Use Log4r as logger in Sinatra App

Question

I want to use log4r with log-levels info, warn and error in a Sinatra 1.3.1 app. The output should go to 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...

score 2 · Answer 1 · answered Oct 08 '11 at 16:56

2

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

answered Oct 08 '11 at 16:56

Konstantin Haase

25,687
2
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Yes, thank you. I admit asking my question out of laziness. I've read up how it's done and I think I can do it now myself. – scrrr Oct 09 '11 at 12:39

Siwei · Answer 2 · 2019-03-28T10:31:22.330

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

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

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

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

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

Use Log4r as logger in Sinatra App

2 Answers2