// getArchive returns the tarfile io.ReadCloser. It is a direct copy of the
// logic found in the official docker client.
// See <https://github.com/docker/docker/blob/78f2b8d8/api/client/build.go#L126-L172>.
func getArchive(contextDir, relDockerfile string) (io.ReadCloser, error) {
	var err error

	// And canonicalize dockerfile name to a platform-independent one
	relDockerfile, err = archive.CanonicalTarNameForPath(relDockerfile)
	if err != nil {
		return nil, fmt.Errorf("cannot canonicalize dockerfile path %s: %v", relDockerfile, err)
	}

	f, err := os.Open(filepath.Join(contextDir, ".dockerignore"))
	if err != nil && !os.IsNotExist(err) {
		return nil, err
	}

	var excludes []string
	if err == nil {
		excludes, err = dockerignore.ReadAll(f)
		if err != nil {
			return nil, 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 daemon will remove them for us, if needed, after it
	// parses the Dockerfile. Ignore errors here, as they will have been
	// caught by validateContextDirectory above.
	var includes = []string{"."}
	keepThem1, _ := fileutils.Matches(".dockerignore", excludes)
	keepThem2, _ := fileutils.Matches(relDockerfile, excludes)
	if keepThem1 || keepThem2 {
		includes = append(includes, ".dockerignore", relDockerfile)
	}

	return archive.TarWithOptions(contextDir, &archive.TarOptions{
		Compression:     archive.Uncompressed,
		ExcludePatterns: excludes,
		IncludeFiles:    includes,
	})
}

// CmdBuild builds a new image from the source code at a given path.
//
// If '-' is provided instead of a path or URL, Docker will build an image from either a Dockerfile or tar archive read from STDIN.
//
// Usage: docker build [OPTIONS] PATH | URL | -
func (cli *DockerCli) CmdBuild(args ...string) error {
	cmd := Cli.Subcmd("build", []string{"PATH | URL | -"}, Cli.DockerCommands["build"].Description, true)
	flTags := opts.NewListOpts(validateTag)
	cmd.Var(&flTags, []string{"t", "-tag"}, "Name and optionally a tag in the 'name:tag' format")
	suppressOutput := cmd.Bool([]string{"q", "-quiet"}, false, "Suppress the build output and print image ID on success")
	noCache := cmd.Bool([]string{"-no-cache"}, false, "Do not use cache when building the image")
	rm := cmd.Bool([]string{"-rm"}, true, "Remove intermediate containers after a successful build")
	forceRm := cmd.Bool([]string{"-force-rm"}, false, "Always remove intermediate containers")
	pull := cmd.Bool([]string{"-pull"}, false, "Always attempt to pull a newer version of the image")
	dockerfileName := cmd.String([]string{"f", "-file"}, "", "Name of the Dockerfile (Default is 'PATH/Dockerfile')")
	flMemoryString := cmd.String([]string{"m", "-memory"}, "", "Memory limit")
	flMemorySwap := cmd.String([]string{"-memory-swap"}, "", "Swap limit equal to memory plus swap: '-1' to enable unlimited swap")
	flShmSize := cmd.String([]string{"-shm-size"}, "", "Size of /dev/shm, default value is 64MB")
	flCPUShares := cmd.Int64([]string{"#c", "-cpu-shares"}, 0, "CPU shares (relative weight)")
	flCPUPeriod := cmd.Int64([]string{"-cpu-period"}, 0, "Limit the CPU CFS (Completely Fair Scheduler) period")
	flCPUQuota := cmd.Int64([]string{"-cpu-quota"}, 0, "Limit the CPU CFS (Completely Fair Scheduler) quota")
	flCPUSetCpus := cmd.String([]string{"-cpuset-cpus"}, "", "CPUs in which to allow execution (0-3, 0,1)")
	flCPUSetMems := cmd.String([]string{"-cpuset-mems"}, "", "MEMs in which to allow execution (0-3, 0,1)")
	flCgroupParent := cmd.String([]string{"-cgroup-parent"}, "", "Optional parent cgroup for the container")
	flBuildArg := opts.NewListOpts(runconfigopts.ValidateEnv)
	cmd.Var(&flBuildArg, []string{"-build-arg"}, "Set build-time variables")
	isolation := cmd.String([]string{"-isolation"}, "", "Container isolation level")

	ulimits := make(map[string]*units.Ulimit)
	flUlimits := runconfigopts.NewUlimitOpt(&ulimits)
	cmd.Var(flUlimits, []string{"-ulimit"}, "Ulimit options")

	cmd.Require(flag.Exact, 1)

	// For trusted pull on "FROM <image>" instruction.
	addTrustedFlags(cmd, true)

	cmd.ParseFlags(args, true)

	var (
		context  io.ReadCloser
		isRemote bool
		err      error
	)

	_, err = exec.LookPath("git")
	hasGit := err == nil

	specifiedContext := cmd.Arg(0)

	var (
		contextDir    string
		tempDir       string
		relDockerfile string
		progBuff      io.Writer
		buildBuff     io.Writer
	)

	progBuff = cli.out
	buildBuff = cli.out
	if *suppressOutput {
		progBuff = bytes.NewBuffer(nil)
		buildBuff = bytes.NewBuffer(nil)
	}

	switch {
	case specifiedContext == "-":
		context, relDockerfile, err = getContextFromReader(cli.in, *dockerfileName)
	case urlutil.IsGitURL(specifiedContext) && hasGit:
		tempDir, relDockerfile, err = getContextFromGitURL(specifiedContext, *dockerfileName)
	case urlutil.IsURL(specifiedContext):
		context, relDockerfile, err = getContextFromURL(progBuff, specifiedContext, *dockerfileName)
	default:
		contextDir, relDockerfile, err = getContextFromLocalDir(specifiedContext, *dockerfileName)
	}

	if err != nil {
		if *suppressOutput && urlutil.IsURL(specifiedContext) {
			fmt.Fprintln(cli.err, progBuff)
		}
		return fmt.Errorf("unable to prepare context: %s", err)
	}

	if tempDir != "" {
		defer os.RemoveAll(tempDir)
		contextDir = tempDir
	}

	if context == nil {
		// And canonicalize dockerfile name to a platform-independent one
		relDockerfile, err = archive.CanonicalTarNameForPath(relDockerfile)
		if err != nil {
			return fmt.Errorf("cannot canonicalize dockerfile path %s: %v", relDockerfile, err)
		}

		f, err := os.Open(filepath.Join(contextDir, ".dockerignore"))
		if err != nil && !os.IsNotExist(err) {
			return err
		}

//.........这里部分代码省略.........

// CmdBuild builds a new image from the source code at a given path.
//
// If '-' is provided instead of a path or URL, Docker will build an image from either a Dockerfile or tar archive read from STDIN.
//
// Usage: docker build [OPTIONS] PATH | URL | -
func (cli *DockerCli) CmdBuild(args ...string) error {
	cmd := cli.Subcmd("build", "PATH | URL | -", "Build a new image from the source code at PATH", true)
	tag := cmd.String([]string{"t", "-tag"}, "", "Repository name (and optionally a tag) for the image")
	suppressOutput := cmd.Bool([]string{"q", "-quiet"}, false, "Suppress the verbose output generated by the containers")
	noCache := cmd.Bool([]string{"#no-cache", "-no-cache"}, false, "Do not use cache when building the image")
	rm := cmd.Bool([]string{"#rm", "-rm"}, true, "Remove intermediate containers after a successful build")
	forceRm := cmd.Bool([]string{"-force-rm"}, false, "Always remove intermediate containers")
	pull := cmd.Bool([]string{"-pull"}, false, "Always attempt to pull a newer version of the image")
	dockerfileName := cmd.String([]string{"f", "-file"}, "", "Name of the Dockerfile (Default is 'PATH/Dockerfile')")
	flMemoryString := cmd.String([]string{"m", "-memory"}, "", "Memory limit")
	flMemorySwap := cmd.String([]string{"-memory-swap"}, "", "Total memory (memory + swap), '-1' to disable swap")
	flCPUShares := cmd.Int64([]string{"c", "-cpu-shares"}, 0, "CPU shares (relative weight)")
	flCpuQuota := cmd.Int64([]string{"-cpu-quota"}, 0, "Limit the CPU CFS (Completely Fair Scheduler) quota")
	flCPUSetCpus := cmd.String([]string{"-cpuset-cpus"}, "", "CPUs in which to allow execution (0-3, 0,1)")
	flCPUSetMems := cmd.String([]string{"-cpuset-mems"}, "", "MEMs in which to allow execution (0-3, 0,1)")
	flCgroupParent := cmd.String([]string{"-cgroup-parent"}, "", "Optional parent cgroup for the container")

	cmd.Require(flag.Exact, 1)
	cmd.ParseFlags(args, true)

	var (
		context  archive.Archive
		isRemote bool
		err      error
	)

	_, err = exec.LookPath("git")
	hasGit := err == nil
	if cmd.Arg(0) == "-" {
		// As a special case, 'docker build -' will build from either an empty context with the
		// contents of stdin as a Dockerfile, or a tar-ed context from stdin.
		buf := bufio.NewReader(cli.in)
		magic, err := buf.Peek(tarHeaderSize)
		if err != nil && err != io.EOF {
			return fmt.Errorf("failed to peek context header from STDIN: %v", err)
		}
		if !archive.IsArchive(magic) {
			dockerfile, err := ioutil.ReadAll(buf)
			if err != nil {
				return fmt.Errorf("failed to read Dockerfile from STDIN: %v", err)
			}

			// -f option has no meaning when we're reading it from stdin,
			// so just use our default Dockerfile name
			*dockerfileName = api.DefaultDockerfileName
			context, err = archive.Generate(*dockerfileName, string(dockerfile))
		} else {
			context = ioutil.NopCloser(buf)
		}
	} else if urlutil.IsURL(cmd.Arg(0)) && (!urlutil.IsGitURL(cmd.Arg(0)) || !hasGit) {
		isRemote = true
	} else {
		root := cmd.Arg(0)
		if urlutil.IsGitURL(root) {
			root, err = utils.GitClone(root)
			if err != nil {
				return err
			}
			defer os.RemoveAll(root)
		}
		if _, err := os.Stat(root); err != nil {
			return err
		}

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

		filename := *dockerfileName // path to Dockerfile

		if *dockerfileName == "" {
			// No -f/--file was specified so use the default
			*dockerfileName = api.DefaultDockerfileName
			filename = filepath.Join(absRoot, *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(*dockerfileName))
				if _, err = os.Lstat(tmpFN); err == nil {
					*dockerfileName = strings.ToLower(*dockerfileName)
					filename = tmpFN
				}
			}
		}

		origDockerfile := *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 {
//.........这里部分代码省略.........

// CmdBuild builds a new image from the source code at a given path.
//
// If '-' is provided instead of a path or URL, Docker will build an image from either a Dockerfile or tar archive read from STDIN.
//
// Usage: docker build [OPTIONS] PATH | URL | -
func (cli *DockerCli) CmdBuild(args ...string) error {
	cmd := Cli.Subcmd("build", []string{"PATH | URL | -"}, Cli.DockerCommands["build"].Description, true)
	flTags := opts.NewListOpts(validateTag)
	cmd.Var(&flTags, []string{"t", "-tag"}, "Name and optionally a tag in the 'name:tag' format")
	suppressOutput := cmd.Bool([]string{"q", "-quiet"}, false, "Suppress the verbose output generated by the containers")
	noCache := cmd.Bool([]string{"#no-cache", "-no-cache"}, false, "Do not use cache when building the image")
	rm := cmd.Bool([]string{"#rm", "-rm"}, true, "Remove intermediate containers after a successful build")
	forceRm := cmd.Bool([]string{"-force-rm"}, false, "Always remove intermediate containers")
	pull := cmd.Bool([]string{"-pull"}, false, "Always attempt to pull a newer version of the image")
	dockerfileName := cmd.String([]string{"f", "-file"}, "", "Name of the Dockerfile (Default is 'PATH/Dockerfile')")
	flMemoryString := cmd.String([]string{"m", "-memory"}, "", "Memory limit")
	flMemorySwap := cmd.String([]string{"-memory-swap"}, "", "Total memory (memory + swap), '-1' to disable swap")
	flCPUShares := cmd.Int64([]string{"#c", "-cpu-shares"}, 0, "CPU shares (relative weight)")
	flCPUPeriod := cmd.Int64([]string{"-cpu-period"}, 0, "Limit the CPU CFS (Completely Fair Scheduler) period")
	flCPUQuota := cmd.Int64([]string{"-cpu-quota"}, 0, "Limit the CPU CFS (Completely Fair Scheduler) quota")
	flCPUSetCpus := cmd.String([]string{"-cpuset-cpus"}, "", "CPUs in which to allow execution (0-3, 0,1)")
	flCPUSetMems := cmd.String([]string{"-cpuset-mems"}, "", "MEMs in which to allow execution (0-3, 0,1)")
	flCgroupParent := cmd.String([]string{"-cgroup-parent"}, "", "Optional parent cgroup for the container")
	flBuildArg := opts.NewListOpts(opts.ValidateEnv)
	cmd.Var(&flBuildArg, []string{"-build-arg"}, "Set build-time variables")

	ulimits := make(map[string]*ulimit.Ulimit)
	flUlimits := opts.NewUlimitOpt(&ulimits)
	cmd.Var(flUlimits, []string{"-ulimit"}, "Ulimit options")

	cmd.Require(flag.Exact, 1)

	// For trusted pull on "FROM <image>" instruction.
	addTrustedFlags(cmd, true)

	cmd.ParseFlags(args, true)

	var (
		context  io.ReadCloser
		isRemote bool
		err      error
	)

	_, err = exec.LookPath("git")
	hasGit := err == nil

	specifiedContext := cmd.Arg(0)

	var (
		contextDir    string
		tempDir       string
		relDockerfile string
	)

	switch {
	case specifiedContext == "-":
		tempDir, relDockerfile, err = getContextFromReader(cli.in, *dockerfileName)
	case urlutil.IsGitURL(specifiedContext) && hasGit:
		tempDir, relDockerfile, err = getContextFromGitURL(specifiedContext, *dockerfileName)
	case urlutil.IsURL(specifiedContext):
		tempDir, relDockerfile, err = getContextFromURL(cli.out, specifiedContext, *dockerfileName)
	default:
		contextDir, relDockerfile, err = getContextFromLocalDir(specifiedContext, *dockerfileName)
	}

	if err != nil {
		return fmt.Errorf("unable to prepare context: %s", err)
	}

	if tempDir != "" {
		defer os.RemoveAll(tempDir)
		contextDir = tempDir
	}

	// Resolve the FROM lines in the Dockerfile to trusted digest references
	// using Notary. On a successful build, we must tag the resolved digests
	// to the original name specified in the Dockerfile.
	newDockerfile, resolvedTags, err := rewriteDockerfileFrom(filepath.Join(contextDir, relDockerfile), cli.trustedReference)
	if err != nil {
		return fmt.Errorf("unable to process Dockerfile: %v", err)
	}
	defer newDockerfile.Close()

	// And canonicalize dockerfile name to a platform-independent one
	relDockerfile, err = archive.CanonicalTarNameForPath(relDockerfile)
	if err != nil {
		return fmt.Errorf("cannot canonicalize dockerfile path %s: %v", relDockerfile, err)
	}

	f, err := os.Open(filepath.Join(contextDir, ".dockerignore"))
	if err != nil && !os.IsNotExist(err) {
		return err
	}

	var excludes []string
	if err == nil {
		excludes, err = utils.ReadDockerIgnore(f)
		if err != nil {
			return err
		}
//.........这里部分代码省略.........

func runBuild(dockerCli *command.DockerCli, options buildOptions) error {

	var (
		buildCtx io.ReadCloser
		err      error
	)

	specifiedContext := options.context

	var (
		contextDir    string
		tempDir       string
		relDockerfile string
		progBuff      io.Writer
		buildBuff     io.Writer
	)

	progBuff = dockerCli.Out()
	buildBuff = dockerCli.Out()
	if options.quiet {
		progBuff = bytes.NewBuffer(nil)
		buildBuff = bytes.NewBuffer(nil)
	}

	switch {
	case specifiedContext == "-":
		buildCtx, relDockerfile, err = builder.GetContextFromReader(dockerCli.In(), options.dockerfileName)
	case urlutil.IsGitURL(specifiedContext):
		tempDir, relDockerfile, err = builder.GetContextFromGitURL(specifiedContext, options.dockerfileName)
	case urlutil.IsURL(specifiedContext):
		buildCtx, relDockerfile, err = builder.GetContextFromURL(progBuff, specifiedContext, options.dockerfileName)
	default:
		contextDir, relDockerfile, err = builder.GetContextFromLocalDir(specifiedContext, options.dockerfileName)
	}

	if err != nil {
		if options.quiet && urlutil.IsURL(specifiedContext) {
			fmt.Fprintln(dockerCli.Err(), progBuff)
		}
		return fmt.Errorf("unable to prepare context: %s", err)
	}

	if tempDir != "" {
		defer os.RemoveAll(tempDir)
		contextDir = tempDir
	}

	if buildCtx == nil {
		// And canonicalize dockerfile name to a platform-independent one
		relDockerfile, err = archive.CanonicalTarNameForPath(relDockerfile)
		if err != nil {
			return fmt.Errorf("cannot canonicalize dockerfile path %s: %v", relDockerfile, err)
		}

		f, err := os.Open(filepath.Join(contextDir, ".dockerignore"))
		if err != nil && !os.IsNotExist(err) {
			return err
		}
		defer f.Close()

		var excludes []string
		if err == nil {
			excludes, err = dockerignore.ReadAll(f)
			if err != nil {
				return err
			}
		}

		if err := builder.ValidateContextDirectory(contextDir, excludes); err != nil {
			return fmt.Errorf("Error checking context: '%s'.", 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 daemon will remove them for us, if needed, after it
		// parses the Dockerfile. Ignore errors here, as they will have been
		// caught by validateContextDirectory above.
		var includes = []string{"."}
		keepThem1, _ := fileutils.Matches(".dockerignore", excludes)
		keepThem2, _ := fileutils.Matches(relDockerfile, excludes)
		if keepThem1 || keepThem2 {
			includes = append(includes, ".dockerignore", relDockerfile)
		}

		buildCtx, err = archive.TarWithOptions(contextDir, &archive.TarOptions{
			Compression:     archive.Uncompressed,
			ExcludePatterns: excludes,
			IncludeFiles:    includes,
		})
		if err != nil {
			return err
		}
	}

	ctx := context.Background()

	var resolvedTags []*resolvedTag
	if command.IsTrusted() {
//.........这里部分代码省略.........

// hyper build [OPTIONS] PATH
func (cli *HyperClient) HyperCmdBuild(args ...string) error {
	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.ParseArgs(args)
	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[0]
	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{"."}

	f, err := os.Open(filepath.Join(root, ".dockerignore"))
	if err != nil && !os.IsNotExist(err) {
		return err
	}
	defer f.Close()

	var excludes []string
	if err == nil {
		excludes, err = utils.ReadDockerIgnore(f)
		if err != nil {
			return err
		}
	}

	if err := utils.ValidateContextDirectory(root, excludes); err != nil {
		return fmt.Errorf("Error checking context: '%s'.", err)
	}

	// If .dockerignore mentions .dockerignore or the Dockerfile
//.........这里部分代码省略.........

// CreateTar create a build context tar for the specified project and service name.
func CreateTar(p *project.Project, name string) (io.ReadCloser, error) {
	// This code was ripped off from docker/api/client/build.go

	serviceConfig := p.Configs[name]
	root := serviceConfig.Build
	dockerfileName := filepath.Join(root, serviceConfig.Dockerfile)

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

	filename := dockerfileName

	if dockerfileName == "" {
		// No -f/--file was specified so use the default
		dockerfileName = DefaultDockerfileName
		filename = filepath.Join(absRoot, 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(dockerfileName))
			if _, err = os.Lstat(tmpFN); err == nil {
				dockerfileName = strings.ToLower(dockerfileName)
				filename = tmpFN
			}
		}
	}

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

	// Now reset the dockerfileName to be relative to the build context
	dockerfileName, err = filepath.Rel(absRoot, filename)
	if err != nil {
		return nil, err
	}

	// And canonicalize dockerfile name to a platform-independent one
	dockerfileName, err = archive.CanonicalTarNameForPath(dockerfileName)
	if err != nil {
		return nil, fmt.Errorf("Cannot canonicalize dockerfile path %s: %v", dockerfileName, err)
	}

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

	dockerIgnorePath := path.Join(root, ".dockerignore")
	dockerIgnore, err := os.Open(dockerIgnorePath)
	if err != nil {
		if !os.IsNotExist(err) {
			return nil, err
		}
		logrus.Warnf("Error while reading .dockerignore (%s) : %s", dockerIgnorePath, err.Error())
		excludes = make([]string, 0)
	} else {
		excludes, err = utils.ReadDockerIgnore(dockerIgnore)
		if err != nil {
			return nil, 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(dockerfileName, excludes)
	if keepThem1 || keepThem2 {
		includes = append(includes, ".dockerignore", dockerfileName)
	}

	if err := utils.ValidateContextDirectory(root, excludes); err != nil {
		return nil, fmt.Errorf("Error checking context is accessible: '%s'. Please check permissions and try again.", err)
	}

	options := &archive.TarOptions{
		Compression:     archive.Uncompressed,
		ExcludePatterns: excludes,
		IncludeFiles:    includes,
	}

	return archive.TarWithOptions(root, options)
}