my_logger.rb

class MyLogger < ActiveSupport::TaggedLogging  
  def initialize(logger)
    super(logger)
    logger.formatter = formatter
  end

  def formatter
    Proc.new{|severity, time, progname, msg|
      formatted_time = time.strftime("%Y-%m-%d %H:%M:%S")
      {
        severity: severity.to_s,
        time: formatted_time,
        msg: msg
      }.to_json
    }
  end
end