time.ParseDuration day, week, month, year -> d, w, M, Y; helper code to ParseDuration

[go-shafaq]

I've simplified the code to make it easier to copy and use.
also same issue[/issues/17767#issue-187078548]

// ParseDuration parses a duration string.
// examples: "10d", "-1.5w" or "3Y4M5d".
// Add time units are "d"="D", "w"="W", "M", "y"="Y".
func ParseDuration(s string) (time.Duration, error) {
	neg := false
	if len(s) > 0 && s[0] == '-' {
		neg = true
		s = s[1:]
	}

	re := regexp.MustCompile(`(\d*\.\d+|\d+)[^\d]*`)
	unitMap := map[string]time.Duration{
		"d": 24,
		"D": 24,
		"w": 7 * 24,
		"W": 7 * 24,
		"M": 30 * 24,
		"y": 365 * 24,
		"Y": 365 * 24,
	}

	strs := re.FindAllString(s, -1)
	var sumDur time.Duration
	for _, str := range strs {
		var _hours time.Duration = 1
		for unit, hours := range unitMap {
			if strings.Contains(str, unit) {
				str = strings.ReplaceAll(str, unit, "h")
				_hours = hours
				break
			}
		}

		dur, err := time.ParseDuration(str)
		if err != nil {
			return 0, err
		}

		sumDur += dur * _hours
	}

	if neg {
		sumDur = -sumDur
	}
	return sumDur, nil
}

[ianlancetaylor]

Thanks, but we intentionally do not use any time unit larger than hour because they are ambiguous. Days are sometimes 24 hours, sometimes 23 or 25 at daylight savings time transitions. Similarly for the other larger units.

[timkuijsten]

I understand the reasoning, but it does look a bit unpractical when used with flag.Duration, i.e. with a 30 day default:

  -whiteexp duration
        duration before whitelists expire (default 720h0m0s)

From poolpOrg/filter-spfgreylist#5

Maybe we should adapt flag.Duration (not time.Duration) to parse days when used as input from the command line?
Previous discussion: #11473

[go-shafaq]

I understand the reasoning, but it does look a bit unpractical when used with flag.Duration, i.e. with a 30 day default:

  -whiteexp duration
        duration before whitelists expire (default 720h0m0s)

From poolpOrg/filter-spfgreylist#5

Maybe we should adapt flag.Duration (not time.Duration) to parse days when used as input from the command line? Previous discussion: #11473

I didnt get you
I made my pkg github.com/go-shafaq/timep
what do you think

[timkuijsten]

I didnt get you

Sorry, I was replying to ianlancetaylor.

I made my pkg github.com/go-shafaq/timep
what do you think

It's nice, although I would prefer to copy paste if it's just a little bit of code. For me just adding days and weeks would help with flags to command line tools and it's less ambiguous than the length of a month.

[go-shafaq]

I didnt get you

Sorry, I was replying to ianlancetaylor.

I made my pkg github.com/go-shafaq/timep
what do you think

It's nice, although I would prefer to copy paste if it's just a little bit of code. For me just adding days and weeks would help with flags to command line tools and it's less ambiguous than the length of a month.

I just copied code from org time pkg and added some flexibility