Golang Event.String方法代码示例

// 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())
	var output bytes.Buffer

	// 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_ROLE="+self.Tags["role"],
	)
	cmd.Stderr = &output
	cmd.Stdout = &output

	// Add all the tags
	for name, val := range self.Tags {
		tag_env := fmt.Sprintf("SERF_TAG_%s=%s", strings.ToUpper(name), 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())
	}

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

	err = cmd.Wait()
	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 && len(output.Bytes()) > 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
}

// 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
}