// NewDockerCli returns a DockerCli instance with IO output and error streams set by in, out and err.
// The key file, protocol (i.e. unix) and address are passed in as strings, along with the tls.Config. If the tls.Config
// is set the client scheme will be set to https.
// The client will be given a 32-second timeout (see https://github.com/docker/docker/pull/8035).
func NewDockerCli(in io.ReadCloser, out, err io.Writer, clientFlags *cli.ClientFlags) *DockerCli {
	//创建cli对象
	cli := &DockerCli{
		in:      in,
		out:     out,
		err:     err,
		keyFile: clientFlags.Common.TrustKey,
	}

	//docker客户端模式的创建过程，如果需要安全认证，需要加载安全认证的证书。
	cli.init = func() error {
		clientFlags.PostParse()
		configFile, e := cliconfig.Load(cliconfig.ConfigDir())
		if e != nil {
			fmt.Fprintf(cli.err, "WARNING: Error loading config file:%v\n", e)
		}
		if !configFile.ContainsAuth() {
			credentials.DetectDefaultStore(configFile)
		}
		cli.configFile = configFile

		host, err := getServerHost(clientFlags.Common.Hosts, clientFlags.Common.TLSOptions)
		if err != nil {
			return err
		}

		customHeaders := cli.configFile.HTTPHeaders
		if customHeaders == nil {
			customHeaders = map[string]string{}
		}
		customHeaders["User-Agent"] = clientUserAgent()

		verStr := api.DefaultVersion.String()
		if tmpStr := os.Getenv("DOCKER_API_VERSION"); tmpStr != "" {
			verStr = tmpStr
		}

		httpClient, err := newHTTPClient(host, clientFlags.Common.TLSOptions)
		if err != nil {
			return err
		}

		client, err := client.NewClient(host, verStr, httpClient, customHeaders)
		if err != nil {
			return err
		}
		cli.client = client

		if cli.in != nil {
			cli.inFd, cli.isTerminalIn = term.GetFdInfo(cli.in)
		}
		if cli.out != nil {
			cli.outFd, cli.isTerminalOut = term.GetFdInfo(cli.out)
		}

		return nil
	}

	return cli
}

// NewDockerCli returns a DockerCli instance with IO output and error streams set by in, out and err.
// The key file, protocol (i.e. unix) and address are passed in as strings, along with the tls.Config. If the tls.Config
// is set the client scheme will be set to https.
// The client will be given a 32-second timeout (see https://github.com/docker/docker/pull/8035).
func NewDockerCli(in io.ReadCloser, out, err io.Writer, clientFlags *cli.ClientFlags) *DockerCli {
	cli := &DockerCli{
		in:      in,
		out:     out,
		err:     err,
		keyFile: clientFlags.Common.TrustKey,
	}

	cli.init = func() error {
		clientFlags.PostParse()
		configFile, e := cliconfig.Load(cliconfig.ConfigDir())
		if e != nil {
			fmt.Fprintf(cli.err, "WARNING: Error loading config file:%v\n", e)
		}
		cli.configFile = configFile

		host, err := getServerHost(clientFlags.Common.Hosts, clientFlags.Common.TLSOptions)
		if err != nil {
			return err
		}

		customHeaders := cli.configFile.HTTPHeaders
		if customHeaders == nil {
			customHeaders = map[string]string{}
		}
		customHeaders["User-Agent"] = "Docker-Client/" + dockerversion.Version + " (" + runtime.GOOS + ")"

		verStr := api.DefaultVersion.String()
		if tmpStr := os.Getenv("DOCKER_API_VERSION"); tmpStr != "" {
			verStr = tmpStr
		}

		clientTransport, err := newClientTransport(clientFlags.Common.TLSOptions)
		if err != nil {
			return err
		}

		client, err := client.NewClient(host, verStr, clientTransport, customHeaders)
		if err != nil {
			return err
		}
		cli.client = client

		if cli.in != nil {
			cli.inFd, cli.isTerminalIn = term.GetFdInfo(cli.in)
		}
		if cli.out != nil {
			cli.outFd, cli.isTerminalOut = term.GetFdInfo(cli.out)
		}

		return nil
	}

	return cli
}

//docker client 创建函数
// NewDockerCli returns a DockerCli instance with IO output and error streams set by in, out and err.
// The key file, protocol (i.e. unix) and address are passed in as strings, along with the tls.Config. If the tls.Config
// is set the client scheme will be set to https.
// The client will be given a 32-second timeout (see https://github.com/docker/docker/pull/8035).
func NewDockerCli(in io.ReadCloser, out, err io.Writer, clientFlags *cli.ClientFlags) *DockerCli {
	cli := &DockerCli{
		in:      in,
		out:     out,
		err:     err,
		keyFile: clientFlags.Common.TrustKey,
	}

	cli.init = func() error {

		clientFlags.PostParse()

		hosts := clientFlags.Common.Hosts

		switch len(hosts) {
		case 0:
			hosts = []string{os.Getenv("DOCKER_HOST")}
		case 1:
			// only accept one host to talk to
		default:
			return errors.New("Please specify only one -H")
		}

		defaultHost := opts.DefaultTCPHost
		if clientFlags.Common.TLSOptions != nil {
			defaultHost = opts.DefaultTLSHost
		}

		var e error
		if hosts[0], e = opts.ParseHost(defaultHost, hosts[0]); e != nil {
			return e
		}

		protoAddrParts := strings.SplitN(hosts[0], "://", 2)
		cli.proto, cli.addr = protoAddrParts[0], protoAddrParts[1]

		if cli.proto == "tcp" {
			// error is checked in pkg/parsers already
			parsed, _ := url.Parse("tcp://" + cli.addr)
			cli.addr = parsed.Host
			cli.basePath = parsed.Path
		}

		if clientFlags.Common.TLSOptions != nil {
			cli.scheme = "https" //启用HTTPS
			var e error
			cli.tlsConfig, e = tlsconfig.Client(*clientFlags.Common.TLSOptions)
			if e != nil {
				return e
			}
		} else {
			cli.scheme = "http"
		}

		if cli.in != nil {
			cli.inFd, cli.isTerminalIn = term.GetFdInfo(cli.in)
		}
		if cli.out != nil {
			cli.outFd, cli.isTerminalOut = term.GetFdInfo(cli.out)
		}

		// The transport is created here for reuse during the client session.
		cli.transport = &http.Transport{
			TLSClientConfig: cli.tlsConfig,
		}
		sockets.ConfigureTCPTransport(cli.transport, cli.proto, cli.addr)

		configFile, e := cliconfig.Load(cliconfig.ConfigDir())
		if e != nil {
			fmt.Fprintf(cli.err, "WARNING: Error loading config file:%v\n", e)
		}
		cli.configFile = configFile

		return nil
	}

	return cli
}