Golang tail.SeekInfo類代碼示例

func logHandler(w http.ResponseWriter, r *http.Request, file string) {
	conn, err := upgrader.Upgrade(w, r, nil)
	if err != nil {
		apilog.Println(err)
		return
	}

	defer conn.Close()

	var more string
	var offset tail.SeekInfo
	offset.Whence = 2
	fi, err := os.Open(file)
	if err != nil {
		apilog.Println(err)
	}
	f, err := fi.Stat()
	if err != nil {
		apilog.Println(err)
	}
	if f.Size() < 10000 {
		offset.Offset = f.Size() * (-1)
	} else {
		offset.Offset = -10000
		more = "... "
	}
	fi.Close()

	conf := tail.Config{
		Follow:   true,
		ReOpen:   true,
		Location: &offset,
		Logger:   tail.DiscardingLogger,
	}

	t, err := tail.TailFile(file, conf)
	if err != nil {
		apilog.Println(err)
	}

	for line := range t.Lines {
		if line.Err == nil {
			if err = conn.WriteMessage(websocket.TextMessage, []byte(more+line.Text)); err != nil {
				apilog.Println(err)
				return
			}
			more = ""
		} else {
			apilog.Println(err)
		}

	}
}

func (t *Tail) Start(acc telegraf.Accumulator) error {
	t.Lock()
	defer t.Unlock()

	t.acc = acc

	var seek tail.SeekInfo
	if !t.FromBeginning {
		seek.Whence = 2
		seek.Offset = 0
	}

	var errS string
	// Create a "tailer" for each file
	for _, filepath := range t.Files {
		g, err := globpath.Compile(filepath)
		if err != nil {
			log.Printf("E! Error Glob %s failed to compile, %s", filepath, err)
		}
		for file, _ := range g.Match() {
			tailer, err := tail.TailFile(file,
				tail.Config{
					ReOpen:    true,
					Follow:    true,
					Location:  &seek,
					MustExist: true,
				})
			if err != nil {
				errS += err.Error() + " "
				continue
			}
			// create a goroutine for each "tailer"
			t.wg.Add(1)
			go t.receiver(tailer)
			t.tailers = append(t.tailers, tailer)
		}
	}

	if errS != "" {
		return fmt.Errorf(errS)
	}
	return nil
}

func (l *LogParserPlugin) Start(acc telegraf.Accumulator) error {
	l.Lock()
	defer l.Unlock()

	l.acc = acc
	l.lines = make(chan string, 1000)
	l.done = make(chan struct{})

	// Looks for fields which implement LogParser interface
	l.parsers = []LogParser{}
	s := reflect.ValueOf(l).Elem()
	for i := 0; i < s.NumField(); i++ {
		f := s.Field(i)

		if !f.CanInterface() {
			continue
		}

		if lpPlugin, ok := f.Interface().(LogParser); ok {
			if reflect.ValueOf(lpPlugin).IsNil() {
				continue
			}
			l.parsers = append(l.parsers, lpPlugin)
		}
	}

	if len(l.parsers) == 0 {
		return fmt.Errorf("ERROR: logparser input plugin: no parser defined.")
	}

	// compile log parser patterns:
	for _, parser := range l.parsers {
		if err := parser.Compile(); err != nil {
			return err
		}
	}

	var seek tail.SeekInfo
	if !l.FromBeginning {
		seek.Whence = 2
		seek.Offset = 0
	}

	l.wg.Add(1)
	go l.parser()

	var errS string
	// Create a "tailer" for each file
	for _, filepath := range l.Files {
		g, err := globpath.Compile(filepath)
		if err != nil {
			log.Printf("ERROR Glob %s failed to compile, %s", filepath, err)
		}
		for file, _ := range g.Match() {
			tailer, err := tail.TailFile(file,
				tail.Config{
					ReOpen:   true,
					Follow:   true,
					Location: &seek,
				})
			if err != nil {
				errS += err.Error() + " "
				continue
			}
			// create a goroutine for each "tailer"
			l.wg.Add(1)
			go l.receiver(tailer)
			l.tailers = append(l.tailers, tailer)
		}
	}

	if errS != "" {
		return fmt.Errorf(errS)
	}
	return nil
}