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https://github.com/kostya/cron_scheduler

Simple job scheduler with crontab patterns for Crystal Language.
https://github.com/kostya/cron_scheduler

Last synced: 12 days ago
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Simple job scheduler with crontab patterns for Crystal Language.

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# CronScheduler

Simple job scheduler with crontab patterns for Crystal Language.

## Installation

Add this to your application's `shard.yml`:

```yaml
dependencies:
cron_scheduler:
github: kostya/cron_scheduler
```

## Usage

```crystal
require "cron_scheduler"
require "log"

CronScheduler.define do

# normal crontab syntax, 5 tokens (minute, hour, day, month, wday)

at("* * * * *") { Log.info { "every 1 minute" } }
at("*/5 20-23 * * *") { Log.info { "every 5 minutes between 20-23 hours" } }
at("*/2 */3 * * *") { Log.info { "every 2 minute every 3 hours" } }
at("45 * * * *") { Log.info { "every hour at :45" } }
at("* * * * SUN") { Log.info { "every 1 minute in sunday" } }

# I added extra syntax, when 6 tokens, first one parsed as seconds
# (second, minute, hour, day, month, wday)

at("*/3 * * * * *") { Log.info { "every 3.seconds" } }
at("20-45/5 * * * * *") { Log.info { "every 5.seconds between 20-45" } }
at("11,22,33,44-60/2 * * * * *") { Log.info { "every 11,22,33,44-60/2 seconds" } }
end

Log.info { "Scheduler started" }

# sleep will prevent exiting at the end of the script
sleep

```

## Crontab Format

![Eye](http://www.webenabled.com/sites/default/files/crontab-syntax.gif)