Setting up configuration settings when writing a gem

Question

I'm writing a gem which I would like to work with and without the Rails environment.

I have a Configuration class to allow configuration of the gem:

module NameChecker
  class Configuration
    attr_accessor :api_key, :log_level

    def initialize
      self.api_key = nil
      self.log_level = 'info'
    end
  end

  class << self
    attr_accessor :configuration
  end

  def self.configure
    self.configuration ||= Configuration.new
    yield(configuration) if block_given?
  end
end

This can now be used like so:

NameChecker.configure do |config|
  config.api_key = 'dfskljkf'
end

However, I don't seem to be able to access my configuration variables from withing the other classes in my gem. For example, when I configure the gem in my spec_helper.rb like so:

# spec/spec_helper.rb
require "name_checker"

NameChecker.configure do |config|
  config.api_key = 'dfskljkf'
end

and reference the configuration from my code:

# lib/name_checker/net_checker.rb
module NameChecker
  class NetChecker
    p NameChecker.configuration.api_key
  end
end

I get an undefined method error:

`<class:NetChecker>': undefined method `api_key' for nil:NilClass (NoMethodError)

What is wrong with my code?

Answer 1

Try refactoring to:

def self.configuration
  @configuration ||=  Configuration.new
end

def self.configure
  yield(configuration) if block_given?
end