Golang mflag.Merge函数代码示例

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 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 TestFindConfigurationConflictsWithMergedValues(t *testing.T) {
	var hosts []string
	config := map[string]interface{}{"hosts": "tcp://127.0.0.1:2345"}
	base := mflag.NewFlagSet("base", mflag.ContinueOnError)
	base.Var(opts.NewNamedListOptsRef("hosts", &hosts, nil), []string{"H", "-host"}, "")

	flags := mflag.NewFlagSet("test", mflag.ContinueOnError)
	mflag.Merge(flags, base)

	err := findConfigurationConflicts(config, flags)
	if err != nil {
		t.Fatal(err)
	}

	flags.Set("-host", "unix:///var/run/docker.sock")
	err = findConfigurationConflicts(config, flags)
	if err == nil {
		t.Fatal("expected error, got nil")
	}
	if !strings.Contains(err.Error(), "hosts: (from flag: [unix:///var/run/docker.sock], from file: tcp://127.0.0.1:2345)") {
		t.Fatalf("expected hosts conflict, got %v", err)
	}
}

// CmdDaemon is the daemon command, called the raw arguments after `docker daemon`.
func (cli *DaemonCli) CmdDaemon(args ...string) error {
	// warn from uuid package when running the daemon
	uuid.Loggerf = logrus.Warnf

	if !commonFlags.FlagSet.IsEmpty() || !clientFlags.FlagSet.IsEmpty() {
		// deny `docker -D daemon`
		illegalFlag := getGlobalFlag()
		fmt.Fprintf(os.Stderr, "invalid flag '-%s'.\nSee 'docker daemon --help'.\n", illegalFlag.Names[0])
		os.Exit(1)
	} else {
		// allow new form `docker daemon -D`
		flag.Merge(cli.flags, commonFlags.FlagSet)
	}

	configFile := cli.flags.String([]string{daemonConfigFileFlag}, defaultDaemonConfigFile, "Daemon configuration file")

	cli.flags.ParseFlags(args, true)
	commonFlags.PostParse()

	if commonFlags.TrustKey == "" {
		commonFlags.TrustKey = filepath.Join(getDaemonConfDir(), defaultTrustKeyFile)
	}
	cliConfig, err := loadDaemonCliConfig(cli.Config, cli.flags, commonFlags, *configFile)
	if err != nil {
		fmt.Fprint(os.Stderr, err)
		os.Exit(1)
	}
	cli.Config = cliConfig

	if cli.Config.Debug {
		utils.EnableDebug()
	}

	if utils.ExperimentalBuild() {
		logrus.Warn("Running experimental build")
	}

	logrus.SetFormatter(&logrus.TextFormatter{
		TimestampFormat: jsonlog.RFC3339NanoFixed,
		DisableColors:   cli.Config.RawLogs,
	})

	if err := setDefaultUmask(); err != nil {
		logrus.Fatalf("Failed to set umask: %v", err)
	}

	if len(cli.LogConfig.Config) > 0 {
		if err := logger.ValidateLogOpts(cli.LogConfig.Type, cli.LogConfig.Config); err != nil {
			logrus.Fatalf("Failed to set log opts: %v", err)
		}
	}

	var pfile *pidfile.PIDFile
	if cli.Pidfile != "" {
		pf, err := pidfile.New(cli.Pidfile)
		if err != nil {
			logrus.Fatalf("Error starting daemon: %v", err)
		}
		pfile = pf
		defer func() {
			if err := pfile.Remove(); err != nil {
				logrus.Error(err)
			}
		}()
	}

	serverConfig := &apiserver.Config{
		AuthorizationPluginNames: cli.Config.AuthorizationPlugins,
		Logging:                  true,
		SocketGroup:              cli.Config.SocketGroup,
		Version:                  dockerversion.Version,
	}
	serverConfig = setPlatformServerConfig(serverConfig, cli.Config)

	if cli.Config.TLS {
		tlsOptions := tlsconfig.Options{
			CAFile:   cli.Config.CommonTLSOptions.CAFile,
			CertFile: cli.Config.CommonTLSOptions.CertFile,
			KeyFile:  cli.Config.CommonTLSOptions.KeyFile,
		}

		if cli.Config.TLSVerify {
			// server requires and verifies client's certificate
			tlsOptions.ClientAuth = tls.RequireAndVerifyClientCert
		}
		tlsConfig, err := tlsconfig.Server(tlsOptions)
		if err != nil {
			logrus.Fatal(err)
		}
		serverConfig.TLSConfig = tlsConfig
	}

	if len(cli.Config.Hosts) == 0 {
		cli.Config.Hosts = make([]string, 1)
	}

	api := apiserver.New(serverConfig)

	for i := 0; i < len(cli.Config.Hosts); i++ {
//.........这里部分代码省略.........

// CmdDaemon is the daemon command, called the raw arguments after `docker daemon`.
func (cli *DaemonCli) CmdDaemon(args ...string) error {
	// warn from uuid package when running the daemon
	uuid.Loggerf = logrus.Warnf

	if !commonFlags.FlagSet.IsEmpty() || !clientFlags.FlagSet.IsEmpty() {
		// deny `docker -D daemon`
		illegalFlag := getGlobalFlag()
		fmt.Fprintf(os.Stderr, "invalid flag '-%s'.\nSee 'docker daemon --help'.\n", illegalFlag.Names[0])
		os.Exit(1)
	} else {
		// allow new form `docker daemon -D`
		flag.Merge(daemonFlags, commonFlags.FlagSet)
	}

	daemonFlags.ParseFlags(args, true)
	commonFlags.PostParse()

	if commonFlags.TrustKey == "" {
		commonFlags.TrustKey = filepath.Join(getDaemonConfDir(), defaultTrustKeyFile)
	}

	if utils.ExperimentalBuild() {
		logrus.Warn("Running experimental build")
	}

	logrus.SetFormatter(&logrus.TextFormatter{TimestampFormat: jsonlog.RFC3339NanoFixed})

	if err := setDefaultUmask(); err != nil {
		logrus.Fatalf("Failed to set umask: %v", err)
	}

	if len(cli.LogConfig.Config) > 0 {
		if err := logger.ValidateLogOpts(cli.LogConfig.Type, cli.LogConfig.Config); err != nil {
			logrus.Fatalf("Failed to set log opts: %v", err)
		}
	}

	var pfile *pidfile.PIDFile
	if cli.Pidfile != "" {
		pf, err := pidfile.New(cli.Pidfile)
		if err != nil {
			logrus.Fatalf("Error starting daemon: %v", err)
		}
		pfile = pf
		defer func() {
			if err := pfile.Remove(); err != nil {
				logrus.Error(err)
			}
		}()
	}

	serverConfig := &apiserver.Config{
		AuthZPluginNames: cli.Config.AuthZPlugins,
		Logging:          true,
		Version:          dockerversion.Version,
	}
	serverConfig = setPlatformServerConfig(serverConfig, cli.Config)

	defaultHost := opts.DefaultHost
	if commonFlags.TLSOptions != nil {
		if !commonFlags.TLSOptions.InsecureSkipVerify {
			// server requires and verifies client's certificate
			commonFlags.TLSOptions.ClientAuth = tls.RequireAndVerifyClientCert
		}
		tlsConfig, err := tlsconfig.Server(*commonFlags.TLSOptions)
		if err != nil {
			logrus.Fatal(err)
		}
		serverConfig.TLSConfig = tlsConfig
		defaultHost = opts.DefaultTLSHost
	}

	if len(commonFlags.Hosts) == 0 {
		commonFlags.Hosts = make([]string, 1)
	}
	for i := 0; i < len(commonFlags.Hosts); i++ {
		var err error
		if commonFlags.Hosts[i], err = opts.ParseHost(defaultHost, commonFlags.Hosts[i]); err != nil {
			logrus.Fatalf("error parsing -H %s : %v", commonFlags.Hosts[i], err)
		}
	}
	for _, protoAddr := range commonFlags.Hosts {
		protoAddrParts := strings.SplitN(protoAddr, "://", 2)
		if len(protoAddrParts) != 2 {
			logrus.Fatalf("bad format %s, expected PROTO://ADDR", protoAddr)
		}
		serverConfig.Addrs = append(serverConfig.Addrs, apiserver.Addr{Proto: protoAddrParts[0], Addr: protoAddrParts[1]})
	}
	api, err := apiserver.New(serverConfig)
	if err != nil {
		logrus.Fatal(err)
	}

	if err := migrateKey(); err != nil {
		logrus.Fatal(err)
	}
	cli.TrustKeyPath = commonFlags.TrustKey

	registryService := registry.NewService(cli.registryOptions)
//.........这里部分代码省略.........

// CmdDaemon is the daemon command, called the raw arguments after `docker daemon`.
func (cli *DaemonCli) CmdDaemon(args ...string) error {
	if *flDaemon {
		// allow legacy forms `docker -D -d` and `docker -d -D`
		logrus.Warn("please use 'docker daemon' instead.")
	} else if !commonFlags.FlagSet.IsEmpty() || !clientFlags.FlagSet.IsEmpty() {
		// deny `docker -D daemon`
		illegalFlag := getGlobalFlag()
		fmt.Fprintf(os.Stderr, "invalid flag '-%s'.\nSee 'docker daemon --help'.\n", illegalFlag.Names[0])
		os.Exit(1)
	} else {
		// allow new form `docker daemon -D`
		flag.Merge(daemonFlags, commonFlags.FlagSet)
	}

	daemonFlags.ParseFlags(args, true)
	commonFlags.PostParse()

	if len(commonFlags.Hosts) == 0 {
		commonFlags.Hosts = []string{opts.DefaultHost}
	}
	if commonFlags.TrustKey == "" {
		commonFlags.TrustKey = filepath.Join(getDaemonConfDir(), defaultTrustKeyFile)
	}

	if utils.ExperimentalBuild() {
		logrus.Warn("Running experimental build")
	}

	logrus.SetFormatter(&logrus.TextFormatter{TimestampFormat: timeutils.RFC3339NanoFixed})

	if err := setDefaultUmask(); err != nil {
		logrus.Fatalf("Failed to set umask: %v", err)
	}

	if len(cli.LogConfig.Config) > 0 {
		if err := logger.ValidateLogOpts(cli.LogConfig.Type, cli.LogConfig.Config); err != nil {
			logrus.Fatalf("Failed to set log opts: %v", err)
		}
	}

	var pfile *pidfile.PIDFile
	if cli.Pidfile != "" {
		pf, err := pidfile.New(cli.Pidfile)
		if err != nil {
			logrus.Fatalf("Error starting daemon: %v", err)
		}
		pfile = pf
		defer func() {
			if err := pfile.Remove(); err != nil {
				logrus.Error(err)
			}
		}()
	}

	if cli.LogConfig.Config == nil {
		cli.LogConfig.Config = make(map[string]string)
	}

	serverConfig := &apiserver.ServerConfig{
		Logging:     true,
		EnableCors:  cli.EnableCors,
		CorsHeaders: cli.CorsHeaders,
		Version:     dockerversion.VERSION,
	}
	serverConfig = setPlatformServerConfig(serverConfig, cli.Config)

	if commonFlags.TLSOptions != nil {
		if !commonFlags.TLSOptions.InsecureSkipVerify {
			// server requires and verifies client's certificate
			commonFlags.TLSOptions.ClientAuth = tls.RequireAndVerifyClientCert
		}
		tlsConfig, err := tlsconfig.Server(*commonFlags.TLSOptions)
		if err != nil {
			logrus.Fatalf("foobar: %v", err)
		}
		serverConfig.TLSConfig = tlsConfig
	}

	api := apiserver.New(serverConfig)

	// The serve API routine 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 := api.ServeApi(commonFlags.Hosts); err != nil {
			logrus.Errorf("ServeAPI error: %v", err)
			serveAPIWait <- err
			return
		}
		serveAPIWait <- nil
	}()

	if err := migrateKey(); err != nil {
		logrus.Fatal(err)
	}
	cli.TrustKeyPath = commonFlags.TrustKey

	registryService := registry.NewService(cli.registryOptions)
//.........这里部分代码省略.........

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

	logrus.SetOutput(stderr)

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

	cobraAdaptor := cobraadaptor.NewCobraAdaptor(clientFlags)

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

		flag.CommandLine.SetOutput(stdout)
		flag.PrintDefaults()

		help := "\nCommands:\n"

		dockerCommands := append(cli.DockerCommandUsage, cobraAdaptor.Usage()...)
		for _, cmd := range sortCommands(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(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.NewDockerCli(stdin, stdout, stderr, clientFlags)

	c := cli.New(clientCli, NewDaemonProxy(), cobraAdaptor)
	if err := c.Run(flag.Args()...); err != nil {
		if sterr, ok := err.(cli.StatusError); ok {
			if sterr.Status != "" {
				fmt.Fprintln(stderr, sterr.Status)
			}
			// StatusError should only be used for errors, and all errors should
			// have a non-zero exit status, so never exit with 0
			if sterr.StatusCode == 0 {
				os.Exit(1)
			}
			os.Exit(sterr.StatusCode)
		}
		fmt.Fprintln(stderr, err)
		os.Exit(1)
	}
}

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.........

// CmdDaemon is the daemon command, called the raw arguments after `docker daemon`.
func (cli *DaemonCli) CmdDaemon(args ...string) error {
	// warn from uuid package when running the daemon
	uuid.Loggerf = logrus.Warnf

	//调整一下daemon的启动方式
	if !commonFlags.FlagSet.IsEmpty() || !clientFlags.FlagSet.IsEmpty() {
		// deny `docker -D daemon`
		illegalFlag := getGlobalFlag()
		fmt.Fprintf(os.Stderr, "invalid flag '-%s'.\nSee 'docker daemon --help'.\n", illegalFlag.Names[0])
		os.Exit(1)
	} else {
		// allow new form `docker daemon -D`
		flag.Merge(cli.flags, commonFlags.FlagSet)
	}

	configFile := cli.flags.String([]string{daemonConfigFileFlag}, defaultDaemonConfigFile, "Daemon configuration file")

	//匹配配置参数
	cli.flags.ParseFlags(args, true)
	//配置参数生效
	commonFlags.PostParse()

	if commonFlags.TrustKey == "" {
		commonFlags.TrustKey = filepath.Join(getDaemonConfDir(), defaultTrustKeyFile)
	}
	cliConfig, err := loadDaemonCliConfig(cli.Config, cli.flags, commonFlags, *configFile)
	if err != nil {
		fmt.Fprint(os.Stderr, err)
		os.Exit(1)
	}
	cli.Config = cliConfig

	if cli.Config.Debug {
		utils.EnableDebug()
	}

	if utils.ExperimentalBuild() {
		logrus.Warn("Running experimental build")
	}

	logrus.SetFormatter(&logrus.TextFormatter{
		TimestampFormat: jsonlog.RFC3339NanoFixed,
		DisableColors:   cli.Config.RawLogs,
	})

	if err := setDefaultUmask(); err != nil {
		logrus.Fatalf("Failed to set umask: %v", err)
	}

	if len(cli.LogConfig.Config) > 0 {
		if err := logger.ValidateLogOpts(cli.LogConfig.Type, cli.LogConfig.Config); err != nil {
			logrus.Fatalf("Failed to set log opts: %v", err)
		}
	}

	var pfile *pidfile.PIDFile
	if cli.Pidfile != "" {
		pf, err := pidfile.New(cli.Pidfile)
		if err != nil {
			logrus.Fatalf("Error starting daemon: %v", err)
		}
		pfile = pf
		defer func() {
			if err := pfile.Remove(); err != nil {
				logrus.Error(err)
			}
		}()
	}

	//定义apiserver的配置，包括认证、日志输出、版本等。
	serverConfig := &apiserver.Config{
		AuthorizationPluginNames: cli.Config.AuthorizationPlugins,
		Logging:                  true,
		SocketGroup:              cli.Config.SocketGroup,
		Version:                  dockerversion.Version,
	}
	serverConfig = setPlatformServerConfig(serverConfig, cli.Config)

	if cli.Config.TLS {
		tlsOptions := tlsconfig.Options{
			CAFile:   cli.Config.CommonTLSOptions.CAFile,
			CertFile: cli.Config.CommonTLSOptions.CertFile,
			KeyFile:  cli.Config.CommonTLSOptions.KeyFile,
		}

		if cli.Config.TLSVerify {
			// server requires and verifies client's certificate
			tlsOptions.ClientAuth = tls.RequireAndVerifyClientCert
		}
		tlsConfig, err := tlsconfig.Server(tlsOptions)
		if err != nil {
			logrus.Fatal(err)
		}
		serverConfig.TLSConfig = tlsConfig
	}

	if len(cli.Config.Hosts) == 0 {
		cli.Config.Hosts = make([]string, 1)
	}
//.........这里部分代码省略.........