rclone/backend/union/upstream/upstream.go
Nick Craig-Wood d846210978 fs: Add context to NewFs #3257 #4685
This adds a context.Context parameter to NewFs and related calls.

This is necessary as part of reading config from the context -
backends need to be able to read the global config.
2020-11-09 18:05:54 +00:00

352 lines
8.2 KiB
Go

package upstream
import (
"context"
"io"
"math"
"path"
"path/filepath"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/pkg/errors"
"github.com/rclone/rclone/fs"
"github.com/rclone/rclone/fs/cache"
)
var (
// ErrUsageFieldNotSupported stats the usage field is not supported by the backend
ErrUsageFieldNotSupported = errors.New("this usage field is not supported")
)
// Fs is a wrap of any fs and its configs
type Fs struct {
fs.Fs
RootFs fs.Fs
RootPath string
writable bool
creatable bool
usage *fs.Usage // Cache the usage
cacheTime time.Duration // cache duration
cacheExpiry int64 // usage cache expiry time
cacheMutex sync.RWMutex
cacheOnce sync.Once
cacheUpdate bool // if the cache is updating
}
// Directory describes a wrapped Directory
//
// This is a wrapped Directory which contains the upstream Fs
type Directory struct {
fs.Directory
f *Fs
}
// Object describes a wrapped Object
//
// This is a wrapped Object which contains the upstream Fs
type Object struct {
fs.Object
f *Fs
}
// Entry describe a wrapped fs.DirEntry interface with the
// information of upstream Fs
type Entry interface {
fs.DirEntry
UpstreamFs() *Fs
}
// New creates a new Fs based on the
// string formatted `type:root_path(:ro/:nc)`
func New(ctx context.Context, remote, root string, cacheTime time.Duration) (*Fs, error) {
_, configName, fsPath, err := fs.ParseRemote(remote)
if err != nil {
return nil, err
}
f := &Fs{
RootPath: root,
writable: true,
creatable: true,
cacheExpiry: time.Now().Unix(),
cacheTime: cacheTime,
usage: &fs.Usage{},
}
if strings.HasSuffix(fsPath, ":ro") {
f.writable = false
f.creatable = false
fsPath = fsPath[0 : len(fsPath)-3]
} else if strings.HasSuffix(fsPath, ":nc") {
f.writable = true
f.creatable = false
fsPath = fsPath[0 : len(fsPath)-3]
}
if configName != "local" {
fsPath = configName + ":" + fsPath
}
rFs, err := cache.Get(ctx, fsPath)
if err != nil && err != fs.ErrorIsFile {
return nil, err
}
f.RootFs = rFs
rootString := path.Join(fsPath, filepath.ToSlash(root))
myFs, err := cache.Get(ctx, rootString)
if err != nil && err != fs.ErrorIsFile {
return nil, err
}
f.Fs = myFs
cache.PinUntilFinalized(f.Fs, f)
return f, err
}
// WrapDirectory wraps an fs.Directory to include the info
// of the upstream Fs
func (f *Fs) WrapDirectory(e fs.Directory) *Directory {
if e == nil {
return nil
}
return &Directory{
Directory: e,
f: f,
}
}
// WrapObject wraps an fs.Object to include the info
// of the upstream Fs
func (f *Fs) WrapObject(o fs.Object) *Object {
if o == nil {
return nil
}
return &Object{
Object: o,
f: f,
}
}
// WrapEntry wraps an fs.DirEntry to include the info
// of the upstream Fs
func (f *Fs) WrapEntry(e fs.DirEntry) (Entry, error) {
switch e.(type) {
case fs.Object:
return f.WrapObject(e.(fs.Object)), nil
case fs.Directory:
return f.WrapDirectory(e.(fs.Directory)), nil
default:
return nil, errors.Errorf("unknown object type %T", e)
}
}
// UpstreamFs get the upstream Fs the entry is stored in
func (e *Directory) UpstreamFs() *Fs {
return e.f
}
// UpstreamFs get the upstream Fs the entry is stored in
func (o *Object) UpstreamFs() *Fs {
return o.f
}
// UnWrap returns the Object that this Object is wrapping or
// nil if it isn't wrapping anything
func (o *Object) UnWrap() fs.Object {
return o.Object
}
// IsCreatable return if the fs is allowed to create new objects
func (f *Fs) IsCreatable() bool {
return f.creatable
}
// IsWritable return if the fs is allowed to write
func (f *Fs) IsWritable() bool {
return f.writable
}
// 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(ctx context.Context, in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
o, err := f.Fs.Put(ctx, in, src, options...)
if err != nil {
return o, err
}
f.cacheMutex.Lock()
defer f.cacheMutex.Unlock()
size := src.Size()
if f.usage.Used != nil {
*f.usage.Used += size
}
if f.usage.Free != nil {
*f.usage.Free -= size
}
if f.usage.Objects != nil {
*f.usage.Objects++
}
return o, nil
}
// 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(ctx context.Context, in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
do := f.Features().PutStream
if do == nil {
return nil, fs.ErrorNotImplemented
}
o, err := do(ctx, in, src, options...)
if err != nil {
return o, err
}
f.cacheMutex.Lock()
defer f.cacheMutex.Unlock()
size := o.Size()
if f.usage.Used != nil {
*f.usage.Used += size
}
if f.usage.Free != nil {
*f.usage.Free -= size
}
if f.usage.Objects != nil {
*f.usage.Objects++
}
return o, nil
}
// Update in to the object with the modTime given of the given size
//
// When called from outside an Fs by rclone, src.Size() will always be >= 0.
// But for unknown-sized objects (indicated by src.Size() == -1), Upload should either
// return an error or update the object properly (rather than e.g. calling panic).
func (o *Object) Update(ctx context.Context, in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) error {
size := o.Size()
err := o.Object.Update(ctx, in, src, options...)
if err != nil {
return err
}
o.f.cacheMutex.Lock()
defer o.f.cacheMutex.Unlock()
delta := o.Size() - size
if delta <= 0 {
return nil
}
if o.f.usage.Used != nil {
*o.f.usage.Used += size
}
if o.f.usage.Free != nil {
*o.f.usage.Free -= size
}
return nil
}
// About gets quota information from the Fs
func (f *Fs) About(ctx context.Context) (*fs.Usage, error) {
if atomic.LoadInt64(&f.cacheExpiry) <= time.Now().Unix() {
err := f.updateUsage()
if err != nil {
return nil, ErrUsageFieldNotSupported
}
}
f.cacheMutex.RLock()
defer f.cacheMutex.RUnlock()
return f.usage, nil
}
// GetFreeSpace get the free space of the fs
func (f *Fs) GetFreeSpace() (int64, error) {
if atomic.LoadInt64(&f.cacheExpiry) <= time.Now().Unix() {
err := f.updateUsage()
if err != nil {
return math.MaxInt64, ErrUsageFieldNotSupported
}
}
f.cacheMutex.RLock()
defer f.cacheMutex.RUnlock()
if f.usage.Free == nil {
return math.MaxInt64, ErrUsageFieldNotSupported
}
return *f.usage.Free, nil
}
// GetUsedSpace get the used space of the fs
func (f *Fs) GetUsedSpace() (int64, error) {
if atomic.LoadInt64(&f.cacheExpiry) <= time.Now().Unix() {
err := f.updateUsage()
if err != nil {
return 0, ErrUsageFieldNotSupported
}
}
f.cacheMutex.RLock()
defer f.cacheMutex.RUnlock()
if f.usage.Used == nil {
return 0, ErrUsageFieldNotSupported
}
return *f.usage.Used, nil
}
// GetNumObjects get the number of objects of the fs
func (f *Fs) GetNumObjects() (int64, error) {
if atomic.LoadInt64(&f.cacheExpiry) <= time.Now().Unix() {
err := f.updateUsage()
if err != nil {
return 0, ErrUsageFieldNotSupported
}
}
f.cacheMutex.RLock()
defer f.cacheMutex.RUnlock()
if f.usage.Objects == nil {
return 0, ErrUsageFieldNotSupported
}
return *f.usage.Objects, nil
}
func (f *Fs) updateUsage() (err error) {
if do := f.RootFs.Features().About; do == nil {
return ErrUsageFieldNotSupported
}
done := false
f.cacheOnce.Do(func() {
f.cacheMutex.Lock()
err = f.updateUsageCore(false)
f.cacheMutex.Unlock()
done = true
})
if done {
return err
}
if !f.cacheUpdate {
f.cacheUpdate = true
go func() {
_ = f.updateUsageCore(true)
f.cacheUpdate = false
}()
}
return nil
}
func (f *Fs) updateUsageCore(lock bool) error {
// Run in background, should not be cancelled by user
ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
defer cancel()
usage, err := f.RootFs.Features().About(ctx)
if err != nil {
f.cacheUpdate = false
if errors.Cause(err) == fs.ErrorDirNotFound {
err = nil
}
return err
}
if lock {
f.cacheMutex.Lock()
defer f.cacheMutex.Unlock()
}
// Store usage
atomic.StoreInt64(&f.cacheExpiry, time.Now().Add(f.cacheTime).Unix())
f.usage = usage
return nil
}