Produces colorized output of the Common Log Format

gistfile1.rb

# Produces colorized output of the Common Log Format
# Usage: $ tail -f access.log | ruby colorpipe.rb

require 'rubygems'
require 'fastercsv'
require 'colorize'
require 'resolv'

colors = String.colors.reject {|c| c == :black || c == :light_cyan}
hosts = {}

loop do
  i = 1
  line = $stdin.readline
  arr = line.gsub(/(\[.*)( )(.*\])/, '\1\3').parse_csv(:col_sep => ' ').
            map {|s| i+=1; s.colorize(colors[i]) }
  if arr.count > 0
    ip = arr[0].uncolorize
    host = hosts.has_key?(ip) ? hosts[ip] : hosts[ip] = (Resolv.getname(ip) rescue ip)
    arr[0] = host.colorize(:yellow)
    puts arr.join(" ")
  end
end