Costom Rails Log

application.rb

# config/application.rb
module MyApp
  class Application < Rails::Application
    config.lograge.enabled = true
    config.lograge.custom_options = lambda { |event| CustomLog::Subscriber.new(event).extract_data }
  end
end

application_controller.rb

# app/controllers/application_controller.rb
class ApplicationController < ActionController::Base
  include CustomLog::ControllerHelper

  protected

  def custom_log_data(payload)
    payload[:custom_log_data] = {
      user_id: current_user.try(:id),
      account_id: current_account.try(:id)
    }
  end
end

controller_helper.rb

# lib/custom_log/controller_helper.rb
module CustomLog
  module ControllerHelper
    extend ActiveSupport::Concern

    included do
      def custom_log_data(payload)
        payload[:custom_log_data] = {}
      end

      def validation_messages
        saved_object.errors.to_json unless saved_object.errors.blank?
      rescue
        nil
      end

      def saved_object
        instance_variable_get("@#{controller_name.singularize}")
      end

      def append_info_to_payload(payload)
        super

        payload[:request] = request
        payload[:session] = session
        payload[:validations] = validation_messages

        custom_log_data(payload)
      end
    end
  end
end

example.log

method=POST path=/things format=html controller=things action=create status=200 duration=262.28 view=108.93 db=3.84 time=’2014-06-15 13:13:47 -0300' session_id=abcde12345 host=app01 request_id=a1b2c3d4e5 remote_ip=179.209.205.143 user_agent=’Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:26.0) Gecko/20100101 Firefox/26.0' referer=/things/new params={“thing”=>{“name”=>”Teste”} flash={:error=>”Não foi possível gravar os dados”} validations={"name":["já está em uso"]} user_id=987 account_id=123

Gemfile

gem "lograge"

log_backtrace.rb

# config/initializers/log_backtrace.rb
# https://github.com/rails/rails/blob/3-2-stable/activesupport/lib/active_support/notifications/instrumenter.rb
module ActiveSupport
  module Notifications
    class Instrumenter
      attr_reader :id

      def initialize(notifier)
        @id = unique_id
        @notifier = notifier
      end

      def instrument(name, payload={})
        started = Time.now

        begin
          yield
        rescue Exception => e
          payload[:exception] = [e.class.name, e.message]
          payload[:backtrace] = e.backtrace
          raise e
        ensure
          @notifier.publish(name, started, Time.now, @id, payload)
        end
      end
    end
  end
end

subscriber.rb

# lib/custom_log/subscriber.rb
module CustomLog
  class Subscriber
    attr_reader :event, :payload
    attr_accessor :data

    def initialize(event)
      @event = event
      @payload = event.payload
      @data = { :time => %Q('#{event.time}') }
    end

    def extract_data
      session_data
      request_data
      params_data
      validations_data
      exception_data
      custom_data

      data
    end

    private

    def custom_data
      custom = payload[:custom_log_data]

      if custom.is_a?(Hash)
        custom.each_pair { |key, value| data[key] = value }
      end
    end

    def session_data
      session = payload[:session]

      if session
        data.merge!({ :session_id => session[:session_id] })
      end
    end

    def request_data
      request = payload[:request]

      if request
        data.merge!({
          :host => request.host,
          :request_id => request.uuid,
          :remote_ip => request.remote_ip,
          :user_agent => %Q('#{request.user_agent}'),
          :referer => request.referer,
          :flash => request.flash.instance_variable_get('@flashes'),
        })
      end
    end

    def params_data
      internal_params = %w(controller action format utf8 authenticity_token commit)
      params = payload[:params]

      if params
        data.merge!({ :params => params.except(*internal_params) })
      end
    end

    def validations_data
      validations = payload[:validations]

      if validations
        data.merge!({ :validations => validations })
      end
    end

    def exception_data
      exception = payload[:exception]
      backtrace = payload[:backtrace]

      if exception
        data.merge!({
          :exception_class => exception.first,
          :exception_message => exception.last,
          :backtrace => %Q('#{Array(backtrace).to_json}'),
        })
      end
    end
  end
end