// CmdHelp displays information on a Docker command.
//
// If more than one command is specified, information is only shown for the first command.
//
// Usage: docker help COMMAND or docker COMMAND --help
// CmdHelp 在Docker命令行上显示提示信息
//
// 如果指定了多个命令，只显示第一个命令的提示信息
//
// 用法：docker help COMMAND 或者 docker COMMAND --help
//
func (cli *Cli) CmdHelp(args ...string) error {
	if len(args) > 1 {
		command, err := cli.command(args[:2]...)
		switch err := err.(type) {
		case nil:
			command("--help")
			return nil
		case initErr:
			return err.error
		}
	}
	if len(args) > 0 {
		command, err := cli.command(args[0])
		switch err := err.(type) {
		case nil:
			command("--help")
			return nil
		case initErr:
			return err.error
		}
		cli.noSuchCommand(args[0])
	}

	if cli.Usage == nil {
		flag.Usage()
	} else {
		cli.Usage()
	}

	return nil
}

func main() {
	var (
		as        []string
		hostMatch string
	)
	mflagext.ListVar(&as, []string{"a", "-alias"}, []string{}, "Specify hostname aliases in the form alias:hostname.  Can be repeated.")
	mflag.StringVar(&hostMatch, []string{"h", "-host-match"}, "*.weave.local", "Specify main host shExpMatch expression in pacfile")
	mflag.Parse()

	var aliases = map[string]string{}
	for _, a := range as {
		parts := strings.SplitN(a, ":", 2)
		if len(parts) != 2 {
			fmt.Printf("'%s' is not a valid alias.\n", a)
			mflag.Usage()
			os.Exit(1)
		}
		aliases[parts[0]] = parts[1]
	}

	go socksProxy(aliases)

	t := template.Must(template.New("pacfile").Parse(pacfile))
	http.HandleFunc("/proxy.pac", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/x-ns-proxy-autoconfig")
		t.Execute(w, pacFileParameters{hostMatch, aliases})
	})

	if err := http.ListenAndServe(":8080", nil); err != nil {
		panic(err)
	}
}

func main() {
	if reexec.Init() {
		return
	}

	// Set terminal emulation based on platform as required.
	stdin, stdout, stderr := term.StdStreams()

	logrus.SetOutput(stderr)

	flag.Merge(flag.CommandLine, clientFlags.FlagSet, commonFlags.FlagSet)

	flag.Usage = func() {
		fmt.Fprint(os.Stdout, "Usage: docker [OPTIONS] COMMAND [arg...]\n"+daemonUsage+"       docker [ -h | --help | -v | --version ]\n\n")
		fmt.Fprint(os.Stdout, "A self-sufficient runtime for containers.\n\nOptions:\n")

		flag.CommandLine.SetOutput(os.Stdout)
		flag.PrintDefaults()

		help := "\nCommands:\n"

		for _, cmd := range dockerCommands {
			help += fmt.Sprintf("    %-10.10s%s\n", cmd.name, cmd.description)
		}

		help += "\nRun 'docker COMMAND --help' for more information on a command."
		fmt.Fprintf(os.Stdout, "%s\n", help)
	}

	flag.Parse()

	if *flVersion {
		showVersion()
		return
	}

	clientCli := client.NewDockerCli(stdin, stdout, stderr, clientFlags)
	// TODO: remove once `-d` is retired
	handleGlobalDaemonFlag()

	if *flHelp {
		// if global flag --help is present, regardless of what other options and commands there are,
		// just print the usage.
		flag.Usage()
		return
	}

	c := cli.New(clientCli, daemonCli)
	if err := c.Run(flag.Args()...); err != nil {
		if sterr, ok := err.(cli.StatusError); ok {
			if sterr.Status != "" {
				fmt.Fprintln(os.Stderr, sterr.Status)
				os.Exit(1)
			}
			os.Exit(sterr.StatusCode)
		}
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}

func readConfig() {
	var (
		configFile            string
		showHelp, showVersion bool
	)
	logFilter = &logutils.LevelFilter{
		Levels:   logLevels,
		MinLevel: logMinLevel,
		Writer:   os.Stderr,
	}
	log.SetOutput(logFilter)
	flag.StringVar(&configFile, []string{"c", "-config"}, "/etc/logear/logear.conf", "config file")
	flag.StringVar(&logFile, []string{"l", "-log"}, "", "log file")
	flag.BoolVar(&showHelp, []string{"h", "-help"}, false, "display the help")
	flag.BoolVar(&showVersion, []string{"v", "-version"}, false, "display version info")
	flag.Parse()
	if showHelp {
		flag.Usage()
		os.Exit(0)
	}
	if showVersion {
		println(versionstring)
		println("OS: " + runtime.GOOS)
		println("Architecture: " + runtime.GOARCH)
		os.Exit(0)
	}
	parseTomlFile(configFile)
	startLogging()
	log.Printf("%s started with pid %d", versionstring, os.Getpid())
}

// CmdHelp displays information on a Docker command.
//
// If more than one command is specified, information is only shown for the first command.
//
// Usage: docker help COMMAND or docker COMMAND --help
func (cli *Cli) CmdHelp(args ...string) error {
	if len(args) > 1 {
		command, err := cli.command(args[:2]...)
		if err == nil {
			command("--help")
			return nil
		}
		if err != errCommandNotFound {
			return err
		}
	}
	if len(args) > 0 {
		command, err := cli.command(args[0])
		if err != nil {
			if err == errCommandNotFound {
				cli.noSuchCommand(args[0])
				return nil
			}
			return err
		}
		command("--help")
		return nil
	}

	if cli.Usage == nil {
		flag.Usage()
	} else {
		cli.Usage()
	}

	return nil
}

func mainDaemon() {
	if flag.NArg() != 0 {
		flag.Usage()
		return
	}
	eng := engine.New()
	signal.Trap(eng.Shutdown)
	// Load builtins
	if err := builtins.Register(eng); err != nil {
		log.Fatal(err)
	}

	// load the daemon in the background so we can immediately start
	// the http api so that connections don't fail while the daemon
	// is booting
	go func() {
		d, err := daemon.NewDaemon(daemonCfg, eng)
		if err != nil {
			log.Fatal(err)
		}
		if err := d.Install(eng); err != nil {
			log.Fatal(err)
		}

		b := &builder.BuilderJob{eng, d}
		b.Install()

		// after the daemon is done setting up we can tell the api to start
		// accepting connections
		if err := eng.Job("acceptconnections").Run(); err != nil {
			log.Fatal(err)
		}
	}()
	// TODO actually have a resolved graphdriver to show?
	log.Printf("docker daemon: %s %s; execdriver: %s; graphdriver: %s",
		dockerversion.VERSION,
		dockerversion.GITCOMMIT,
		daemonCfg.ExecDriver,
		daemonCfg.GraphDriver,
	)

	// Serve api
	job := eng.Job("serveapi", flHosts...)
	job.SetenvBool("Logging", true)
	job.SetenvBool("EnableCors", *flEnableCors)
	job.Setenv("Version", dockerversion.VERSION)
	job.Setenv("SocketGroup", *flSocketGroup)

	job.SetenvBool("Tls", *flTls)
	job.SetenvBool("TlsVerify", *flTlsVerify)
	job.Setenv("TlsCa", *flCa)
	job.Setenv("TlsCert", *flCert)
	job.Setenv("TlsKey", *flKey)
	job.Setenv("TrustKey", *flTrustKey)
	job.SetenvBool("BufferRequests", true)
	if err := job.Run(); err != nil {
		log.Fatal(err)
	}
}

// doFlags defines the cmdline Usage string and parses flag options.
func doFlags() {
	flag.Usage = func() {
		fmt.Fprintf(os.Stderr, "  Usage: %s [OPTIONS] REGISTRY REPO [REPO...]\n", os.Args[0])
		fmt.Fprintf(os.Stderr, "\n  REGISTRY:\n")
		fmt.Fprintf(os.Stderr, "\tURL of your Docker registry; use index.docker.io for Docker Hub, use local.host to collect images from local Docker host\n")
		fmt.Fprintf(os.Stderr, "\n  REPO:\n")
		fmt.Fprintf(os.Stderr, "\tOne or more repos to gather info about; if no repo is specified Collector will gather info on *all* repos in the Registry\n")
		fmt.Fprintf(os.Stderr, "\n  Environment variables:\n")
		fmt.Fprintf(os.Stderr, "\tCOLLECTOR_DIR:   (Required) Directory that contains the \"data\" folder with Collector default scripts, e.g., $GOPATH/src/github.com/banyanops/collector\n")
		fmt.Fprintf(os.Stderr, "\tCOLLECTOR_ID:    ID provided by Banyan web interface to register Collector with the Banyan service\n")
		fmt.Fprintf(os.Stderr, "\tBANYAN_HOST_DIR: Host directory mounted into Collector/Target containers where results are stored (default: $HOME/.banyan)\n")
		fmt.Fprintf(os.Stderr, "\tBANYAN_DIR:      (Specify only in Dockerfile) Directory in the Collector container where host directory BANYAN_HOST_DIR is mounted\n")
		fmt.Fprintf(os.Stderr, "\tDOCKER_{HOST,CERT_PATH,TLS_VERIFY}: If set, e.g., by docker-machine, then they take precedence over --dockerProto and --dockerAddr\n")
		printExampleUsage()
		fmt.Fprintf(os.Stderr, "  Options:\n")
		flag.PrintDefaults()
	}
	flag.Parse()
	if config.COLLECTORDIR() == "" {
		flag.Usage()
		os.Exit(except.ErrorExitStatus)
	}
	if len(flag.Args()) < 1 {
		flag.Usage()
		os.Exit(except.ErrorExitStatus)
	}
	if *dockerProto != "unix" && *dockerProto != "tcp" {
		flag.Usage()
		os.Exit(except.ErrorExitStatus)
	}
	requiredDirs := []string{config.BANYANDIR(), filepath.Dir(*imageList), filepath.Dir(*repoList), *config.BanyanOutDir, collector.DefaultScriptsDir, collector.UserScriptsDir, collector.BinDir}
	for _, dir := range requiredDirs {
		blog.Debug("Creating directory: " + dir)
		err := fsutil.CreateDirIfNotExist(dir)
		if err != nil {
			except.Fail(err, ": Error in creating a required directory: ", dir)
		}
	}
	collector.RegistrySpec = flag.Arg(0)
	// EqualFold: case insensitive comparison
	if strings.EqualFold(flag.Arg(0), "local.host") {
		collector.LocalHost = true
	}
	//nextMaxImages = *maxImages
}

func dnetCommand(stdout, stderr io.Writer) error {
	flag.Parse()

	if *flHelp {
		flag.Usage()
		return nil
	}

	if *flLogLevel != "" {
		lvl, err := logrus.ParseLevel(*flLogLevel)
		if err != nil {
			fmt.Fprintf(stderr, "Unable to parse logging level: %s\n", *flLogLevel)
			return err
		}
		logrus.SetLevel(lvl)
	} else {
		logrus.SetLevel(logrus.InfoLevel)
	}

	if *flDebug {
		logrus.SetLevel(logrus.DebugLevel)
	}

	if *flHost == "" {
		defaultHost := os.Getenv("DNET_HOST")
		if defaultHost == "" {
			// TODO : Add UDS support
			defaultHost = fmt.Sprintf("tcp://%s:%d", DefaultHTTPHost, DefaultHTTPPort)
		}
		*flHost = defaultHost
	}

	dc, err := newDnetConnection(*flHost)
	if err != nil {
		if *flDaemon {
			logrus.Error(err)
		} else {
			fmt.Fprint(stderr, err)
		}
		return err
	}

	if *flDaemon {
		err := dc.dnetDaemon()
		if err != nil {
			logrus.Errorf("dnet Daemon exited with an error : %v", err)
		}
		return err
	}

	cli := client.NewNetworkCli(stdout, stderr, dc.httpCall)
	if err := cli.Cmd("dnet", flag.Args()...); err != nil {
		fmt.Fprintln(stderr, err)
		return err
	}
	return nil
}

func main() {
	if reexec.Init() {
		return
	}

	// Set terminal emulation based on platform as required.
	_, stdout, stderr := term.StdStreams()

	logrus.SetOutput(stderr)

	flag.Merge(flag.CommandLine, daemonCli.commonFlags.FlagSet)

	flag.Usage = func() {
		fmt.Fprint(stdout, "Usage: dockerd [ --help | -v | --version ]\n\n")
		fmt.Fprint(stdout, "A self-sufficient runtime for containers.\n\nOptions:\n")

		flag.CommandLine.SetOutput(stdout)
		flag.PrintDefaults()
	}
	flag.CommandLine.ShortUsage = func() {
		fmt.Fprint(stderr, "\nUsage:\tdockerd [OPTIONS]\n")
	}

	if err := flag.CommandLine.ParseFlags(os.Args[1:], false); err != nil {
		os.Exit(1)
	}

	if *flVersion {
		showVersion()
		return
	}

	if *flHelp {
		// if global flag --help is present, regardless of what other options and commands there are,
		// just print the usage.
		flag.Usage()
		return
	}

	// On Windows, this may be launching as a service or with an option to
	// register the service.
	stop, err := initService()
	if err != nil {
		logrus.Fatal(err)
	}

	if !stop {
		err = daemonCli.start()
		notifyShutdown(err)
		if err != nil {
			logrus.Fatal(err)
		}
	}
}

func main() {
	fmt.Print("Hello, world\n")

	// Define global flag here

	// end global flag definition

	flag.Usage = func() {
		fmt.Fprint(os.Stdout, "Usage: docking [OPTIONS] COMMAND [arg...]\n       docking [ --help | -v | --version ]\n\n")
		fmt.Fprint(os.Stdout, "A self-sufficient runtime for containers.\n\nOptions:\n")

		flag.CommandLine.SetOutput(os.Stdout)
		flag.PrintDefaults()

		help := "\nCommands:\n"

		for _, cmd := range dockingCommands {
			help += fmt.Sprintf("    %-10.10s%s\n", cmd.Name, cmd.Description)
		}

		help += "\nRun 'docking COMMAND --help' for more information on a command."
		fmt.Fprintf(os.Stdout, "%s\n", help)
	}
	flag.Parse()

	if *flVersion {
		showVersion()
		return
	}

	if *flHelp {
		// if global flag --help is present, regardless of what other options and commands there are,
		// just print the usage.
		flag.Usage()
		return
	}

	clientCli := client.NewDockingCli(os.Stdin, os.Stdout, os.Stderr, clientFlags)

	c := cli.New(clientCli)
	if err := c.Run(flag.Args()...); err != nil {
		if sterr, ok := err.(cli.StatusError); ok {
			if sterr.Status != "" {
				fmt.Fprintln(os.Stderr, sterr.Status)
				os.Exit(1)
			}
			os.Exit(sterr.StatusCode)
		}
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}

}

// Cmd is borrowed from Docker UI and acts as the entry point for network UI commands.
// network UI commands are designed to be invoked from multiple parent chains
func (cli *NetworkCli) Cmd(chain string, args ...string) error {
	if len(args) > 1 {
		method, exists := cli.getMethod(args[:2]...)
		if exists {
			return method(chain+" "+args[0], args[2:]...)
		}
	}
	if len(args) > 0 {
		method, exists := cli.getMethod(args[0])
		if !exists {
			return fmt.Errorf("%s: '%s' is not a %s command. See '%s --help'.\n", chain, args[0], chain, chain)
		}
		return method(chain, args[1:]...)
	}
	flag.Usage()
	return nil
}

func (dcli *DockerfCli) CmdContainer(args ...string) error {

	flag.CommandLine.Parse(args)

	if *flVersion {
		showVersion()
		os.Exit(1)
	}

	if *flDaemon {
		if *flHelp {
			flag.Usage()
			os.Exit(1)
		}
		fmt.Printf("dockerf container does not support daemon.\n")
		os.Exit(1)
	}

	if *flMachine == "" {
		app := path.Base(os.Args[0])
		cmd := "container"
		fmt.Printf("%s: \"%s\" requires --machine flag for manage any container. See '%s %s --help'. \n", app, cmd, app, cmd)
		os.Exit(1)
	}

	cluster := ""
	if *flSwarm {
		cluster = "swarm"
	}
	rewriteTLSFlags(dcli, *flMachine, cluster)

	cli := newDockerClient()
	if err := cli.Cmd(flag.Args()...); err != nil {
		if sterr, ok := err.(client.StatusError); ok {
			if sterr.Status != "" {
				fmt.Fprintln(cli.Err(), sterr.Status)
				os.Exit(1)
			}
			os.Exit(sterr.StatusCode)
		}
		fmt.Fprintln(cli.Err(), err)
		os.Exit(1)
	}
	return nil
}

func main() {
	flag.Usage = func() {
		fmt.Fprint(os.Stdout, "Usage: gofind [OPTIONS] COMMAND [arg...]\ngofind [ --help | -v | --version ]\n")
		flag.CommandLine.SetOutput(os.Stdout)
		flag.PrintDefaults()
	}
	if h {
		flag.Usage()
	} else {
		fmt.Printf("Path: %s\n", path)
		fmt.Printf("Name: %s\n", name)
		fmt.Printf("ARGS: %v\n", flag.Args())
		err := finder(path, name)
		if err != nil {
			fmt.Println(err)
			return
		}

	}
}

// CmdHelp displays information on a Docker command.
//
// If more than one command is specified, information is only shown for the first command.
//
// Usage: docker help COMMAND or docker COMMAND --help
func (cli *DockerCli) CmdHelp(args ...string) error {
	if len(args) > 1 {
		method, exists := cli.getMethod(args[:2]...)
		if exists {
			method("--help")
			return nil
		}
	}
	if len(args) > 0 {
		method, exists := cli.getMethod(args[0])
		if !exists {
			return fmt.Errorf("docker: '%s' is not a docker command. See 'docker --help'.", args[0])
		}
		method("--help")
		return nil
	}

	flag.Usage()

	return nil
}

// CmdHelp displays information on a Docker command.
//
// If more than one command is specified, information is only shown for the first command.
//
// Usage: docker help COMMAND or docker COMMAND --help
func (cli *DockerCli) CmdHelp(args ...string) error {
	if len(args) > 1 {
		method, exists := cli.getMethod(args[:2]...)
		if exists {
			method("--help")
			return nil
		}
	}
	if len(args) > 0 {
		method, exists := cli.getMethod(args[0])
		if !exists {
			fmt.Fprintf(cli.err, "docker: '%s' is not a docker command. See 'docker --help'.\n", args[0])
			os.Exit(1)
		} else {
			method("--help")
			return nil
		}
	}

	flag.Usage()

	return nil
}

func mainDaemon() {
	if flag.NArg() != 0 {
		flag.Usage()
		return
	}
	eng := engine.New()
	signal.Trap(eng.Shutdown)

	if err := migrateKey(); err != nil {
		logrus.Fatal(err)
	}
	daemonCfg.TrustKeyPath = *flTrustKey

	// Load builtins
	if err := builtins.Register(eng); err != nil {
		logrus.Fatal(err)
	}

	// load registry service
	if err := registry.NewService(registryCfg).Install(eng); err != nil {
		logrus.Fatal(err)
	}

	// load the daemon in the background so we can immediately start
	// the http api so that connections don't fail while the daemon
	// is booting
	daemonInitWait := make(chan error)
	go func() {
		d, err := daemon.NewDaemon(daemonCfg, eng)
		if err != nil {
			daemonInitWait <- err
			return
		}

		logrus.Infof("docker daemon: %s %s; execdriver: %s; graphdriver: %s",
			dockerversion.VERSION,
			dockerversion.GITCOMMIT,
			d.ExecutionDriver().Name(),
			d.GraphDriver().String(),
		)

		if err := d.Install(eng); err != nil {
			daemonInitWait <- err
			return
		}

		b := &builder.BuilderJob{eng, d}
		b.Install()

		// after the daemon is done setting up we can tell the api to start
		// accepting connections
		if err := eng.Job("acceptconnections").Run(); err != nil {
			daemonInitWait <- err
			return
		}
		daemonInitWait <- nil
	}()

	// Serve api
	job := eng.Job("serveapi", flHosts...)
	job.SetenvBool("Logging", true)
	job.SetenvBool("EnableCors", daemonCfg.EnableCors)
	job.Setenv("CorsHeaders", daemonCfg.CorsHeaders)
	job.Setenv("Version", dockerversion.VERSION)
	job.Setenv("SocketGroup", daemonCfg.SocketGroup)

	job.SetenvBool("Tls", *flTls)
	job.SetenvBool("TlsVerify", *flTlsVerify)
	job.Setenv("TlsCa", *flCa)
	job.Setenv("TlsCert", *flCert)
	job.Setenv("TlsKey", *flKey)
	job.SetenvBool("BufferRequests", true)

	// The serve API job never exits unless an error occurs
	// We need to start it as a goroutine and wait on it so
	// daemon doesn't exit
	serveAPIWait := make(chan error)
	go func() {
		if err := job.Run(); err != nil {
			logrus.Errorf("ServeAPI error: %v", err)
			serveAPIWait <- err
			return
		}
		serveAPIWait <- nil
	}()

	// Wait for the daemon startup goroutine to finish
	// This makes sure we can actually cleanly shutdown the daemon
	logrus.Debug("waiting for daemon to initialize")
	errDaemon := <-daemonInitWait
	if errDaemon != nil {
		eng.Shutdown()
		outStr := fmt.Sprintf("Shutting down daemon due to errors: %v", errDaemon)
		if strings.Contains(errDaemon.Error(), "engine is shutdown") {
			// if the error is "engine is shutdown", we've already reported (or
			// will report below in API server errors) the error
			outStr = "Shutting down daemon due to reported errors"
		}
		// we must "fatal" exit here as the API server may be happy to
		// continue listening forever if the error had no impact to API
//.........这里部分代码省略.........

func main() {
	//启动前检查，防止出现已经启动的情况
	if reexec.Init() {
		return
	}

	// Set terminal emulation based on platform as required.
	stdin, stdout, stderr := term.StdStreams()

	logrus.SetOutput(stderr)

	//合并参数类型，所有的参数类型都是FlagSet类，该类定义如下：
	//type FlagSet struct {
	// Usage is the function called when an error occurs while parsing flags.
	// The field is a function (not a method) that may be changed to point to
	// a custom error handler.
	/*Usage      func()
		ShortUsage func()

		name             string
		parsed           bool
		actual           map[string]*Flag
		formal           map[string]*Flag
		args             []string // arguments after flags
		errorHandling    ErrorHandling
		output           io.Writer // nil means stderr; use Out() accessor
		nArgRequirements []nArgRequirement
	}*/
	//合并参数到flag.CommandLine中。CommandLine中对应的是Options。
	flag.Merge(flag.CommandLine, clientFlags.FlagSet, commonFlags.FlagSet)

	//打印docker的使用方式。这里其实只是设置Usage这个函数的实现，以便需要打印的时候打印。
	flag.Usage = func() {
		//第一行是正常的使用方式；第二行是daemon的使用方式；第三行固定输出
		fmt.Fprint(stdout, "Usage: docker [OPTIONS] COMMAND [arg...]\n"+daemonUsage+"       docker [ --help | -v | --version ]\n\n")
		fmt.Fprint(stdout, "A self-sufficient runtime for containers.\n\nOptions:\n")

		//输出Options的内容，打印CommandLine中的内容。这一行设置输出到标准输出。
		flag.CommandLine.SetOutput(stdout)
		//真实的打印内容
		flag.PrintDefaults()

		//开始打印可选择的命令Commands。
		help := "\nCommands:\n"

		//循环输出dockerCommands命令中的可选择命令，分别打印他们的名字和描述信息。
		//dockerCommands最终由cli.DockerCommands中提供。
		for _, cmd := range dockerCommands {
			help += fmt.Sprintf("    %-10.10s%s\n", cmd.Name, cmd.Description)
		}

		help += "\nRun 'docker COMMAND --help' for more information on a command."
		//真实的打印
		fmt.Fprintf(stdout, "%s\n", help)
	}

	//解析参数
	flag.Parse()

	//version单独处理，这里通过判断flVersion的返回结果是否为真进行处理。
	if *flVersion {
		showVersion()
		return
	}
	//help信息单独处理
	if *flHelp {
		// if global flag --help is present, regardless of what other options and commands there are,
		// just print the usage.
		flag.Usage()
		return
	}

	//创建client模式的docker，详细分析请见api/client/cli.go包中的NewDockerCli函数。
	clientCli := client.NewDockerCli(stdin, stdout, stderr, clientFlags)

	//合并client模式的docker和daemonCli模式的docker，实际中只会有一个在工作。
	//daemonCli对象的创建请见docker/daemon.go中的daemonCli cli.Handler = NewDaemonCli()
	//cli.New接受两个参数，分别是dockercli对象和daemoncli对象，两个对象结构不同。
	//但是返回的是一个cli对象:
	/*
			type Cli struct {
			    Stderr   io.Writer
			    handlers []Handler
			    Usage    func()
		            }
	*/
	//clientClie和daemoncli就放在句柄handlers数组中。
	c := cli.New(clientCli, daemonCli)
	//c.Run函数见cli中的cli.go的func (cli *Cli) Run(args ...string) error
	if err := c.Run(flag.Args()...); err != nil {
		if sterr, ok := err.(cli.StatusError); ok {
			if sterr.Status != "" {
				fmt.Fprintln(stderr, sterr.Status)
				os.Exit(1)
			}
			os.Exit(sterr.StatusCode)
		}
		fmt.Fprintln(stderr, err)
		os.Exit(1)
	}
//.........这里部分代码省略.........

func showHelp() {
	mflag.Usage()
}

func main() {
	if reexec.Init() {
		return
	}

	// Set terminal emulation based on platform as required.
	stdin, stdout, stderr := term.StdStreams()

	initLogging(stderr)

	flag.Parse()
	// FIXME: validate daemon flags here

	if *flVersion {
		showVersion()
		return
	}

	if *flConfigDir != "" {
		cliconfig.SetConfigDir(*flConfigDir)
	}

	if *flLogLevel != "" {
		lvl, err := logrus.ParseLevel(*flLogLevel)
		if err != nil {
			fmt.Fprintf(os.Stderr, "Unable to parse logging level: %s\n", *flLogLevel)
			os.Exit(1)
		}
		setLogLevel(lvl)
	} else {
		setLogLevel(logrus.InfoLevel)
	}

	if *flDebug {
		os.Setenv("DEBUG", "1")
		setLogLevel(logrus.DebugLevel)
	}

	if len(flHosts) == 0 {
		defaultHost := os.Getenv("DOCKER_HOST")
		if defaultHost == "" || *flDaemon {
			if runtime.GOOS != "windows" {
				// If we do not have a host, default to unix socket
				defaultHost = fmt.Sprintf("unix://%s", opts.DefaultUnixSocket)
			} else {
				// If we do not have a host, default to TCP socket on Windows
				defaultHost = fmt.Sprintf("tcp://%s:%d", opts.DefaultHTTPHost, opts.DefaultHTTPPort)
			}
		}
		defaultHost, err := opts.ValidateHost(defaultHost)
		if err != nil {
			if *flDaemon {
				logrus.Fatal(err)
			} else {
				fmt.Fprint(os.Stderr, err)
			}
			os.Exit(1)
		}
		flHosts = append(flHosts, defaultHost)
	}

	setDefaultConfFlag(flTrustKey, defaultTrustKeyFile)

	// Regardless of whether the user sets it to true or false, if they
	// specify --tlsverify at all then we need to turn on tls
	// *flTlsVerify can be true even if not set due to DOCKER_TLS_VERIFY env var, so we need to check that here as well
	if flag.IsSet("-tlsverify") || *flTlsVerify {
		*flTls = true
	}

	if *flDaemon {
		if *flHelp {
			flag.Usage()
			return
		}
		mainDaemon()
		return
	}

	// From here on, we assume we're a client, not a server.

	if len(flHosts) > 1 {
		fmt.Fprintf(os.Stderr, "Please specify only one -H")
		os.Exit(0)
	}
	protoAddrParts := strings.SplitN(flHosts[0], "://", 2)

	var tlsConfig *tls.Config
	if *flTls {
		tlsOptions.InsecureSkipVerify = !*flTlsVerify
		if !flag.IsSet("-tlscert") {
			if _, err := os.Stat(tlsOptions.CertFile); os.IsNotExist(err) {
				tlsOptions.CertFile = ""
			}
		}
		if !flag.IsSet("-tlskey") {
			if _, err := os.Stat(tlsOptions.KeyFile); os.IsNotExist(err) {
				tlsOptions.KeyFile = ""
			}
		}
//.........这里部分代码省略.........

func main() {
	if len(dockerConfDir) == 0 {
		dockerConfDir = filepath.Join(os.Getenv("HOME"), ".docker")
	}
	if selfPath := utils.SelfPath(); strings.Contains(selfPath, ".dockerinit") {
		// Running in init mode
		sysinit.SysInit()
		return
	}

	var (
		flVersion            = flag.Bool([]string{"v", "-version"}, false, "Print version information and quit")
		flDaemon             = flag.Bool([]string{"d", "-daemon"}, false, "Enable daemon mode")
		flGraphOpts          opts.ListOpts
		flDebug              = flag.Bool([]string{"D", "-debug"}, false, "Enable debug mode")
		flAutoRestart        = flag.Bool([]string{"r", "-restart"}, true, "Restart previously running containers")
		bridgeName           = flag.String([]string{"b", "-bridge"}, "", "Attach containers to a pre-existing network bridge\nuse 'none' to disable container networking")
		bridgeIp             = flag.String([]string{"#bip", "-bip"}, "", "Use this CIDR notation address for the network bridge's IP, not compatible with -b")
		pidfile              = flag.String([]string{"p", "-pidfile"}, "/var/run/docker.pid", "Path to use for daemon PID file")
		flRoot               = flag.String([]string{"g", "-graph"}, "/var/lib/docker", "Path to use as the root of the Docker runtime")
		flSocketGroup        = flag.String([]string{"G", "-group"}, "docker", "Group to assign the unix socket specified by -H when running in daemon mode\nuse '' (the empty string) to disable setting of a group")
		flEnableCors         = flag.Bool([]string{"#api-enable-cors", "-api-enable-cors"}, false, "Enable CORS headers in the remote API")
		flDns                = opts.NewListOpts(opts.ValidateIPAddress)
		flDnsSearch          = opts.NewListOpts(opts.ValidateDnsSearch)
		flEnableIptables     = flag.Bool([]string{"#iptables", "-iptables"}, true, "Enable Docker's addition of iptables rules")
		flEnableIpForward    = flag.Bool([]string{"#ip-forward", "-ip-forward"}, true, "Enable net.ipv4.ip_forward")
		flDefaultIp          = flag.String([]string{"#ip", "-ip"}, "0.0.0.0", "Default IP address to use when binding container ports")
		flInterContainerComm = flag.Bool([]string{"#icc", "-icc"}, true, "Enable inter-container communication")
		flGraphDriver        = flag.String([]string{"s", "-storage-driver"}, "", "Force the Docker runtime to use a specific storage driver")
		flExecDriver         = flag.String([]string{"e", "-exec-driver"}, "native", "Force the Docker runtime to use a specific exec driver")
		flHosts              = opts.NewListOpts(api.ValidateHost)
		flMtu                = flag.Int([]string{"#mtu", "-mtu"}, 0, "Set the containers network MTU\nif no value is provided: default to the default route MTU or 1500 if no default route is available")
		flTls                = flag.Bool([]string{"-tls"}, false, "Use TLS; implied by tls-verify flags")
		flTlsVerify          = flag.Bool([]string{"-tlsverify"}, false, "Use TLS and verify the remote (daemon: verify client, client: verify daemon)")
		flCa                 = flag.String([]string{"-tlscacert"}, filepath.Join(dockerConfDir, defaultCaFile), "Trust only remotes providing a certificate signed by the CA given here")
		flCert               = flag.String([]string{"-tlscert"}, filepath.Join(dockerConfDir, defaultCertFile), "Path to TLS certificate file")
		flKey                = flag.String([]string{"-tlskey"}, filepath.Join(dockerConfDir, defaultKeyFile), "Path to TLS key file")
		flSelinuxEnabled     = flag.Bool([]string{"-selinux-enabled"}, false, "Enable selinux support. SELinux does not presently support the BTRFS storage driver")
	)
	flag.Var(&flDns, []string{"#dns", "-dns"}, "Force Docker to use specific DNS servers")
	flag.Var(&flDnsSearch, []string{"-dns-search"}, "Force Docker to use specific DNS search domains")
	flag.Var(&flHosts, []string{"H", "-host"}, "The socket(s) to bind to in daemon mode\nspecified using one or more tcp://host:port, unix:///path/to/socket, fd://* or fd://socketfd.")
	flag.Var(&flGraphOpts, []string{"-storage-opt"}, "Set storage driver options")

	flag.Parse()

	if *flVersion {
		showVersion()
		return
	}
	if flHosts.Len() == 0 {
		defaultHost := os.Getenv("DOCKER_HOST")

		if defaultHost == "" || *flDaemon {
			// If we do not have a host, default to unix socket
			defaultHost = fmt.Sprintf("unix://%s", api.DEFAULTUNIXSOCKET)
		}
		if _, err := api.ValidateHost(defaultHost); err != nil {
			log.Fatal(err)
		}
		flHosts.Set(defaultHost)
	}

	if *bridgeName != "" && *bridgeIp != "" {
		log.Fatal("You specified -b & --bip, mutually exclusive options. Please specify only one.")
	}

	if !*flEnableIptables && !*flInterContainerComm {
		log.Fatal("You specified --iptables=false with --icc=false. ICC uses iptables to function. Please set --icc or --iptables to true.")
	}

	if net.ParseIP(*flDefaultIp) == nil {
		log.Fatalf("Specified --ip=%s is not in correct format \"0.0.0.0\".", *flDefaultIp)
	}

	if *flDebug {
		os.Setenv("DEBUG", "1")
	}

	if *flDaemon {
		if runtime.GOOS != "linux" {
			log.Fatalf("The Docker daemon is only supported on linux")
		}
		if os.Geteuid() != 0 {
			log.Fatalf("The Docker daemon needs to be run as root")
		}

		if flag.NArg() != 0 {
			flag.Usage()
			return
		}

		// set up the TempDir to use a canonical path
		tmp := os.TempDir()
		realTmp, err := utils.ReadSymlinkedDirectory(tmp)
		if err != nil {
			log.Fatalf("Unable to get the full path to the TempDir (%s): %s", tmp, err)
		}
		os.Setenv("TMPDIR", realTmp)

//.........这里部分代码省略.........