Capistrano MySQL backup task

mysql_backup.rb

namespace :mysql do
  desc "Performs a backup (using mysqldump) in app shared dir"
  task :backup, :roles => :db, :only => { :primary => true } do
    if rails_env != 'production'
      puts 'Backup will be performed for production environment only! Exiting.'
    else
      keep_backups = 15
      filename = "#{application}.#{rails_env}.db_backup.#{Time.now.strftime '%d.%m.%Y_%H-%M'}.sql"
      backups = "#{shared_path}/backups"
      filepath = "#{backups}/#{filename}"

      text = capture "cat #{deploy_to}/current/config/database.yml"
      yaml = YAML::load(text)['production']

      count = capture("ls #{backups}/ | wc -l").to_i
      run "rm -rf `ls #{backups}/ | head -n 1`" if count > keep_backups

      on_rollback { run "rm #{filepath}" }
      run "mysqldump -u#{yaml['username']} -p#{yaml['password']} -h #{yaml['host']} #{yaml['database']} > #{filepath}"
    end
  end
end

before 'deploy:update_code', 'mysql:backup'