152 lines
2.8 KiB
Go

package duration
import (
"errors"
"fmt"
"strconv"
"time"
"unicode"
"unicode/utf8"
)
const (
Day = 24 * time.Hour
Week = 7 * Day
)
type durations []duration
type duration struct {
magnitude int64
unit string
}
var (
ErrInvalidUnit = errors.New("duration must be week(w), day(d), hour(h), min(m), sec(s), millisec(ms), microsec(us), or nanosec(ns)")
ErrInvalidRune = errors.New("invalid rune in declaration")
)
// RawDurationToTimeDuration extends the builtin duration-parser to support days(d) and weeks(w) as parseable units.
// The core implementation is copied from InfluxDB OSS's task engine, which itself copied the logic from an
// internal module in Flux.
func RawDurationToTimeDuration(raw string) (time.Duration, error) {
if raw == "" {
return 0, nil
}
if dur, err := time.ParseDuration(raw); err == nil {
return dur, nil
}
parsed, err := parseSignedDuration(raw)
if err != nil {
return 0, err
}
var dur time.Duration
for _, d := range parsed {
if d.magnitude < 0 {
return 0, errors.New("must be greater than 0")
}
mag := time.Duration(d.magnitude)
switch d.unit {
case "w":
dur += mag * Week
case "d":
dur += mag * Day
case "h":
dur += mag * time.Hour
case "m":
dur += mag * time.Minute
case "s":
dur += mag * time.Second
case "ms":
dur += mag * time.Millisecond
case "us":
dur += mag * time.Microsecond
case "ns":
dur += mag * time.Nanosecond
default:
return 0, ErrInvalidUnit
}
}
return dur, nil
}
func parseSignedDuration(text string) (durations, error) {
if r, s := utf8.DecodeRuneInString(text); r == '-' {
d, err := parseDuration(text[s:])
if err != nil {
return nil, err
}
for i := range d {
d[i].magnitude = -d[i].magnitude
}
return d, nil
}
d, err := parseDuration(text)
if err != nil {
return nil, err
}
return d, nil
}
// parseDuration will convert a string into components of the duration.
func parseDuration(input string) (durations, error) {
lit := input
var values durations
for len(lit) > 0 {
n := 0
for n < len(lit) {
ch, size := utf8.DecodeRuneInString(lit[n:])
if size == 0 {
return nil, ErrInvalidRune
}
if !unicode.IsDigit(ch) {
break
}
n += size
}
if n == 0 {
return nil, fmt.Errorf("invalid duration %s", lit)
}
magnitude, err := strconv.ParseInt(lit[:n], 10, 64)
if err != nil {
return nil, err
}
lit = lit[n:]
n = 0
for n < len(lit) {
ch, size := utf8.DecodeRuneInString(lit[n:])
if size == 0 {
return nil, ErrInvalidRune
}
if !unicode.IsLetter(ch) {
break
}
n += size
}
if n == 0 {
return nil, fmt.Errorf("duration is missing a unit: %s", input)
}
unit := lit[:n]
if unit == "µs" {
unit = "us"
}
values = append(values, duration{
magnitude: magnitude,
unit: unit,
})
lit = lit[n:]
}
return values, nil
}