Backgroundrb devel - Dec 2006 - can Timeout::timeout(...) be used in a Worker ?

Hi ,

I was wondering if anyone else has tried to use the Timeout::timeout  
method in a backgroundrb Worker and had Timeout raise an exception  
after the allotted amount of time .
I ask because i have written a test script to make sure Timeout would  
work .  I have tested the script by directly feeding it to ruby with :
$ ruby test_script.rb

and piping the script to the rails console:
$ script/console < test_script.rb

Both of which work as expected .

I am using the latest release of backgroundrb: 0.2.1 (Released  
November 28, 2006 - r162) .

If it is not possible to use TImeout::timeout in a Worker currently,  
is there another means to accomplish the same goal as Timeout::timeout ?

thanks ,


george .

This doesn''t help at all, I know, but I use it in the older version of
backgroundrb with no problems.

Let us know your results, I don''t see why it wouldn''t work.

On 12/14/06, george. <george at initiatecommerce.com>
wrote:
> Hi ,
>
> I was wondering if anyone else has tried to use the Timeout::timeout
> method in a backgroundrb Worker and had Timeout raise an exception
> after the allotted amount of time .
> I ask because i have written a test script to make sure Timeout would
> work .  I have tested the script by directly feeding it to ruby with :
> $ ruby test_script.rb
>
> and piping the script to the rails console:
> $ script/console < test_script.rb
>
> Both of which work as expected .
>
> I am using the latest release of backgroundrb: 0.2.1 (Released
> November 28, 2006 - r162) .
>
> If it is not possible to use TImeout::timeout in a Worker currently,
> is there another means to accomplish the same goal as Timeout::timeout ?
>
> thanks ,
>
>
> george .
> _______________________________________________
> Backgroundrb-devel mailing list
> Backgroundrb-devel at rubyforge.org
> http://rubyforge.org/mailman/listinfo/backgroundrb-devel
>

-- 
Charles Brian Quinn
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What is it that doesn''t work with Timeout::timeout?

  class TimeoutWorker < BackgrounDRb::Worker::Base
    require ''timeout''
  
    def do_work(args)
      self.rescued_timeout
      #self.simple_timeout
    end
  
    def simple_timeout
      Timeout::timeout(5) { sleep 10 }
    end
  
    def rescued_timeout
      begin
        self.simple_timeout
      rescue Timeout::Error
        "timed out"
      end
    end
  
  end
  TimeoutWorker.register

There is a number of things to notice with this. You need to make sure
that to handle exceptions in do_work properly. ''do_work'' is
called
automatically as a backgrounded call, so an exception will never reach
the caller. The work_thread worker method will terminate the worker on
an unhandled exception. Above, I''ve commented out self.simple_timeout,
since it would always result in the worker getting terminated.

If you want to call

  worker(new_worker(:class => :timeout_worker, :job_key =>
:timeout)).simple_timeout

directly, you will also need to require ''timeout'' on the
caller side,
otherwise Timeout::Error will be an unknown symbol for DRb.

The resuced_timout method properly handle the exception in the worker.

/skaar



* george . (george at initiatecommerce.com) [061214
22:12]:
> Hi ,
> 
> I was wondering if anyone else has tried to use the Timeout::timeout  
> method in a backgroundrb Worker and had Timeout raise an exception  
> after the allotted amount of time .
> I ask because i have written a test script to make sure Timeout would  
> work .  I have tested the script by directly feeding it to ruby with :
> $ ruby test_script.rb
> 
> and piping the script to the rails console:
> $ script/console < test_script.rb
> 
> Both of which work as expected .
> 
> I am using the latest release of backgroundrb: 0.2.1 (Released  
> November 28, 2006 - r162) .
> 
> If it is not possible to use TImeout::timeout in a Worker currently,  
> is there another means to accomplish the same goal as Timeout::timeout ?
> 
> thanks ,
> 
> 
> george .
> _______________________________________________
> Backgroundrb-devel mailing list
> Backgroundrb-devel at rubyforge.org
> http://rubyforge.org/mailman/listinfo/backgroundrb-devel
-- 
----------------------------------------------------------------------
|\|\             where in the       |          s_u_b_s_t_r_u_c_t_i_o_n 
| | >===========  W.A.S.T.E.        |                  genarratologies 
|/|/    (_)     is the wisdom       |                  skaar at waste.org
----------------------------------------------------------------------

I have been investigating the problem some more since the first  
reply .  I have successfully been able to use sleep() and have  
Timeout work with no problems .  So i began to dig deeper into the  
functions i am executing in the Timeout block .  I have not found  
anything definitive yet but i want to share some more information in  
hopes that it might spark a new approach to troubleshooting the cause .

First, here is some more information about the block of code i am  
executing inside the Timeout .  I am working with FasterCSV and have  
a fairly large (~7mb) tab delimited file which is malformed and  
causes FasterCSV to not be so fast .  I  am attempting to wrap the  
parser.each method in a Timeout block for a reasonable amount of  
time , which should throw an exception if the parsing takes too  
long .  However, this seems to not work when i am running in the  
context of Backgroundrb .  I have verified this in both a Rails +  
Backgroundrb development environment and using "script/backgroundrb  
console" , both of which produce the same results (i.e. they have the  
same issue of not timing out) .

After some time i got the feeling it was not just Backgroundrb which  
might be the issue but rather the combination of Backgroundrb and  
FasterCSV .  Digging into the FasterCSV code i noticed it is using an  
underlying IO object and a few regular expressions to do the bulk of  
the processing work .  I am now wondering if the IO.gets method or  
the regular expressions are not allowing the Timeout thread a chance  
to throw the exception .
An interesting thing i did notice is if i add any   
BackgrounDRb::ServerLogger.logger.debug calls in the FasterCSV  
processing code the Timeout works as expected while in Backgroundrb ,  
but when i take the logger calls out Timeout does not throw the  
exception .

This is currently where i am .  If someone has an idea of something  
else i can try to narrow down the problem please do let me know .

thanks ,


george .