application_controller.rb

## app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
  @@silenced_actions = [:home]

  def home
  end
end

init_quiet_logger.rb

## config/initializers/init_quiet_logger.rb

# Set our own QuietLogger as the default logger.
Rails::Application.config.middleware.swap Rails::Rack::Logger, Utils::QuietLogger

quiet_logger.rb

## lib/utils/quiet_logger

module Utils
  class QuietLogger < Rails::Rack::Logger
    def initialize(app, opts = {})
      @app = app
      @opts = opts
      super
    end

    def call(env)
      route = Rails.application.routes.recognize_path(env['PATH_INFO'])
      action = route[:action]
      controller = route[:controller]

      # Had to go wild here since we're using nested controllers.
      controller_klass = (controller.split('/').map { |p| p.camelize }.join('::') + 'Controller').constantize

      if controller_klass.class_variable_defined?(:@@silenced_actions) &&
          controller_klass.class_variable_get(:@@silenced_actions).include?(action.to_sym)
        log_only_errors do
          @app.call(env)
        end
      else
        super(env)
      end
    rescue # recognize_path might throw RoutingError if some static dispatcher or else comes after QuietLogger.
      super(env)
    end

    def log_only_errors
      old_level = Rails.logger.level
      Rails.logger.level = Logger::ERROR
      r = yield
      Rails.logger.level = old_level
      r
    end
  end
end