Setting variables on the fly

If you wish to override variables in your schedule.rb file at runtime you can do so using the --set option. This is especially useful for changing your environment when deploying to a staging server or something similar.

Example:

whenever --set environment=staging

You can set more than one variable by forming a query string. Make sure to use quotes.

whenever --set 'environment=staging&cron_log=/my/other/log.txt'

A couple of notes:

• Be aware of escaping and/or quoting when using --set with multiple key/value pairs (in other words, be careful with the “&”).
• Use --set cron_log=PATH from the command-line to override any set :output, PATH calls in your schedule.rb (--set output=PATH DOES NOT work).

So you can define different tasks per environment:

case @environment
when 'production'
  every 1.day, :at => "#{Time.parse('12:00 A').getlocal.strftime("%H:%M")}" do
    runner "Company.send_later(:create_daily_stories!)"
  end 
when 'staging'
  every 15.minutes do
    command "thinking_sphinx_searchd  reindex"
  end
end

Gotchas:

In some situations, you must set the environment with a separate bash command, as seen in this cap task:

  desc "Update the crontab file"
  task :update_crontab, :roles => :db do
    run "cd #{release_path}; whenever --set environment=staging; whenever --update-crontab #{application}"
  end