacheFlush = false
}
}
if clearChangeNotify {
features.ChangeNotify = nil
}
if clearDirCacheFlush {
features.DirCacheFlush = nil
}
f.features = features
// Get common intersection of hashes
hashSet := f.remotes[0].Hashes()
for _, remote := range f.remotes[1:] {
hashSet = hashSet.Overlap(remote.Hashes())
}
f.hashSet = hashSet
return f, nil
}
// Check the interfaces are satisfied
var (
_ fs.Fs = (*Fs)(nil)
_ fs.Purger = (*Fs)(nil)
_ fs.PutStreamer = (*Fs)(nil)
_ fs.Copier = (*Fs)(nil)
_ fs.Mover = (*Fs)(nil)
_ fs.DirMover = (*Fs)(nil)
_ fs.DirCacheFlusher = (*Fs)(nil)
_ fs.ChangeNotifier = (*Fs)(nil)
_ fs.Abouter = (*Fs)(nil)
)