gron

Gron provides a clear syntax for writing and deploying cron jobs.

Goals

Minimalist APIs for scheduling jobs.
Thread safety.
Customizable Job Type.
Customizable Schedule.

Installation

$ go get github.com/roylee0704/gron

Usage

Create schedule.go

package main

import (
    "fmt"
    "time"
    "github.com/roylee0704/gron"
)

func main() {
    c := gron.New()
    c.AddFunc(gron.Every(1*time.Hour), func() {
        fmt.Println("runs every hour.")
    })
    c.Start()
}

Schedule Parameters

All scheduling is done in the machine's local time zone (as provided by the Go time package).

Setup basic periodic schedule with gron.Every().

gron.Every(1*time.Second)
gron.Every(1*time.Minute)
gron.Every(1*time.Hour)

Also support Day, Week by importing gron/xtime:

import "github.com/roylee0704/gron/xtime"

gron.Every(1 * xtime.Day)
gron.Every(1 * xtime.Week)

Schedule to run at specific time with .At(hh:mm)

gron.Every(30 * xtime.Day).At("00:00")
gron.Every(1 * xtime.Week).At("23:59")

Custom Job Type

You may define custom job types by implementing gron.Job interface: Run().

For example:

type Reminder struct {
    Msg string
}

func (r Reminder) Run() {
  fmt.Println(r.Msg)
}

After job has defined, instantiate it and schedule to run in Gron.

c := gron.New()
r := Reminder{ "Feed the baby!" }
c.Add(gron.Every(8*time.Hour), r)
c.Start()

Custom Job Func

You may register Funcs to be executed on a given schedule. Gron will run them in their own goroutines, asynchronously.

c := gron.New()
c.AddFunc(gron.Every(1*time.Second), func() {
    fmt.Println("runs every second")
})
c.Start()

Custom Schedule

Schedule is the interface that wraps the basic Next method: Next(p time.Duration) time.Time

In gron, the interface value Schedule has the following concrete types:

periodicSchedule. adds time instant t to underlying period p.
atSchedule. reoccurs every period p, at time components(hh:mm).

For more info, checkout schedule.go.

Full Example

package main

import (
    "fmt"
    "github.com/roylee0704/gron"
    "github.com/roylee0704/gron/xtime"
)

type PrintJob struct{ Msg string }

func (p PrintJob) Run() {
    fmt.Println(p.Msg)
}

func main() {

    var (
        // schedules
        daily     = gron.Every(1 * xtime.Day)
        weekly    = gron.Every(1 * xtime.Week)
        monthly   = gron.Every(30 * xtime.Day)
        yearly    = gron.Every(365 * xtime.Day)

        // contrived jobs
        purgeTask = func() { fmt.Println("purge aged records") }
        printFoo  = printJob{"Foo"}
        printBar  = printJob{"Bar"}
    )

    c := gron.New()

    c.Add(daily.At("12:30"), printFoo)
    c.AddFunc(weekly, func() { fmt.Println("Every week") })
    c.Start()

    // Jobs may also be added to a running Gron
    c.Add(monthly, printBar)
    c.AddFunc(yearly, purgeTask)

    // Stop Gron (running jobs are not halted).
    c.Stop()
}

roylee0704 / gron

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