Rails crontab with “whenever” gem ?

Rails crontab with “whenever” gem ?

Introduction

gem “whenever“  provides you with the valid cronjob syntax and also writes / updates the crontab file for you.

Installation

1.  Install the gem

gem install whenever

2. Add below line to your config/environment.rb

config.gem ‘whenever’, :lib=>false, :source=>’http://gemcutter.org’

3.  Go to your application root directory and run the below command

wheneverize .

   This will create a “config/schedule.rb” file for you.

  EXAMPLE “config/schedule.rb”

  set :environment, :development

  set :path, "/var/www/MyApp"

  # Scheduled Hourly

   every 4.hours do
   command "/usr/bin/your_command"
   end

  # Scheduled Daily

   every 1.day, :at => '12:00 am' do
   runner "MyModel.yourmethod"
   end

   # Scheduled Weekly

   every :monday, :at => '11:00 pm' do
   rake   "your:rake:task"
   end

Consider the above as the contents of your config/schedule.rb file.

4.  Now from application root directory, run the below command

whenever

The above command will output valid syntax for the crontab as below.

 0 0 * * * /var/www/MyApp/script/runner -e development “Model.your_method”

 0 0,4,8,12,16,20 * * * /usr/bin/your_command

 0 23 * * 1 cd /var/www/MyApp && RAILS_ENV=development /usr/bin/env rake your:rake_task


5. Now, To write the above content in your Crontab file run the below command.

whenever –update-crontab

you can see the above entries in your crontab file by running “crontab -e”.

That’s it, you are ready to go.