Use Log4r as logger in Sinatra App

I want to use log4r with log-levels info, warn and error in a Sinatra 1.3.1 app. The output should go to 开发者_运维知识库requests.log (http requests), error.log and sinatra.log (other outputs).

How do I go about configuring it?

I've just spent a lot of time googling related articles, but haven't found anything. Help is appreciated...

---

Write a middleware that replaces env['rack.errors'] and env['rack.logger'].

---

I assume you are using classic sinatra. ( only have 1 file named app.rb, and you run it with $ ruby app.rb)

1. in app.rb:

   require 'sinatra'
   
   # load the lib/logger_tool.rb
   Dir[File.join(__dir__, 'lib', '*.rb')].each { |file| require file }
   
   # define the logger as global variable.
   $logger = LoggerTool.get_logger log_file_postfix: ENV['market_id'], 
       name: Sinatra::Application.environment.to_s
   
   get '/' do
     $logger.info "-- in hihihi"
     'hihihi'
   end
   

2. in lib/logger_file.rb

   require 'log4r'
   require 'log4r/yamlconfigurator'
   require 'log4r/outputter/datefileoutputter'
   
   class LoggerTool
     include Log4r
   
     def self.get_logger options
   
       log4r_config= YAML.load_file(File.join(File.dirname(__FILE__), '..', "config", "log4r.yml"))
       temp = log4r_config['log4r_config']
   
       # change the log filename to xx.log (must end with .log)
       # this is optional
       temp["outputters"][0]['filename'] = "my_log_#{options[:log_file_postfix]}.log"
   
       # in test environment, let's rename it as "test.log"
       if options[:name] == 'test'
         temp["outputters"][0]['filename'] = "test"
       end
   
       YamlConfigurator.decode_yaml(temp)
   
       return Log4r::Logger[options[:name]]
     end
   end
   

3. in 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
       - name      : test
         level     : DEBUG
         trace     : 'true'
         outputters :
         - datefile
   
     outputters:
     - type: DateFileOutputter
       name: datefile
       dirname: "log"
       #filename: "my_app.log"   # here we comment it out. 
       formatter:
         date_pattern: '%H:%M:%S'
         pattern     : '%d %l: %m '
         type        : PatternFormatter
   

4. run sinatra via $ ruby app.rb and visit http://localhost:4567/, you will find in your log folder a newly create log file out there.

   log/my_log_xx_2019_03_27.log