ruby_to_slf4j_logger.rb

# In Rails config: config.logger = RubyToSlf4jLogger.new(config.paths.log.first)

require "java"

class RubyToSlf4jLogger < Logger
  include_class "org.slf4j.LoggerFactory"

  def initialize(logdev)
    super
    @logger = LoggerFactory.getLogger("ruby")

    @logger.info("Ruby -> SLF4J logger initialized")
  end

  def add(severity, message=nil, progname=nil, &block)
    super

    # Copied from super method
    progname ||= @progname
    if message.nil?
      if block_given?
        message = yield
      else
        message = progname
      end
    end

    case severity
      when DEBUG
        @logger.debug(message)
      when INFO
        @logger.info(message)
      when WARN
        @logger.warn(message)
      when ERROR
        @logger.error(message)
      when FATAL
        @logger.error(message)
      when UNKNOWN
        @logger.warn(message)
    end
  end
end