gistfile1.rb

#!/usr/bin/env ruby

class Munin
  class LogReader
    attr_accessor :log_file, :me, :pluginstatedir, :statefile

    def initialize(file_name)
      @file_name = file_name
      @me = File.basename($0)
      @pluginstatedir = ENV['MUNIN_PLUGSTATE'] || '/var/lib/munin/plugin-state'
      @statefile = File.join(@pluginstatedir, @me)
    end

    def collect!
      File.open(@file_name, "r") do |f|
        load_saved_state(f)
        process(f)
        save_state(f)
      end
    end
    
    def load_saved_state(log_file)
      return unless File.exists?(statefile) && !(state = File.read(statefile)).nil?
      pos, last_file_size = Marshal.load(state)
      
      # Check for log rotation
      return if File.size(@file_name) < last_file_size
      
      log_file.pos = pos
    end
    
    def process(log_file)
      # Only subclasses know how to process each type of logfile
      puts "NEED IMPLEMENTATION"
    end
    
    def save_state(log_file)
      File.open(statefile, "w") do |f|
        f.write(Marshal.dump([log_file.pos, File.size(log_file)]))
      end
    end
    
    def print_data
      data.each do |k, v|
        puts "#{k}.value #{v}"
      end
    end
    
    def data
      [] # Left for subclasses
    end
  end
  
  class Rails < LogReader
    def data
      @data ||= Hash.new {|h, k| h[k] = Array.new}
    end
    
    def process(log_file)
      begin
        count = 0
        loop do
          line = log_file.readline
          count += 1
          next unless line.match(/^Completed in/)
        
          chunks = line.split(/\s/)
          data[:total] << chunks[2].to_f
          data[:rendering] << chunks[7].to_f
          data[:memcache] << chunks[11].to_f
          data[:db] << chunks[14].to_f
        end
      rescue EOFError
      end
      
      puts "Counted #{count} lines"
      data.each do |k, v|
        data[k] = data[k].inject(0) {|sum, i| sum + i} / data[k].length rescue 0
      end
    end
    
    def config
      puts <<-LABEL                     
graph_title Rails Response Breakdown
graph_vlabel response time          
graph_category Rails                
total.label total                   
rendering.label rendering           
db.label db                         
memcache.label memcache             
      LABEL
    end
  end
end


APP = File.basename($0).split('_').first       
RAILS_ROOT = "/var/www/apps/#{APP}/current"    
RAILS_ENV = File.basename($0).split('_')[1]    
log_file = "#{RAILS_ROOT}/log/#{RAILS_ENV}.log"
ALLOWED_COMMANDS = ['config']                               
                                                            
rails = Munin::Rails.new("tmp/live.log")

if cmd = ARGV[0] and ALLOWED_COMMANDS.include? cmd then     
  rails.send(cmd.to_sym)                                    
else
  rails.collect!
  rails.print_data
end