227 lines
6 KiB
Go
227 lines
6 KiB
Go
package union
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import (
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"fmt"
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"io"
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"path"
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"path/filepath"
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"strings"
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"time"
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"github.com/ncw/rclone/fs"
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"github.com/ncw/rclone/fs/config/configmap"
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"github.com/ncw/rclone/fs/config/configstruct"
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"github.com/ncw/rclone/fs/hash"
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"github.com/pkg/errors"
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)
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// Register with Fs
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func init() {
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fsi := &fs.RegInfo{
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Name: "union",
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Description: "A stackable unification remote, which can appear to merge the contents of several remotes",
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NewFs: NewFs,
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Options: []fs.Option{{
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Name: "remotes",
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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.",
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Required: true,
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}},
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}
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fs.Register(fsi)
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}
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// Options defines the configuration for this backend
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type Options struct {
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Remotes fs.SpaceSepList `config:"remotes"`
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}
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// Fs represents a remote acd server
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type Fs struct {
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name string // name of this remote
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features *fs.Features // optional features
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opt Options // options for this Fs
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root string // the path we are working on
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remotes []fs.Fs // slice of remotes
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}
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// Name of the remote (as passed into NewFs)
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func (f *Fs) Name() string {
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return f.name
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}
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// Root of the remote (as passed into NewFs)
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func (f *Fs) Root() string {
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return f.root
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}
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// String converts this Fs to a string
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func (f *Fs) String() string {
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return fmt.Sprintf("union root '%s'", f.root)
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}
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// Features returns the optional features of this Fs
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func (f *Fs) Features() *fs.Features {
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return f.features
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}
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// Rmdir removes the root directory of the Fs object
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func (f *Fs) Rmdir(dir string) error {
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return f.remotes[len(f.remotes)-1].Rmdir(dir)
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}
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// Hashes returns hash.HashNone to indicate remote hashing is unavailable
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func (f *Fs) Hashes() hash.Set {
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// This could probably be set if all remotes share the same hashing algorithm
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return hash.Set(hash.None)
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}
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// Mkdir makes the root directory of the Fs object
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func (f *Fs) Mkdir(dir string) error {
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return f.remotes[len(f.remotes)-1].Mkdir(dir)
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}
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// Put in to the remote path with the modTime given of the given size
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//
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// May create the object even if it returns an error - if so
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// will return the object and the error, otherwise will return
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// nil and the error
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func (f *Fs) Put(in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
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return f.remotes[len(f.remotes)-1].Put(in, src, options...)
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}
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// List the objects and directories in dir into entries. The
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// entries can be returned in any order but should be for a
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// complete directory.
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//
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// dir should be "" to list the root, and should not have
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// trailing slashes.
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//
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// This should return ErrDirNotFound if the directory isn't
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// found.
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func (f *Fs) List(dir string) (entries fs.DirEntries, err error) {
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set := make(map[string]fs.DirEntry)
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found := false
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for _, remote := range f.remotes {
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var remoteEntries, err = remote.List(dir)
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if err == fs.ErrorDirNotFound {
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continue
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}
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if err != nil {
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return nil, errors.Wrapf(err, "List failed on %v", remote)
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}
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found = true
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for _, remoteEntry := range remoteEntries {
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set[remoteEntry.Remote()] = remoteEntry
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}
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}
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if !found {
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return nil, fs.ErrorDirNotFound
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}
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for key := range set {
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entries = append(entries, set[key])
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}
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return entries, nil
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}
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// NewObject creates a new remote union file object based on the first Object it finds (reverse remote order)
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func (f *Fs) NewObject(path string) (fs.Object, error) {
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for i := range f.remotes {
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var remote = f.remotes[len(f.remotes)-i-1]
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var obj, err = remote.NewObject(path)
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if err == fs.ErrorObjectNotFound {
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continue
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}
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if err != nil {
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return nil, errors.Wrapf(err, "NewObject failed on %v", remote)
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}
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return obj, nil
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}
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return nil, fs.ErrorObjectNotFound
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}
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// Precision is the greatest Precision of all remotes
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func (f *Fs) Precision() time.Duration {
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var greatestPrecision time.Duration
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for _, remote := range f.remotes {
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if remote.Precision() > greatestPrecision {
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greatestPrecision = remote.Precision()
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}
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}
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return greatestPrecision
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}
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// NewFs constructs an Fs from the path.
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//
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// The returned Fs is the actual Fs, referenced by remote in the config
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func NewFs(name, root string, m configmap.Mapper) (fs.Fs, error) {
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// Parse config into Options struct
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opt := new(Options)
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err := configstruct.Set(m, opt)
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if err != nil {
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return nil, err
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}
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if len(opt.Remotes) == 0 {
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return nil, errors.New("union can't point to an empty remote - check the value of the remotes setting")
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}
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if len(opt.Remotes) == 1 {
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return nil, errors.New("union can't point to a single remote - check the value of the remotes setting")
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}
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for _, remote := range opt.Remotes {
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if strings.HasPrefix(remote, name+":") {
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return nil, errors.New("can't point union remote at itself - check the value of the remote setting")
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}
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}
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var remotes []fs.Fs
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for i := range opt.Remotes {
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// Last remote first so we return the correct (last) matching fs in case of fs.ErrorIsFile
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var remote = opt.Remotes[len(opt.Remotes)-i-1]
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_, configName, fsPath, err := fs.ParseRemote(remote)
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if err != nil {
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return nil, err
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}
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var rootString = path.Join(fsPath, filepath.ToSlash(root))
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if configName != "local" {
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rootString = configName + ":" + rootString
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}
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myFs, err := fs.NewFs(rootString)
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if err != nil {
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if err == fs.ErrorIsFile {
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return myFs, err
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}
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return nil, err
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}
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remotes = append(remotes, myFs)
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}
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// Reverse the remotes again so they are in the order as before
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for i, j := 0, len(remotes)-1; i < j; i, j = i+1, j-1 {
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remotes[i], remotes[j] = remotes[j], remotes[i]
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}
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f := &Fs{
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name: name,
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root: root,
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opt: *opt,
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remotes: remotes,
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}
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var features = (&fs.Features{
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CaseInsensitive: true,
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DuplicateFiles: false,
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ReadMimeType: true,
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WriteMimeType: true,
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CanHaveEmptyDirectories: true,
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BucketBased: true,
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}).Fill(f)
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for _, remote := range f.remotes {
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features = features.Mask(remote)
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}
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f.features = features
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return f, nil
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}
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// Check the interfaces are satisfied
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var (
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_ fs.Fs = &Fs{}
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)
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