proc_title.rb

class Rack::ProcTitle
  F = ::File
  PROGNAME = F.basename($0)

  def initialize(app)
    @app = app
    @appname = Dir.pwd.split('/').reverse.
      find { |name| name !~ /^(\d+|current|releases)$/ } || PROGNAME
    @requests = 0
    $0 = "#{PROGNAME} [#{@appname}] init ..."
  end

  def call(env)
    host, port = env['SERVER_NAME'], env['SERVER_PORT']
    meth, path = env['REQUEST_METHOD'], env['PATH_INFO']
    @requests += 1
    $0 = "#{PROGNAME} [#{@appname}/#{port}] (#{@requests}) " \
         "#{meth} #{path}"

    @app.call(env)
  ensure
    $0 = "#{PROGNAME} [#{@appname}/#{port}] (#{@requests}) idle..."
  end
end

Exactly right.