Really quick and dirty hack to "parse" Rails log files looking for a request/response pair.

logmung.rb

filename = ARGV.first

puts "Opening #{filename}"
file = File.open(filename)

puts "Reading contents"
contents = file.read.encode('UTF-8', invalid: :replace)

puts "Splitting into requests"
requests = contents.split("\n\n\n")

puts "Found #{requests.length} requests"
puts "Looking for matches"

matches = requests.select do |request|
  lines = request.split("\n")
  lines.first.match(/^Started GET "\/" for/) && !lines.last.match(/^Completed 200/)
end

puts "Found #{matches.length} matches"
matches.each do |match|
  puts "\n\n"
  puts match
end