whenever/README.rdoc

== Introduction

Whenever is a Ruby gem that provides a clear syntax for writing and deploying cron jobs.

== Installation
  
  $ gem install whenever

Or with Bundler in your Gemfile.

  gem 'whenever', :require => false
 
== Getting started

  $ cd /my/rails/app
  $ wheneverize .

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

== Example schedule.rb file
  
  every 3.hours do
    runner "MyModel.some_process"       
    rake "my:rake:task"                 
    command "/usr/bin/my_great_command"
  end

  every 1.day, :at => '4:30 am' do 
    runner "MyModel.task_to_run_at_four_thirty_in_the_morning"
  end

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

  every :sunday, :at => '12pm' do # Use any day of the week or :weekend, :weekday 
    runner "Task.do_something_great"
  end

More examples on the wiki: http://wiki.github.com/javan/whenever/instructions-and-examples

== Define your own job types

Whenever ships with three pre-defined job types: command, runner, and rake. You can define your own with `job_type`.

For example:

  job_type :awesome, '/usr/local/bin/awesome :task :fun_level'
  
  every 2.hours do
    awesome "party", :fun_level => "extreme"
  end
  
Would run `/usr/local/bin/awesome party extreme` every two hours. `:task` is always replaced with the first argument, and any additional `:whatevers` are replaced with the options passed in or by variables that have been defined with `set`.

The default job types that ship with Whenever are defined like so:

  job_type :command, ":task :output"
  job_type :rake,    "cd :path && RAILS_ENV=:environment rake :task :output"
  job_type :runner,  "cd :path && script/runner -e :environment ':task' :output"
  
If a script/rails file is detected (like in a Rails 3 app), runner will be defined to fit:

  job_type :runner,  "cd :path && script/rails runner -e :environment ':task' :output"

If a `:path` is not set it will default to the directory in which `whenever` was executed. `:environment` will default to 'production'. `:output` will be replaced with your output redirection settings which you can read more about here: http://github.com/javan/whenever/wiki/Output-redirection-(logging-your-cron-jobs)

All jobs are by default run with `bash -l -c 'command...'`. Among other things, this allows your cron jobs to play nice with RVM by loading the entire environment instead of cron's somewhat limited environment. Read more: http://blog.scoutapp.com/articles/2010/09/07/rvm-and-cron-in-production

You can change this by setting your own job_template.

  set :job_template, "bash -l -c ':job'"
  
Or set the job_template to nil to have your jobs execute normally.

  set :job_template, nil

== Cron output

  $ cd /my/rails/app
  $ whenever

And you'll see your schedule.rb converted to cron sytax. Note: running `whenever' with no options does not display your current crontab file, it simply shows you the output of converting your schedule.rb file.

== Capistrano integration

In your "config/deploy.rb" file do something like:

  after "deploy:symlink", "deploy:update_crontab"

  namespace :deploy do
    desc "Update the crontab file"
    task :update_crontab, :roles => :db do
      run "cd #{release_path} && whenever --update-crontab #{application}"
    end
  end

This will update your crontab file, leaving any existing entries unharmed. When using the `--update-crontab` option, Whenever will only update the entries in your crontab file related to the current schedule.rb file. You can replace the `#{application}` with any identifying string you'd like. You can have any number of apps deploy to the same crontab file peacefully given they each use a different identifier.

If you wish to simply overwrite your crontab file each time you deploy, use the `--write-crontab` option. This is ideal if you are only working with one app and every crontab entry is contained in a single schedule.rb file.

By mixing and matching the `--load-file` and `--user` options with your various :roles in Capistrano it is entirely possible to deploy different crontab schedules under different users to all your various servers. Get creative!

If you want to override a variable (like your environment) at the time of deployment you can do so with the `--set` option: http://wiki.github.com/javan/whenever/setting-variables-on-the-fly

== Discussion / Feedback / Issues / Bugs

For general discussion and questions, please use the google group: http://groups.google.com/group/whenever-gem

If you've found a genuine bug or issue, please use the Issues section on github: http://github.com/javan/whenever/issues

Ryan Bates created a great Railscast about Whenever: http://railscasts.com/episodes/164-cron-in-ruby
It's a little bit dated now, but remains a good introduction.

== Credit

Whenever was created for use at Inkling (http://inklingmarkets.com) where I work. Their take on it: http://blog.inklingmarkets.com/2009/02/whenever-easy-way-to-do-cron-jobs-from.html

== License

Copyright (c) 2009+ Javan Makhmali

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.