Loggable Ruby module

loggable.rb

require 'logger'

module Core
  def self.logger
    @logger ||= Loggable::Logger.new(STDOUT, progname: name, level: Logger::DEBUG)
  end
end

module Loggable
  class Logger < ::Logger
    # TODO: add filters based on progname
  end

  def self.included(klass)
    klass.extend(ClassMethods)
  end

  module ClassMethods
    def logger
      @logger ||= Core.logger.dup.tap { |l| l.progname = name }
    end

    attr_writer :logger
  end

  def logger
    @logger || singleton_class.logger
  end

  attr_writer :logger
end

module Demo
  module Foo
    include Loggable

    def hello
      Foo.logger.warn { 'foo meth' }
    end

    def self.hello
      logger.warn { 'foo mod' }
    end

    module Bar
      def hello
        Foo.logger.warn { 'bar' }
      end
    end
  end

  module Baz
    include Loggable

    def hello
      Baz.logger.warn { 'baz' }
    end
  end

  class A
    include Foo
  end
  
  class B
    include Foo::Bar
  end
  
  class C
    include Baz
  end

  class D
    include Loggable

    def hello
      logger.warn { 'qux meth' }
    end

    def self.hello
      logger.warn { 'qux class' }
    end
  end
end

Demo::Foo.hello
Demo::A.new.hello
Demo::B.new.hello
Demo::C.new.hello
Demo::D.hello
Demo::D.new.hello

# W, [2022-01-21T18:59:17.137446 #735301]  WARN -- Demo::Foo: foo mod
# W, [2022-01-21T18:59:17.137500 #735301]  WARN -- Demo::Foo: foo meth
# W, [2022-01-21T18:59:17.137543 #735301]  WARN -- Demo::Foo: bar
# W, [2022-01-21T18:59:17.137553 #735301]  WARN -- Demo::Baz: baz
# W, [2022-01-21T18:59:17.137560 #735301]  WARN -- Demo::D: qux class
# W, [2022-01-21T18:59:17.137569 #735301]  WARN -- : qux meth