Configuration

Last updated 2026-10-21

This page covers go-scheduler's scheduler settings, per-task options, and the runtime defaults for logging and the worker pool.

Scheduler Settings

type Config struct {
	Location *time.Location
}

Field	Default	Effect
`Location`	`time.Local`	Timezone used to compute the next fire time of cron expressions and descriptors

loc, err := time.LoadLocation("Asia/Taipei")
if err != nil {
	log.Fatal(err)
}
c, err := core.New(core.Config{Location: loc})
if err != nil {
	log.Fatal(err)
}
if _, err := c.Add("30 9 * * 1-5", func() error {
	return sendReport()
}, "weekday report"); err != nil {
	log.Fatal(err)
}

30 9 * * 1-5 fires at 09:30 Monday to Friday in Asia/Taipei time.
The package reads no environment variables or configuration files.

Task Options

Add identifies variadic arguments by type, in any order:

func (c *cron) Add(spec string, action interface{}, arg ...interface{}) (int64, error)

Type	Sets	Notes
`string`	Task description	Logged by the dependency worker
`time.Duration`	Execution limit	Not a start delay; `0` means no limit
`func()`	Timeout callback	Called only when the execution limit is exceeded
`[]core.Wait`	Prerequisites	Action must be `func() error`
`[]int64`	Prerequisites (deprecated)	Each ID becomes `Wait{ID: id}` with the `Stop` policy

When the same type is passed more than once, the last string / time.Duration / func() wins, while []core.Wait and []int64 accumulate.

_, err := c.Add("*/10 * * * *", func() error {
	return syncInventory()
}, "inventory sync", 2*time.Minute, func() {
	log.Println("inventory sync exceeded 2m")
}, []core.Wait{
	{ID: authID, State: core.Stop},
	{ID: cacheID, State: core.Skip},
})
if err != nil {
	log.Fatal(err)
}

Dependency Settings

Field	Value	Effect
`ID`	Prerequisite task ID	Dependent task fails when the ID does not exist
`State`	`core.Stop` (default)	Dependent task fails when the prerequisite fails
`State`	`core.Skip`	Failed prerequisite is ignored
`Delay`	Any	Currently not applied; the wait limit is fixed at 1 minute

Runtime Defaults

Item	Value	Source
Logger	syslog (`LOG_INFO\|LOG_LOCAL0`, tag `goCron`) in JSON	`core/instance.go`
Logger fallback	stderr text, Info level	When syslog cannot be opened
Dependency workers	`runtime.NumCPU()`, or 2 when CPUs ≤ 2	`core/depend.go`
Wait queue capacity	1024	`core/depend.go`
Dependency poll interval	1ms	`core/dependManager.go`
`@every` minimum interval	30 seconds	`core/schedule.go`

None of these values can be changed by callers.
See Task Dependencies and Timeouts for runtime behavior.