add expr-lang.org support (use with -e)

This commit is contained in:
2026-08-15 00:10:01 +02:00
parent 1bb24327e5
commit b72f8ea9d8
7 changed files with 397 additions and 6 deletions

142
pkg/runexpr/duration.go Normal file
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package runexpr
import (
"fmt"
"log"
"math"
"strconv"
"time"
)
const maxDuration time.Duration = 1<<63 - 1
// humanDuration represents a ES duration with day support
type humanDuration struct {
days, hours, minutes, seconds int
}
func parseDuration(duration string) time.Duration {
var seconds int64
for _, match := range matchDuration.FindAllStringSubmatch(duration, -1) {
if len(match) == 3 {
durationvalue, err := strconv.ParseInt(match[1], 10, 64)
if err != nil {
log.Fatal(err)
}
switch match[2][0] {
case 'y':
seconds += durationvalue * 31536000
case 'd':
seconds += durationvalue * 86400
case 'h':
seconds += durationvalue * 3600
case 'm':
seconds += durationvalue * 60
case 's':
seconds += durationvalue
}
}
}
if seconds >= int64(maxDuration.Seconds()) {
log.Fatal("duration overflow, choose a smaller duration")
}
dur := time.Duration(seconds) * time.Second
return dur
}
// extractDuration parses a ES duration and returns an esDuration
func extractDuration(duration string) humanDuration {
esd := humanDuration{}
for _, match := range matchDuration.FindAllStringSubmatch(duration, -1) {
if len(match) == 3 {
durationvalue, _ := strconv.Atoi(match[1])
switch match[2][0] {
case 'd':
esd.days = durationvalue
case 'h':
esd.hours = durationvalue
case 'm':
esd.minutes = durationvalue
case 's':
esd.seconds = durationvalue
}
}
}
return esd
}
// formatDays returns days string, unless days is larger than 365,
// then it returns years and days, e.g. 3y/34d
func formatDays(days float64) string {
if days > 365 {
years := days / 365
days := math.Remainder(days, 365)
return fmt.Sprintf("%dy/%dd", int64(years), int64(days))
}
return fmt.Sprintf("%dd", int64(days))
}
// formatDuration converts a time.Duration to a prettier human
// readable form, like 156h6m15.095s-6d/12h/6m => 6d/12h/6m
func formatDuration(val time.Duration) string {
esd := extractDuration(val.String())
daysF := float64(esd.hours) / 24.0
days := math.Floor(daysF)
hoursLeft := (daysF - days) * 24
switch {
case val.Minutes() < 1:
return fmt.Sprintf("%ds", int64(esd.seconds))
case val.Hours() < 1:
return fmt.Sprintf("%dm", int64(esd.minutes))
case val.Hours() < 24:
if esd.minutes == 0 {
return fmt.Sprintf("%dh", esd.hours)
}
return fmt.Sprintf("%dh/%dm", esd.hours, int64(esd.minutes))
default:
if esd.minutes == 0 && hoursLeft == 0 {
return formatDays(days)
}
return fmt.Sprintf("%s/%dh/%dm",
formatDays(days),
int64(hoursLeft),
esd.minutes,
)
}
}
func toYears(d time.Duration) float64 {
return d.Hours() / 24 / 365
}
func toDays(d time.Duration) float64 {
return d.Hours() / 24
}
func toHours(d time.Duration) float64 {
return d.Hours()
}
func toMinutes(d time.Duration) float64 {
return d.Minutes()
}
func toSeconds(d time.Duration) float64 {
return d.Seconds()
}

63
pkg/runexpr/run.go Normal file
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package runexpr
import (
"fmt"
"time"
"github.com/expr-lang/expr"
)
type Env struct {
Now func() time.Time
Dur, D func(string) time.Duration
Strf func(any, ...any) string
Diff func(a, b time.Time) time.Duration
Add func(time.Time, time.Duration) time.Time
Time, T func(string, ...string) time.Time
Human func(time.Duration) string
Years, Days, Hours, Minutes, Seconds func(time.Duration) float64
Clock func(time.Time) string
Unix func(time.Time) int64
TZ func(time.Time, any) time.Time
}
func RunExpr(code string) {
env := Env{
Now: time.Now,
Dur: parseDuration,
D: parseDuration,
Strf: strfTime,
Diff: timeDiff,
Add: timeAdd,
Time: newTime,
T: newTime,
Human: formatDuration,
Years: toYears,
Days: toDays,
Hours: toHours,
Minutes: toMinutes,
Seconds: toSeconds,
Clock: toClock,
Unix: toUnix,
TZ: toTZ,
}
options := []expr.Option{
expr.Env(Env{}),
expr.Operator("-", "Diff"), // custom operator to diff two time.Time's
expr.Operator("+", "Add"), // custom operator to add time.Duration to a time.Time
}
program, err := expr.Compile(code, options...)
if err != nil {
fmt.Printf("%v", err)
return
}
output, err := expr.Run(program, env)
if err != nil {
panic(err)
}
fmt.Println(output)
}

159
pkg/runexpr/time.go Normal file
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package runexpr
import (
"fmt"
"log"
"reflect"
"regexp"
"time"
"github.com/lestrrat-go/strftime"
)
var (
// matchDuration is a regex which matches ES durations, which
// supports days (in contrast to time.Duration which does not)
matchDuration = regexp.MustCompile(`(\d+)([ydhms])`)
timeFormats = []string{
time.RFC3339,
time.RFC1123Z,
time.RFC1123,
time.RFC850,
time.RFC822Z,
time.RFC822,
time.RubyDate,
time.UnixDate,
time.DateTime,
time.DateOnly,
time.TimeOnly,
"02.01.2006 15:04:05", // german
"02/01/2006 15:04:05",
"20060102",
"02.01.2006", // german
"20060102150405",
"15:04:05",
"15:04",
}
)
// setDefault# either returns the first element if item if set or
// replace. Types must match expect.
func setDefault(item []any, replace any, expect reflect.Type) any {
if reflect.TypeOf(replace) != expect {
log.Fatal("setDefault(): invalid types called")
}
if len(item) == 1 {
return item[0]
} else {
return replace
}
}
// strfTime formats a time.Time. Args are any,any to be able to use it in a pipe.
//
// eg:
//
// now | strftime("%D")
// strftime(now, "%D")
// "%d.%m" | strftime(now)
func strfTime(fst any, snd ...any) string {
var ts time.Time
var format string
switch firstVal := fst.(type) {
case string:
format = firstVal
ts = setDefault(snd, time.Now(), reflect.TypeFor[time.Time]()).(time.Time)
case time.Time:
ts = firstVal
format = setDefault(snd, "%D", reflect.TypeFor[string]()).(string)
}
if format == "" || ts.IsZero() {
log.Fatal("strftime(): invalid args")
}
formatted, err := strftime.Format(format, ts)
if err != nil {
log.Fatal(err)
}
return formatted
}
// timeDiff returns the time.Duration diff between time.Time a and
// b. It syncs timezones first and exchanges a+b if a>b
func timeDiff(a, b time.Time) time.Duration {
if a.Location() != b.Location() {
b = b.In(a.Location())
}
if a.After(b) {
a, b = b, a
}
return b.Sub(a)
}
// newTime returns a new tim.Time object if ts matches one of the
// predefined formats. If format is set, use this.
func newTime(ts string, format ...string) time.Time {
if len(format) > 0 {
t, err := time.Parse(format[0], ts)
if err == nil {
return t
}
}
for _, format := range timeFormats {
t, err := time.Parse(format, ts)
if err == nil {
return t
}
}
log.Fatal("new(): failed to parse timestamp")
return time.Time{}
}
// toClock returns the HH:MM:SS time part of a time.Time
func toClock(t time.Time) string {
h, m, s := t.Clock()
return fmt.Sprintf("%02d:%02d:%02d", h, m, s)
}
// timeAdd adds d to t
func timeAdd(t time.Time, d time.Duration) time.Time {
return t.Add(d)
}
// toUnix returns the epoch of t
func toUnix(t time.Time) int64 {
return t.Unix()
}
// toTZ converts t to given time zone
func toTZ(t time.Time, tz any) time.Time {
var z *time.Location
var err error
switch val := tz.(type) {
case string:
z, err = time.LoadLocation(val)
if err != nil {
log.Fatal(err)
}
case int:
f := fmt.Sprintf("UTC+%d", val)
if val < 0 {
f = fmt.Sprintf("UTC%d", val)
}
z = time.FixedZone(f, val*60*60)
}
return t.In(z)
}