cronplan

Overview

Cron expression parser for Amazon EventBridge.

Try with curl

$ curl cronplan.in -d '5 0 10 * ? *'
Tue, 10 Oct 2023 00:05:00
Fri, 10 Nov 2023 00:05:00
Sun, 10 Dec 2023 00:05:00
Wed, 10 Jan 2024 00:05:00
Sat, 10 Feb 2024 00:05:00
Sun, 10 Mar 2024 00:05:00
Wed, 10 Apr 2024 00:05:00
Fri, 10 May 2024 00:05:00
Mon, 10 Jun 2024 00:05:00
Wed, 10 Jul 2024 00:05:00

Installation

go get github.com/winebarrel/cronplan

Usage

package main

import (
	"fmt"
	"time"

	"github.com/winebarrel/cronplan"
)

func main() {
	cron, err := cronplan.Parse("0 10 * * ? *")

	if err != nil {
		panic(err)
	}

	fmt.Println(cron.Minute.Exps[0].Number) //=> 0
	fmt.Println(cron.Hour.Exps[0].Number)   //=> 10
	fmt.Println(cron.String())              //=> "0 10 * * ? *"

	fmt.Println(cron.Match(time.Date(2022, 11, 3, 9, 0, 0, 0, time.UTC)))
	//=> false
	fmt.Println(cron.Match(time.Date(2022, 11, 3, 10, 0, 0, 0, time.UTC)))
	//=> true

	fmt.Println(cron.Next(time.Date(2022, 11, 3, 10, 0, 0, 0, time.UTC)))
	//=> 2022-11-03 10:00:00 +0000 UTC
	fmt.Println(cron.Next(time.Date(2022, 11, 3, 11, 0, 0, 0, time.UTC)))
	//=> 2022-11-04 10:00:00 +0000 UTC
	fmt.Println(cron.NextN(time.Date(2022, 11, 3, 10, 0, 0, 0, time.UTC), 3))
	//=> [2022-11-03 10:00:00 +0000 UTC 2022-11-04 10:00:00 +0000 UTC 2022-11-05 10:00:00 +0000 UTC]

	fmt.Println(cron.Between(
		time.Date(2022, 11, 3, 10, 0, 0, 0, time.UTC),
		time.Date(2022, 11, 4, 10, 0, 0, 0, time.UTC),
	))
	//=> [2022-11-03 10:00:00 +0000 UTC 2022-11-04 10:00:00 +0000 UTC]
}

Behavior of "L" in day-of-week

If you specify "L" for day-of-week, the last day of the week of each month is usually matched.

# cron(0 0 ? * 6L *)
Fri, 27 Oct 2023 00:00:00
Fri, 24 Nov 2023 00:00:00
Fri, 29 Dec 2023 00:00:00
Fri, 26 Jan 2024 00:00:00
Fri, 23 Feb 2024 00:00:00

However, if you do not specify the day of the week before "L", the behavior will be the same as when you specify "SAT".

# cron(0 0 ? * L *) = cron(0 0 ? * SAT *)
Sat, 07 Oct 2023 00:00:00
Sat, 14 Oct 2023 00:00:00
Sat, 21 Oct 2023 00:00:00
Sat, 28 Oct 2023 00:00:00
Sat, 04 Nov 2023 00:00:00

cronplan CLI

CLI to show next triggers.

Installation

brew install winebarrel/cronplan/cronplan

Usage

Usage: cronplan [OPTION] CRON_EXPR
  -h int
    	hour to add
  -n int
    	number of next triggers (default 10)
  -version
    	print version and exit

$ cronplan '*/10 10 ? * MON-FRI *'
Tue, 11 Oct 2022 10:00:00
Tue, 11 Oct 2022 10:10:00
Tue, 11 Oct 2022 10:20:00
Tue, 11 Oct 2022 10:30:00
Tue, 11 Oct 2022 10:40:00
Tue, 11 Oct 2022 10:50:00
Wed, 12 Oct 2022 10:00:00
Wed, 12 Oct 2022 10:10:00
Wed, 12 Oct 2022 10:20:00
Wed, 12 Oct 2022 10:30:00

$ cronplan -h -9 '*/10 10 ? * MON-FRI *'
Tue, 11 Oct 2022 01:00:00
Tue, 11 Oct 2022 01:10:00
Tue, 11 Oct 2022 01:20:00
Tue, 11 Oct 2022 01:30:00
Tue, 11 Oct 2022 01:40:00
Tue, 11 Oct 2022 01:50:00
Wed, 12 Oct 2022 01:00:00
Wed, 12 Oct 2022 01:10:00
Wed, 12 Oct 2022 01:20:00
Wed, 12 Oct 2022 01:30:00

cronmatch CLI

CLI to check if datetime matches cron expression.

Installation

brew install winebarrel/cronplan/cronmatch

Usage

Usage: cronmatch [OPTION] CRON_EXPR DATE
  -h int
    	hour to add
  -no-color
    	disable color output
  -version
    	print version and exit

$ cronmatch -h -9 '0 1 * * ? *' '2022/10/20 10:00'
'0 1 * * ? *' matches '2022/10/20 10:00' (offset: -9h)

$ cronmatch '0 10 * * ? *' 'Oct 10, 2022, 10:10'
'0 10 * * ? *' does not match 'Oct 10, 2022, 10:10'

cf. https://github.com/araddon/dateparse

cronviz CLI

CLI to visualize cron schedule.

inspired by cronv, aws-cronv.

Installation

brew install winebarrel/cronplan/cronviz

Usage

Usage: cronviz [OPTION] [FILE]
  -f string
    	from date (default current date)
  -h int
    	hour to add
  -p string
    	period (default "1d")
  -version
    	print version and exit

$ cat cron.txt
batch1  0 * * * ? *
batch2  30 */2 * * ? *
batch3  15,45 */3 * * ? *

$ cronviz cron.txt > output.html
$ open output.html

cf. https://raw.githack.com/winebarrel/cronplan/main/_example/timeline.html

crongrep CLI

CLI to grep with cron expression.

Installation

brew install winebarrel/cronplan/crongrep

Usage

Usage: crongrep [OPTION] CRON_EXPR
  -version
    	print version and exit

$ cronplan -n 5 '10 12 */5 * ? *'
Fri, 06 Oct 2023 12:10:00
Wed, 11 Oct 2023 12:10:00
Mon, 16 Oct 2023 12:10:00
Sat, 21 Oct 2023 12:10:00
Thu, 26 Oct 2023 12:10:00

$ cronplan -n 5 '10 12 */5 * ? *' | crongrep '* * ? * WED-FRI *'
Fri, 06 Oct 2023 12:10:00
Wed, 11 Oct 2023 12:10:00
Thu, 26 Oct 2023 12:10:00

Related Links

• Cron expressions reference - Amazon EventBridge
• https://github.com/winebarrel/terraform-provider-cronplan
• Cron Trigger Tutorial