restic/internal/backend/gs/gs.go

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package gs
import (
"context"
"fmt"
"io"
"os"
"path"
"strings"
"time"
"github.com/pkg/errors"
"github.com/restic/restic/internal/backend"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/restic"
"io/ioutil"
"golang.org/x/oauth2/google"
"google.golang.org/api/googleapi"
storage "google.golang.org/api/storage/v1"
)
// Backend stores data on an gs endpoint.
type Backend struct {
service *storage.Service
projectID string
sem *backend.Semaphore
bucketName string
prefix string
backend.Layout
}
// make sure that *Backend implements backend.Backend
var _ restic.Backend = &Backend{}
func getStorageService(jsonKeyPath string) (*storage.Service, error) {
raw, err := ioutil.ReadFile(jsonKeyPath)
if err != nil {
return nil, errors.Wrap(err, "ReadFile")
}
conf, err := google.JWTConfigFromJSON(raw, storage.DevstorageReadWriteScope)
if err != nil {
return nil, err
}
client := conf.Client(context.TODO())
service, err := storage.New(client)
if err != nil {
return nil, err
}
return service, nil
}
func open(cfg Config) (*Backend, error) {
debug.Log("open, config %#v", cfg)
service, err := getStorageService(cfg.JSONKeyPath)
if err != nil {
return nil, errors.Wrap(err, "getStorageService")
}
sem, err := backend.NewSemaphore(cfg.Connections)
if err != nil {
return nil, err
}
be := &Backend{
service: service,
projectID: cfg.ProjectID,
sem: sem,
bucketName: cfg.Bucket,
prefix: cfg.Prefix,
Layout: &backend.DefaultLayout{
Path: cfg.Prefix,
Join: path.Join,
},
}
return be, nil
}
// Open opens the gs backend at bucket and region.
func Open(cfg Config) (restic.Backend, error) {
return open(cfg)
}
// Create opens the S3 backend at bucket and region and creates the bucket if
// it does not exist yet.
func Create(cfg Config) (restic.Backend, error) {
be, err := open(cfg)
if err != nil {
return nil, errors.Wrap(err, "open")
}
// Create bucket if not exists
if _, err := be.service.Buckets.Get(be.bucketName).Do(); err != nil {
bucket := &storage.Bucket{
Name: be.bucketName,
}
if _, err := be.service.Buckets.Insert(be.projectID, bucket).Do(); err != nil {
return nil, errors.Wrap(err, "service.Buckets.Insert")
}
}
return be, nil
}
// IsNotExist returns true if the error is caused by a not existing file.
func (be *Backend) IsNotExist(err error) bool {
debug.Log("IsNotExist(%T, %#v)", err, err)
if os.IsNotExist(err) {
return true
}
if er, ok := err.(*googleapi.Error); ok {
if er.Code == 404 {
return true
}
}
return false
}
// Join combines path components with slashes.
func (be *Backend) Join(p ...string) string {
return path.Join(p...)
}
type fileInfo struct {
name string
size int64
mode os.FileMode
modTime time.Time
isDir bool
}
func (fi fileInfo) Name() string { return fi.name } // base name of the file
func (fi fileInfo) Size() int64 { return fi.size } // length in bytes for regular files; system-dependent for others
func (fi fileInfo) Mode() os.FileMode { return fi.mode } // file mode bits
func (fi fileInfo) ModTime() time.Time { return fi.modTime } // modification time
func (fi fileInfo) IsDir() bool { return fi.isDir } // abbreviation for Mode().IsDir()
func (fi fileInfo) Sys() interface{} { return nil } // underlying data source (can return nil)
// ReadDir returns the entries for a directory.
func (be *Backend) ReadDir(dir string) (list []os.FileInfo, err error) {
debug.Log("ReadDir(%v)", dir)
// make sure dir ends with a slash
if dir[len(dir)-1] != '/' {
dir += "/"
}
obj, err := be.service.Objects.List(be.bucketName).Prefix(dir).Delimiter("/").Do()
if err != nil {
return nil, err
}
for _, item := range obj.Prefixes {
entry := fileInfo{
name: strings.TrimPrefix(item, dir),
isDir: true,
mode: os.ModeDir | 0755,
}
list = append(list, entry)
}
for _, item := range obj.Items {
entry := fileInfo{
name: strings.TrimPrefix(item.Name, dir),
isDir: false,
mode: 0644,
size: int64(item.Size),
//modTime: item.Updated,
}
if entry.name != "" {
list = append(list, entry)
}
}
return list, nil
}
// Location returns this backend's location (the bucket name).
func (be *Backend) Location() string {
return be.Join(be.bucketName, be.prefix)
}
// Path returns the path in the bucket that is used for this backend.
func (be *Backend) Path() string {
return be.prefix
}
// Save stores data in the backend at the handle.
func (be *Backend) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err error) {
if err := h.Valid(); err != nil {
return err
}
objName := be.Filename(h)
debug.Log("Save %v at %v", h, objName)
// Check key does not already exist
if _, err := be.service.Objects.Get(be.bucketName, objName).Do(); err == nil {
debug.Log("%v already exists", h)
return errors.New("key already exists")
}
be.sem.GetToken()
debug.Log("InsertObject(%v, %v)", be.bucketName, objName)
info, err := be.service.Objects.Insert(be.bucketName,
&storage.Object{
Name: objName,
}).Media(rd).Do()
be.sem.ReleaseToken()
debug.Log("%v -> %v bytes, err %#v: %v", objName, info.Size, err, err)
return errors.Wrap(err, "service.Objects.Insert")
}
// wrapReader wraps an io.ReadCloser to run an additional function on Close.
type wrapReader struct {
io.ReadCloser
f func()
}
func (wr wrapReader) Close() error {
err := wr.ReadCloser.Close()
wr.f()
return err
}
// Load returns a reader that yields the contents of the file at h at the
// given offset. If length is nonzero, only a portion of the file is
// returned. rd must be closed after use.
func (be *Backend) Load(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error) {
debug.Log("Load %v, length %v, offset %v from %v", h, length, offset, be.Filename(h))
if err := h.Valid(); err != nil {
return nil, err
}
if offset < 0 {
return nil, errors.New("offset is negative")
}
if length < 0 {
return nil, errors.Errorf("invalid length %d", length)
}
objName := be.Filename(h)
be.sem.GetToken()
var byteRange string
if length > 0 {
byteRange = fmt.Sprintf("bytes=%d-%d", offset, offset+int64(length-1))
} else {
byteRange = fmt.Sprintf("bytes=%d-", offset)
}
req := be.service.Objects.Get(be.bucketName, objName)
// https://cloud.google.com/storage/docs/json_api/v1/parameters#range
req.Header().Set("Range", byteRange)
res, err := req.Download()
if err != nil {
be.sem.ReleaseToken()
return nil, err
}
closeRd := wrapReader{
ReadCloser: res.Body,
f: func() {
debug.Log("Close()")
be.sem.ReleaseToken()
},
}
return closeRd, err
}
// Stat returns information about a blob.
func (be *Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInfo, err error) {
debug.Log("%v", h)
objName := be.Filename(h)
obj, err := be.service.Objects.Get(be.bucketName, objName).Do()
if err != nil {
debug.Log("GetObject() err %v", err)
return restic.FileInfo{}, errors.Wrap(err, "service.Objects.Get")
}
return restic.FileInfo{Size: int64(obj.Size)}, nil
}
// Test returns true if a blob of the given type and name exists in the backend.
func (be *Backend) Test(ctx context.Context, h restic.Handle) (bool, error) {
found := false
objName := be.Filename(h)
_, err := be.service.Objects.Get(be.bucketName, objName).Do()
if err == nil {
found = true
}
// If error, then not found
return found, nil
}
// Remove removes the blob with the given name and type.
func (be *Backend) Remove(ctx context.Context, h restic.Handle) error {
objName := be.Filename(h)
err := be.service.Objects.Delete(be.bucketName, objName).Do()
if er, ok := err.(*googleapi.Error); ok {
if er.Code == 404 {
err = nil
}
}
debug.Log("Remove(%v) at %v -> err %v", h, objName, err)
return errors.Wrap(err, "client.RemoveObject")
}
// List returns a channel that yields all names of blobs of type t. A
// goroutine is started for this. If the channel done is closed, sending
// stops.
func (be *Backend) List(ctx context.Context, t restic.FileType) <-chan string {
debug.Log("listing %v", t)
ch := make(chan string)
prefix := be.Dirname(restic.Handle{Type: t})
// make sure prefix ends with a slash
if prefix[len(prefix)-1] != '/' {
prefix += "/"
}
go func() {
defer close(ch)
obj, err := be.service.Objects.List(be.bucketName).Prefix(prefix).Do()
if err != nil {
return
}
for _, item := range obj.Items {
m := strings.TrimPrefix(item.Name, prefix)
if m == "" {
continue
}
select {
case ch <- path.Base(m):
case <-ctx.Done():
return
}
}
}()
return ch
}
// Remove keys for a specified backend type.
func (be *Backend) removeKeys(ctx context.Context, t restic.FileType) error {
for key := range be.List(ctx, restic.DataFile) {
err := be.Remove(ctx, restic.Handle{Type: restic.DataFile, Name: key})
if err != nil {
return err
}
}
return nil
}
// Delete removes all restic keys in the bucket. It will not remove the bucket itself.
func (be *Backend) Delete(ctx context.Context) error {
alltypes := []restic.FileType{
restic.DataFile,
restic.KeyFile,
restic.LockFile,
restic.SnapshotFile,
restic.IndexFile}
for _, t := range alltypes {
err := be.removeKeys(ctx, t)
if err != nil {
return nil
}
}
return be.Remove(ctx, restic.Handle{Type: restic.ConfigFile})
}
// Close does nothing
func (be *Backend) Close() error { return nil }