parameters.yml configuration during capifony deployment for Symfony2

deploy.rb

set :shared_files,    [app_path + "/config/parameters.yml"]

namespace :symfony do
  namespace :configure do
    def shared_parameters_path
      "#{shared_path}/#{app_path}/config/parameters.yml"
    end

    def app_parameters_path
      "#{latest_release}/#{app_path}/config/parameters.yml"
    end

    def shared_parameters_config
      @shared_parameters_config ||= fetch_yaml "#{shared_parameters_path}"
    end

    def app_parameters_config
      @app_parameters_config ||= fetch_yaml "#{app_parameters_path}"
    end

    def fetch_yaml (yaml_path)
      require 'yaml'
      file = capture("cat #{yaml_path}")
      YAML::load(file)
    end

    task :parameters do
      conf_files_exists = capture("if test -s #{shared_parameters_path} ; then echo 'exists' ; fi").strip
      conf_file_changed = false

      if !conf_files_exists.eql?("exists")
        run "mkdir -p #{shared_path}/#{app_path}/config"
        run "cp #{app_parameters_path} #{shared_parameters_path}"
        shared_parameters_config['parameters'].sort.map do |key, value|
          prompt_with_default(:"#{key}", app_config_parameters.fetch(:"#{key}", value))
          shared_parameters_config['parameters'][key] = eval key;
        end
        conf_file_changed = true
      end

      app_parameters_config['parameters'].sort.map do |key, value|
        if !shared_parameters_config['parameters'].has_key?(key)
          prompt_with_default(:"#{key}", app_config_parameters.fetch(:"#{key}", value))
          shared_parameters_config['parameters'][key] = eval key;
          conf_file_changed = true
        end
      end

      if conf_file_changed
        put shared_parameters_config.to_yaml, "#{shared_parameters_path}"
      end
    end
  end
end

before "deploy:finalize_update" do
  symfony.configure.parameters
end