Cron expression parser for Amazon EventBridge.
$ 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 00:05:00go get github.com/winebarrel/cronplanpackage main import ( "fmt" "time" "github.com/winebarrel/cronplan/v2" ) func main() { cron, err := cronplan.Parse("0 10 * * ? *") if err != nil { panic(err) } fmt.Println( cron.Minute.Exps[0].Number, //=> 0 cron.Hour.Exps[0].Number, //=> 10 cron.String(), //=> "0 10 * * ? *" ) cron.Match(time.Date(2022, 11, 3, 9, 0, 0, 0, time.UTC)) //=> false cron.Match(time.Date(2022, 11, 3, 10, 0, 0, 0, time.UTC)) //=> true // NOTE: If you don't want to include `from`, add `1 * time.Minute` cron.Next(time.Date(2022, 11, 3, 10, 0, 0, 0, time.UTC)) //=> 2022-11-03 10:00:00 +0000 UTC cron.Next(time.Date(2022, 11, 3, 11, 0, 0, 0, time.UTC)) //=> 2022-11-04 10:00:00 +0000 UTC 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] 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] iter := cron.Iter(time.Date(2022, 11, 3, 10, 0, 0, 0, time.UTC)) for i := range 3 { fmt.Println(i, iter.Next()) //=> 0 2022-11-03 10:00:00 +0000 UTC //=> 1 2022-11-04 10:00:00 +0000 UTC //=> 2 2022-11-05 10:00:00 +0000 UTC } for next := range iter.Seq() { fmt.Println(next) //=> 2022-11-06 10:00:00 +0000 UTC break } }https://github.com/winebarrel/cronplan/blob/main/_example/cron/main.go
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 If you specify "31W" for day-of-month, months without a 31st day will be skipped.
(I'm not sure if this is the correct behavior)
# cron(5 0 31W * ? 2026) Fri, 30 Jan 2026 00:05:00 Tue, 31 Mar 2026 00:05:00 Fri, 29 May 2026 00:05:00 Fri, 31 Jul 2026 00:05:00 Mon, 31 Aug 2026 00:05:00 Fri, 30 Oct 2026 00:05:00 Thu, 31 Dec 2026 00:05:00 If you want the last weekday of the month, use "LW".
# cron(5 0 LW * ? 2026) Fri, 30 Jan 2026 00:05:00 Fri, 27 Feb 2026 00:05:00 Tue, 31 Mar 2026 00:05:00 Thu, 30 Apr 2026 00:05:00 Fri, 29 May 2026 00:05:00 Tue, 30 Jun 2026 00:05:00 Fri, 31 Jul 2026 00:05:00 Mon, 31 Aug 2026 00:05:00 Wed, 30 Sep 2026 00:05:00 Fri, 30 Oct 2026 00:05:00 CLI to show next triggers.
brew install winebarrel/cronplan/cronplan 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 CLI to check if datetime matches cron expression.
brew install winebarrel/cronplan/cronmatch 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://pkg.go.dev/github.com/araddon/dateparse#readme-extended-example
CLI to visualize cron schedule.
brew install winebarrel/cronplan/cronviz 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
CLI to grep with cron expression.
brew install winebarrel/cronplan/crongrep 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 CLI to show a schedule of cron expressions.
brew install winebarrel/cronplan/cronskd Usage: cronskd [OPTION] [FILE] -e string end date (default: end of day) -s string start date (default: beginning of day) -version print version and exit $ cat exprs.txt 0 10 * * ? * 15 12 * * ? * 0 18 ? * MON-FRI * 0 8 1 * ? * 5 8-10 ? * MON-FRI * $ cronskd -s '2024-11-11' exprs.txt Mon, 11 Nov 2024 08:05:00 5 8-10 ? * MON-FRI * Mon, 11 Nov 2024 09:05:00 5 8-10 ? * MON-FRI * Mon, 11 Nov 2024 10:00:00 0 10 * * ? * Mon, 11 Nov 2024 10:05:00 5 8-10 ? * MON-FRI * Mon, 11 Nov 2024 12:15:00 15 12 * * ? * Mon, 11 Nov 2024 18:00:00 0 18 ? * MON-FRI * $ cronskd -s '2024/11/12 10:00' -e 'Nov 13, 2024, 12:00' exprs.txt Tue, 12 Nov 2024 10:00:00 0 10 * * ? * Tue, 12 Nov 2024 10:05:00 5 8-10 ? * MON-FRI * Tue, 12 Nov 2024 12:15:00 15 12 * * ? * Tue, 12 Nov 2024 18:00:00 0 18 ? * MON-FRI * Wed, 13 Nov 2024 08:05:00 5 8-10 ? * MON-FRI * Wed, 13 Nov 2024 09:05:00 5 8-10 ? * MON-FRI * Wed, 13 Nov 2024 10:00:00 0 10 * * ? * Wed, 13 Nov 2024 10:05:00 5 8-10 ? * MON-FRI * cf. https://pkg.go.dev/github.com/araddon/dateparse#readme-extended-example
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