在RoR 4.1上使用log4r的不需要的日志

Question

我正在使用RoR 4.1.12和log4r gem来格式化日志。我认为一切正常，但如果我想改变日志级别，它根本就没有影响力。

我有以下config/log4r_init.rb：

require 'log4r'
require 'log4r/yamlconfigurator'
require 'log4r/outputter/fileoutputter'
require 'log4r/outputter/datefileoutputter'

# The problem is that Rails 4.2 (not sure about other versions at the moment) expects a method
# on the logger called formatter(). Log4r, however, defines formatter() on each outputter of 
# the logger (i.e. so that each outputter can have a different format). 
# We could monkey-patch it like this
Log4r::Logger.class_eval do
  def formatter
    # Give it the first formatter we have?
    outputters[0].formatter if outputters.any?
  end
end

# log4r.yml configuration is expected to be in the same directory as this file. 
log4r_config = YAML.load(ERB.new(File.read(File.expand_path(File.dirname(__FILE__) + "/log4r.yml"))).result)
Log4r::YamlConfigurator.decode_yaml(log4r_config['log4r_config'])

V2p0::Application.config.logger = Log4r::Logger[Rails.env]

以及以下config/log4r.yml：

log4r_config:
  loggers:
    - name : development
      level : WARN
      additive : 'false'
      trace : 'true'
      outputters:
      - standard_plus_trace_log_outputter
      - stderr_outputter
    - name : test
      level : DEBUG
      additive : 'false'
      trace : 'true'
      outputters:
      - standard_plus_trace_log_outputter
    - name : staging
      level : INFO
      additive : 'false'
      trace : 'true'
      outputters:
      - standard_plus_trace_log_outputter
      - stderr_outputter
    - name : production
      level : INFO
      additive : 'false'
      trace : 'true'
      outputters:
      - standard_plus_trace_log_outputter
      - stderr_outputter

  outputters:
    - type : StderrOutputter
     name : stderr_outputter
      level : INFO
      formatter:
        date_pattern: '%Y-%m-%d %H:%M:%S'
        pattern : "[SXS] [%d] PID:%p %t %l %m"
        type : PatternFormatter
    - type : FileOutputter
      name : standard_log_outputter
      trunc : 'false'
      filename : <%= "#{Rails.root}/log/#{Rails.env}.log" %>
      formatter :
        date_pattern: '%Y-%m-%d %H:%M:%S.%3N'
        pattern : "[SXS] [%d] %l %m"
        type : PatternFormatter
    - type : FileOutputter
      name : standard_plus_trace_log_outputter
      trunc : 'false'
      filename : <%= "#{Rails.root}/log/#{Rails.env}.log" %>
      formatter :
        date_pattern: '%Y-%m-%d %H:%M:%S.%3N'
        pattern : "[SXS] [%d] %t %l %m"
        type : PatternFormatter

即使在开发模式下该级别为WARN，我也会在错误输出上看到很多类似的日志消息：

[SXS] [2017-12-19 14:11:32] PID:947 /home/ntibor/.bundle/ruby/2.2.0/rails-9bfb9f2c3b8b/activesupport/lib/active_support/log_subscriber.rb:93:in `info' INFO   Rendered shared/_common_scripts.html.erb (5.6ms)

有什么问题？