Change cron syntax to standard format (#2678)

* Change cron syntax to standard format
* Add standard cron example in showschedule command

Signed-off-by: Shubham Nazare <shubham4443@gmail.com>

pkg/apis/core/v1/timetrigger_webhook.go

@@ -17,7 +17,6 @@ limitations under the License.
 package v1
 
 import (
-	"github.com/robfig/cron"
 	"go.uber.org/zap"
 	"k8s.io/apimachinery/pkg/runtime"
 	ctrl "sigs.k8s.io/controller-runtime"
@@ -59,7 +58,7 @@ func (r *TimeTrigger) ValidateCreate() error {
 		return err
 	}
 
-	_, err = cron.Parse(r.Spec.Cron)
+	err = IsValidCronSpec(r.Spec.Cron)
 	if err != nil {
 		err = ferror.MakeError(ferror.ErrorInvalidArgument, "TimeTrigger cron spec is not valid")
 		return err
@@ -76,7 +75,7 @@ func (r *TimeTrigger) ValidateUpdate(old runtime.Object) error {
 		return err
 	}
 
-	_, err = cron.Parse(r.Spec.Cron)
+	err = IsValidCronSpec(r.Spec.Cron)
 	if err != nil {
 		err = ferror.MakeError(ferror.ErrorInvalidArgument, "TimeTrigger cron spec is not valid")
 		return err

pkg/apis/core/v1/validation.go

@@ -25,7 +25,7 @@ import (
 	"strings"
 
 	"github.com/hashicorp/go-multierror"
-	"github.com/robfig/cron"
+	"github.com/robfig/cron/v3"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/util/validation"
 
@@ -170,7 +170,8 @@ func ValidateKubeReference(refName string, name string, namespace string) error
 }
 
 func IsValidCronSpec(spec string) error {
-	_, err := cron.Parse(spec)
+	cronSpecParser := cron.NewParser(cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor)
+	_, err := cronSpecParser.Parse(spec)
 	return err
 }
 

pkg/controller/timeTriggerApi.go

@@ -25,7 +25,6 @@ import (
 	restful "github.com/emicklei/go-restful/v3"
 	"github.com/go-openapi/spec"
 	"github.com/gorilla/mux"
-	"github.com/robfig/cron"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	fv1 "github.com/fission/fission/pkg/apis/core/v1"
@@ -135,7 +134,7 @@ func (a *API) TimeTriggerApiCreate(w http.ResponseWriter, r *http.Request) {
 	}
 
 	// validate
-	_, err = cron.Parse(t.Spec.Cron)
+	err = fv1.IsValidCronSpec(t.Spec.Cron)
 	if err != nil {
 		err = ferror.MakeError(ferror.ErrorInvalidArgument, "TimeTrigger cron spec is not valid")
 		a.respondWithError(w, err)
@@ -211,7 +210,7 @@ func (a *API) TimeTriggerApiUpdate(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	_, err = cron.Parse(t.Spec.Cron)
+	err = fv1.IsValidCronSpec(t.Spec.Cron)
 	if err != nil {
 		err = ferror.MakeError(ferror.ErrorInvalidArgument, "TimeTrigger cron spec is not valid")
 		a.respondWithError(w, err)

pkg/fission-cli/cmd/timetrigger/create.go

@@ -23,7 +23,7 @@ import (
 	"github.com/fission/fission/pkg/fission-cli/cmd"
 
 	"github.com/pkg/errors"
-	"github.com/robfig/cron"
+	"github.com/robfig/cron/v3"
 	uuid "github.com/satori/go.uuid"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
@@ -74,7 +74,7 @@ func (opts *CreateSubCommand) complete(input cli.Input) (err error) {
 
 	cronSpec := input.String(flagkey.TtCron)
 	if len(cronSpec) == 0 {
-		return errors.New("Need a cron spec like '0 30 * * * *', '@every 1h30m', or '@hourly'; use --cron")
+		return errors.New("Need a cron spec like '30 * * * *', '@every 1h30m', or '@hourly'; use --cron")
 	}
 
 	if input.Bool(flagkey.SpecSave) {
@@ -160,7 +160,8 @@ func (opts *CreateSubCommand) run(input cli.Input) error {
 }
 
 func getCronNextNActivationTime(cronSpec string, serverTime time.Time, round int) error {
-	sched, err := cron.Parse(cronSpec)
+	cronSpecParser := cron.NewParser(cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor)
+	sched, err := cronSpecParser.Parse(cronSpec)
 	if err != nil {
 		return err
 	}

pkg/fission-cli/cmd/timetrigger/test.go

@@ -42,7 +42,7 @@ func (opts *ShowSubCommand) run(flaginput cli.Input) error {
 	cronSpec := flaginput.String(flagkey.TtCron)
 
 	if len(cronSpec) == 0 {
-		return errors.New("need a cron spec like '0 30 * * * *', '@every 1h30m', or '@hourly'; use --cron")
+		return errors.New("need a cron spec like '0 30 * * * *', '*/2 * * * *', '@every 1h30m', or '@hourly'; use --cron")
 	}
 
 	t := util.GetServerInfo(flaginput, opts.Client()).ServerTime.CurrentTime.UTC()

pkg/timer/timer.go

@@ -17,7 +17,7 @@ limitations under the License.
 package timer
 
 import (
-	"github.com/robfig/cron"
+	"github.com/robfig/cron/v3"
 	"go.uber.org/zap"
 
 	fv1 "github.com/fission/fission/pkg/apis/core/v1"
@@ -54,7 +54,10 @@ func MakeTimer(logger *zap.Logger, publisher publisher.Publisher) *Timer {
 }
 
 func (timer *Timer) newCron(t fv1.TimeTrigger) *cron.Cron {
-	c := cron.New()
+	c := cron.New(
+		cron.WithParser(
+			cron.NewParser(
+				cron.SecondOptional | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor)))
 	c.AddFunc(t.Spec.Cron, func() { //nolint: errCheck
 		headers := map[string]string{
 			"X-Fission-Timer-Name": t.Name,