CronScheduler

Simple job scheduler with crontab patterns for Crystal Language.

Installation

Add this to your application's shard.yml:

dependencies:
  cron_scheduler:
    github: kostya/cron_scheduler

Usage

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