unicorn.rb

before_fork do |server, worker|
  # dirty hack to shut up Rack::CommonLogger for assets
  next unless ENV['RACK_ENV'] == 'development'
  app = server.app
  app = app.instance_variable_get(:@app) until
        app.kind_of?(Rack::CommonLogger) ||
        app.instance_variable_get(:@app).nil?

  app.instance_eval{
    @logger.puts "Silencing #{app.class} to #{IO::NULL}..."
    @logger = File.open(IO::NULL, 'w')
  } if app && IO.const_defined?(:NULL)
end