使用capistrano重新启动delayed_job时,并不总是创建pid文件

Question

当sshing进入网络服务器时,我可以整天重启delayed_job而不会出现问题.它会关闭现有的worker,启动一个新的worker并将tmp/pids/delayed_job.pid写入其进程ID.(我也在重新启动乘客以模仿我将要使用的capistrano)

app@StagingServer:/app/current$ touch tmp/restart.txt; RAILS_ENV=staging script/delayed_job restart
delayed_job: trying to stop process with pid 22170...
delayed_job: process with pid 22170 successfully stopped.
delayed_job: process with pid 22284 started.
app@StagingServer:/app/current$ touch tmp/restart.txt; RAILS_ENV=staging script/delayed_job restart
delayed_job: trying to stop process with pid 22284...
delayed_job: process with pid 22284 successfully stopped.
delayed_job: process with pid 22355 started.
app@StagingServer:/app/current$ touch tmp/restart.txt; RAILS_ENV=staging script/delayed_job restart
delayed_job: trying to stop process with pid 22355...
delayed_job: process with pid 22355 successfully stopped.
delayed_job: process with pid 22427 started.
app@StagingServer:/app/current$

但是,当我使用capistrano部署时

dev@ubuntu:~/app-site$ cap passenger:restart
    triggering start callbacks for `passenger:restart'
  * executing `multistage:ensure'
*** Defaulting to `staging'
  * executing `staging'
  * executing `passenger:restart'
  * executing "touch /app/current/tmp/restart.txt"
    servers: ["staging.app.com"]
    [staging.app.com] executing command
    command finished in 242ms
  * executing "cd /app/current;RAILS_ENV=staging script/delayed_job restart"
    servers: ["staging.app.com"]
    [staging.app.com] executing command
 ** [out :: staging.app.com] delayed_job: trying to stop process with pid 21646...
 ** [out :: staging.app.com] delayed_job: process with pid 21646 successfully stopped.
    command finished in 11889ms

好像不错？虽然不打印delayed_job的最后一行(我认为由于它没有以换行结尾),但这确实成功地创建了一个新进程.但是,它不会创建.pid文件,因此当我尝试重新启动时:

dev@ubuntu:~/app-site$ cap passenger:restart
    triggering start callbacks for `passenger:restart'
  * executing `multistage:ensure'
*** Defaulting to `staging'
  * executing `staging'
  * executing `passenger:restart'
  * executing "touch /app/current/tmp/restart.txt"
    servers: ["staging.app.com"]
    [staging.app.com] executing command
    command finished in 398ms
  * executing "cd /app/current;RAILS_ENV=staging script/delayed_job restart"
    servers: ["staging.app.com"]
    [staging.app.com] executing command
 ** [out :: staging.app.com] Warning: no instances running. Starting...
 ** [out :: staging.app.com] delayed_job: process with pid 21950 started.
    command finished in 6758ms

它不会阻止现有流程.奇怪的是,这次它将创建一个新进程,它是.pid文件.

这使得我运行了2个delayed_jobs进程,并且只有一个在.pid文件中.每增加2个上限,我会添加另一个delayed_job进程.之前的流程使用旧版本的应用程序,基本上打破了它.

配置/ deploy.rb:

namespace :passenger do
  desc "Restart Application"  
  task :restart do  
    run "touch #{current_path}/tmp/restart.txt"
    run "cd #{current_path};RAILS_ENV=#{deploy_env} script/delayed_job restart"
  end
end
after :deploy, "passenger:restart"

• Ubuntu,nginx,乘客
• 守护进程(1.1.4)
• delayed_job(2.1.4)
• 铁轨(3.0.9)

在当地

• 卡皮斯特拉诺(2.9.0)
• capistrano-ext(1.2.1)

更新:

阅读,似乎可能与守护进程内的竞争条件有关.但是我有点困惑为什么它在使用capistrano时只显示(并且始终如一).我会尝试将命令更改为停止,然后睡眠然后启动.

Answer 1

通过使用停止和启动而不是重新启动来解决.由于竞争条件可能由守护进程宝石造成.

我还是想知道其他人是否有更好的解决方案.