Golang errors.Wrap函数代码示例

// Stat returns information about a blob.
func (b *restBackend) Stat(h restic.Handle) (restic.FileInfo, error) {
	if err := h.Valid(); err != nil {
		return restic.FileInfo{}, err
	}

	<-b.connChan
	resp, err := b.client.Head(restPath(b.url, h))
	b.connChan <- struct{}{}
	if err != nil {
		return restic.FileInfo{}, errors.Wrap(err, "client.Head")
	}

	io.Copy(ioutil.Discard, resp.Body)
	if err = resp.Body.Close(); err != nil {
		return restic.FileInfo{}, errors.Wrap(err, "Close")
	}

	if resp.StatusCode != 200 {
		return restic.FileInfo{}, errors.Errorf("unexpected HTTP response code %v", resp.StatusCode)
	}

	if resp.ContentLength < 0 {
		return restic.FileInfo{}, errors.New("negative content length")
	}

	bi := restic.FileInfo{
		Size: resp.ContentLength,
	}

	return bi, nil
}

// Rename temp file to final name according to type and name.
func (r *SFTP) renameFile(oldname string, t restic.FileType, name string) error {
	filename := r.filename(t, name)

	// create directories if necessary
	if t == restic.DataFile {
		err := r.mkdirAll(path.Dir(filename), backend.Modes.Dir)
		if err != nil {
			return err
		}
	}

	// test if new file exists
	if _, err := r.c.Lstat(filename); err == nil {
		return errors.Errorf("Close(): file %v already exists", filename)
	}

	err := r.c.Rename(oldname, filename)
	if err != nil {
		return errors.Wrap(err, "Rename")
	}

	// set mode to read-only
	fi, err := r.c.Lstat(filename)
	if err != nil {
		return errors.Wrap(err, "Lstat")
	}

	err = r.c.Chmod(filename, fi.Mode()&os.FileMode(^uint32(0222)))
	return errors.Wrap(err, "Chmod")
}

func (node Node) restoreMetadata(path string) error {
	var err error

	err = lchown(path, int(node.UID), int(node.GID))
	if err != nil {
		return errors.Wrap(err, "Lchown")
	}

	if node.Type != "symlink" {
		err = fs.Chmod(path, node.Mode)
		if err != nil {
			return errors.Wrap(err, "Chmod")
		}
	}

	if node.Type != "dir" {
		err = node.RestoreTimestamps(path)
		if err != nil {
			debug.Log("error restoring timestamps for dir %v: %v", path, err)
			return err
		}
	}

	return nil
}

// ReadPassword reads the password from a password file, the environment
// variable RESTIC_PASSWORD or prompts the user.
func ReadPassword(opts GlobalOptions, prompt string) (string, error) {
	if opts.PasswordFile != "" {
		s, err := ioutil.ReadFile(opts.PasswordFile)
		return strings.TrimSpace(string(s)), errors.Wrap(err, "Readfile")
	}

	if pwd := os.Getenv("RESTIC_PASSWORD"); pwd != "" {
		return pwd, nil
	}

	var (
		password string
		err      error
	)

	if stdinIsTerminal() {
		password, err = readPasswordTerminal(os.Stdin, os.Stderr, prompt)
	} else {
		password, err = readPassword(os.Stdin)
	}

	if err != nil {
		return "", errors.Wrap(err, "unable to read password")
	}

	if len(password) == 0 {
		return "", errors.Fatal("an empty password is not a password")
	}

	return password, nil
}

// Stat returns information about a blob.
func (be s3) Stat(h restic.Handle) (bi restic.FileInfo, err error) {
	debug.Log("%v", h)

	path := be.s3path(h.Type, h.Name)
	var obj *minio.Object

	obj, err = be.client.GetObject(be.bucketname, path)
	if err != nil {
		debug.Log("GetObject() err %v", err)
		return restic.FileInfo{}, errors.Wrap(err, "client.GetObject")
	}

	// make sure that the object is closed properly.
	defer func() {
		e := obj.Close()
		if err == nil {
			err = errors.Wrap(e, "Close")
		}
	}()

	fi, err := obj.Stat()
	if err != nil {
		debug.Log("Stat() err %v", err)
		return restic.FileInfo{}, errors.Wrap(err, "Stat")
	}

	return restic.FileInfo{Size: fi.Size}, nil
}

// Open opens the S3 backend at bucket and region. The bucket is created if it
// does not exist yet.
func Open(cfg Config) (restic.Backend, error) {
	debug.Log("open, config %#v", cfg)

	client, err := minio.New(cfg.Endpoint, cfg.KeyID, cfg.Secret, !cfg.UseHTTP)
	if err != nil {
		return nil, errors.Wrap(err, "minio.New")
	}

	be := &s3{client: client, bucketname: cfg.Bucket, prefix: cfg.Prefix}
	be.createConnections()

	ok, err := client.BucketExists(cfg.Bucket)
	if err != nil {
		debug.Log("BucketExists(%v) returned err %v, trying to create the bucket", cfg.Bucket, err)
		return nil, errors.Wrap(err, "client.BucketExists")
	}

	if !ok {
		// create new bucket with default ACL in default region
		err = client.MakeBucket(cfg.Bucket, "")
		if err != nil {
			return nil, errors.Wrap(err, "client.MakeBucket")
		}
	}

	return be, nil
}

// Remove removes the blob with the given name and type.
func (b *restBackend) Remove(t restic.FileType, name string) error {
	h := restic.Handle{Type: t, Name: name}
	if err := h.Valid(); err != nil {
		return err
	}

	req, err := http.NewRequest("DELETE", restPath(b.url, h), nil)
	if err != nil {
		return errors.Wrap(err, "http.NewRequest")
	}
	<-b.connChan
	resp, err := b.client.Do(req)
	b.connChan <- struct{}{}

	if err != nil {
		return errors.Wrap(err, "client.Do")
	}

	if resp.StatusCode != 200 {
		return errors.New("blob not removed")
	}

	io.Copy(ioutil.Discard, resp.Body)
	return resp.Body.Close()
}

// Save stores data in the backend at the handle.
func (b *restBackend) Save(h restic.Handle, p []byte) (err error) {
	if err := h.Valid(); err != nil {
		return err
	}

	<-b.connChan
	resp, err := b.client.Post(restPath(b.url, h), "binary/octet-stream", bytes.NewReader(p))
	b.connChan <- struct{}{}

	if resp != nil {
		defer func() {
			io.Copy(ioutil.Discard, resp.Body)
			e := resp.Body.Close()

			if err == nil {
				err = errors.Wrap(e, "Close")
			}
		}()
	}

	if err != nil {
		return errors.Wrap(err, "client.Post")
	}

	if resp.StatusCode != 200 {
		return errors.Errorf("unexpected HTTP response code %v", resp.StatusCode)
	}

	return nil
}

// Load returns the data stored in the backend for h at the given offset
// and saves it in p. Load has the same semantics as io.ReaderAt.
func (r *SFTP) Load(h restic.Handle, p []byte, off int64) (n int, err error) {
	debug.Log("load %v, %d bytes, offset %v", h, len(p), off)
	if err := r.clientError(); err != nil {
		return 0, err
	}

	if err := h.Valid(); err != nil {
		return 0, err
	}

	f, err := r.c.Open(r.filename(h.Type, h.Name))
	if err != nil {
		return 0, errors.Wrap(err, "Open")
	}

	defer func() {
		e := f.Close()
		if err == nil && e != nil {
			err = errors.Wrap(e, "Close")
		}
	}()

	switch {
	case off > 0:
		_, err = f.Seek(off, 0)
	case off < 0:
		_, err = f.Seek(off, 2)
	}

	if err != nil {
		return 0, errors.Wrap(err, "Seek")
	}

	return io.ReadFull(f, p)
}

// writeToTempfile saves p into a tempfile in tempdir.
func writeToTempfile(tempdir string, p []byte) (filename string, err error) {
	tmpfile, err := ioutil.TempFile(tempdir, "temp-")
	if err != nil {
		return "", errors.Wrap(err, "TempFile")
	}

	n, err := tmpfile.Write(p)
	if err != nil {
		return "", errors.Wrap(err, "Write")
	}

	if n != len(p) {
		return "", errors.New("not all bytes writen")
	}

	if err = tmpfile.Sync(); err != nil {
		return "", errors.Wrap(err, "Syncn")
	}

	err = tmpfile.Close()
	if err != nil {
		return "", errors.Wrap(err, "Close")
	}

	return tmpfile.Name(), nil
}

// Load returns the data stored in the backend for h at the given offset and
// saves it in p. Load has the same semantics as io.ReaderAt, with one
// exception: when off is lower than zero, it is treated as an offset relative
// to the end of the file.
func (b *Local) Load(h restic.Handle, p []byte, off int64) (n int, err error) {
	debug.Log("Load %v, length %v at %v", h, len(p), off)
	if err := h.Valid(); err != nil {
		return 0, err
	}

	f, err := fs.Open(filename(b.p, h.Type, h.Name))
	if err != nil {
		return 0, errors.Wrap(err, "Open")
	}

	defer func() {
		e := f.Close()
		if err == nil {
			err = errors.Wrap(e, "Close")
		}
	}()

	switch {
	case off > 0:
		_, err = f.Seek(off, 0)
	case off < 0:
		_, err = f.Seek(off, 2)
	}

	if err != nil {
		return 0, errors.Wrap(err, "Seek")
	}

	return io.ReadFull(f, p)
}

func (node Node) createFileAt(path string, repo Repository) error {
	f, err := fs.OpenFile(path, os.O_CREATE|os.O_WRONLY, 0600)
	defer f.Close()

	if err != nil {
		return errors.Wrap(err, "OpenFile")
	}

	var buf []byte
	for _, id := range node.Content {
		size, err := repo.LookupBlobSize(id, DataBlob)
		if err != nil {
			return err
		}

		buf = buf[:cap(buf)]
		if uint(len(buf)) < size {
			buf = make([]byte, size)
		}

		n, err := repo.LoadBlob(DataBlob, id, buf)
		if err != nil {
			return err
		}
		buf = buf[:n]

		_, err = f.Write(buf)
		if err != nil {
			return errors.Wrap(err, "Write")
		}
	}

	return nil
}

// savePacker stores p in the backend.
func (r *Repository) savePacker(p *pack.Packer) error {
	debug.Log("save packer with %d blobs\n", p.Count())
	n, err := p.Finalize()
	if err != nil {
		return err
	}

	tmpfile := p.Writer().(*os.File)
	f, err := fs.Open(tmpfile.Name())
	if err != nil {
		return errors.Wrap(err, "Open")
	}

	data := make([]byte, n)
	m, err := io.ReadFull(f, data)
	if err != nil {
		return errors.Wrap(err, "ReadFul")
	}

	if uint(m) != n {
		return errors.Errorf("read wrong number of bytes from %v: want %v, got %v", tmpfile.Name(), n, m)
	}

	if err = f.Close(); err != nil {
		return errors.Wrap(err, "Close")
	}

	id := restic.Hash(data)
	h := restic.Handle{Type: restic.DataFile, Name: id.String()}

	err = r.be.Save(h, data)
	if err != nil {
		debug.Log("Save(%v) error: %v", h, err)
		return err
	}

	debug.Log("saved as %v", h)

	err = fs.Remove(tmpfile.Name())
	if err != nil {
		return errors.Wrap(err, "Remove")
	}

	// update blobs in the index
	for _, b := range p.Blobs() {
		debug.Log("  updating blob %v to pack %v", b.ID.Str(), id.Str())
		r.idx.Current().Store(restic.PackedBlob{
			Blob: restic.Blob{
				Type:   b.Type,
				ID:     b.ID,
				Offset: b.Offset,
				Length: uint(b.Length),
			},
			PackID: id,
		})
	}

	return nil
}

func (node *Node) UnmarshalJSON(data []byte) error {
	type nodeJSON Node
	nj := (*nodeJSON)(node)

	err := json.Unmarshal(data, nj)
	if err != nil {
		return errors.Wrap(err, "Unmarshal")
	}

	nj.Name, err = strconv.Unquote(`"` + nj.Name + `"`)
	return errors.Wrap(err, "Unquote")
}

func startClient(program string, args ...string) (*SFTP, error) {
	// Connect to a remote host and request the sftp subsystem via the 'ssh'
	// command.  This assumes that passwordless login is correctly configured.
	cmd := exec.Command(program, args...)

	// prefix the errors with the program name
	stderr, err := cmd.StderrPipe()
	if err != nil {
		return nil, errors.Wrap(err, "cmd.StderrPipe")
	}

	go func() {
		sc := bufio.NewScanner(stderr)
		for sc.Scan() {
			fmt.Fprintf(os.Stderr, "subprocess %v: %v\n", program, sc.Text())
		}
	}()

	// ignore signals sent to the parent (e.g. SIGINT)
	cmd.SysProcAttr = ignoreSigIntProcAttr()

	// get stdin and stdout
	wr, err := cmd.StdinPipe()
	if err != nil {
		return nil, errors.Wrap(err, "cmd.StdinPipe")
	}
	rd, err := cmd.StdoutPipe()
	if err != nil {
		return nil, errors.Wrap(err, "cmd.StdoutPipe")
	}

	// start the process
	if err := cmd.Start(); err != nil {
		return nil, errors.Wrap(err, "cmd.Start")
	}

	// wait in a different goroutine
	ch := make(chan error, 1)
	go func() {
		err := cmd.Wait()
		debug.Log("ssh command exited, err %v", err)
		ch <- errors.Wrap(err, "cmd.Wait")
	}()

	// open the SFTP session
	client, err := sftp.NewClientPipe(rd, wr)
	if err != nil {
		return nil, errors.Errorf("unable to start the sftp session, error: %v", err)
	}

	return &SFTP{c: client, cmd: cmd, result: ch}, nil
}