logger

logger.rb

module Logger
  module ClassMethods
    def __log(method_name)
      orig_method_name = :"orig_#{method_name}"
      alias_method orig_method_name, method_name.to_sym

      define_method(method_name) do |*args, &block|
        begin
        puts "Before: #{args.inspect}"
        5 / 0
        rescue => e
          puts "Error in logging: #{e}"
        ensure
          return_val = send(orig_method_name, *args, &block)
          begin
            puts "After: #{args.inspect}"

          rescue => e
            puts "Error in logging"
          end
        end

        return return_val
      end
    end
  end

  def self.included(base)
    base.extend(ClassMethods)

    base.instance_methods.each do |method_name|
      if method_name[0..0] =~ /[a-z]/ && ![:send].include?(method_name)
        base.send(:__log, method_name)
      end
    end
  end
end

class Something

  def do_stuff
    puts "Do stuff"
  end

  def be_awesome
    puts "being awesome"
    5 / 0
  end

  include Logger
end

something = Something.new
something.do_stuff
something.be_awesome