Logging in Sinatra?

Question

I\'m having trouble figuring out how to log messages with Sinatra. I\'m not looking to log requests, but rather custom messages at certain points in my app. For example, whe

Answer 1

Here's another solution:

module MySinatraAppLogger
  extend ActiveSupport::Concern

  class << self
    def logger_instance
      @logger_instance ||= ::Logger.new(log_file).tap do |logger|
        ::Logger.class_eval { alias :write :'<<' }
        logger.level = ::Logger::INFO
      end
    end

    def log_file
      @log_file ||= File.new("#{MySinatraApp.settings.root}/log/#{MySinatraApp.settings.environment}.log", 'a+').tap do |log_file|
        log_file.sync = true
      end
    end
  end

  included do
    configure do
      enable :logging
      use Rack::CommonLogger, MySinatraAppLogger.logger_instance
    end

    before { env["rack.errors"] = MySinatraAppLogger.log_file }
  end

  def logger
    MySinatraAppLogger.logger_instance
  end
end

class MySinatraApp < Sinatra::Base
  include MySinatraAppLogger
  get '/' do
    logger.info params.inspect
  end
end

Of course, you can do it without ActiveSupport::Concern by putting the configure and before blocks straight into MySinatraApp, but what I like about this approach is that it's very clean--all logging configuration is totally abstracted out of the main app class.

It's also very easy to spot where you can change it. For instance, the SO asked about making it log to console in development. It's pretty obvious here that all you need to do is a little if-then logic in the log_file method.