// getContextFromGitURL uses a Git URL as context for a `docker build`. The
// git repo is cloned into a temporary directory used as the context directory.
// Returns the absolute path to the temporary context directory, the relative
// path of the dockerfile in that context directory, and a non-nil error on
// success.
func getContextFromGitURL(gitURL, dockerfileName string) (absContextDir, relDockerfile string, err error) {
	if absContextDir, err = utils.GitClone(gitURL); err != nil {
		return "", "", fmt.Errorf("unable to 'git clone' to temporary context directory: %v", err)
	}

	return getDockerfileRelPath(absContextDir, dockerfileName)
}

// MakeGitContext returns a Context from gitURL that is cloned in a temporary directory.
func MakeGitContext(gitURL string) (ModifiableContext, error) {
	root, err := utils.GitClone(gitURL)
	if err != nil {
		return nil, err
	}

	c, err := archive.Tar(root, archive.Uncompressed)
	if err != nil {
		return nil, err
	}

	defer func() {
		// TODO: print errors?
		c.Close()
		os.RemoveAll(root)
	}()
	return MakeTarSumContext(c)
}

// 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	pull := cmd.Bool([]string{"-pull"}, false, "Always attempt to pull a newer version of the image")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.........

// Build is the main interface of the package, it gathers the Builder
// struct and calls builder.Run() to do all the real build job.
func Build(d *daemon.Daemon, buildConfig *Config) error {
	var (
		repoName string
		tag      string
		context  io.ReadCloser
	)
	sf := streamformatter.NewJSONStreamFormatter()

	repoName, tag = parsers.ParseRepositoryTag(buildConfig.RepoName)
	if repoName != "" {
		if err := registry.ValidateRepositoryName(repoName); err != nil {
			return err
		}
		if len(tag) > 0 {
			if err := tags.ValidateTagName(tag); err != nil {
				return err
			}
		}
	}

	if buildConfig.RemoteURL == "" {
		context = ioutil.NopCloser(buildConfig.Context)
	} else if urlutil.IsGitURL(buildConfig.RemoteURL) {
		root, err := utils.GitClone(buildConfig.RemoteURL)
		if err != nil {
			return err
		}
		defer os.RemoveAll(root)

		c, err := archive.Tar(root, archive.Uncompressed)
		if err != nil {
			return err
		}
		context = c
	} else if urlutil.IsURL(buildConfig.RemoteURL) {
		f, err := httputils.Download(buildConfig.RemoteURL)
		if err != nil {
			return fmt.Errorf("Error downloading remote context %s: %v", buildConfig.RemoteURL, err)
		}
		defer f.Body.Close()
		ct := f.Header.Get("Content-Type")
		clen := int(f.ContentLength)
		contentType, bodyReader, err := inspectResponse(ct, f.Body, clen)

		defer bodyReader.Close()

		if err != nil {
			return fmt.Errorf("Error detecting content type for remote %s: %v", buildConfig.RemoteURL, err)
		}
		if contentType == httputils.MimeTypes.TextPlain {
			dockerFile, err := ioutil.ReadAll(bodyReader)
			if err != nil {
				return err
			}

			// When we're downloading just a Dockerfile put it in
			// the default name - don't allow the client to move/specify it
			buildConfig.DockerfileName = api.DefaultDockerfileName

			c, err := archive.Generate(buildConfig.DockerfileName, string(dockerFile))
			if err != nil {
				return err
			}
			context = c
		} else {
			// Pass through - this is a pre-packaged context, presumably
			// with a Dockerfile with the right name inside it.
			prCfg := progressreader.Config{
				In:        bodyReader,
				Out:       buildConfig.Stdout,
				Formatter: sf,
				Size:      clen,
				NewLines:  true,
				ID:        "Downloading context",
				Action:    buildConfig.RemoteURL,
			}
			context = progressreader.New(prCfg)
		}
	}

	defer context.Close()

	builder := &builder{
		Daemon: d,
		OutStream: &streamformatter.StdoutFormater{
			Writer:          buildConfig.Stdout,
			StreamFormatter: sf,
		},
		ErrStream: &streamformatter.StderrFormater{
			Writer:          buildConfig.Stdout,
			StreamFormatter: sf,
		},
		Verbose:         !buildConfig.SuppressOutput,
		UtilizeCache:    !buildConfig.NoCache,
		Remove:          buildConfig.Remove,
		ForceRemove:     buildConfig.ForceRemove,
		Pull:            buildConfig.Pull,
		OutOld:          buildConfig.Stdout,
//.........这里部分代码省略.........

func Build(d *daemon.Daemon, buildConfig *Config) error {
	var (
		repoName string
		tag      string
		context  io.ReadCloser
	)

	repoName, tag = parsers.ParseRepositoryTag(buildConfig.RepoName)
	if repoName != "" {
		if err := registry.ValidateRepositoryName(repoName); err != nil {
			return err
		}
		if len(tag) > 0 {
			if err := tags.ValidateTagName(tag); err != nil {
				return err
			}
		}
	}

	if buildConfig.RemoteURL == "" {
		context = ioutil.NopCloser(buildConfig.Context)
	} else if urlutil.IsGitURL(buildConfig.RemoteURL) {
		root, err := utils.GitClone(buildConfig.RemoteURL)
		if err != nil {
			return err
		}
		defer os.RemoveAll(root)

		c, err := archive.Tar(root, archive.Uncompressed)
		if err != nil {
			return err
		}
		context = c
	} else if urlutil.IsURL(buildConfig.RemoteURL) {
		f, err := httputils.Download(buildConfig.RemoteURL)
		if err != nil {
			return err
		}
		defer f.Body.Close()
		dockerFile, err := ioutil.ReadAll(f.Body)
		if err != nil {
			return err
		}

		// When we're downloading just a Dockerfile put it in
		// the default name - don't allow the client to move/specify it
		buildConfig.DockerfileName = api.DefaultDockerfileName

		c, err := archive.Generate(buildConfig.DockerfileName, string(dockerFile))
		if err != nil {
			return err
		}
		context = c
	}
	defer context.Close()

	sf := streamformatter.NewJSONStreamFormatter()

	builder := &Builder{
		Daemon: d,
		OutStream: &streamformatter.StdoutFormater{
			Writer:          buildConfig.Stdout,
			StreamFormatter: sf,
		},
		ErrStream: &streamformatter.StderrFormater{
			Writer:          buildConfig.Stdout,
			StreamFormatter: sf,
		},
		Verbose:         !buildConfig.SuppressOutput,
		UtilizeCache:    !buildConfig.NoCache,
		Remove:          buildConfig.Remove,
		ForceRemove:     buildConfig.ForceRemove,
		Pull:            buildConfig.Pull,
		OutOld:          buildConfig.Stdout,
		StreamFormatter: sf,
		AuthConfig:      buildConfig.AuthConfig,
		ConfigFile:      buildConfig.ConfigFile,
		dockerfileName:  buildConfig.DockerfileName,
		cpuShares:       buildConfig.CpuShares,
		cpuPeriod:       buildConfig.CpuPeriod,
		cpuQuota:        buildConfig.CpuQuota,
		cpuSetCpus:      buildConfig.CpuSetCpus,
		cpuSetMems:      buildConfig.CpuSetMems,
		cgroupParent:    buildConfig.CgroupParent,
		memory:          buildConfig.Memory,
		memorySwap:      buildConfig.MemorySwap,
		cancelled:       buildConfig.WaitCancelled(),
	}

	id, err := builder.Run(context)
	if err != nil {
		return err
	}

	if repoName != "" {
		return d.Repositories().Tag(repoName, tag, id, true)
	}
	return nil
}