Go code snippets

fragments of Go code which don't deserve their own library

return the file path for the last modified file which matches the provided regex

func GetLatestModifiedFileWhichMatchesRegex(dir string, regex *regexp.Regexp) (string, error) {
	var ret *struct {
		time time.Time
		path string
	}

	entries, err := os.ReadDir(dir)
	if err != nil {
		return "", err
	}

	for _, entry := range entries {
		if entry.IsDir() || !regex.MatchString(entry.Name()) {
			continue
		}

		path := filepath.Join(dir, entry.Name())

		if info, err := os.Stat(path); err != nil {
			return "", err
		} else {
			if ret == nil || ret.time.Before(info.ModTime()) {
				ret = &struct {
					time time.Time
					path string
				}{
					time: info.ModTime(),
					path: path,
				}
			}
		}
	}

	if ret == nil {
		return "", fmt.Errorf("no files match regex")
	}

	return ret.path, nil
}

open a json file and parse it returning errors

var s Structure
if fd, err := os.Open(path); err != nil {
	return nil, err
} else {
	if err := json.NewDecoder(fd).Decode(&s); err != nil {
        return nil, err
	}
}