How to make Rails add line numbers / time stamps to log messages?

Question

I use tail -f to display the log file when developing my Rails app. It shows the log messages (in color! :), which is great.

But with so much information in the 80-width console, it becomes difficult to track where a certain "set" of log messages started when, say, I clicked on a button to GET a resource.

It would be easier if there was a line number or even a time stamp at the start of each log message/line. This way I could remember that I need to start looking at the log "after line number 2365" or "after 2010/10/10 23:33:23:45".

Is this possible to do? Is there some Rails internal option for this ?

Answer 1

why don't you just edit your desired environment's log tags

development.rb

config.log_tags [ lambda {|r| DateTime.now } ]

Answer 2

If you wanted to get a time stamp:

class ApplicationController < ActionController::Base
  # ...
  before_filter :log_tracker

  def log_tracker
    Rails.logger.add(1, "Log Date: #{DateTime.now}")
  end
end

And format the date however you see fit....

That would work for Rails 2.1 +, prior you could access the ActiveSupport::Buffered log object with the constant: RAILS_DEFAULT_LOGGER

Get access to the actual log file with Rails.logger.instance_values["log"]

Getting the number of lines is difficult because the logger only opens the file for writing, probably for economy. I get an IOError: not opened for reading when I try. `

Answer 3

Thanks @scaney.

I found a solution here.

I modified that code to add my own coloring highlights (for development only of course!) and now I can see things like 'parameters' in yellow in the console and I'm very pleased now!

In case someone is interested, here is the code I put at the end of environment.rb. Here is my current (dirty) implementation. Will probably fix this up later (maybe make a gem, but for now this serves me fine)

WARNING

DIRTY CODE FOLLOWS! Use at your own risk!

module ActiveSupport
  class BufferedLogger

    #define the ANSI escape codes for normal and bright colors
    $my_my_ansi_colors = {

      :normal => "\x1B[0m",

      :black => "\x1B[30m",
      :red => "\x1B[31m", #red
      :green => "\x1B[32m",
      :yellow => "\x1B[33m",
      :blue => "\x1B[34m",
      :magenta => "\x1B[35m",
      :cyan => "\x1B[36m",
      :white => "\x1B[37m",

      :bred => "\x1B[1m\x1B[31m", #bright red
      :bgreen => "\x1B[1m\x1B[32m",
      :byellow => "\x1B[1m\x1B[33m",
      :bblue => "\x1B[1m\x1B[34m",
      :bmagenta => "\x1B[1m\x1B[35m",
      :bcyan => "\x1B[1m\x1B[36m",
      :bwhite => "\x1B[1m\x1B[37m",
    }

    #take a string and using the keys in the hash, replace the keys in the 
    #string but surround the keys with ANSI color codes
    #No idea how to retain the case of the key!(TODO someday)
    def my_highlight msgx,hash
      return msgx if msgx.blank?
      return msgx if hash.empty?
      hash.each_pair do |k,v|
        if not k.nil?
          msgx.gsub! Regexp.new(k, Regexp::IGNORECASE), $my_my_ansi_colors[:normal]+$my_my_ansi_colors[v]+k.upcase+$my_my_ansi_colors[:normal]
        end
      end
      msgx
    end


    def add(severity, message = nil, progname = nil, &block)
      return if @level > severity

      message = (message || (block && block.call) || progname).to_s

      #INSERT BEGINS
      if not $myownglobalnumbercounter.nil?
        $myownglobalnumbercounter += 1
      else
        $myownglobalnumbercounter = 1
      end

      level = {
        0 => "DEBUG",
        1 => "INFO",
        2 => "WARN",
        3 => "ERROR",
        4 => "FATAL"
      }[severity] || "U"

      message = "\x1B[0m[%d %s] : %s" % [$myownglobalnumbercounter,level,message]
      message = my_highlight message, {
        "debug" => :white,
        "error" => :bred,
        "info" => :bwhite,
        "warning" => :byellow,
        "warn" => :byellow ,
        "parameters" => :byellow,
        "#" => :bgreen,
        "ms " => :bmagenta,
        "GET " => :bmagenta,
        "PUT " => :bmagenta,
        "POST " => :bmagenta,
        "DELETE " => :bmagenta
        }
      #INSERT ENDS

      message = "#{message}\n" unless message[-1] == ?\n
      buffer << message
      auto_flush
      message
    end
  end
end