ab.rb

require 'rubygems'
require 'optparse'
require 'URI'
require 'Time'
require 'eventmachine'


@fails = 0
@requests = 0
@request_timings = []

@options = { :requests => 100, :concurrency => 10 }
@uri = URI.parse ARGV[-1]

OptionParser.new do |opts|  
  opts.banner = 'Usage: ruby ab.rb [OPTIONS] URI'
  opts.on('-n requests', Integer,
          'Number of requests to perform') { |n| @options[:requests] = n }
  opts.on('-c concurrency', Integer,
          'Number of multiple requests to make') { |c| @options[:concurrency] = c }
end.parse!


EventMachine.run do
  
  def make_request
    
    EventMachine.stop if @requests >= @options[:requests]
    
    start_time = Time.now.to_f
    
    http = EventMachine::Protocols::HttpClient.request(
      :host => @uri.host, :port => @uri.port,
      :request => @uri.path, :query_string => @uri.query
    )
    
    http.callback do |response|
      http.unbind
      @request_timings.push Time.now.to_f - start_time
      @requests += 1
      @fails += 1 if response[:status] != 200
      make_request
    end
    
  end
  
  @options[:concurrency].times do
    make_request
  end
  
end

average_time = @request_timings.inject { |a, b| a + b }
rps = (@options[:concurrency] / (average_time / @request_timings.length)).to_i

puts "#{@requests} requests, #{@fails} fails"
puts "#{rps} rps"