https://github.com/maennchen/crontab

:alarm_clock: Parse Cron Expressions, Compose Cron Expression Strings and Caluclate Execution Dates.
https://github.com/maennchen/crontab

cron crontab elixir schedule

Last synced: 7 days ago
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:alarm_clock: Parse Cron Expressions, Compose Cron Expression Strings and Caluclate Execution Dates.

• Host: GitHub
• URL: https://github.com/maennchen/crontab
• Owner: maennchen
• License: mit
• Created: 2016-12-21T23:43:07.000Z (about 8 years ago)
• Default Branch: main
• Last Pushed: 2024-10-23T14:28:00.000Z (4 months ago)
• Last Synced: 2025-01-28T16:11:57.734Z (14 days ago)
• Topics: cron, crontab, elixir, schedule
• Language: Elixir
• Homepage: https://hex.pm/packages/crontab
• Size: 365 KB
• Stars: 94
• Watchers: 5
• Forks: 33
• Open Issues: 6
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        

  

  

  

# Crontab

[![CI](https://github.com/maennchen/crontab/workflows/.github/workflows/elixir.yml/badge.svg)](https://github.com/maennchen/crontab/actions?query=workflow%3A.github%2Fworkflows%2Felixir.yml)

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[![Module Version](https://img.shields.io/hexpm/v/crontab.svg)](https://hex.pm/packages/crontab)

[![Hex Docs](https://img.shields.io/badge/hex-docs-lightgreen.svg)](https://hexdocs.pm/crontab/)

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[![License](https://img.shields.io/hexpm/l/crontab.svg)](https://github.com/maennchen/crontab/blob/main/LICENSE)

[![Last Updated](https://img.shields.io/github/last-commit/maennchen/crontab.svg)](https://github.com/maennchen/crontab/commits/main)

Elixir library for parsing, writing, and calculating Cron format strings.




## Installation

Add `:crontab` to your list of dependencies in `mix.exs`:

```elixir

def deps do

  [

    {:crontab, "~> 1.1"}

  ]

end

```

## Usage

### Import Cron expression sigil

Everywhere you want to use the Cron expression sigil (`e[cron expression]`).

```elixir

import Crontab.CronExpression

```

### Extended Cron expressions

An extended Cron expression has more precision than a normal Cron expression.

It also specifies the second.

If you want to use extended Cron expressions with the sigil, just append an `e`.

### Checking if a Cron Expression Matches a date

```elixir

iex> import Crontab.CronExpression

iex> Crontab.DateChecker.matches_date?(~e[*/2], ~N[2017-01-01 01:01:00])

false

iex> Crontab.DateChecker.matches_date?(~e[*], ~N[2017-01-01 01:01:00])

true

```

### Find Next / Previous Execution Date candidates

All the date parameters default to now.

For previous, just replace `next` in the code below.

```elixir

iex> import Crontab.CronExpression

iex> Crontab.Scheduler.get_next_run_date(~e[*/2], ~N[2017-01-01 01:01:00])

{:ok, ~N[2017-01-01 01:02:00]}

iex> Crontab.Scheduler.get_next_run_date!(~e[*/2], ~N[2017-01-01 01:01:00])

~N[2017-01-01 01:02:00]

```

```elixir

iex> Enum.take(Crontab.Scheduler.get_next_run_dates(~e[*/2], ~N[2017-01-01 01:01:00]), 3)

[~N[2017-01-01 01:02:00], ~N[2017-01-01 01:04:00], ~N[2017-01-01 01:06:00]]

```

### Parse Cron Expressions

If you statically define cron expressions, use the `~e[cron expression]` sigil.

For dynamic cron expressions, there is a Parser module.

The parser module takes an optional `extended` flag. This is to mark if the

expression contains seconds. This defaults to `false`.

```elixir

iex> Crontab.CronExpression.Parser.parse "* * * * *"

{:ok,

  %Crontab.CronExpression{day: [:*], hour: [:*], minute: [:*],

  month: [:*], weekday: [:*], year: [:*]}}

iex> Crontab.CronExpression.Parser.parse! "* * * * *"

%Crontab.CronExpression{day: [:*], hour: [:*], minute: [:*],

 month: [:*], weekday: [:*], year: [:*]}

```

### Compose Cron expressions

```elixir

iex> Crontab.CronExpression.Composer.compose %Crontab.CronExpression{}

"* * * * * *"

iex> Crontab.CronExpression.Composer.compose %Crontab.CronExpression{minute: [9, {:-, 4, 6}, {:/, :*, 9}]}

"9,4-6,*/9 * * * * *"

```

## Copyright and License

Copyright (c) 2016, SK & T AG, JOSHMARTIN GmbH, Jonatan Männchen

This library is MIT licensed. See the [LICENSE](https://github.com/maennchen/crontab/blob/main/LICENSE) for details.