如何使用Rails 3.0.x配置Log4r？

Question

基于这篇文章，我尝试使用Rails 3.0.4配置log4r：http://www.dansketcher.com/2007/06/16/integrating-log4r-and-ruby-on-rails/

/Users/toto/.rvm/gems/ruby-1.9.2-p0/gems/log4r-1.1.9/lib/log4r/yamlconfigurator.rb:166:in `sub!': can't convert Pathname into String (TypeError)
    from /Users/toto/.rvm/gems/ruby-1.9.2-p0/gems/log4r-1.1.9/lib/log4r/yamlconfigurator.rb:166:in `block in paramsub'
    from /Users/toto/.rvm/gems/ruby-1.9.2-p0/gems/log4r-1.1.9/lib/log4r/yamlconfigurator.rb:165:in `each'
    from /Users/toto/.rvm/gems/ruby-1.9.2-p0/gems/log4r-1.1.9/lib/log4r/yamlconfigurator.rb:165:in `paramsub'
    from /Users/toto/.rvm/gems/ruby-1.9.2-p0/gems/log4r-1.1.9/lib/log4r/yamlconfigurator.rb:156:in `block in decode_hash_params'

我已经在谷歌上搜索过Rails 3的集成，但还没有找到一个可行的解决方案。谁能给我一个工作代码片段，它允许使用YAML文件进行日志配置，并在运行时进行初始化？

作为参考，我将示例配置放在logger.rb /initializers文件夹中，将log4r.yml放在配置目录中。

谢谢

Answer 1

Log4r的...The想法来自于著名的"Log4j"，这是我在java编程生活中最喜欢的记录器。然而log4r的文档真的很差，对于新手来说真的很难。让我展示一下我的解决方案：

Step1。创建log4r配置文件：(文件名: config/log4r.yml)

log4r_config:
  # define all loggers ...
  loggers:
    - name      : production
      level     : WARN
      trace     : 'false'
      outputters :
      - datefile
    - name      : development
      level     : DEBUG
      trace     : 'true'
      outputters :
      - datefile

  # define all outputters (incl. formatters)
  outputters:
  - type: DateFileOutputter
    name: datefile
    dirname: "log"
    # notice the file extension is needed! 
    # if you want the file is named by the process, just comment it,
    # then it will automatically get the same name with its process,
    # e.g.  rails_2017-05-03.log
    filename: "my_app.log" 
    formatter:
      date_pattern: '%H:%M:%S'
      pattern     : '%d %l: %m '
      type        : PatternFormatter

step2。修改config/application.rb

require 'rails/all'
# add these line for log4r
require 'log4r'
require 'log4r/yamlconfigurator'
require 'log4r/outputter/datefileoutputter'
include Log4r

Bundler.require(:default, Rails.env) if defined?(Bundler)
module Zurich
  class Application < Rails::Application
    #...
    # assign log4r's logger as rails' logger.
    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

step3。将这一行添加到Gemfile中。

# which is the latest version and support "datefileoutputter"
gem 'log4r', '1.1.9'  

(如果您使用的是Rails 4+ (包括Rails6)，则仍然存在配置:将此文件添加到step4/initializers文件夹中

# config/initializers/log4r_patch_for_rails4.rb
class Log4r::Logger
  def formatter()       # for rails4+
    Proc.new{|severity, time, progname, msg|
      formatted_severity = sprintf("%-5s",severity.to_s)
      formatted_time = time.strftime("%Y-%m-%d %H:%M:%S")
      "[#{formatted_severity} #{formatted_time} #{$$}]\n #{msg}\n"
    }

  end
  def formatter= temp   # for rails6+
  end
end  

)

就这样办。现在将"cd“放入您的Rails应用程序文件夹，运行”log4r“安装包，然后运行"rails s"，您将在"/log”文件夹中找到日志文件，如下所示：

May  9 17:05 rails_2011-05-09.log
May 10 13:42 rails_2011-05-10.log

日志内容为(我最喜欢的格式)：

$ tail log/rails_2011-05-10.log
Started GET "/????_settings/19/edit" for 127.0.0.1 at ...
13:42:11 INFO:   Processing by ????SettingsController ...
13:42:11 INFO:   Parameters: {"id"=>"19"}
13:42:12 DEBUG:   ????Setting Load (0.0ms)  SELECT "d ...
13:42:12 INFO: Completed 200 OK in 750ms

我的环境：

i386-mingw32

• rails：

• OS:在XP

• ruby 1.8.7 (2011-02-18 patchlevel 334) cygwin 3.0.5

• gem: 1.6.0

中运行

有任何问题请告诉我~ :-)

请参阅：https://stackoverflow.com/a/20154414/445908和rails6 log4r tagged_logging.rb:22:in `call': wrong number of arguments

Answer 2

为了模拟rails日志记录行为(登录到依赖于环境的日志文件)，我使用以下log4r.yml：

log4r_config:
  # define all loggers ...
  loggers:
  - name      : production
    level     : WARN
    trace     : 'false'
    outputters :
    - datefile_production
  - name      : development
    level     : DEBUG
    trace     : 'true'
    outputters :
    - datefile_development
  - name      : test
    level     : DEBUG
    trace     : 'true'
    outputters :
    - datefile_test

  # define all outputters (incl. formatters)
  outputters:
  - type: DateFileOutputter
    name: datefile_production
    dirname: "log"
    filename: "production.log"
    formatter:
      date_pattern: '%H:%M:%S'
      pattern     : '%d %l: %m '
      type        : PatternFormatter
  - type: DateFileOutputter
    name: datefile_development
    dirname: "log"
    filename: "development.log"
    formatter:
      date_pattern: '%H:%M:%S'
      pattern     : '%d %l: %m '
      type        : PatternFormatter
  - type: DateFileOutputter
    name: datefile_test
    dirname: "log"
    filename: "test.log"
    formatter:
      date_pattern: '%H:%M:%S'
      pattern     : '%d %l: %m '
      type        : PatternFormatter

Answer 3

谁能给我一个可以工作的代码片段，允许使用YAML文件进行日志配置，并在运行时进行初始化？

我以一种替代标准rails记录器的方式编写了一个detailed blogpost about how to set up log4r。此外，我还详细介绍了如何使用多个记录器，如何使用日志级别，以及如何使用Log4r记录Mongoid、ActiveRecord和异常(包括堆栈跟踪)。

在与这篇文章对应的HackerNews thread上的评论中提出了另一个明显更成熟的gem "Logging“，所以对Log4r感兴趣的人可能也想看看这个gem。