func tailFile()

in main/logtail.go [14:40]

• 24 lines of code
• 7 McCabe index (conditional complexity)

func tailFile(path string, max int64) ([]byte, error) {
	f, err := os.Open(path)
	if err != nil && os.IsNotExist(err) {
		return nil, nil
	} else if err != nil {
		return nil, errors.Wrap(err, "error opening file")
	}
	defer f.Close()

	fi, err := f.Stat()
	if err != nil {
		return nil, errors.Wrap(err, "error retrieving file info")
	}
	size := fi.Size()

	n := max
	if size < n {
		n = size
	}
	_, err = f.Seek(-n, io.SeekEnd)
	if err != nil {
		return nil, errors.Wrapf(err, "error seeking file: offset=%d whence=%v", n, io.SeekEnd)
	}

	b, err := ioutil.ReadAll(io.LimitReader(f, max))
	return b, errors.Wrap(err, "error reading from file")
}