CODEWITHSUNDEEP
rubylogging
user2562153
user2562153

Reputation: 317

Singleton logger usage in ruby

I have the code like below:

require 'logger'
require 'singleton'

class Logger
    include Singleton
    @@old_initialize = Logger.instance_method :initialize

    def initialize
        @@old_initialize.bind(self).call(STDERR)
    end  
end 

class MyClass
    def initialize
        @logger = Logger.new("output.log")
    end
end

I am getting following error while running MyClass.

in initialize': private methodnew' called for Logger:Class (NoMethodError)

I'm using Ruby Version:

ruby 1.8.6 (2009-08-04 patchlevel 383) [x86_64-linux]

Upvotes: 0

Views: 2533

Answers (1)

Konrad Reiche
Konrad Reiche

Reputation: 29503

Let us look at the documentation of Module: Singleton. Including the module ensures, that only one instance of your class can be created by making the initialize method private. Hence, you receive NoMethodError - new is private error. Further it says:

The instance is created at upon the first call of Klass.instance().

So instead of .new you make a call to .instance

class MyClass
  def initialize
     @logger = Logger.instance()
  end
end

Now you can call MyClass.new and it will return your logger object. This way, however, you cannot pass an additional parameter. So the question here really is, why does it need to be a Singleton in the first place?

Upvotes: 3

Related Questions