Crono — Job scheduler for Rails

[](https://travis-ci.org/plashchynski/ crono)

Crono is a time-based background job scheduler daemon (just like Cron) for Ruby on Rails. It's pure Ruby. It doesn't use Unix Cron and other platform-dependent things. So you can use it everywhere.

Requirements

Tested with latest MRI Ruby (2.2, 2.1 and 2.0) and Rails 3.2+ Other versions are untested but might work fine.

Installation

Add the following line to your application's Gemfile:

gem 'crono'

Run the bundle command to install it. After you install Crono, you can run the generator:

rails generate crono:install

It will create a configuration file config/cronotab.rb Now you are ready to move forward to create a job and schedule it.

Usage

Create Job

Crono can use Active Job jobs in app/jobs/. The only requirements is that the perform method should take no arguments.

Here's an example of a test job: app/jobs/test_job.rb

class TestJob < ActiveJob::Base
  def perform
    # put you scheduled code here
    # Comments.deleted.clean_up...
  end
end

The Active Job jobs is convenient because you can use one class in both periodic and enqueued ways. But it doesn't necessarily. Any class can be used as Job if it has a method perform without arguments:

class TestJob # this is not active job class
  def perform
    # put you scheduled code here
    # Comments.deleted.clean_up...
  end
end

Schedule Jobs

The schedule described in the configuration file config/cronotab.rb, that we created using rails generate crono:install or manually. The semantic is pretty straightforward:

Crono.perform(TestJob).every 2.days, at: "15:30"

You can schedule one job a few times if you want the job to be performed a few times a day:

Crono.perform(TestJob).every 1.days, at: "00:00"
Crono.perform(TestJob).every 1.days, at: "12:00"

The at can be a Hash:

Crono.perform(TestJob).every 1.days, at: {hour: 12, min: 15}

Run daemon

To run Crono daemon, in your Rails project root directory:

bundle exec crono RAILS_ENV=development

crono usage:

Usage: crono [options]
    -C, --cronotab PATH              Path to cronotab file (Default: config/cronotab.rb)
    -L, --logfile PATH               Path to writable logfile (Default: log/crono.log)
    -P, --pidfile PATH               Path to pidfile (Default: tmp/pids/crono.pid)
    -d, --[no-]daemonize             Daemonize process (Default: false)

License

Copyright 2015 Dzmitry Plashchynski plashchynski@gmail.com
Licensed under the Apache License, Version 2.0
Please see LICENSE for licensing details.