smitt04/scheduler

Task scheduler for Golang

Go Task Scheduler

Go Task scheduler is a small library that you can use within your application that enables you to execute callbacks (goroutines) after a pre-defined amount of time. GTS also provides task storage which is used to invoke callbacks for tasks which couldn’t be executed during down-time as well as maintaining a history of the callbacks that got executed.

Features

• Execute tasks based after a specific duration or at a specific point in time
• Job stores for history & recovery, provided stores out of the box:
  • Sqlite3
  • Redis (Coming soon)

Installation

go get github.com/smitt04/scheduler

How To Use

Instantiate a scheduler as follows:

s := scheduler.New(storage)

GTS currently supports 2 kinds of storages:

1. NoOpStorage: Does nothing

noOpStorage := storage.NewNoOpStorage()

1. MemoryStorage: Does nothing

memStorage := storage.NewMemoryStorage()

1. SqliteStorage: Persists tasks into a SQLite3 database.

sqliteStorage := storage.NewSqlite3Storage()

Example:

storage := storage.NewSqlite3Storage(
	storage.Sqlite3Config{
		DbName: "db.store",
	},
)
if err := storage.Connect(); err != nil {
	log.Fatal("Could not connect to db", err)
}

if err := storage.Initialize(); err != nil {
	log.Fatal("Could not intialize database", err)
}

and then pass it to the scheduler.

Scheduling tasks can be done in 3 ways:

Execute a task after 5 seconds.

func MyFunc(arg1 string, arg2 string)
taskID := s.RunAfter(5*time.Second, MyFunc, "Hello", "World")

Execute a task at a specific time.

func MyFunc(arg1 string, arg2 string)
taskID := s.RunAt(time.Now().Add(24 * time.Hour), MyFunc, "Hello", "World")

Execute a task every 1 minute.

func MyFunc(arg1 string, arg2 string)
taskID := s.RunEvery(1 * time.Minute, MyFunc, "Hello", "World")

Examples

The Examples folder contains a bunch of code samples you can look into.

Custom Storage

GTS supports the ability to provide a custom storage, the newly created storage has to implement the TaskStore interface

type TaskStore interface {
	Store(task *TaskAttributes) error
        Remove(task *TaskAttributes) error
	Fetch() ([]TaskAttributes, error)
}

TaskAttributes looks as follows:

type TaskAttributes struct {
	Hash        string
	Name        string
	LastRun     string
	NextRun     string
	Duration    string
	IsRecurring string
	Params      string
}

TODOs

• [ ] Design a cron-like task schedule for RunEvery method

Credit

This package is heavily inspired by APScheduler for Python & GoCron

License

MIT