класс Rails::Rack::Logger

# File railties/lib/rails/rack/logger.rb, line 17
def initialize(app, taggers = nil)
  @app          = app
  @taggers      = taggers || []
end

# File railties/lib/rails/rack/logger.rb, line 22
def call(env)
  request = ActionDispatch::Request.new(env)

  if logger.respond_to?(:tagged)
    logger.tagged(compute_tags(request)) { call_app(request, env) }
  else
    call_app(request, env)
  end
end

# File railties/lib/rails/rack/logger.rb, line 33
def call_app(request, env) # :doc:
  instrumenter = ActiveSupport::Notifications.instrumenter
  instrumenter.start "request.action_dispatch", request: request
  logger.info { started_request_message(request) }
  status, headers, body = @app.call(env)
  body = ::Rack::BodyProxy.new(body) { finish(request) }
  [status, headers, body]
rescue Exception
  finish(request)
  raise
ensure
  ActiveSupport::LogSubscriber.flush_all!
end

# File railties/lib/rails/rack/logger.rb, line 56
def compute_tags(request) # :doc:
  @taggers.collect do |tag|
    case tag
    when Proc
      tag.call(request)
    when Symbol
      request.send(tag)
    else
      tag
    end
  end
end

# File railties/lib/rails/rack/logger.rb, line 48
def started_request_message(request) # :doc:
  'Started %s "%s" for %s at %s' % [
    request.raw_request_method,
    request.filtered_path,
    request.remote_ip,
    Time.now.to_default_s ]
end