Ruby headless watir-webdriver Xvfb 僵尸

Question

我有两个应用程序在一个服务器上运行，它们执行 headless (headless)浏览任务。每次浏览时，Xvfb 进程并没有死，而是变成了僵尸。我可以用以下脚本确认这一点。

require 'headless'
require 'watir-webdriver'
require 'yaml'

zombies_at_start = `ps axo pid=,stat= | awk '$2~/^Z/ { print $1 }'`.split("\n").count

5.times do
  begin
    d = YAML.load_file("/path/to/config/headless.yml")['build_number'] #=> "98"
    h = Headless.new(:display => d) 
    h.start
    b = Watir::Browser.new :firefox
    b.goto 'http://google.com'
    sleep(0.5)
  ensure
    b.close
    h.destroy
  end
  sleep(0.5)
end

zombies_at_end = `ps axo pid=,stat= | awk '$2~/^Z/ { print $1 }'`.split("\n").count

puts "Created #{zombies_at_end - zombies_at_start} more zombies." 
#=> Created 5 more zombies.

为什么？我该如何解决这个问题？

---

版本信息:

• xorg-x11-server-Xvfb-1.15.0-26.el6.centos.i686
• CentOS 6.5 版(最终版)
• ruby-2.0.0-p353
• rvm 1.25.25
• selenium-webdriver (2.45.0, 2.44.0)
• watir-webdriver (0.7.0)
• headless (headless)(2.1.0)

Answer 1

更新: A pull request提交给 Headless 等待默认被接受。哇!

---

headless (headless) gem changed the way it starts, stops (kills) and verifies the Xvfb process .虽然我不完全确定为什么，但在 CentOS 6 上，这会导致进程僵尸化。由于 .destroy 之前没有引起问题，它一定与 headless 启动 Xvfb 进程(同时重写)的方式有关。

但是gem同时引入了.destroy_sync，等待进程死亡，不产生僵尸。

require 'headless'
require 'watir-webdriver'
require 'yaml'

zombies_at_start = `ps axo pid=,stat= | awk '$2~/^Z/ { print $1 }'`.split("\n").count

5.times do
  begin
    d = YAML.load_file("/path/to/config/headless.yml")['build_number'] #=> "98"
    h = Headless.new(:display => d) 
    h.start
    b = Watir::Browser.new :firefox
    b.goto 'http://google.com'
    sleep(0.5)
  ensure
    b.close
    # h.destroy
    h.destroy_sync
  end
  sleep(0.5)
end

zombies_at_end = `ps axo pid=,stat= | awk '$2~/^Z/ { print $1 }'`.split("\n").count

puts "Created #{zombies_at_end - zombies_at_start} more zombies." 
#=> Created 0 more zombies.