Script to extract, from a Rails log, all the SELECT queries and the duration of each one in a csv format

rails_log_query_select_scraper.rb

require "csv"

module Script
  def self.run(input_path, output_path)
    log = File.read(input_path)
    lines_count = log.lines.count
    index = 0

    File.open(output_path, "w") do |output_file|

      log.each_line do |line|
        puts "Reading line [#{index + 1} of #{lines_count}]"
        if line.match("SELECT")
          ms = line.scan(/\((\d*\.\d+)ms\)/)[0][0]
          select = line.scan(/SELECT.*/)[0]
          output_file.write("#{ms},\"#{select}\"\n")
        end
        index += 1
      end
    end
    puts "File written in '#{output_path}'"
  end
end

if(ARGV.length != 2)
  puts "use: script.rb <path to your Rails log> <file output path>"
  exit 1
end

Script.run(ARGV[0], ARGV[1])