// addAgentInfo adds agent-required information to the agent's directory
// and returns the agent directory name.
func (cfg *MachineConfig) addAgentInfo(c *cloudinit.Config, tag string) (agent.Config, error) {
	acfg, err := cfg.agentConfig(tag)
	if err != nil {
		return nil, err
	}
	acfg.SetValue(agent.AgentServiceName, cfg.MachineAgentServiceName)
	cmds, err := acfg.WriteCommands()
	if err != nil {
		return nil, errors.Annotate(err, "failed to write commands")
	}
	c.AddScripts(cmds...)
	return acfg, nil
}

// ComposeUserData fills out the provided cloudinit configuration structure
// so it is suitable for initialising a machine with the given configuration,
// and then renders it and returns it as a binary (gzipped) blob of user data.
//
// If the provided cloudcfg is nil, a new one will be created internally.
func ComposeUserData(mcfg *cloudinit.MachineConfig, cloudcfg *coreCloudinit.Config) ([]byte, error) {
	if cloudcfg == nil {
		cloudcfg = coreCloudinit.New()
	}
	if err := configureCloudinit(mcfg, cloudcfg); err != nil {
		return nil, err
	}
	data, err := cloudcfg.Render()
	logger.Tracef("Generated cloud init:\n%s", string(data))
	if err != nil {
		return nil, err
	}
	return utils.Gzip(data), nil
}

// MaybeAddCloudArchiveCloudTools adds the cloud-archive cloud-tools
// pocket to apt sources, if the series requires it.
func MaybeAddCloudArchiveCloudTools(c *cloudinit.Config, series string) {
	if series != "precise" {
		// Currently only precise; presumably we'll
		// need to add each LTS in here as they're
		// added to the cloud archive.
		return
	}
	const url = "http://ubuntu-cloud.archive.canonical.com/ubuntu"
	name := fmt.Sprintf("deb %s %s-updates/cloud-tools main", url, series)
	prefs := &cloudinit.AptPreferences{
		Path:        cloudinit.CloudToolsPrefsPath,
		Explanation: "Pin with lower priority, not to interfere with charms",
		Package:     "*",
		Pin:         fmt.Sprintf("release n=%s-updates/cloud-tools", series),
		PinPriority: 400,
	}
	c.AddAptSource(name, CanonicalCloudArchiveSigningKey, prefs)
}

// addAgentInfo adds agent-required information to the agent's directory
// and returns the agent directory name.
func addAgentInfo(
	cfg *MachineConfig,
	c *cloudinit.Config,
	tag names.Tag,
	toolsVersion version.Number,
) (agent.Config, error) {
	acfg, err := cfg.agentConfig(tag, toolsVersion)
	if err != nil {
		return nil, err
	}
	acfg.SetValue(agent.AgentServiceName, cfg.MachineAgentServiceName)
	cmds, err := acfg.WriteCommands(cfg.Series)
	if err != nil {
		return nil, errors.Annotate(err, "failed to write commands")
	}
	c.AddScripts(cmds...)
	return acfg, nil
}

// ConfigureScript generates the bash script that applies
// the specified cloud-config.
func ConfigureScript(cloudcfg *cloudinit.Config) (string, error) {
	if cloudcfg == nil {
		panic("cloudcfg is nil")
	}

	// TODO(axw): 2013-08-23 bug 1215777
	// Carry out configuration for ssh-keys-per-user,
	// machine-updates-authkeys, using cloud-init config.
	//
	// We should work with smoser to get a supported
	// command in (or next to) cloud-init for manually
	// invoking cloud-config. This would address the
	// above comment by removing the need to generate a
	// script "by hand".

	// Bootcmds must be run before anything else,
	// as they may affect package installation.
	bootcmds, err := cmdlist(cloudcfg.BootCmds())
	if err != nil {
		return "", err
	}

	// Depending on cloudcfg, potentially add package sources and packages.
	pkgcmds, err := addPackageCommands(cloudcfg)
	if err != nil {
		return "", err
	}

	// Runcmds come last.
	runcmds, err := cmdlist(cloudcfg.RunCmds())
	if err != nil {
		return "", err
	}

	// We prepend "set -xe". This is already in runcmds,
	// but added here to avoid relying on that to be
	// invariant.
	script := []string{"#!/bin/bash", "set -e"}
	// We must initialise progress reporting before entering
	// the subshell and redirecting stderr.
	script = append(script, cloudinit.InitProgressCmd())
	stdout, stderr := cloudcfg.Output(cloudinit.OutAll)
	script = append(script, "(")
	if stderr != "" {
		script = append(script, "(")
	}
	script = append(script, bootcmds...)
	script = append(script, pkgcmds...)
	script = append(script, runcmds...)
	if stderr != "" {
		script = append(script, ") "+stdout)
		script = append(script, ") "+stderr)
	} else {
		script = append(script, ") "+stdout+" 2>&1")
	}
	return strings.Join(script, "\n"), nil
}

// ConfigureBasic updates the provided cloudinit.Config with
// basic configuration to initialise an OS image, such that it can
// be connected to via SSH, and log to a standard location.
//
// Any potentially failing operation should not be added to the
// configuration, but should instead be done in ConfigureJuju.
//
// Note: we don't do apt update/upgrade here so as not to have to wait on
// apt to finish when performing the second half of image initialisation.
// Doing it later brings the benefit of feedback in the face of errors,
// but adds to the running time of initialisation due to lack of activity
// between image bringup and start of agent installation.
func ConfigureBasic(cfg *MachineConfig, c *cloudinit.Config) error {
	c.AddScripts(
		"set -xe", // ensure we run all the scripts or abort.
	)
	c.AddSSHAuthorizedKeys(cfg.AuthorizedKeys)
	c.SetOutput(cloudinit.OutAll, "| tee -a "+cfg.CloudInitOutputLog, "")
	// Create a file in a well-defined location containing the machine's
	// nonce. The presence and contents of this file will be verified
	// during bootstrap.
	//
	// Note: this must be the last runcmd we do in ConfigureBasic, as
	// the presence of the nonce file is used to gate the remainder
	// of synchronous bootstrap.
	noncefile := path.Join(cfg.DataDir, NonceFile)
	c.AddFile(noncefile, cfg.MachineNonce, 0644)
	return nil
}

func (cfg *MachineConfig) addMachineAgentToBoot(c *cloudinit.Config, tag, machineId string) error {
	// Make the agent run via a symbolic link to the actual tools
	// directory, so it can upgrade itself without needing to change
	// the upstart script.
	toolsDir := agenttools.ToolsDir(cfg.DataDir, tag)
	// TODO(dfc) ln -nfs, so it doesn't fail if for some reason that the target already exists
	c.AddScripts(fmt.Sprintf("ln -s %v %s", cfg.Tools.Version, shquote(toolsDir)))

	name := cfg.MachineAgentServiceName
	conf := upstart.MachineAgentUpstartService(name, toolsDir, cfg.DataDir, cfg.LogDir, tag, machineId, nil)
	cmds, err := conf.InstallCommands()
	if err != nil {
		return errors.Annotatef(err, "cannot make cloud-init upstart script for the %s agent", tag)
	}
	c.AddRunCmd(cloudinit.LogProgressCmd("Starting Juju machine agent (%s)", name))
	c.AddScripts(cmds...)
	return nil
}

// ConfigureJuju updates the provided cloudinit.Config with configuration
// to initialise a Juju machine agent.
func ConfigureJuju(cfg *MachineConfig, c *cloudinit.Config) error {
	if err := verifyConfig(cfg); err != nil {
		return err
	}

	// Initialise progress reporting. We need to do separately for runcmd
	// and (possibly, below) for bootcmd, as they may be run in different
	// shell sessions.
	initProgressCmd := cloudinit.InitProgressCmd()
	c.AddRunCmd(initProgressCmd)

	// If we're doing synchronous bootstrap or manual provisioning, then
	// ConfigureBasic won't have been invoked; thus, the output log won't
	// have been set. We don't want to show the log to the user, so simply
	// append to the log file rather than teeing.
	if stdout, _ := c.Output(cloudinit.OutAll); stdout == "" {
		c.SetOutput(cloudinit.OutAll, ">> "+cfg.CloudInitOutputLog, "")
		c.AddBootCmd(initProgressCmd)
		c.AddBootCmd(cloudinit.LogProgressCmd("Logging to %s on remote host", cfg.CloudInitOutputLog))
	}

	if !cfg.DisablePackageCommands {
		AddAptCommands(cfg.AptProxySettings, c)
	}

	// Write out the normal proxy settings so that the settings are
	// sourced by bash, and ssh through that.
	c.AddScripts(
		// We look to see if the proxy line is there already as
		// the manual provider may have had it aleady. The ubuntu
		// user may not exist (local provider only).
		`([ ! -e /home/ubuntu/.profile ] || grep -q '.juju-proxy' /home/ubuntu/.profile) || ` +
			`printf '\n# Added by juju\n[ -f "$HOME/.juju-proxy" ] && . "$HOME/.juju-proxy"\n' >> /home/ubuntu/.profile`)
	if (cfg.ProxySettings != proxy.Settings{}) {
		exportedProxyEnv := cfg.ProxySettings.AsScriptEnvironment()
		c.AddScripts(strings.Split(exportedProxyEnv, "\n")...)
		c.AddScripts(
			fmt.Sprintf(
				`[ -e /home/ubuntu ] && (printf '%%s\n' %s > /home/ubuntu/.juju-proxy && chown ubuntu:ubuntu /home/ubuntu/.juju-proxy)`,
				shquote(cfg.ProxySettings.AsScriptEnvironment())))
	}

	// Make the lock dir and change the ownership of the lock dir itself to
	// ubuntu:ubuntu from root:root so the juju-run command run as the ubuntu
	// user is able to get access to the hook execution lock (like the uniter
	// itself does.)
	lockDir := path.Join(cfg.DataDir, "locks")
	c.AddScripts(
		fmt.Sprintf("mkdir -p %s", lockDir),
		// We only try to change ownership if there is an ubuntu user
		// defined, and we determine this by the existance of the home dir.
		fmt.Sprintf("[ -e /home/ubuntu ] && chown ubuntu:ubuntu %s", lockDir),
		fmt.Sprintf("mkdir -p %s", cfg.LogDir),
		fmt.Sprintf("chown syslog:adm %s", cfg.LogDir),
	)

	// Make a directory for the tools to live in, then fetch the
	// tools and unarchive them into it.
	var copyCmd string
	if strings.HasPrefix(cfg.Tools.URL, fileSchemePrefix) {
		copyCmd = fmt.Sprintf("cp %s $bin/tools.tar.gz", shquote(cfg.Tools.URL[len(fileSchemePrefix):]))
	} else {
		curlCommand := "curl -sSfw 'tools from %{url_effective} downloaded: HTTP %{http_code}; time %{time_total}s; size %{size_download} bytes; speed %{speed_download} bytes/s '"
		if cfg.DisableSSLHostnameVerification {
			curlCommand += " --insecure"
		}
		copyCmd = fmt.Sprintf("%s -o $bin/tools.tar.gz %s", curlCommand, shquote(cfg.Tools.URL))
		c.AddRunCmd(cloudinit.LogProgressCmd("Fetching tools: %s", copyCmd))
	}
	toolsJson, err := json.Marshal(cfg.Tools)
	if err != nil {
		return err
	}
	c.AddScripts(
		"bin="+shquote(cfg.jujuTools()),
		"mkdir -p $bin",
		copyCmd,
		fmt.Sprintf("sha256sum $bin/tools.tar.gz > $bin/juju%s.sha256", cfg.Tools.Version),
		fmt.Sprintf(`grep '%s' $bin/juju%s.sha256 || (echo "Tools checksum mismatch"; exit 1)`,
			cfg.Tools.SHA256, cfg.Tools.Version),
		fmt.Sprintf("tar zxf $bin/tools.tar.gz -C $bin"),
		fmt.Sprintf("rm $bin/tools.tar.gz && rm $bin/juju%s.sha256", cfg.Tools.Version),
		fmt.Sprintf("printf %%s %s > $bin/downloaded-tools.txt", shquote(string(toolsJson))),
	)

	// We add the machine agent's configuration info
	// before running bootstrap-state so that bootstrap-state
	// has a chance to rerwrite it to change the password.
	// It would be cleaner to change bootstrap-state to
	// be responsible for starting the machine agent itself,
	// but this would not be backwardly compatible.
	machineTag := names.NewMachineTag(cfg.MachineId).String()
	_, err = cfg.addAgentInfo(c, machineTag)
	if err != nil {
		return err
	}

	// Add the cloud archive cloud-tools pocket to apt sources
//.........这里部分代码省略.........

// AddAptCommands update the cloudinit.Config instance with the necessary
// packages, the request to do the apt-get update/upgrade on boot, and adds
// the apt proxy settings if there are any.
func AddAptCommands(proxySettings proxy.Settings, c *cloudinit.Config) {
	// Bring packages up-to-date.
	c.SetAptUpdate(true)
	c.SetAptUpgrade(true)
	c.SetAptGetWrapper("eatmydata")

	c.AddPackage("curl")
	c.AddPackage("cpu-checker")
	// TODO(axw) 2014-07-02 #1277359
	// Don't install bridge-utils in cloud-init;
	// leave it to the networker worker.
	c.AddPackage("bridge-utils")
	c.AddPackage("rsyslog-gnutls")

	// Write out the apt proxy settings
	if (proxySettings != proxy.Settings{}) {
		filename := apt.ConfFile
		c.AddBootCmd(fmt.Sprintf(
			`[ -f %s ] || (printf '%%s\n' %s > %s)`,
			filename,
			shquote(apt.ProxyContent(proxySettings)),
			filename))
	}
}

// addPackageCommands returns a slice of commands that, when run,
// will add the required apt repositories and packages.
func addPackageCommands(cfg *cloudinit.Config) ([]string, error) {
	var cmds []string
	if len(cfg.AptSources()) > 0 {
		// Ensure add-apt-repository is available.
		cmds = append(cmds, cloudinit.LogProgressCmd("Installing add-apt-repository"))
		cmds = append(cmds, aptget+"install python-software-properties")
	}
	for _, src := range cfg.AptSources() {
		// PPA keys are obtained by add-apt-repository, from launchpad.
		if !strings.HasPrefix(src.Source, "ppa:") {
			if src.Key != "" {
				key := utils.ShQuote(src.Key)
				cmd := fmt.Sprintf("printf '%%s\\n' %s | apt-key add -", key)
				cmds = append(cmds, cmd)
			}
		}
		cmds = append(cmds, cloudinit.LogProgressCmd("Adding apt repository: %s", src.Source))
		cmds = append(cmds, "add-apt-repository -y "+utils.ShQuote(src.Source))
		if src.Prefs != nil {
			path := utils.ShQuote(src.Prefs.Path)
			contents := utils.ShQuote(src.Prefs.FileContents())
			cmds = append(cmds, "install -D -m 644 /dev/null "+path)
			cmds = append(cmds, `printf '%s\n' `+contents+` > `+path)
		}
	}
	if len(cfg.AptSources()) > 0 || cfg.AptUpdate() {
		cmds = append(cmds, cloudinit.LogProgressCmd("Running apt-get update"))
		cmds = append(cmds, aptget+"update")
	}
	if cfg.AptUpgrade() {
		cmds = append(cmds, cloudinit.LogProgressCmd("Running apt-get upgrade"))
		cmds = append(cmds, aptget+"upgrade")
	}
	for _, pkg := range cfg.Packages() {
		cmds = append(cmds, cloudinit.LogProgressCmd("Installing package: %s", pkg))
		if !strings.Contains(pkg, "--target-release") {
			// We only need to shquote the package name if it does not
			// contain additional arguments.
			pkg = utils.ShQuote(pkg)
		}
		cmd := fmt.Sprintf(aptget+"install %s", pkg)
		cmds = append(cmds, cmd)
	}
	if len(cmds) > 0 {
		// setting DEBIAN_FRONTEND=noninteractive prevents debconf
		// from prompting, always taking default values instead.
		cmds = append([]string{"export DEBIAN_FRONTEND=noninteractive"}, cmds...)
	}
	return cmds, nil
}

// AddAptCommands update the cloudinit.Config instance with the necessary
// packages, the request to do the apt-get update/upgrade on boot, and adds
// the apt proxy settings if there are any.
func AddAptCommands(proxySettings proxy.Settings, c *cloudinit.Config) {
	// Bring packages up-to-date.
	c.SetAptUpdate(true)
	c.SetAptUpgrade(true)

	// juju requires git for managing charm directories.
	c.AddPackage("git")
	c.AddPackage("curl")
	c.AddPackage("cpu-checker")
	c.AddPackage("bridge-utils")
	c.AddPackage("rsyslog-gnutls")

	// Write out the apt proxy settings
	if (proxySettings != proxy.Settings{}) {
		filename := apt.ConfFile
		c.AddBootCmd(fmt.Sprintf(
			`[ -f %s ] || (printf '%%s\n' %s > %s)`,
			filename,
			shquote(apt.ProxyContent(proxySettings)),
			filename))
	}
}

// AddAptCommands update the cloudinit.Config instance with the necessary
// packages, the request to do the apt-get update/upgrade on boot, and adds
// the apt proxy settings if there are any.
func AddAptCommands(
	proxySettings proxy.Settings,
	c *cloudinit.Config,
	addUpdateScripts bool,
	addUpgradeScripts bool,
) {
	// Check preconditions
	if c == nil {
		panic("c is nil")
	}

	// Bring packages up-to-date.
	c.SetAptUpdate(addUpdateScripts)
	c.SetAptUpgrade(addUpgradeScripts)
	c.SetAptGetWrapper("eatmydata")

	// If we're not doing an update, adding these packages is
	// meaningless.
	if addUpdateScripts {
		c.AddPackage("curl")
		c.AddPackage("cpu-checker")
		// TODO(axw) 2014-07-02 #1277359
		// Don't install bridge-utils in cloud-init;
		// leave it to the networker worker.
		c.AddPackage("bridge-utils")
		c.AddPackage("rsyslog-gnutls")
	}

	// Write out the apt proxy settings
	if (proxySettings != proxy.Settings{}) {
		filename := apt.ConfFile
		c.AddBootCmd(fmt.Sprintf(
			`[ -f %s ] || (printf '%%s\n' %s > %s)`,
			filename,
			shquote(apt.ProxyContent(proxySettings)),
			filename))
	}
}

// addPackageCommands returns a slice of commands that, when run,
// will add the required apt repositories and packages.
func addPackageCommands(cfg *cloudinit.Config) ([]string, error) {
	if cfg == nil {
		panic("cfg is nil")
	} else if !cfg.AptUpdate() && len(cfg.AptSources()) > 0 {
		return nil, fmt.Errorf("update sources were specified, but OS updates have been disabled.")
	}

	// If apt_get_wrapper is specified, then prepend it to aptget.
	aptget := aptget
	wrapper := cfg.AptGetWrapper()
	switch wrapper.Enabled {
	case true:
		aptget = utils.ShQuote(wrapper.Command) + " " + aptget
	case "auto":
		aptget = fmt.Sprintf("$(which %s || true) %s", utils.ShQuote(wrapper.Command), aptget)
	}

	var cmds []string
	if len(cfg.AptSources()) > 0 {
		// Ensure add-apt-repository is available.
		cmds = append(cmds, cloudinit.LogProgressCmd("Installing add-apt-repository"))
		cmds = append(cmds, aptget+"install python-software-properties")
	}
	for _, src := range cfg.AptSources() {
		// PPA keys are obtained by add-apt-repository, from launchpad.
		if !strings.HasPrefix(src.Source, "ppa:") {
			if src.Key != "" {
				key := utils.ShQuote(src.Key)
				cmd := fmt.Sprintf("printf '%%s\\n' %s | apt-key add -", key)
				cmds = append(cmds, cmd)
			}
		}
		cmds = append(cmds, cloudinit.LogProgressCmd("Adding apt repository: %s", src.Source))
		cmds = append(cmds, "add-apt-repository -y "+utils.ShQuote(src.Source))
		if src.Prefs != nil {
			path := utils.ShQuote(src.Prefs.Path)
			contents := utils.ShQuote(src.Prefs.FileContents())
			cmds = append(cmds, "install -D -m 644 /dev/null "+path)
			cmds = append(cmds, `printf '%s\n' `+contents+` > `+path)
		}
	}

	if cfg.AptUpdate() {
		cmds = append(cmds, cloudinit.LogProgressCmd("Running apt-get update"))
		cmds = append(cmds, aptget+"update")
	}

	if cfg.AptUpgrade() {
		cmds = append(cmds, cloudinit.LogProgressCmd("Running apt-get upgrade"))
		cmds = append(cmds, aptget+"upgrade")
	}
	for _, pkg := range cfg.Packages() {
		cmds = append(cmds, cloudinit.LogProgressCmd("Installing package: %s", pkg))
		if !strings.Contains(pkg, "--target-release") {
			// We only need to shquote the package name if it does not
			// contain additional arguments.
			pkg = utils.ShQuote(pkg)
		}
		cmd := fmt.Sprintf(aptget+"install %s", pkg)
		cmds = append(cmds, cmd)
	}
	if len(cmds) > 0 {
		// setting DEBIAN_FRONTEND=noninteractive prevents debconf
		// from prompting, always taking default values instead.
		cmds = append([]string{"export DEBIAN_FRONTEND=noninteractive"}, cmds...)
	}
	return cmds, nil
}