feat: add optional schedule parser into the NewManager

README.md

@@ -80,3 +80,26 @@ Please see `examples/main.go` for basic usage.
 
     http.HandleFunc("/debug/cron", m.Handler)
 ```
+
+## Schedule parser customization
+
+To use non-default schedule parser, invoke the `NewManagerWithParser()` function:
+
+```go
+// Init some custom parser, 
+// see https://pkg.go.dev/github.com/robfig/cron/v3#hdr-Alternative_Formats for more info.
+m := cron.NewManagerWithParser(cron.WithParseOptions(cron.Second | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor))
+
+// Or use the predefined one:
+m = cron.NewManagerWithParser(cron.ParserWithSeconds)
+
+// Use a schedule format acceptable by the custom parser.
+m.AddFunc("f1", "* * * * * *", func(_ context.Context) error {
+    // Do some important stuff...
+    return nil
+})
+
+if err := m.Run(context.Background()); err != nil {
+    log.Fatal(err)
+}
+```

cron.go

@@ -27,6 +27,11 @@ var (
 	ErrDuplicate = errors.New("duplicate cron name")
 )
 
+var (
+	// ParserWithSeconds is a schedule parser with the leading seconds support.
+	ParserWithSeconds = cron.NewParser(cron.Second | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow | cron.Descriptor)
+)
+
 type (
 	contextKey string
 	cronState  string
@@ -48,6 +53,7 @@ func (ss Schedule) IsActive() bool { return ss != Schedule(stateDisabled) && ss
 // Manager is a Cron manager with context and middleware support.
 type Manager struct {
 	cron       *cron.Cron
+	parser     *cron.Parser
 	middleware []MiddlewareFunc
 	jobs       []job
 	muState    sync.Mutex
@@ -78,6 +84,14 @@ func NewManager() *Manager {
 	}
 }
 
+// NewManagerWithParser creates new Manager instance with the custom schedule parser.
+func NewManagerWithParser(parser cron.Parser) *Manager {
+	return &Manager{
+		cron:   cron.New(cron.WithParser(parser)),
+		parser: &parser,
+	}
+}
+
 // AddFunc adds func to cron.
 func (cm *Manager) AddFunc(name string, schedule Schedule, fn Func) {
 	cm.jobs = append(cm.jobs, newJob(name, schedule, fn, false))
@@ -106,7 +120,7 @@ func (cm *Manager) validateJobs() (string, error) {
 
 		// parse schedule
 		if job.schedule.IsActive() {
-			_, err := cron.ParseStandard(job.schedule.String())
+			_, err := cm.parseSchedule(job.schedule)
 			if err != nil {
 				return job.name, err
 			}
@@ -189,6 +203,18 @@ func (cm *Manager) Stop() context.Context {
 	return cm.cron.Stop()
 }
 
+// parseSchedule parses the given schedule using the registered Parser or with Standard Parser if none.
+func (cm *Manager) parseSchedule(s Schedule) (cron.Schedule, error) {
+	var fn func(s string) (cron.Schedule, error)
+	if cm.parser != nil {
+		fn = cm.parser.Parse
+	} else {
+		fn = cron.ParseStandard
+	}
+
+	return fn(s.String())
+}
+
 // updateState set.
 func (cm *Manager) updateState(idx int, state cronState, err error) {
 	cm.muState.Lock()

cron_test.go

@@ -47,6 +47,46 @@ func TestManager_Validate(t *testing.T) {
 	})
 }
 
+func TestManager_Options(t *testing.T) {
+	Convey("Test NewManager with custom parser", t, func() {
+		m := NewManagerWithParser(ParserWithSeconds)
+
+		Convey("When standard schedule format", func() {
+			m.AddFunc("f1", "0 0 * * *", newCronFunc("f1"))
+
+			name, err := m.validateJobs()
+			So(err, ShouldNotBeNil)
+			So(name, ShouldEqual, "f1")
+		})
+
+		Convey("When custom schedule format", func() {
+			m.AddFunc("f2", "10 * * * * *", newCronFunc("f1"))
+
+			_, err := m.validateJobs()
+			So(err, ShouldBeNil)
+		})
+	})
+
+	Convey("Test NewManager with standard parser", t, func() {
+		m := NewManager()
+
+		Convey("When standard schedule format", func() {
+			m.AddFunc("f1", "0 0 * * *", newCronFunc("f1"))
+
+			_, err := m.validateJobs()
+			So(err, ShouldBeNil)
+		})
+
+		Convey("When custom schedule format", func() {
+			m.AddFunc("f2", "10 * * * * *", newCronFunc("f1"))
+
+			name, err := m.validateJobs()
+			So(err, ShouldNotBeNil)
+			So(name, ShouldEqual, "f2")
+		})
+	})
+}
+
 func TestManager_Run(t *testing.T) {
 	Convey("Test validate function", t, func() {
 		ctx := t.Context()