restic/internal/backend/local/local.go

290 lines
6.4 KiB
Go

package local
import (
"context"
"io"
"os"
"path/filepath"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/restic"
"github.com/restic/restic/internal/backend"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/fs"
)
// Local is a backend in a local directory.
type Local struct {
Config
backend.Layout
}
// ensure statically that *Local implements restic.Backend.
var _ restic.Backend = &Local{}
const defaultLayout = "default"
// dirExists returns true if the name exists and is a directory.
func dirExists(name string) bool {
f, err := fs.Open(name)
if err != nil {
return false
}
fi, err := f.Stat()
if err != nil {
return false
}
if err = f.Close(); err != nil {
return false
}
return fi.IsDir()
}
// Open opens the local backend as specified by config.
func Open(cfg Config) (*Local, error) {
debug.Log("open local backend at %v (layout %q)", cfg.Path, cfg.Layout)
l, err := backend.ParseLayout(&backend.LocalFilesystem{}, cfg.Layout, defaultLayout, cfg.Path)
if err != nil {
return nil, err
}
be := &Local{Config: cfg, Layout: l}
// if data dir exists, make sure that all subdirs also exist
datadir := be.Dirname(restic.Handle{Type: restic.DataFile})
if dirExists(datadir) {
debug.Log("datadir %v exists", datadir)
for _, d := range be.Paths() {
if !fs.HasPathPrefix(datadir, d) {
debug.Log("%v is not subdir of datadir %v", d, datadir)
continue
}
debug.Log("MkdirAll %v", d)
err := fs.MkdirAll(d, backend.Modes.Dir)
if err != nil {
return nil, errors.Wrap(err, "MkdirAll")
}
}
}
return be, nil
}
// Create creates all the necessary files and directories for a new local
// backend at dir. Afterwards a new config blob should be created.
func Create(cfg Config) (*Local, error) {
debug.Log("create local backend at %v (layout %q)", cfg.Path, cfg.Layout)
l, err := backend.ParseLayout(&backend.LocalFilesystem{}, cfg.Layout, defaultLayout, cfg.Path)
if err != nil {
return nil, err
}
be := &Local{
Config: cfg,
Layout: l,
}
// test if config file already exists
_, err = fs.Lstat(be.Filename(restic.Handle{Type: restic.ConfigFile}))
if err == nil {
return nil, errors.New("config file already exists")
}
// create paths for data and refs
for _, d := range be.Paths() {
err := fs.MkdirAll(d, backend.Modes.Dir)
if err != nil {
return nil, errors.Wrap(err, "MkdirAll")
}
}
return be, nil
}
// Location returns this backend's location (the directory name).
func (b *Local) Location() string {
return b.Path
}
// IsNotExist returns true if the error is caused by a non existing file.
func (b *Local) IsNotExist(err error) bool {
return os.IsNotExist(errors.Cause(err))
}
// Save stores data in the backend at the handle.
func (b *Local) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err error) {
debug.Log("Save %v", h)
if err := h.Valid(); err != nil {
return err
}
if h.Type == restic.LockFile {
lockDir := b.Dirname(h)
if !dirExists(lockDir) {
debug.Log("locks/ does not exist yet, creating now.")
if err := fs.MkdirAll(lockDir, backend.Modes.Dir); err != nil {
return errors.Wrap(err, "MkdirAll")
}
}
}
filename := b.Filename(h)
// create new file
f, err := fs.OpenFile(filename, os.O_CREATE|os.O_EXCL|os.O_WRONLY, backend.Modes.File)
if err != nil {
return errors.Wrap(err, "OpenFile")
}
// save data, then sync
_, err = io.Copy(f, rd)
if err != nil {
_ = f.Close()
return errors.Wrap(err, "Write")
}
if err = f.Sync(); err != nil {
_ = f.Close()
return errors.Wrap(err, "Sync")
}
err = f.Close()
if err != nil {
return errors.Wrap(err, "Close")
}
return setNewFileMode(filename, backend.Modes.File)
}
// 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 (b *Local) Load(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error) {
debug.Log("Load %v, length %v, offset %v", h, length, offset)
if err := h.Valid(); err != nil {
return nil, err
}
if offset < 0 {
return nil, errors.New("offset is negative")
}
f, err := fs.Open(b.Filename(h))
if err != nil {
return nil, err
}
if offset > 0 {
_, err = f.Seek(offset, 0)
if err != nil {
_ = f.Close()
return nil, err
}
}
if length > 0 {
return backend.LimitReadCloser(f, int64(length)), nil
}
return f, nil
}
// Stat returns information about a blob.
func (b *Local) Stat(ctx context.Context, h restic.Handle) (restic.FileInfo, error) {
debug.Log("Stat %v", h)
if err := h.Valid(); err != nil {
return restic.FileInfo{}, err
}
fi, err := fs.Stat(b.Filename(h))
if err != nil {
return restic.FileInfo{}, errors.Wrap(err, "Stat")
}
return restic.FileInfo{Size: fi.Size()}, nil
}
// Test returns true if a blob of the given type and name exists in the backend.
func (b *Local) Test(ctx context.Context, h restic.Handle) (bool, error) {
debug.Log("Test %v", h)
_, err := fs.Stat(b.Filename(h))
if err != nil {
if os.IsNotExist(errors.Cause(err)) {
return false, nil
}
return false, errors.Wrap(err, "Stat")
}
return true, nil
}
// Remove removes the blob with the given name and type.
func (b *Local) Remove(ctx context.Context, h restic.Handle) error {
debug.Log("Remove %v", h)
fn := b.Filename(h)
// reset read-only flag
err := fs.Chmod(fn, 0666)
if err != nil {
return errors.Wrap(err, "Chmod")
}
return fs.Remove(fn)
}
func isFile(fi os.FileInfo) bool {
return fi.Mode()&(os.ModeType|os.ModeCharDevice) == 0
}
// List returns a channel that yields all names of blobs of type t. A
// goroutine is started for this.
func (b *Local) List(ctx context.Context, t restic.FileType) <-chan string {
debug.Log("List %v", t)
ch := make(chan string)
go func() {
defer close(ch)
fs.Walk(b.Basedir(t), func(path string, fi os.FileInfo, err error) error {
if err != nil {
return err
}
if !isFile(fi) {
return err
}
select {
case ch <- filepath.Base(path):
case <-ctx.Done():
return err
}
return err
})
}()
return ch
}
// Delete removes the repository and all files.
func (b *Local) Delete(ctx context.Context) error {
debug.Log("Delete()")
return fs.RemoveAll(b.Path)
}
// Close closes all open files.
func (b *Local) Close() error {
debug.Log("Close()")
// this does not need to do anything, all open files are closed within the
// same function.
return nil
}