Beispiel #1
0
func (s *TagStore) Import(src string, repo string, tag string, imageImportConfig *ImageImportConfig) error {
	var (
		sf      = streamformatter.NewJSONStreamFormatter()
		archive archive.ArchiveReader
		resp    *http.Response
	)

	if src == "-" {
		archive = imageImportConfig.InConfig
	} else {
		u, err := url.Parse(src)
		if err != nil {
			return err
		}
		if u.Scheme == "" {
			u.Scheme = "http"
			u.Host = src
			u.Path = ""
		}
		imageImportConfig.OutStream.Write(sf.FormatStatus("", "Downloading from %s", u))
		resp, err = httputils.Download(u.String())
		if err != nil {
			return err
		}
		progressReader := progressreader.New(progressreader.Config{
			In:        resp.Body,
			Out:       imageImportConfig.OutStream,
			Formatter: sf,
			Size:      int(resp.ContentLength),
			NewLines:  true,
			ID:        "",
			Action:    "Importing",
		})
		defer progressReader.Close()
		archive = progressReader
	}

	img, err := s.graph.Create(archive, "", "", "Imported from "+src, "", nil, imageImportConfig.ContainerConfig)
	if err != nil {
		return err
	}
	// Optionally register the image at REPO/TAG
	if repo != "" {
		if err := s.Tag(repo, tag, img.ID, true); err != nil {
			return err
		}
	}
	imageImportConfig.OutStream.Write(sf.FormatStatus("", img.ID))
	logID := img.ID
	if tag != "" {
		logID = utils.ImageReference(logID, tag)
	}

	s.eventsService.Log("import", logID, "")
	return nil
}
Beispiel #2
0
func (s *TagStore) pushImage(r *registry.Session, out io.Writer, imgID, ep string, token []string, sf *streamformatter.StreamFormatter) (checksum string, err error) {
	out = ioutils.NewWriteFlusher(out)
	jsonRaw, err := ioutil.ReadFile(filepath.Join(s.graph.Root, imgID, "json"))
	if err != nil {
		return "", fmt.Errorf("Cannot retrieve the path for {%s}: %s", imgID, err)
	}
	out.Write(sf.FormatProgress(stringid.TruncateID(imgID), "Pushing", nil))

	imgData := &registry.ImgData{
		ID: imgID,
	}

	// Send the json
	if err := r.PushImageJSONRegistry(imgData, jsonRaw, ep); err != nil {
		if err == registry.ErrAlreadyExists {
			out.Write(sf.FormatProgress(stringid.TruncateID(imgData.ID), "Image already pushed, skipping", nil))
			return "", nil
		}
		return "", err
	}

	layerData, err := s.graph.TempLayerArchive(imgID, sf, out)
	if err != nil {
		return "", fmt.Errorf("Failed to generate layer archive: %s", err)
	}
	defer os.RemoveAll(layerData.Name())

	// Send the layer
	glog.V(1).Infof("rendered layer for %s of [%d] size", imgData.ID, layerData.Size)

	checksum, checksumPayload, err := r.PushImageLayerRegistry(imgData.ID,
		progressreader.New(progressreader.Config{
			In:        layerData,
			Out:       out,
			Formatter: sf,
			Size:      int(layerData.Size),
			NewLines:  false,
			ID:        stringid.TruncateID(imgData.ID),
			Action:    "Pushing",
		}), ep, jsonRaw)
	if err != nil {
		return "", err
	}
	imgData.Checksum = checksum
	imgData.ChecksumPayload = checksumPayload
	// Send the checksum
	if err := r.PushImageChecksumRegistry(imgData, ep); err != nil {
		return "", err
	}

	out.Write(sf.FormatProgress(stringid.TruncateID(imgData.ID), "Image successfully pushed", nil))
	return imgData.Checksum, nil
}
Beispiel #3
0
// PushV2Image pushes the image content to the v2 registry, first buffering the contents to disk
func (s *TagStore) pushV2Image(r *registry.Session, img *image.Image, endpoint *registry.Endpoint, imageName string, sf *streamformatter.StreamFormatter, out io.Writer, auth *registry.RequestAuthorization) (string, error) {
	out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Buffering to Disk", nil))

	image, err := s.graph.Get(img.ID)
	if err != nil {
		return "", err
	}
	arch, err := image.TarLayer()
	if err != nil {
		return "", err
	}
	defer arch.Close()

	tf, err := s.graph.newTempFile()
	if err != nil {
		return "", err
	}
	defer func() {
		tf.Close()
		os.Remove(tf.Name())
	}()

	size, dgst, err := bufferToFile(tf, arch)

	// Send the layer
	glog.V(1).Infof("rendered layer for %s of [%d] size", img.ID, size)

	if err := r.PutV2ImageBlob(endpoint, imageName, dgst,
		progressreader.New(progressreader.Config{
			In:        tf,
			Out:       out,
			Formatter: sf,
			Size:      int(size),
			NewLines:  false,
			ID:        stringid.TruncateID(img.ID),
			Action:    "Pushing",
		}), auth); err != nil {
		out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Image push failed", nil))
		return "", err
	}
	out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Image successfully pushed", nil))
	return dgst.String(), nil
}
Beispiel #4
0
func (s *TagStore) pullV2Tag(r *registry.Session, out io.Writer, endpoint *registry.Endpoint, repoInfo *registry.RepositoryInfo, tag string, sf *streamformatter.StreamFormatter, auth *registry.RequestAuthorization) (bool, error) {
	glog.V(1).Infof("Pulling tag from V2 registry: %q", tag)

	remoteDigest, manifestBytes, err := r.GetV2ImageManifest(endpoint, repoInfo.RemoteName, tag, auth)
	if err != nil {
		return false, err
	}

	// loadManifest ensures that the manifest payload has the expected digest
	// if the tag is a digest reference.
	localDigest, manifest, verified, err := s.loadManifest(manifestBytes, tag, remoteDigest)
	if err != nil {
		return false, fmt.Errorf("error verifying manifest: %s", err)
	}

	if verified {
		glog.Infof("Image manifest for %s has been verified", utils.ImageReference(repoInfo.CanonicalName, tag))
	}
	out.Write(sf.FormatStatus(tag, "Pulling from %s", repoInfo.CanonicalName))

	// downloadInfo is used to pass information from download to extractor
	type downloadInfo struct {
		imgJSON    []byte
		img        *image.Image
		digest     digest.Digest
		tmpFile    *os.File
		length     int64
		downloaded bool
		err        chan error
	}

	downloads := make([]downloadInfo, len(manifest.FSLayers))

	for i := len(manifest.FSLayers) - 1; i >= 0; i-- {
		var (
			sumStr  = manifest.FSLayers[i].BlobSum
			imgJSON = []byte(manifest.History[i].V1Compatibility)
		)

		img, err := image.NewImgJSON(imgJSON)
		if err != nil {
			return false, fmt.Errorf("failed to parse json: %s", err)
		}
		downloads[i].img = img

		// Check if exists
		if s.graph.Exists(img.ID) {
			glog.V(1).Infof("Image already exists: %s", img.ID)
			continue
		}

		dgst, err := digest.ParseDigest(sumStr)
		if err != nil {
			return false, err
		}
		downloads[i].digest = dgst

		out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Pulling fs layer", nil))

		downloadFunc := func(di *downloadInfo) error {
			glog.V(1).Infof("pulling blob %q to V1 img %s", sumStr, img.ID)

			if c, err := s.poolAdd("pull", "img:"+img.ID); err != nil {
				if c != nil {
					out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Layer already being pulled by another client. Waiting.", nil))
					<-c
					out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Download complete", nil))
				} else {
					glog.V(1).Infof("Image (id: %s) pull is already running, skipping: %v", img.ID, err)
				}
			} else {
				defer s.poolRemove("pull", "img:"+img.ID)
				tmpFile, err := ioutil.TempFile("", "GetV2ImageBlob")
				if err != nil {
					return err
				}

				r, l, err := r.GetV2ImageBlobReader(endpoint, repoInfo.RemoteName, di.digest, auth)
				if err != nil {
					return err
				}
				defer r.Close()

				verifier, err := digest.NewDigestVerifier(di.digest)
				if err != nil {
					return err
				}

				if _, err := io.Copy(tmpFile, progressreader.New(progressreader.Config{
					In:        ioutil.NopCloser(io.TeeReader(r, verifier)),
					Out:       out,
					Formatter: sf,
					Size:      int(l),
					NewLines:  false,
					ID:        stringid.TruncateID(img.ID),
					Action:    "Downloading",
				})); err != nil {
					return fmt.Errorf("unable to copy v2 image blob data: %s", err)
				}

				out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Verifying Checksum", nil))

				if !verifier.Verified() {
					return fmt.Errorf("image layer digest verification failed for %q", di.digest)
				}

				out.Write(sf.FormatProgress(stringid.TruncateID(img.ID), "Download complete", nil))

				glog.V(1).Infof("Downloaded %s to tempfile %s", img.ID, tmpFile.Name())
				di.tmpFile = tmpFile
				di.length = l
				di.downloaded = true
			}
			di.imgJSON = imgJSON

			return nil
		}

		downloads[i].err = make(chan error)
		go func(di *downloadInfo) {
			di.err <- downloadFunc(di)
		}(&downloads[i])
	}

	var tagUpdated bool
	for i := len(downloads) - 1; i >= 0; i-- {
		d := &downloads[i]
		if d.err != nil {
			if err := <-d.err; err != nil {
				return false, err
			}
		}
		if d.downloaded {
			// if tmpFile is empty assume download and extracted elsewhere
			defer os.Remove(d.tmpFile.Name())
			defer d.tmpFile.Close()
			d.tmpFile.Seek(0, 0)
			if d.tmpFile != nil {
				err = s.graph.Register(d.img,
					progressreader.New(progressreader.Config{
						In:        d.tmpFile,
						Out:       out,
						Formatter: sf,
						Size:      int(d.length),
						ID:        stringid.TruncateID(d.img.ID),
						Action:    "Extracting",
					}))
				if err != nil {
					return false, err
				}

				// FIXME: Pool release here for parallel tag pull (ensures any downloads block until fully extracted)
			}
			out.Write(sf.FormatProgress(stringid.TruncateID(d.img.ID), "Pull complete", nil))
			tagUpdated = true
		} else {
			out.Write(sf.FormatProgress(stringid.TruncateID(d.img.ID), "Already exists", nil))
		}

	}

	// Check for new tag if no layers downloaded
	if !tagUpdated {
		repo, err := s.Get(repoInfo.LocalName)
		if err != nil {
			return false, err
		}
		if repo != nil {
			if _, exists := repo[tag]; !exists {
				tagUpdated = true
			}
		} else {
			tagUpdated = true
		}
	}

	if verified && tagUpdated {
		out.Write(sf.FormatStatus(utils.ImageReference(repoInfo.CanonicalName, tag), "The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security."))
	}

	if localDigest != remoteDigest { // this is not a verification check.
		// NOTE(stevvooe): This is a very defensive branch and should never
		// happen, since all manifest digest implementations use the same
		// algorithm.
		out.Write(sf.FormatStatus("", "Remote Digest: %s", remoteDigest))
	}

	out.Write(sf.FormatStatus("", "Digest: %s", localDigest))

	if tag == localDigest.String() {
		// TODO(stevvooe): Ideally, we should always set the digest so we can
		// use the digest whether we pull by it or not. Unfortunately, the tag
		// store treats the digest as a separate tag, meaning there may be an
		// untagged digest image that would seem to be dangling by a user.

		if err = s.SetDigest(repoInfo.LocalName, localDigest.String(), downloads[0].img.ID); err != nil {
			return false, err
		}
	}

	if !utils.DigestReference(tag) {
		// only set the repository/tag -> image ID mapping when pulling by tag (i.e. not by digest)
		if err = s.Tag(repoInfo.LocalName, tag, downloads[0].img.ID, true); err != nil {
			return false, err
		}
	}

	return tagUpdated, nil
}
Beispiel #5
0
func (s *TagStore) pullImage(r *registry.Session, out io.Writer, imgID, endpoint string, token []string, sf *streamformatter.StreamFormatter) (bool, error) {
	history, err := r.GetRemoteHistory(imgID, endpoint)
	if err != nil {
		return false, err
	}
	out.Write(sf.FormatProgress(stringid.TruncateID(imgID), "Pulling dependent layers", nil))
	// FIXME: Try to stream the images?
	// FIXME: Launch the getRemoteImage() in goroutines

	layersDownloaded := false
	for i := len(history) - 1; i >= 0; i-- {
		id := history[i]

		// ensure no two downloads of the same layer happen at the same time
		if c, err := s.poolAdd("pull", "layer:"+id); err != nil {
			glog.V(1).Infof("Image (id: %s) pull is already running, skipping: %v", id, err)
			<-c
		}
		defer s.poolRemove("pull", "layer:"+id)

		if !s.graph.Exists(id) {
			out.Write(sf.FormatProgress(stringid.TruncateID(id), "Pulling metadata", nil))
			var (
				imgJSON []byte
				imgSize int
				err     error
				img     *image.Image
			)
			retries := 5
			for j := 1; j <= retries; j++ {
				imgJSON, imgSize, err = r.GetRemoteImageJSON(id, endpoint)
				if err != nil && j == retries {
					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
					return layersDownloaded, err
				} else if err != nil {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				}
				img, err = image.NewImgJSON(imgJSON)
				layersDownloaded = true
				if err != nil && j == retries {
					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
					return layersDownloaded, fmt.Errorf("Failed to parse json: %s", err)
				} else if err != nil {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				} else {
					break
				}
			}

			for j := 1; j <= retries; j++ {
				// Get the layer
				status := "Pulling fs layer"
				if j > 1 {
					status = fmt.Sprintf("Pulling fs layer [retries: %d]", j)
				}
				out.Write(sf.FormatProgress(stringid.TruncateID(id), status, nil))
				layer, err := r.GetRemoteImageLayer(img.ID, endpoint, int64(imgSize))
				if uerr, ok := err.(*url.Error); ok {
					err = uerr.Err
				}
				if terr, ok := err.(net.Error); ok && terr.Timeout() && j < retries {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				} else if err != nil {
					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error pulling dependent layers", nil))
					return layersDownloaded, err
				}
				layersDownloaded = true
				defer layer.Close()

				err = s.graph.Register(img,
					progressreader.New(progressreader.Config{
						In:        layer,
						Out:       out,
						Formatter: sf,
						Size:      imgSize,
						NewLines:  false,
						ID:        stringid.TruncateID(id),
						Action:    "Downloading",
					}))
				if terr, ok := err.(net.Error); ok && terr.Timeout() && j < retries {
					time.Sleep(time.Duration(j) * 500 * time.Millisecond)
					continue
				} else if err != nil {
					out.Write(sf.FormatProgress(stringid.TruncateID(id), "Error downloading dependent layers", nil))
					return layersDownloaded, err
				} else {
					break
				}
			}
		}
		out.Write(sf.FormatProgress(stringid.TruncateID(id), "Download complete", nil))
	}
	return layersDownloaded, nil
}
Beispiel #6
0
func calcCopyInfo(b *Builder, cmdName string, cInfos *[]*copyInfo, origPath string, destPath string, allowRemote bool, allowDecompression bool, allowWildcards bool) error {

	if origPath != "" && origPath[0] == '/' && len(origPath) > 1 {
		origPath = origPath[1:]
	}
	origPath = strings.TrimPrefix(origPath, "./")

	// Twiddle the destPath when its a relative path - meaning, make it
	// relative to the WORKINGDIR
	if !filepath.IsAbs(destPath) {
		hasSlash := strings.HasSuffix(destPath, "/")
		destPath = filepath.Join("/", b.Config.WorkingDir, destPath)

		// Make sure we preserve any trailing slash
		if hasSlash {
			destPath += "/"
		}
	}

	// In the remote/URL case, download it and gen its hashcode
	if urlutil.IsURL(origPath) {
		if !allowRemote {
			return fmt.Errorf("Source can't be a URL for %s", cmdName)
		}

		ci := copyInfo{}
		ci.origPath = origPath
		ci.hash = origPath // default to this but can change
		ci.destPath = destPath
		ci.decompress = false
		*cInfos = append(*cInfos, &ci)

		// Initiate the download
		resp, err := httputils.Download(ci.origPath)
		if err != nil {
			return err
		}

		// Create a tmp dir
		tmpDirName, err := ioutil.TempDir(b.contextPath, "docker-remote")
		if err != nil {
			return err
		}
		ci.tmpDir = tmpDirName

		// Create a tmp file within our tmp dir
		tmpFileName := filepath.Join(tmpDirName, "tmp")
		tmpFile, err := os.OpenFile(tmpFileName, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
		if err != nil {
			return err
		}

		// Download and dump result to tmp file
		if _, err := io.Copy(tmpFile, progressreader.New(progressreader.Config{
			In:        resp.Body,
			Out:       b.OutOld,
			Formatter: b.StreamFormatter,
			Size:      int(resp.ContentLength),
			NewLines:  true,
			ID:        "",
			Action:    "Downloading",
		})); err != nil {
			tmpFile.Close()
			return err
		}
		fmt.Fprintf(b.OutStream, "\n")
		tmpFile.Close()

		// Set the mtime to the Last-Modified header value if present
		// Otherwise just remove atime and mtime
		times := make([]syscall.Timespec, 2)

		lastMod := resp.Header.Get("Last-Modified")
		if lastMod != "" {
			mTime, err := http.ParseTime(lastMod)
			// If we can't parse it then just let it default to 'zero'
			// otherwise use the parsed time value
			if err == nil {
				times[1] = syscall.NsecToTimespec(mTime.UnixNano())
			}
		}

		if err := system.UtimesNano(tmpFileName, times); err != nil {
			return err
		}

		ci.origPath = filepath.Join(filepath.Base(tmpDirName), filepath.Base(tmpFileName))

		// If the destination is a directory, figure out the filename.
		if strings.HasSuffix(ci.destPath, "/") {
			u, err := url.Parse(origPath)
			if err != nil {
				return err
			}
			path := u.Path
			if strings.HasSuffix(path, "/") {
				path = path[:len(path)-1]
			}
			parts := strings.Split(path, "/")
			filename := parts[len(parts)-1]
			if filename == "" {
				return fmt.Errorf("cannot determine filename from url: %s", u)
			}
			ci.destPath = ci.destPath + filename
		}

		// Calc the checksum, even if we're using the cache
		r, err := archive.Tar(tmpFileName, archive.Uncompressed)
		if err != nil {
			return err
		}
		tarSum, err := tarsum.NewTarSum(r, true, tarsum.Version0)
		if err != nil {
			return err
		}
		if _, err := io.Copy(ioutil.Discard, tarSum); err != nil {
			return err
		}
		ci.hash = tarSum.Sum(nil)
		r.Close()

		return nil
	}

	// Deal with wildcards
	if allowWildcards && ContainsWildcards(origPath) {
		for _, fileInfo := range b.context.GetSums() {
			if fileInfo.Name() == "" {
				continue
			}
			match, _ := filepath.Match(origPath, fileInfo.Name())
			if !match {
				continue
			}

			// Note we set allowWildcards to false in case the name has
			// a * in it
			calcCopyInfo(b, cmdName, cInfos, fileInfo.Name(), destPath, allowRemote, allowDecompression, false)
		}
		return nil
	}

	// Must be a dir or a file

	if err := b.checkPathForAddition(origPath); err != nil {
		return err
	}
	fi, _ := os.Stat(filepath.Join(b.contextPath, origPath))

	ci := copyInfo{}
	ci.origPath = origPath
	ci.hash = origPath
	ci.destPath = destPath
	ci.decompress = allowDecompression
	*cInfos = append(*cInfos, &ci)

	// Deal with the single file case
	if !fi.IsDir() {
		// This will match first file in sums of the archive
		fis := b.context.GetSums().GetFile(ci.origPath)
		if fis != nil {
			ci.hash = "file:" + fis.Sum()
		}
		return nil
	}

	// Must be a dir
	var subfiles []string
	absOrigPath := filepath.Join(b.contextPath, ci.origPath)

	// Add a trailing / to make sure we only pick up nested files under
	// the dir and not sibling files of the dir that just happen to
	// start with the same chars
	if !strings.HasSuffix(absOrigPath, "/") {
		absOrigPath += "/"
	}

	// Need path w/o / too to find matching dir w/o trailing /
	absOrigPathNoSlash := absOrigPath[:len(absOrigPath)-1]

	for _, fileInfo := range b.context.GetSums() {
		absFile := filepath.Join(b.contextPath, fileInfo.Name())
		// Any file in the context that starts with the given path will be
		// picked up and its hashcode used.  However, we'll exclude the
		// root dir itself.  We do this for a coupel of reasons:
		// 1 - ADD/COPY will not copy the dir itself, just its children
		//     so there's no reason to include it in the hash calc
		// 2 - the metadata on the dir will change when any child file
		//     changes.  This will lead to a miss in the cache check if that
		//     child file is in the .dockerignore list.
		if strings.HasPrefix(absFile, absOrigPath) && absFile != absOrigPathNoSlash {
			subfiles = append(subfiles, fileInfo.Sum())
		}
	}
	sort.Strings(subfiles)
	hasher := sha256.New()
	hasher.Write([]byte(strings.Join(subfiles, ",")))
	ci.hash = "dir:" + hex.EncodeToString(hasher.Sum(nil))

	return nil
}
Beispiel #7
0
// hyper build [OPTIONS] PATH
func (cli *HyperClient) HyperCmdBuild(args ...string) error {
	if len(args) == 0 {
		return fmt.Errorf("%s ERROR: Can not accept the 'run' command without argument!\n", os.Args[0])
	}
	var opts struct {
		ImageName      string `long:"tag" short:"t" default:"" value-name:"\"\"" default-mask:"-" description:"Repository name (and optionally a tag) to be applied to the resulting image in case of success"`
		DockerfileName string `long:"file" short:"f" default:"" value-name:"\"\"" default-mask:"-" description:"Customized docker file"`
	}

	var parser = gflag.NewParser(&opts, gflag.Default)
	parser.Usage = "build [OPTIONS] PATH\n\nBuild a new image from the source code at PATH"
	args, err := parser.Parse()
	if err != nil {
		if !strings.Contains(err.Error(), "Usage") {
			return err
		} else {
			return nil
		}
	}

	if len(args) == 0 {
		return fmt.Errorf("%s: \"build\" requires a minimum of 1 argument, See 'hyper build --help'.", os.Args[0])
	}
	var (
		filename = ""
		context  archive.Archive
		name     = ""
	)
	root := args[1]
	if _, err := os.Stat(root); err != nil {
		return err
	}

	absRoot, err := filepath.Abs(root)
	if err != nil {
		return err
	}

	filename = opts.DockerfileName // path to Dockerfile

	if opts.DockerfileName == "" {
		// No -f/--file was specified so use the default
		opts.DockerfileName = api.DefaultDockerfileName
		filename = filepath.Join(absRoot, opts.DockerfileName)

		// Just to be nice ;-) look for 'dockerfile' too but only
		// use it if we found it, otherwise ignore this check
		if _, err = os.Lstat(filename); os.IsNotExist(err) {
			tmpFN := path.Join(absRoot, strings.ToLower(opts.DockerfileName))
			if _, err = os.Lstat(tmpFN); err == nil {
				opts.DockerfileName = strings.ToLower(opts.DockerfileName)
				filename = tmpFN
			}
		}
	}

	origDockerfile := opts.DockerfileName // used for error msg
	if filename, err = filepath.Abs(filename); err != nil {
		return err
	}

	// Verify that 'filename' is within the build context
	filename, err = symlink.FollowSymlinkInScope(filename, absRoot)
	if err != nil {
		return fmt.Errorf("The Dockerfile (%s) must be within the build context (%s)", origDockerfile, root)
	}

	// Now reset the dockerfileName to be relative to the build context
	opts.DockerfileName, err = filepath.Rel(absRoot, filename)
	if err != nil {
		return err
	}
	// And canonicalize dockerfile name to a platform-independent one
	opts.DockerfileName, err = archive.CanonicalTarNameForPath(opts.DockerfileName)
	if err != nil {
		return fmt.Errorf("Cannot canonicalize dockerfile path %s: %v", opts.DockerfileName, err)
	}

	if _, err = os.Lstat(filename); os.IsNotExist(err) {
		return fmt.Errorf("Cannot locate Dockerfile: %s", origDockerfile)
	}
	var includes = []string{"."}

	excludes, err := utils.ReadDockerIgnore(path.Join(root, ".dockerignore"))
	if err != nil {
		return err
	}

	// If .dockerignore mentions .dockerignore or the Dockerfile
	// then make sure we send both files over to the daemon
	// because Dockerfile is, obviously, needed no matter what, and
	// .dockerignore is needed to know if either one needs to be
	// removed.  The deamon will remove them for us, if needed, after it
	// parses the Dockerfile.
	keepThem1, _ := fileutils.Matches(".dockerignore", excludes)
	keepThem2, _ := fileutils.Matches(opts.DockerfileName, excludes)
	if keepThem1 || keepThem2 {
		includes = append(includes, ".dockerignore", opts.DockerfileName)
	}

	if err := utils.ValidateContextDirectory(root, excludes); err != nil {
		return fmt.Errorf("Error checking context: '%s'.", err)
	}
	options := &archive.TarOptions{
		Compression:     archive.Uncompressed,
		ExcludePatterns: excludes,
		IncludeFiles:    includes,
	}
	context, err = archive.TarWithOptions(root, options)
	if err != nil {
		return err
	}
	var body io.Reader
	// Setup an upload progress bar
	// FIXME: ProgressReader shouldn't be this annoying to use
	if context != nil {
		sf := streamformatter.NewStreamFormatter()
		body = progressreader.New(progressreader.Config{
			In:        context,
			Out:       os.Stdout,
			Formatter: sf,
			NewLines:  true,
			ID:        "",
			Action:    "Sending build context to Docker daemon",
		})
	}

	if opts.ImageName == "" {
		// set a image name
		name = rand.RandStr(10, "alphanum")
	} else {
		name = opts.ImageName
		repository, tag := parsers.ParseRepositoryTag(name)
		if err := registry.ValidateRepositoryName(repository); err != nil {
			return err
		}
		if len(tag) > 0 {
			if err := tags.ValidateTagName(tag); err != nil {
				return err
			}
		}
	}
	v := url.Values{}
	v.Set("name", name)
	headers := http.Header(make(map[string][]string))
	if context != nil {
		headers.Set("Content-Type", "application/tar")
	}
	err = cli.stream("POST", "/image/build?"+v.Encode(), body, cli.out, headers)
	if err != nil {
		return err
	}
	return nil
}