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Build PkgGoDev Go Report Card codecov

A minimalistic and zero-dependency scheduling library for Go.


Inspired by the Quartz Java scheduler.

Library building blocks

Scheduler interface

type Scheduler interface {
	// Start starts the scheduler. The scheduler will run until
	// the Stop method is called or the context is canceled. Use
	// the Wait method to block until all running jobs have completed.

	// IsStarted determines whether the scheduler has been started.
	IsStarted() bool

	// ScheduleJob schedules a job using a specified trigger.
	ScheduleJob(ctx context.Context, job Job, trigger Trigger) error

	// GetJobKeys returns the keys of all of the scheduled jobs.
	GetJobKeys() []int

	// GetScheduledJob returns the scheduled job with the specified key.
	GetScheduledJob(key int) (*ScheduledJob, error)

	// DeleteJob removes the job with the specified key from the Scheduler's execution queue.
	DeleteJob(key int) error

	// Clear removes all of the scheduled jobs.

	// Stop shutdowns the scheduler.

	// Wait blocks until the scheduler stops running and all jobs
	// have returned. Wait will return when the context passed to
	// it has expired. Until the context passed to start is
	// cancelled or Stop is called directly.

Implemented Schedulers

  • StdScheduler

Trigger interface

type Trigger interface {
	// NextFireTime returns the next time at which the Trigger is scheduled to fire.
	NextFireTime(prev int64) (int64, error)

	// Description returns the description of the Trigger.
	Description() string

Implemented Triggers

  • CronTrigger
  • SimpleTrigger
  • RunOnceTrigger

Job interface

Any type that implements it can be scheduled.

type Job interface {
	// Execute is called by a Scheduler when the Trigger associated with this job fires.

	// Description returns the description of the Job.
	Description() string

	// Key returns the unique key for the Job.
	Key() int

Implemented Jobs

  • ShellJob
  • CurlJob
  • FunctionJob

Cron expression format

Field Name Mandatory Allowed Values Allowed Special Characters
Seconds YES 0-59 , - * /
Minutes YES 0-59 , - * /
Hours YES 0-23 , - * /
Day of month YES 1-31 , - * ? /
Month YES 1-12 or JAN-DEC , - * /
Day of week YES 1-7 or SUN-SAT , - * ? /
Year NO empty, 1970- , - * /


To set a custom logger, use the logger.SetDefault function.
The argument must implement the logger.Logger interface.

The following example shows how to disable library logs.

import ""

logger.SetDefault(logger.NewSimpleLogger(nil, logger.LevelOff))


package main

import (


func main() {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// create scheduler
	sched := quartz.NewStdScheduler()

	// async start scheduler

	// create jobs
	cronTrigger, _ := quartz.NewCronTrigger("1/5 * * * * *")
	shellJob := quartz.NewShellJob("ls -la")

	request, _ := http.NewRequest(http.MethodGet, "", nil)
	curlJob := quartz.NewCurlJob(request)

	functionJob := quartz.NewFunctionJob(func(_ context.Context) (int, error) { return 42, nil })

	// register jobs to scheduler
	sched.ScheduleJob(ctx, shellJob, cronTrigger)
	sched.ScheduleJob(ctx, curlJob, quartz.NewSimpleTrigger(time.Second*7))
	sched.ScheduleJob(ctx, functionJob, quartz.NewSimpleTrigger(time.Second*5))

	// stop scheduler

	// wait for all workers to exit

More code samples can be found in the examples directory.


Licensed under the MIT License.