Execute system command with Rake outside Bundle scope - ruby-on-rails-4

Question

Let say I have this Rake task:
namespace :db do
namespace :dump do.
desc 'Backup database dump to s3'
task :backup => :environment do
cmd = ['backup', 'perform', '-t project_backup', "-c #{Rails.root.join 'lib', 'backup', 'config.rb'}"]
system(*cmd) # ...I've tried `` & exec() sa well, same thing
end
end
end
Backup gem is stand alone ruby gem application which dependencies needs to be isolated from application bundler. In other words it cannot be part of Gemfile. This gem is simply installed over gem install backup
When I run backup command over bash console, it successfully run:
$ backup perform -t validations_backup -c /home/equivalent/my_project/lib/backup/config.rb
When I execute rake db:dump:backup I will get
backup is not part of the bundle. Add it to Gemfile. (Gem::LoadError)
...which is the same thing when I run backup command with bundle exec from bash
$ bundle exec backup perform -t validations_backup -c /home/equivalent/my_project/lib/backup/config.rb
...meaning that the backup command is executed over bundler when run as part of rake task.
my question: How can I run rake db:dump:backup outsite the bundle scope, meaning that backup command won`t be executed over bundler?
Thank you

Answer 1

I found a workaround for this problem here:
namespace :db do
namespace :dump do
desc 'Backup database dump to s3'
task :backup do
Bundler.with_clean_env do
sh "backup perform -t project_backup -c #{Rails.root.join 'lib', 'backup', 'config.rb'}"
end
end
end
end
The key here is to enclose the code that must not run under bundler's environment in a block like this:
Bundler.with_clean_env do
# Code that needs to run without the bundler environment loaded
end

Answer 2

Here is the Capistrano solution I was mentioning for those who need it while we figure out how to fix Rake.
class BackupDatabaseCmd
def self.cmd
# some logic to calculate :
'RAILS_ENV=production backup perform -t name_of_backup_task -c /home/deploy/apps/my_project/current/lib/backup/config.rb'
# in the configuration file I'm loading `config/database.yml`
# and passing them to backup gem configuration
end
end
namespace :backup do
namespace :database do
task :to_s3 do
on roles(:web) do
within release_path do
with rails_env: fetch(:rails_env) do
execute(BackupDatabaseCmd.cmd)
end
end
end
end
end
end
# cap production backup:database:to_s3