Remove hacks from ScheduledJobs cron spec parsing

Previusly github.com/robfig/cron library did not allow passing cron spec without
seconds. Previous commit updates the library, which has additional
method ParseStandard which follows the standard cron spec, iow. minute,
hour, day of month, month, day of week.

pkg/apis/batch/validation/validation.go

@@ -199,12 +199,7 @@ func validateConcurrencyPolicy(concurrencyPolicy *batch.ConcurrencyPolicy, fldPa
 
 func validateScheduleFormat(schedule string, fldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
-	// TODO soltysh: this should be removed when https://github.com/robfig/cron/issues/58 is fixed
-	tmpSchedule := schedule
-	if len(schedule) > 0 && schedule[0] != '@' {
-		tmpSchedule = "0 " + schedule
-	}
-	if _, err := cron.Parse(tmpSchedule); err != nil {
+	if _, err := cron.ParseStandard(schedule); err != nil {
 		allErrs = append(allErrs, field.Invalid(fldPath, schedule, err.Error()))
 	}
 

pkg/controller/scheduledjob/utils.go

@@ -109,8 +109,7 @@ func getNextStartTimeAfter(schedule string, now time.Time) (time.Time, error) {
 	// How to handle concurrency control.
 	// How to detect changes to schedules or deleted schedules and then
 	// update the jobs?
-	tmpSched := addSeconds(schedule)
-	sched, err := cron.Parse(tmpSched)
+	sched, err := cron.Parse(schedule)
 	if err != nil {
 		return time.Unix(0, 0), fmt.Errorf("Unparseable schedule: %s : %s", schedule, err)
 	}
@@ -123,8 +122,7 @@ func getNextStartTimeAfter(schedule string, now time.Time) (time.Time, error) {
 // If there were missed times prior to the last known start time, then those are not returned.
 func getRecentUnmetScheduleTimes(sj batch.ScheduledJob, now time.Time) ([]time.Time, error) {
 	starts := []time.Time{}
-	tmpSched := addSeconds(sj.Spec.Schedule)
-	sched, err := cron.Parse(tmpSched)
+	sched, err := cron.ParseStandard(sj.Spec.Schedule)
 	if err != nil {
 		return starts, fmt.Errorf("Unparseable schedule: %s : %s", sj.Spec.Schedule, err)
 	}
@@ -172,15 +170,6 @@ func getRecentUnmetScheduleTimes(sj batch.ScheduledJob, now time.Time) ([]time.T
 	return starts, nil
 }
 
-// TODO soltysh: this should be removed when https://github.com/robfig/cron/issues/58 is fixed
-func addSeconds(schedule string) string {
-	tmpSched := schedule
-	if len(schedule) > 0 && schedule[0] != '@' {
-		tmpSched = "0 " + schedule
-	}
-	return tmpSched
-}
-
 // XXX unit test this
 
 // getJobFromTemplate makes a Job from a ScheduledJob