分割されたApacheのログをマージする。This program merge divided Apache log.

aplogmerge.rb

#!/usr/bin/env ruby

files = ARGV.map {|f| File.open(f)}
DT_PARSE = /[^\[]+\[([0-9]+)\/([A-z0-9]+)\/([0-9]+):([0-9]+):([0-9]+):([0-9]+) ([0-9+-]+)\].+/
MONTH = {
  'Jan'=>0,'Feb'=>1,'Mar'=>2,'Apr'=>3,'May'=>4,'Jun'=>5,
  'Jul'=>6,'Aug'=>7,'Sep'=>8,'Oct'=>9,'Nov'=>10,'Dec'=>11}

class PreRead
  attr_accessor :file, :line, :dt
  def initialize file, line, dt
    @file = file
    @line = line
    @dt = dt
  end
end

pre_reads = files.map {|f| PreRead.new(f, nil, 0)}

def parse_dt str
  if DT_PARSE =~ str
    year = $1.to_i - 2000
    month = MONTH[$2]
    day = $3.to_i-1
    hour = $4.to_i
    min = $5.to_i
    sec = $6.to_i
    (year*365 + month*31 + day)*86400 + hour*3600 + min*60 + sec
  else
    nil
  end
end

begin
  a = pre_reads.reject {|v| not v.line.nil?}
  a.each do |pr|
    dt = nil
    begin
      break if pr.file.eof?
      pr.line = pr.file.readline
      dt = parse_dt(pr.line)
    end while dt.nil?
    pr.dt = dt
  end
  pr = pre_reads.min {|a,b| a.dt<=>b.dt}
  puts pr.line
  pr.line = nil
  if pr.file.eof?
    pre_reads.delete(pr)
    pr.file.close
  end
end while pre_reads.length > 0