middleman/middleman-core/lib/middleman-core/logger.rb

# Use the Ruby/Rails logger
require 'active_support/notifications'
require 'active_support/logger'
require 'thread'

module Middleman
  # The Middleman Logger
  class Logger < ActiveSupport::Logger
    def self.singleton(*args)
      if !@_logger || args.length > 0
        if args.length == 1 && (args.first.is_a?(::String) || args.first.respond_to?(:write))
          args = [0, false, args.first]
        end
        @_logger = new(*args)
      end

      @_logger
    end

    def initialize(log_level=1, is_instrumenting=false, target=$stdout)
      super(target)

      self.level = log_level
      @instrumenting = is_instrumenting

      if @instrumenting != false
        ::ActiveSupport::Notifications.subscribe(/\.middleman$/, self)
      end

      @mutex = Mutex.new
    end

    def add(*args)
      @mutex.synchronize do
        super
      end
    end

    def call(message, *args)
      return if @instrumenting.is_a?(String) && @instrumenting != 'instrument' && !message.include?(@instrumenting)

      evt = ::ActiveSupport::Notifications::Event.new(message, *args)
      info "== Instrument (#{evt.name.sub(/.middleman$/, '')}): #{evt.duration}ms\n#{args.last}"
    end
  end
end