Ejemplo n.º 1
0
// TailFile begins tailing the file. Output stream is made available
// via the `Tail.Lines` channel. To handle errors during tailing,
// invoke the `Wait` or `Err` method after finishing reading from the
// `Lines` channel.
func TailFile(filename string, config Config) (*Tail, error) {
	if config.ReOpen && !config.Follow {
		util.Fatal("cannot set ReOpen without Follow.")
	}

	t := &Tail{
		Filename: filename,
		Lines:    make(chan *Line),
		Config:   config,
	}

	// when Logger was not specified in config, use default logger
	if t.Logger == nil {
		t.Logger = log.New(os.Stderr, "", log.LstdFlags)
	}

	if t.Poll {
		t.watcher = watch.NewPollingFileWatcher(filename)
	} else {
		t.tracker = watch.NewInotifyTracker()
		w, err := t.tracker.NewWatcher()
		if err != nil {
			return nil, err
		}
		t.Logger.Printf("start InotifyFileWatcher: %s", filename)
		t.watcher = watch.NewInotifyFileWatcher(filename, w)
	}

	if t.MustExist {
		var err error
		t.file, err = OpenFile(t.Filename)
		if err != nil {
			return nil, err
		}
	}

	go t.tailFileSync()

	return t, nil
}
Ejemplo n.º 2
0
func (fw *InotifyFileWatcher) ChangeEvents(t *tomb.Tomb, fi os.FileInfo) *FileChanges {
	changes := NewFileChanges()

	err := fw.w.Watch(fw.Filename)
	if err != nil {
		util.Fatal("Error watching %v: %v", fw.Filename, err)
	}

	fw.Size = fi.Size()
	fw.ModTime = fi.ModTime()

	go func() {
		defer fw.w.RemoveWatch(fw.Filename)
		defer changes.Close()

		for {
			prevSize := fw.Size

			var evt *fsnotify.FileEvent
			var ok bool

			select {
			case evt, ok = <-fw.w.Event:
				if !ok {
					return
				}
			case <-t.Dying():
				return
			}

			switch {
			case evt.IsDelete():
				fallthrough

			case evt.IsRename():
				changes.NotifyDeleted()
				continue
				//return

			case evt.IsModify():
				fi, err := os.Stat(fw.Filename)
				if err != nil {
					if os.IsNotExist(err) {
						changes.NotifyDeleted()
						return
					}
					// XXX: report this error back to the user
					util.Fatal("Failed to stat file %v: %v", fw.Filename, err)
				}
				fw.Size = fi.Size()

				if prevSize > 0 && prevSize > fw.Size {
					log.Printf("prevSize:%d,fw.Size:%d", prevSize, fw.Size)
					changes.NotifyTruncated()
				} else if prevSize > 0 && prevSize == fw.Size && fw.Size <= headerSize && fi.ModTime().Sub(fw.ModTime) > logrotateTime {
					log.Printf("logrotateTime:%s", logrotateTime)
					// also capture log_header only updates
					changes.NotifyTruncated()
				} else {
					changes.NotifyModified()
				}
				prevSize = fw.Size
			}
		}
	}()

	return changes
}