# Backgroundrb Usage in Rails App

**URL:** <https://www.ruby-forum.com/t/backgroundrb-usage-in-rails-app/127142>\
**Category:** Rails\
**Created:** [January 25, 2008, 12:28pm UTC](https://www.ruby-forum.com/t/backgroundrb-usage-in-rails-app/127142 "2008-01-25T12:28:02Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![xgamerx](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/d2c977/32.png) [@xgamerx](https://www.ruby-forum.com/u/xgamerx)\
**Post date:** [January 25, 2008, 12:28pm UTC](https://www.ruby-forum.com/t/backgroundrb-usage-in-rails-app/127142/1 "2008-01-25T12:28:02Z")

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Hey Guys, ’

I am developing a rails application for a client. Suffice it to say I  
have to do some long running tasks so of course I used my favorite  
plugin backgroundrb. Unfortunately I have a problem. I recently put some  
new work into a background task that requires the use of ruburple (a gem  
for connecting to IM protocols). Since then, I noticed that the worker  
that uses it sometimes just stops running with no explanation.

I checked the logs and I assume the relevant code is below:

libnm\_glib\_nm\_state\_cb: dbus returned an error.  
(org.freedesktop.DBus.Error.ServiceUnknown) The name  
org.freedesktop.NetworkManager was not provided by any .service files

\*\* (process:13909): CRITICAL \*\*: xmlnode\_set\_attrib: assertion `value !=  
NULL’ failed

\*\* (process:13909): CRITICAL \*\*: xmlnode\_set\_attrib: assertion `value !=  
NULL’ failed

\*\* (process:13909): CRITICAL \*\*: xmlnode\_set\_attrib: assertion `value !=  
NULL’ failed  
#{my\_rails\_app}/releases/…/vendor/plugins/backgroundrb/framework/core.rb:149:  
[BUG] Segmentation fault  
ruby 1.8.6 (2007-06-07) [i486-linux]

My question is two-fold:

1. what’s the best way to go about fixing this? How can I get more  
detailed information regarding the problem here. I assume the  
combination of the CRITICAL and the always fun segmentation fault is  
killing the thread. How can I find and eliminate the problem or  
implement exception handling so it ignores the issue.

2. How can I just force the thread back up if it dies. There has to be a  
way to have backgroundrb recreate the thread if it dies, right? I mean  
sure, that segmentation fault shouldn’t happen but if it does, I need a  
way to bring the thread back online.

So if you could help with that I would appreciate it. I know ezra pokes  
around here every once in a while.

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**Author:** ![xgamerx](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/d2c977/32.png) [@xgamerx](https://www.ruby-forum.com/u/xgamerx)\
**Post date:** [January 25, 2008, 12:37pm UTC](https://www.ruby-forum.com/t/backgroundrb-usage-in-rails-app/127142/2 "2008-01-25T12:37:08Z")

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BTW the app is running on

ruby 1.8.6 (2007-06-07) [i486-linux]  
rails 2.0.1  
ubuntu 7.10  
gems are updated

and the weird part is that the “segmentation fault” doesn’t happen every  
time. Most of the time it works just fine. However 1/5 times the fault  
will occur and the thread dies.

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<div class="post-metadata">

**Author:** ![xgamerx](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/d2c977/32.png) [@xgamerx](https://www.ruby-forum.com/u/xgamerx)\
**Post date:** [January 25, 2008, 12:48pm UTC](https://www.ruby-forum.com/t/backgroundrb-usage-in-rails-app/127142/3 "2008-01-25T12:48:45Z")

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BTW, the line that it references for the segmentation fault:

backgroundrb/framework/core.rb:149

# method starts event loop in the process

```
  def start_reactor
    Signal.trap("TERM") { terminate_me }
    Signal.trap("INT") { shutdown }
    loop do
      check_for_timer_events
      user_thread_window #=> let user level threads run for a while
      ready_fds = select(@read_ios,@write_ios,nil,0.005) # HERE IT 

```

FAILS!!!  
#next if ready\_fds.blank?

```
      next if !ready_fds or ready_fds.empty?

      ready_fds = ready_fds.flatten.compact
      ready_fds.each do |t_sock|
        if t_sock.is_a? UNIXSocket
          handle_internal_messages(t_sock)
        else
          handle_external_messages(t_sock)
        end
      end
    end
  end
```

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<div class="post-metadata">

**Author:** ![xgamerx](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/x/d2c977/32.png) [@xgamerx](https://www.ruby-forum.com/u/xgamerx)\
**Post date:** [January 25, 2008, 4:22pm UTC](https://www.ruby-forum.com/t/backgroundrb-usage-in-rails-app/127142/4 "2008-01-25T16:22:31Z")

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On Fri, Jan 25, 2008 at 5:18 PM, Nathan E.  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> ```
> Signal.trap("INT") { shutdown }
> ready_fds.each do |t_sock|
> if t_sock.is_a? UNIXSocket
> handle_internal_messages(t_sock)
> else
> handle_external_messages(t_sock)
> end
> end
> end
> end
> 
> ```

By any chance, can you run this thing with gdb? Also segmentation  
fault is one error from which process itself can’t recover and must be  
restarted from outside. You can have a monit script for that.

–  
Let them talk of their oriental summer climes of everlasting  
conservatories; give me the privilege of making my own summer with my  
own coals.

[http://gnufied.org](http://gnufied.org)