gistfile1.rb

class RackProctitle
  def initialize(app, options = nil)
    @app = app
    @prefix = options.delete(:prefix) if options
    
    @revision = APPLICATION_VERSION if defined?(APPLICATION_VERSION)
    @mutex = Mutex.new
    @titles = []
    @request_threads = []
    @queue_length = 0
    @request_count = 0

    @updater_thread = Thread.new do
      while true
        @mutex.synchronize do
          set_request_list_title
        end
        sleep 0.5
      end
    end
  end

  def call(env)
    Thread.current[:request_str] = ((env["REQUEST_URI"].nil? || env["REQUEST_URI"].empty?) ? "/" : env["REQUEST_URI"]).split("?", 2)[0]
    Thread.current[:arrived_at] = Time.now.to_f
    @mutex.synchronize do
      @request_threads.push(Thread.current)
      @queue_length += 1
      set_request_list_title
    end
    
    begin
      @app.call(env)
    ensure
      @mutex.synchronize do
        @queue_length -= 1
        @request_count += 1

        @last_time = Time.now.to_f - Thread.current[:arrived_at].to_f
        @last_request_str = Thread.current[:request_str].to_s

        @request_threads.delete(Thread.current)
        set_request_list_title
      end
    end
  end

  protected
  def set_request_list_title
    @title = if @request_threads.empty?
      idle_message
    else
      now = Time.now.to_f
      list = @request_threads.inject([]) do |str, thread|
        str << "#{time_delta_abbriv(now - thread[:arrived_at])} #{thread[:request_str]}"
      end.join(" | ")
      "handling #{list}"
    end
    update_process_title
  end

  def idle_message
    str = "idle#{' '*20}"
    str << "[last #{time_delta_abbriv(@last_time)} #{@last_request_str}]" if @last_time && @last_request_str
    str
  end

  def update_process_title
    title = "#{@prefix || 'rack'}"
    title << "/#{@revision}" if @revision
    title << " ["
    title << "#{@queue_length}/"
    title << "#{@request_count}"
    title << "]: #{@title}"
    $0 = title
  end

  def time_delta_abbriv(delta)
    if delta < 60
      "%.1fs" % delta
    elsif delta < 3600
      "#{delta.to_i / 60}m#{delta.to_i % 60}s"
    elsif delta < 86400
      "#{delta.to_i / 3600}h#{(delta.to_i % 3600) / 60}m"
    else
      "#{delta.to_i / 86400}d#{(delta.to_i % 86400) / 3600}h"
    end
  end
end