whenever gem schedule.rb file: doesn't recognize RAILS_ROOT variable

Question

In schedule.rb file, the statement:

require "#{RAILS_ROOT}/config/environment.rb"

 every "10 10 2 * * *" do
      command "mysqldump -u #{@db_username} -p#{@db_password} --single-transaction #{@db_name} > #{@backup_Path}/#{@db_name}.sql 2> log/error_crontab.log"
 end

When i try to execute the whenever cmd from terminal, getting the following error:

 config/schedule.rb:48:in `initialize': uninitialized constant Whenever::JobList::RAILS_ROOT (NameError)
    from /usr/local/lib/ruby/gems/1.9.1/gems/whenever-0.7.0/lib/whenever/job_list.rb:19:in `instance_eval'
    from /usr/local/lib/ruby/gems/1.9.1/gems/whenever-0.7.0/lib/whenever/job_list.rb:19:in `initialize'
    from /usr/local/lib/ruby/gems/1.9.1/gems/whenever-0.7.0/lib/whenever.rb:16:in `new'
    from /usr/local/lib/ruby/gems/1.9.1/gems/whenever-0.7.0/lib/whenever.rb:16:in `cron'
    from /usr/local/lib/ruby/gems/1.9.1/gems/whenever-0.7.0/lib/whenever/command_line.rb:40:in `run'
    from /usr/local/lib/ruby/gems/1.9.1/gems/whenever-0.7.0/lib/whenever/command_line.rb:7:in `execute'
    from /usr/local/lib/ruby/gems/1.9.1/gems/whenever-0.7.0/bin/whenever:38:in `<top (required)>'
    from /usr/local/bin/whenever:19:in `load'
    from /usr/local/bin/whenever:19:in `<main>'

i am using the require statement to get the dynamic values from the form to schedule the job. Please help to solve this issue?

Note: i have seen the following stackoverflow queries: How to detect Rails environment inside whenever

Following this thread to get dynamic values, but facing problem with require statement. Rails - Whenever gem - Dynamic values

Ruby/Rails - Whenever gem - Loop cron tasks

config file in schedule.rb with Rails Whenever gem?

Answer 1

Whenever doesn't require or depend on Rails at all, so when it runs, RAILS_ROOT is not defined, however because whenever's schedule.rb is generally kept in /config/schedule.rb, we can make an assumption that it is in a rails project, and set our own RAILS_ROOT like this:

# in schedule.rb
RAILS_ROOT = File.dirname(__FILE__) + '/..'

Edit: in the case that you actually need Rails loaded, do this:

# in schedule.rb
# this will require config/environment and load your entire rails environment
require File.expand_path(File.dirname(__FILE__) + "/environment")