Function TailFile

tail.go:103–136

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.

(filename string, config Config)

// 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.watcher = watch.NewInotifyFileWatcher(filename)
	}

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

	go t.tailFileSync()

	return t, nil
}

// Return the file's current position, like stdio's ftell().
// But this value is not very accurate.