Cron Expression in GO
Validate standard 5-field Unix cron expressions: minute, hour, day-of-month, month, day-of-week.
Try it in the GO tester →Pattern
regexGO
^(\*|([0-5]?\d))\s+(\*|([01]?\d|2[0-3]))\s+(\*|([1-9]|[12]\d|3[01]))\s+(\*|([1-9]|1[0-2]))\s+(\*|[0-7])$Go (RE2) code
goGo
package main
import (
"fmt"
"regexp"
)
func main() {
re := regexp.MustCompile(`^(\*|([0-5]?\d))\s+(\*|([01]?\d|2[0-3]))\s+(\*|([1-9]|[12]\d|3[01]))\s+(\*|([1-9]|1[0-2]))\s+(\*|[0-7])$`)
input := `0 9 * * 1`
for _, match := range re.FindAllString(input, -1) {
fmt.Println(match)
}
}Uses `regexp.MustCompile` (panics on bad patterns at startup) and `FindAllString` for all matches.
How the pattern works
Each of the five fields is validated against its allowed range. Minute: 0–59. Hour: 0–23. Day-of-month: 1–31. Month: 1–12. Day-of-week: 0–7 (0 and 7 both mean Sunday). Each field also accepts * for any value.
Examples
Input
0 9 * * 1Matches
0 9 * * 1
Input
*/15 * * * *No match
—Input
60 25 * * *No match
—