func ExecuteCommand(command *ExecCmd) (output string, err error) {

	// Execute the command using a shell
	var shell, flag string
	if runtime.GOOS == "windows" {
		shell = "cmd"
		flag = "/C"
	} else {
		shell = "/bin/sh"
		flag = "-c"
	}

	// Setup the reader that will read the lines from the command
	pr, pw := io.Pipe()
	copyDoneCh := make(chan struct{})
	go copyOutput(pr, copyDoneCh)

	// Setup the command
	cmd := exec.Command(shell, flag, command.Cmd)
	out, _ := circbuf.NewBuffer(maxBufSize)
	cmd.Stderr = io.MultiWriter(out, pw)
	cmd.Stdout = io.MultiWriter(out, pw)

	// Run the command to completion
	runErr := cmd.Run()
	pw.Close()
	<-copyDoneCh

	if runErr != nil {
		return string(out.Bytes()), fmt.Errorf("Error running command '%s': %v. Output: %s", command, runErr, out.Bytes())
	}

	return string(out.Bytes()), nil
}

// invokeJob will execute the given job. Depending on the event.
func (a *AgentCommand) invokeJob(execution *Execution) error {
	job := execution.Job

	output, _ := circbuf.NewBuffer(maxBufSize)

	// Determine the shell invocation based on OS
	var shell, flag string
	if runtime.GOOS == windows {
		shell = "cmd"
		flag = "/C"
	} else {
		shell = "/bin/sh"
		flag = "-c"
	}

	cmd := exec.Command(shell, flag, job.Command)
	cmd.Stderr = output
	cmd.Stdout = output

	// Start a timer to warn about slow handlers
	slowTimer := time.AfterFunc(2*time.Hour, func() {
		log.Warnf("proc: Script '%s' slow, execution exceeding %v", job.Command, 2*time.Hour)
	})

	if err := cmd.Start(); err != nil {
		return err
	}

	// Warn if buffer is overritten
	if output.TotalWritten() > output.Size() {
		log.Warnf("proc: Script '%s' generated %d bytes of output, truncated to %d", job.Command, output.TotalWritten(), output.Size())
	}

	var success bool
	err := cmd.Wait()
	slowTimer.Stop()
	log.WithFields(logrus.Fields{
		"output": output,
	}).Debug("proc: Command output")
	if err != nil {
		log.WithFields(logrus.Fields{
			"err": err,
		}).Error("proc: command error output")
		success = false
	} else {
		success = true
	}

	execution.FinishedAt = time.Now()
	execution.Success = success
	execution.Output = output.Bytes()

	rpcServer, err := a.queryRPCConfig()
	if err != nil {
		return err
	}

	rc := &RPCClient{ServerAddr: string(rpcServer)}
	return rc.callExecutionDone(execution)
}

func (p *ResourceProvisioner) Apply(
	o terraform.UIOutput,
	s *terraform.InstanceState,
	c *terraform.ResourceConfig) error {

	// Get the command
	commandRaw, ok := c.Config["command"]
	if !ok {
		return fmt.Errorf("local-exec provisioner missing 'command'")
	}
	command, ok := commandRaw.(string)
	if !ok {
		return fmt.Errorf("local-exec provisioner command must be a string")
	}

	// Execute the command using a shell
	var shell, flag string
	if runtime.GOOS == "windows" {
		shell = "cmd"
		flag = "/C"
	} else {
		shell = "/bin/sh"
		flag = "-c"
	}

	// Setup the reader that will read the lines from the command
	pr, pw := io.Pipe()
	copyDoneCh := make(chan struct{})
	go p.copyOutput(o, pr, copyDoneCh)

	// Setup the command
	cmd := exec.Command(shell, flag, command)
	output, _ := circbuf.NewBuffer(maxBufSize)
	cmd.Stderr = io.MultiWriter(output, pw)
	cmd.Stdout = io.MultiWriter(output, pw)

	// Output what we're about to run
	o.Output(fmt.Sprintf(
		"Executing: %s %s \"%s\"",
		shell, flag, command))

	// Run the command to completion
	err := cmd.Run()

	// Close the write-end of the pipe so that the goroutine mirroring output
	// ends properly.
	pw.Close()
	<-copyDoneCh

	if err != nil {
		return fmt.Errorf("Error running command '%s': %v. Output: %s",
			command, err, output.Bytes())
	}

	return nil
}

func (u *packerUi) init() {
	// Allocating the circular buffer. The circular buffer should only
	// keep track up to the point that there is a \n found so it doesn't
	// need to be huge, but it also limits the max length of an event.
	var err error
	u.buf, err = circbuf.NewBuffer(4096)
	if err != nil {
		panic(err)
	}
}

// makeWatchHandler returns a handler for the given watch
func makeWatchHandler(logOutput io.Writer, params interface{}, reapLock *sync.RWMutex) watch.HandlerFunc {
	script := params.(string)
	logger := log.New(logOutput, "", log.LstdFlags)
	fn := func(idx uint64, data interface{}) {
		// Disable child process reaping so that we can get this command's
		// return value. Note that we take the read lock here since we are
		// waiting on a specific PID and don't need to serialize all waits.
		reapLock.RLock()
		defer reapLock.RUnlock()

		// Create the command
		cmd, err := ExecScript(script)
		if err != nil {
			logger.Printf("[ERR] agent: Failed to setup watch: %v", err)
			return
		}
		cmd.Env = append(os.Environ(),
			"CONSUL_INDEX="+strconv.FormatUint(idx, 10),
		)

		// Collect the output
		output, _ := circbuf.NewBuffer(WatchBufSize)
		cmd.Stdout = output
		cmd.Stderr = output

		// Setup the input
		var inp bytes.Buffer
		enc := json.NewEncoder(&inp)
		if err := enc.Encode(data); err != nil {
			logger.Printf("[ERR] agent: Failed to encode data for watch '%s': %v", script, err)
			return
		}
		cmd.Stdin = &inp

		// Run the handler
		if err := cmd.Run(); err != nil {
			logger.Printf("[ERR] agent: Failed to invoke watch handler '%s': %v", script, err)
		}

		// Get the output, add a message about truncation
		outputStr := string(output.Bytes())
		if output.TotalWritten() > output.Size() {
			outputStr = fmt.Sprintf("Captured %d of %d bytes\n...\n%s",
				output.Size(), output.TotalWritten(), outputStr)
		}

		// Log the output
		logger.Printf("[DEBUG] agent: watch handler '%s' output: %s", script, outputStr)
	}
	return fn
}

// check is invoked periodically to perform the HTTP check
func (c *CheckHTTP) check() {
	req, err := http.NewRequest("GET", c.HTTP, nil)
	if err != nil {
		c.Logger.Printf("[WARN] agent: http request failed '%s': %s", c.HTTP, err)
		c.Notify.UpdateCheck(c.CheckID, structs.HealthCritical, err.Error())
		return
	}

	req.Header.Set("User-Agent", HttpUserAgent)
	req.Header.Set("Accept", "text/plain, text/*, */*")

	resp, err := c.httpClient.Do(req)
	if err != nil {
		c.Logger.Printf("[WARN] agent: http request failed '%s': %s", c.HTTP, err)
		c.Notify.UpdateCheck(c.CheckID, structs.HealthCritical, err.Error())
		return
	}
	defer resp.Body.Close()

	// Read the response into a circular buffer to limit the size
	output, _ := circbuf.NewBuffer(CheckBufSize)
	if _, err := io.Copy(output, resp.Body); err != nil {
		c.Logger.Printf("[WARN] agent: check '%v': Get error while reading body: %s", c.CheckID, err)
	}

	// Format the response body
	result := fmt.Sprintf("HTTP GET %s: %s Output: %s", c.HTTP, resp.Status, output.String())

	if resp.StatusCode >= 200 && resp.StatusCode <= 299 {
		// PASSING (2xx)
		c.Logger.Printf("[DEBUG] agent: check '%v' is passing", c.CheckID)
		c.Notify.UpdateCheck(c.CheckID, structs.HealthPassing, result)

	} else if resp.StatusCode == 429 {
		// WARNING
		// 429 Too Many Requests (RFC 6585)
		// The user has sent too many requests in a given amount of time.
		c.Logger.Printf("[WARN] agent: check '%v' is now warning", c.CheckID)
		c.Notify.UpdateCheck(c.CheckID, structs.HealthWarning, result)

	} else {
		// CRITICAL
		c.Logger.Printf("[WARN] agent: check '%v' is now critical", c.CheckID)
		c.Notify.UpdateCheck(c.CheckID, structs.HealthCritical, result)
	}
}

// makeWatchHandler returns a handler for the given watch
func makeWatchHandler(logOutput io.Writer, params interface{}) watch.HandlerFunc {
	script := params.(string)
	logger := log.New(logOutput, "", log.LstdFlags)
	fn := func(idx uint64, data interface{}) {
		// Create the command
		cmd, err := ExecScript(script)
		if err != nil {
			logger.Printf("[ERR] agent: Failed to setup watch: %v", err)
			return
		}
		cmd.Env = append(os.Environ(),
			"CONSUL_INDEX="+strconv.FormatUint(idx, 10),
		)

		// Collect the output
		output, _ := circbuf.NewBuffer(WatchBufSize)
		cmd.Stdout = output
		cmd.Stderr = output

		// Setup the input
		var inp bytes.Buffer
		enc := json.NewEncoder(&inp)
		if err := enc.Encode(data); err != nil {
			logger.Printf("[ERR] agent: Failed to encode data for watch '%s': %v", script, err)
			return
		}
		cmd.Stdin = &inp

		// Run the handler
		if err := cmd.Run(); err != nil {
			logger.Printf("[ERR] agent: Failed to invoke watch handler '%s': %v", script, err)
		}

		// Get the output, add a message about truncation
		outputStr := string(output.Bytes())
		if output.TotalWritten() > output.Size() {
			outputStr = fmt.Sprintf("Captured %d of %d bytes\n...\n%s",
				output.Size(), output.TotalWritten(), outputStr)
		}

		// Log the output
		logger.Printf("[DEBUG] agent: watch handler '%s' output: %s", script, outputStr)
	}
	return fn
}

// Run runs a script check inside a docker container
func (d *DockerScriptCheck) Run() *cstructs.CheckResult {
	var (
		exec    *docker.Exec
		err     error
		execRes *docker.ExecInspect
		time    = time.Now()
	)

	if client, err = d.dockerClient(); err != nil {
		return &cstructs.CheckResult{Err: err}
	}
	client = client
	execOpts := docker.CreateExecOptions{
		AttachStdin:  false,
		AttachStdout: true,
		AttachStderr: true,
		Tty:          false,
		Cmd:          append([]string{d.cmd}, d.args...),
		Container:    d.containerID,
	}
	if exec, err = client.CreateExec(execOpts); err != nil {
		return &cstructs.CheckResult{Err: err}
	}

	output, _ := circbuf.NewBuffer(int64(cstructs.CheckBufSize))
	startOpts := docker.StartExecOptions{
		Detach:       false,
		Tty:          false,
		OutputStream: output,
		ErrorStream:  output,
	}

	if err = client.StartExec(exec.ID, startOpts); err != nil {
		return &cstructs.CheckResult{Err: err}
	}
	if execRes, err = client.InspectExec(exec.ID); err != nil {
		return &cstructs.CheckResult{Err: err}
	}
	return &cstructs.CheckResult{
		ExitCode:  execRes.ExitCode,
		Output:    string(output.Bytes()),
		Timestamp: time,
	}
}

// invokeJob will execute the given job. Depending on the event.
func (a *AgentCommand) invokeJob(job *Job, execution *Execution) error {
	output, _ := circbuf.NewBuffer(maxBufSize)

	cmd := buildCmd(job)
	cmd.Stderr = output
	cmd.Stdout = output

	// Start a timer to warn about slow handlers
	slowTimer := time.AfterFunc(2*time.Hour, func() {
		log.Warnf("proc: Script '%s' slow, execution exceeding %v", job.Command, 2*time.Hour)
	})

	err := cmd.Start()

	// Warn if buffer is overritten
	if output.TotalWritten() > output.Size() {
		log.Warnf("proc: Script '%s' generated %d bytes of output, truncated to %d", job.Command, output.TotalWritten(), output.Size())
	}

	var success bool
	err = cmd.Wait()
	slowTimer.Stop()
	log.WithFields(logrus.Fields{
		"output": output,
	}).Debug("proc: Command output")
	if err != nil {
		log.WithError(err).Error("proc: command error output")
		success = false
	} else {
		success = true
	}

	execution.FinishedAt = time.Now()
	execution.Success = success
	execution.Output = output.Bytes()

	rpcServer, err := a.queryRPCConfig()
	if err != nil {
		return err
	}

	rc := &RPCClient{ServerAddr: string(rpcServer)}
	return rc.callExecutionDone(execution)
}

// Run runs an exec script check
func (e *ExecScriptCheck) Run() *cstructs.CheckResult {
	buf, _ := circbuf.NewBuffer(int64(cstructs.CheckBufSize))
	cmd := exec.Command(e.cmd, e.args...)
	cmd.Stdout = buf
	cmd.Stderr = buf
	e.setChroot(cmd)
	ts := time.Now()
	if err := cmd.Start(); err != nil {
		return &cstructs.CheckResult{Err: err}
	}
	errCh := make(chan error, 2)
	go func() {
		errCh <- cmd.Wait()
	}()
	for {
		select {
		case err := <-errCh:
			endTime := time.Now()
			if err == nil {
				return &cstructs.CheckResult{
					ExitCode:  0,
					Output:    string(buf.Bytes()),
					Timestamp: ts,
				}
			}
			exitCode := 1
			if exitErr, ok := err.(*exec.ExitError); ok {
				if status, ok := exitErr.Sys().(syscall.WaitStatus); ok {
					exitCode = status.ExitStatus()
				}
			}
			return &cstructs.CheckResult{
				ExitCode:  exitCode,
				Output:    string(buf.Bytes()),
				Timestamp: ts,
				Duration:  endTime.Sub(ts),
			}
		case <-time.After(e.Timeout()):
			errCh <- fmt.Errorf("timed out after waiting 30s")
		}
	}
	return nil
}

func (p *ResourceProvisioner) Apply(
	s *terraform.ResourceState,
	c *terraform.ResourceConfig) error {

	// Get the command
	commandRaw, ok := c.Config["command"]
	if !ok {
		return fmt.Errorf("local-exec provisioner missing 'command'")
	}
	command, ok := commandRaw.(string)
	if !ok {
		return fmt.Errorf("local-exec provisioner command must be a string")
	}

	// Execute the command using a shell
	var shell, flag string
	if runtime.GOOS == "windows" {
		shell = "cmd"
		flag = "/C"
	} else {
		shell = "/bin/sh"
		flag = "-c"
	}

	// Setup the command
	cmd := exec.Command(shell, flag, command)
	output, _ := circbuf.NewBuffer(maxBufSize)
	cmd.Stderr = output
	cmd.Stdout = output

	// Run the command to completion
	if err := cmd.Run(); err != nil {
		return fmt.Errorf("Error running command '%s': %v. Output: %s",
			command, err, output.Bytes())
	}
	return nil
}

// check is invoked periodically to perform the script check
func (c *CheckMonitor) check() {
	// Create the command
	cmd, err := ExecScript(c.Script)
	if err != nil {
		c.Logger.Printf("[ERR] agent: failed to setup invoke '%s': %s", c.Script, err)
		c.Notify.UpdateCheck(c.CheckID, structs.HealthUnknown, err.Error())
		return
	}

	// Collect the output
	output, _ := circbuf.NewBuffer(CheckBufSize)
	cmd.Stdout = output
	cmd.Stderr = output

	// Start the check
	if err := cmd.Start(); err != nil {
		c.Logger.Printf("[ERR] agent: failed to invoke '%s': %s", c.Script, err)
		c.Notify.UpdateCheck(c.CheckID, structs.HealthUnknown, err.Error())
		return
	}

	// Wait for the check to complete
	errCh := make(chan error, 2)
	go func() {
		errCh <- cmd.Wait()
	}()
	go func() {
		time.Sleep(30 * time.Second)
		errCh <- fmt.Errorf("Timed out running check '%s'", c.Script)
	}()
	err = <-errCh

	// Get the output, add a message about truncation
	outputStr := string(output.Bytes())
	if output.TotalWritten() > output.Size() {
		outputStr = fmt.Sprintf("Captured %d of %d bytes\n...\n%s",
			output.Size(), output.TotalWritten(), outputStr)
	}

	c.Logger.Printf("[DEBUG] agent: check '%s' script '%s' output: %s",
		c.CheckID, c.Script, outputStr)

	// Check if the check passed
	if err == nil {
		c.Logger.Printf("[DEBUG] Check '%v' is passing", c.CheckID)
		c.Notify.UpdateCheck(c.CheckID, structs.HealthPassing, outputStr)
		return
	}

	// If the exit code is 1, set check as warning
	exitErr, ok := err.(*exec.ExitError)
	if ok {
		if status, ok := exitErr.Sys().(syscall.WaitStatus); ok {
			code := status.ExitStatus()
			if code == 1 {
				c.Logger.Printf("[WARN] Check '%v' is now warning", c.CheckID)
				c.Notify.UpdateCheck(c.CheckID, structs.HealthWarning, outputStr)
				return
			}
		}
	}

	// Set the health as critical
	c.Logger.Printf("[WARN] Check '%v' is now critical", c.CheckID)
	c.Notify.UpdateCheck(c.CheckID, structs.HealthCritical, outputStr)
}

// invokeJob will execute the given job. Depending on the event.
func (a *AgentCommand) invokeJob(job *Job, execution *Execution) error {
	output, _ := circbuf.NewBuffer(maxBufSize)

	// Determine the shell invocation based on OS
	var shell, flag string
	if runtime.GOOS == windows {
		shell = "cmd"
		flag = "/C"
	} else {
		shell = "/bin/sh"
		flag = "-c"
	}

	cmd := exec.Command(shell, flag, job.Command)
	cmd.Stderr = output
	cmd.Stdout = output

	// Start a timer to warn about slow handlers
	slowTimer := time.AfterFunc(2*time.Hour, func() {
		log.Warnf("Script '%s' slow, execution exceeding %v", job.Command, 2*time.Hour)
	})

	if err := cmd.Start(); err != nil {
		return err
	}

	// Warn if buffer is overritten
	if output.TotalWritten() > output.Size() {
		log.Warnf("Script '%s' generated %d bytes of output, truncated to %d", job.Command, output.TotalWritten(), output.Size())
	}

	var success bool
	err := cmd.Wait()
	slowTimer.Stop()
	log.Debugf("Command output: %s", output)
	if err != nil {
		log.Error(err)
		success = false
	} else {
		success = true
	}

	execution.FinishedAt = time.Now()
	execution.Success = success
	execution.Output = output.Bytes()

	executionJson, _ := json.Marshal(execution)

	params := &serf.QueryParam{
		FilterTags: map[string]string{"server": "true"},
		RequestAck: true,
	}

	qr, err := a.serf.Query(QueryExecutionDone, executionJson, params)
	if err != nil {
		log.WithFields(logrus.Fields{
			"query": QueryExecutionDone,
			"error": err,
		}).Debug("Error sending query")
	}
	defer qr.Close()

	ackCh := qr.AckCh()
	respCh := qr.ResponseCh()

	for !qr.Finished() {
		select {
		case ack, ok := <-ackCh:
			if ok {
				log.WithFields(logrus.Fields{
					"query": QueryExecutionDone,
					"from":  ack,
				}).Debug("Received ack")
			}
		case resp, ok := <-respCh:
			if ok {
				log.WithFields(logrus.Fields{
					"query":   QueryExecutionDone,
					"from":    resp.From,
					"payload": string(resp.Payload),
				}).Debug("Received response")
			}
		}
	}
	log.Debugf("Done receiving acks and responses from %s query", QueryExecutionDone)

	return nil
}

func (p *Processor) Run() {
	log.Debugf("Run job[%s] by worker", p.Job)

	//get job script
	scriptBts, _, _ := p.zk.Get("/swiss/jobscript/" + strconv.Itoa(p.Job.JobId))
	script := string(scriptBts)
	log.Debugf("Get the job script:%s", script)

	fullFilePath := "/Users/yws/Documents/dev/works/" + strconv.Itoa(p.Job.ExeId)
	log.Debugf("Job script full path:%s", fullFilePath)

	//write to file
	fout, err := os.Create(fullFilePath)
	if err != nil {
		log.Errorf("Job script full path,%s,%s", fullFilePath, err)
		return
	}
	fout.Write(scriptBts)
	fout.Close()
	defer func() {
		os.Remove(fullFilePath)
	}()
	//end write file

	//设置超时提醒
	slowTimer := time.AfterFunc(2*time.Hour, func() {
		log.Warningf("proc: Script '%s' slow, execution exceeding %v", script, 2*time.Hour)
	})

	//防止job的log太多,限制为256k, 当超过256k后,最早出现的日志将会逐步被代替
	output, _ := circbuf.NewBuffer(256000)

	//封装成cmd
	if p.Job.ScriptType == Shell {

	}

	var shell, flag string

	switch p.Job.ScriptType {
	case Shell:
		if runtime.GOOS == "windows" {
			shell = "cmd"
			flag = ""
		} else {
			shell = "/bin/sh"
			flag = ""
		}
	case Hive:
		shell = "hive"
		flag = "-f"
	case Python:
		shell = "python"
		flag = "-f"
	}

	cmd := exec.Command(shell, fullFilePath)
	cmd.Stderr = output
	cmd.Stdout = output
	//运行job
	var success, done bool

	log.Debugf("Start the cmd, Shell:%s, flag:%s", shell, flag)
	cmd.Start()
	go func() {
		err = cmd.Wait()
		slowTimer.Stop()

		if err != nil {
			log.Errorf("proc: command error output: %s", err)
			success = false
		} else {
			success = true
		}

		done = true
	}()

	for !done {
		log.Info(output.String())
		time.Sleep(1 * time.Second)
	}

	log.Info("Job run completed, and success status is -> ", success)
	//execution.FinishedAt = time.Now()
	//execution.Success = success
	//execution.Output = output.Bytes()
}

// invokeEventScript will execute the given event script with the given
// event. Depending on the event, the semantics of how data are passed
// are a bit different. For all events, the SERF_EVENT environmental
// variable is the type of the event. For user events, the SERF_USER_EVENT
// environmental variable is also set, containing the name of the user
// event that was fired.
//
// In all events, data is passed in via stdin to faciliate piping. See
// the various stdin functions below for more information.
func invokeEventScript(logger *log.Logger, script string, self serf.Member, event serf.Event) error {
	defer metrics.MeasureSince([]string{"agent", "invoke", script}, time.Now())
	output, _ := circbuf.NewBuffer(maxBufSize)

	// Determine the shell invocation based on OS
	var shell, flag string
	if runtime.GOOS == windows {
		shell = "cmd"
		flag = "/C"
	} else {
		shell = "/bin/sh"
		flag = "-c"
	}

	cmd := exec.Command(shell, flag, script)
	cmd.Env = append(os.Environ(),
		"SERF_EVENT="+event.EventType().String(),
		"SERF_SELF_NAME="+self.Name,
		"SERF_SELF_IP="+self.Addr.String(),
		"SERF_SELF_PORT="+fmt.Sprintf("%v", self.Port),
		"SERF_SELF_ROLE="+self.Tags["role"],
	)
	cmd.Stderr = output
	cmd.Stdout = output

	// Add all the tags
	for name, val := range self.Tags {
		//http://stackoverflow.com/questions/2821043/allowed-characters-in-linux-environment-variable-names
		//(http://pubs.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap08.html for the long version)
		//says that env var names must be in [A-Z0-9_] and not start with [0-9].
		//we only care about the first part, so convert all chars not in [A-Z0-9_] to _
		sanitizedName := sanitizeTagRegexp.ReplaceAllString(strings.ToUpper(name), "_")
		tag_env := fmt.Sprintf("SERF_TAG_%s=%s", sanitizedName, val)
		cmd.Env = append(cmd.Env, tag_env)
	}

	stdin, err := cmd.StdinPipe()
	if err != nil {
		return err
	}

	switch e := event.(type) {
	case serf.MemberEvent:
		go memberEventStdin(logger, stdin, &e)
	case serf.UserEvent:
		cmd.Env = append(cmd.Env, "SERF_USER_EVENT="+e.Name)
		cmd.Env = append(cmd.Env, fmt.Sprintf("SERF_USER_LTIME=%d", e.LTime))
		go streamPayload(logger, stdin, e.Payload)
	case *serf.Query:
		cmd.Env = append(cmd.Env, "SERF_QUERY_NAME="+e.Name)
		cmd.Env = append(cmd.Env, fmt.Sprintf("SERF_QUERY_LTIME=%d", e.LTime))
		go streamPayload(logger, stdin, e.Payload)
	default:
		return fmt.Errorf("Unknown event type: %s", event.EventType().String())
	}

	// Start a timer to warn about slow handlers
	slowTimer := time.AfterFunc(warnSlow, func() {
		logger.Printf("[WARN] agent: Script '%s' slow, execution exceeding %v",
			script, warnSlow)
	})

	if err := cmd.Start(); err != nil {
		return err
	}

	// Warn if buffer is overritten
	if output.TotalWritten() > output.Size() {
		logger.Printf("[WARN] agent: Script '%s' generated %d bytes of output, truncated to %d",
			script, output.TotalWritten(), output.Size())
	}

	err = cmd.Wait()
	slowTimer.Stop()
	logger.Printf("[DEBUG] agent: Event '%s' script output: %s",
		event.EventType().String(), output.String())
	if err != nil {
		return err
	}

	// If this is a query and we have output, respond
	if query, ok := event.(*serf.Query); ok && output.TotalWritten() > 0 {
		if err := query.Respond(output.Bytes()); err != nil {
			logger.Printf("[WARN] agent: Failed to respond to query '%s': %s",
				event.String(), err)
		}
	}

	return nil
}