log4rの使い方

application.rb

# config/application.rb

require 'rails/all'

require 'log4r'
require 'log4r/yamlconfigurator'
require 'log4r/outputter/datefileoutputter'
include Log4r

module HogeHoge
  class Application < Rails::Application
    # ...
    #
    # log4r
    log4r_config= YAML.load_file(File.join(File.dirname(__FILE__), 'log4r.yml'))
    YamlConfigurator.decode_yaml(log4r_config['log4r_config'])
    config.logger = Log4r::Logger[Rails.env]
  end
end

Gemfile

# Gemfile

gem 'log4r'

log4r.yml

# config/log4r.yml

log4r_config:
  loggers:
    - name      : development
      level     : DEBUG
      trace     : 'true'
      outputters :
      - development_log
    - name      : test
      level     : DEBUG
      trace     : 'true'
      outputters :
      - test_log
    - name      : production
      level     : WARN
      trace     : 'false'
      outputters :
      - production_log

  outputters:
  - type: FileOutputter
    name: development_log
    filename: 'log/development.log'
    formatter:
      date_pattern: '%Y/%m/%d %H:%M:%S'
      pattern     : '%d [%l]: %M'
      type        : PatternFormatter
  - type: FileOutputter
    name: test_log
    filename: 'log/test.log'
    formatter:
      date_pattern: '%Y/%m/%d %H:%M:%S'
      pattern     : '%d [%l]: %M'
      type        : PatternFormatter
  - type: FileOutputter
    name: production_log
    filename: 'log/production.log'
    formatter:
      date_pattern: '%Y/%m/%d %H:%M:%S'
      pattern     : '%d [%l]: %M'
      type        : PatternFormatter