active_support_logger.rb

# backported from rails 4 to use inside rails 3
# if you're using rails 4, you do not actually need this.
module ActiveSupport
  class Logger < ::Logger
    # extend ActiveSupport::TaggedLogging
    # Broadcasts logs to multiple loggers. Returns a module to be
    # `extended`'ed into other logger instances.
    def self.broadcast(logger)
      Module.new do
        define_method(:add) do |*args, &block|
          logger.add(*args, &block)
          super(*args, &block)
        end

        define_method(:<<) do |x|
          logger << x
          super(x)
        end

        define_method(:close) do
          logger.close
          super()
        end

        define_method(:progname=) do |name|
          logger.progname = name
          super(name)
        end

        define_method(:formatter=) do |formatter|
          logger.formatter = formatter
          super(formatter)
        end

        define_method(:level=) do |level|
          logger.level = level
          super(level)
        end

      end # Module.new
    end # broadcast

    def initialize(*args)
      super
      @formatter = SimpleFormatter.new
    end

    # Simple formatter which only displays the message.
    class SimpleFormatter < ::Logger::Formatter
      # This method is invoked when a log event occurs
      def call(severity, time, progname, msg)
        # caller it's —  stacktrace array. caller[4] — a filename and methodname which puts a message.
        # E.G.: "[b4bc77d7a61a8641755544e74e6ee824"] 2015-03-13 15:48:40 INFO log_subscriber.rb:105:in `info' --   SOME MESSAGE
        # caller[4]l: log_subscriber.rb:105:in `info'. log_subscriber.rb:105 — filename and line No, `info' — method called.
        element = caller[4] ? caller[4].split("/").last : "UNDEFINED"
        "#{Thread.current[:logstash_logger_tags]||nil } #{time.to_s(:db)} #{severity} #{element} -- #{String === msg ? msg : msg.inspect}\n"
      end # call
    end # class SimpleFormatter
  end # class Logger
end # module ActiveSupport

app_logger = ActiveSupport::Logger.new(Rails.root.join("log/#{Rails.env}.log"))

# Rails logger did not get log level from config because of... stains on the Sun.
# So, we just override it here.
app_logger.level = Logger::INFO if Rails.env.production?


# For rails 4 use just this line
Rails.logger.extend(ActiveSupport::Logger.broadcast(app_logger))

development.rb

config.log_tags = [:uuid]
config.logger = LogStashLogger.new([
  {type: :file, path: "log/logstash_development.log"}
])


# adding backtrace fragment to logstash
# this line will add caller method and line number to the log by default.
# E.G. ["db7ce7ebcf3960ca4b2f4efe53c33f2c"] 2016-03-21 09:12:44 INFO log_subscriber.rb:105:in `info' -- Processing by PspController#entrypoint as */*

LogStashLogger.configure do |config|
  config.customize_event do |event|
    event["@caller"] = caller[6] ? caller[6].split("/").last : "UNDEFINED"
  end
end

sidekiq.rb

Sidekiq.redis = {host: ENV['redis_host'], port: (ENV['redis_port'] || 6379)}

class SidekiqLoggerFormatter < ::Logger::Formatter
  SPACE = ' '
  # Provide a call() method that returns the formatted message.
  def call(severity, time, _program_name, message)
    "#{time.utc.iso8601(3)} #{::Process.pid}"\
    " TID-#{Thread.current.object_id.to_s(36)}"\
    " #{context} #{severity}: #{message}\n"
  end

  def context
    ctx = Thread.current[:sidekiq_context]
    "#{ctx}#{SPACE}" if ctx
  end
end # class SimpleFormatter

if %(staging production development).include? Rails.env
  type = ENV['logstash_type'].to_sym
  host = ENV['logstash_host']
  port = ENV['logstash_port']

  Sidekiq::Logging.logger = LogStashLogger.new(
    [{ type: :file,
       path: 'log/logstash_sidekiq_'\
             "#{Rails.env}.log"
     },
     { type: type,
       host: host,
       port: port
     }
    ])
  sidekiq_logger = ActiveSupport::Logger.new(Rails.root.join('log/sidekiq.log'))
  Sidekiq::Logging.logger.extend(ActiveSupport::Logger.broadcast(sidekiq_logger))

  Sidetiq.logger = LogStashLogger.new(
    [{ type: :file,
       path: "log/logstash_sidetiq_#{Rails.env}.log"
     },
     { type: type,
       host: host,
       port: port
     }
    ])
  sidetiq_logger = ActiveSupport::Logger.new(Rails.root.join('log/sidetiq.log'))
  Sidekiq::Logging.logger.extend(ActiveSupport::Logger.broadcast(sidetiq_logger))

end

Sidekiq.logger.formatter = SidekiqLoggerFormatter.new