analyze_rails_log.rb

#!/usr/bin/env ruby

data = File.read(ARGV.first)

reqs = data.scan(/Completed in (\d+)ms/).map { |r| r.first.to_i }
total_ms = reqs.inject(0) { |s, i| s += i }
avg_ms_per_req = total_ms / reqs.length
reqs_over_500ms = reqs.select { |r| r > 500 }

puts "#{reqs.length} total requests"
puts "#{avg_ms_per_req} average ms/req"
puts "#{reqs_over_500ms.length} requests > 500ms"
puts