README.rdoc

Introduction¶ ↑

Whenever is a ruby gem that provides a ruby syntax for defining cron jobs. It outputs valid cron syntax and can even write your crontab file for you. It is designed to work well with Rails applications and can be deployed with Capistrano. Whenever works fine independently as well.

Installation¶ ↑

Regular (non-Rails) install:

$ gem sources -a http://gems.github.com (you only need to run this once)
$ sudo gem install javan-whenever

In a Rails (2.1 or greater) application:

in your “config/environment.rb” file:

Rails::Initializer.run do |config|
  config.gem 'javan-whenever', :lib => false, :version => '>= 0.1.3' :source => 'http://gems.github.com'
end

To install this gem (and all other missing gem dependencies), run rake gems:install (use sudo if necessary).

In older versions of Rails:

$ gem sources -a http://gems.github.com
$ gem install javan-whenever

in your “config/environment.rb” file:

Rails::Initializer.run do |config|
  ...
end

require 'whenever'

NOTE: Requiring the whenever gem inside your Rails application is technically optional. However, if you plan to use something like Capistrano to automatically deploy and write your crontab file, you’ll need to have the gem installed on your servers, and requiring it in your app is one to ensure this.

Getting started¶ ↑

$ cd /my/rails/app
$ wheneverize .

This will create an initial “config/schedule.rb” file you.

Example schedule.rb file¶ ↑

set :path, '/var/www/apps/my_app' # Whenever will try to use your RAILS_ROOT if this isn't set
set :environment, :production     # Whenever defaults to production so you only need to set this for something different
set :cron_log, '/my/cronlog.log'  # Where to log (this should NOT be your Rails log)

every 2.hours do
  runner "MyModel.some_process"       # runners are the script/runners you know and love
  rake "my:rake:task"                 # conveniently run rake tasks
  command "/usr/bin/my_great_command" # commands are any unix command
end

every 1.day, :at => '4:30 am' do         # If not :at option is set these jobs will run at midnight
  runner "DB.Backup", :cron_log => false # You can specify false for no logging or a string with a different log file to override any global logging.
end

every :hour do # Many shortcuts available: :hour, :day, :month, :year, :reboot
  runner "SomeModel.ladeeda"
end

every :sunday do # Use any day of the week or :weekend, :weekday
  runner "Task.do_something_great"
end

Cron output¶ ↑

$ cd /my/rails/app
$ whenever

And you’ll see your schedule.rb converted to cron sytax

Capistrano integration¶ ↑

in your “config/deploy.rb” file do something like:

after "deploy:symlink", "deploy:write_crontab"

namespace :deploy do
  desc "write the crontab file"
  task :write_crontab, :roles => :app do
    run "cd #{release_path} && whenever -c"
  end
end

THIS WILL COMPLETELY OVERWRITE ANY EXISTING CRONTAB ENTRIES!

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Better documentation on the way!