Golang Context.Log方法代码示例

// ReplayHistory sends back the history to a subscriber.
//
// This should be called before the client goes into active listening.
//
// Params:
// - topic (string): The topic to fetch.
//
// Returns:
// 	- int: The number of history messages sent to the client.
func ReplayHistory(c cookoo.Context, p *cookoo.Params) (interface{}, cookoo.Interrupt) {
	req := c.Get("http.Request", nil).(*http.Request)
	res := c.Get("http.ResponseWriter", nil).(ResponseWriterFlusher)
	medium, _ := getMedium(c)
	name := p.Get("topic", "").(string)

	// This does not manage topics. If there is no topic set, we silently fail.
	if len(name) == 0 {
		c.Log("info", "No topic name given to ReplayHistory.")
		return 0, nil
	}
	top, ok := medium.Topic(name)
	if !ok {
		c.Logf("info", "No topic named %s exists yet. No history replayed.", name)
		return 0, nil
	}

	topic, ok := top.(HistoriedTopic)
	if !ok {
		c.Logf("info", "No history for topic %s.", name)
		res.Header().Add(XHistoryEnabled, "False")
		return 0, nil
	}
	res.Header().Add(XHistoryEnabled, "True")

	since := req.Header.Get(XHistorySince)
	max := req.Header.Get(XHistoryLength)

	// maxLen can be used either on its own or paired with X-History-Since.
	maxLen := 0
	if len(max) > 0 {
		m, err := parseHistLen(max)
		if err != nil {
			c.Logf("info", "failed to parse X-History-Length %s", max)
		} else {
			maxLen = m
		}
	}
	if len(since) > 0 {
		ts, err := parseSince(since)
		if err != nil {
			c.Logf("warn", "Failed to parse X-History-Since field %s: %s", since, err)
			return 0, nil
		}
		toSend := topic.Since(ts)

		// If maxLen is also set, we trim the list by sending the newest.
		ls := len(toSend)
		if maxLen > 0 && ls > maxLen {
			offset := ls - maxLen - 1
			toSend = toSend[offset:]
		}
		return sendHistory(c, res, toSend)
	} else if maxLen > 0 {
		toSend := topic.Last(maxLen)
		return sendHistory(c, res, toSend)
	}

	return 0, nil
}

// KillOnExit kills PIDs when the program exits.
//
// Otherwise, this blocks until an os.Interrupt or os.Kill is received.
//
// Params:
//  This treats Params as a map of process names (unimportant) to PIDs. It then
// attempts to kill all of the pids that it receives.
func KillOnExit(c cookoo.Context, p *cookoo.Params) (interface{}, cookoo.Interrupt) {
	sigs := make(chan os.Signal, 1)
	signal.Notify(sigs, os.Interrupt, os.Kill)

	safely.GoDo(c, func() {
		log.Info(c, "Builder is running.")

		<-sigs

		c.Log("info", "Builder received signal to stop.")
		pids := p.AsMap()
		killed := 0
		for name, pid := range pids {
			if pid, ok := pid.(int); ok {
				if proc, err := os.FindProcess(pid); err == nil {
					log.Infof(c, "Killing %s (pid=%d)", name, pid)
					proc.Kill()
					killed++
				}
			}
		}
	})
	return nil, nil
}

func send(c cookoo.Context, l LogLevel, args ...interface{}) {
	if Level >= l {
		c.Log(Label[l], args...)
	}
}