Backgroundrb devel - Jul 2006 - Problems with ActiveRecord in workers

Hi *,

are there some special settings except of "load_rails: true" to make
ActiveRecord models accessible within my workers?
I''ve just installed the latest version of this great plugin, but I keep
getting

  undefined method [] for #<DRb::DRbUnknown:0x12345> (line 105 in
backgroundrb.rb)

when one of the arguments for the worker is an ActiveRecord object.
I assume that the MiddleMan somehow doesn''t see my models. I have
already tried to put

  model :blabla, :foo, :bar

in application.rb, but this didn''t help.

Any ideas?

Regards,
Max

On Jul 7, 2006, at 10:52 AM, Maximilian Sch?fmann wrote:
> Hi *,
>
> are there some special settings except of "load_rails: true" to
make
> ActiveRecord models accessible within my workers?
> I''ve just installed the latest version of this great plugin, but I
> keep
> getting
>
>   undefined method [] for #<DRb::DRbUnknown:0x12345> (line 105 in
> backgroundrb.rb)
>
> when one of the arguments for the worker is an ActiveRecord object.
> I assume that the MiddleMan somehow doesn''t see my models. I have
> already tried to put
>
>   model :blabla, :foo, :bar
>
> in application.rb, but this didn''t help.
>
> Any ideas?
>
> Regards,
> Max

Hey Max-


	If you need to pass an active record object to one of your workers  
as an argument then you need to add one line of code to each model  
that you intend on using this way. So if the model you want to send  
from rails to the drb server is Post then you need to add this line:

class Post < ActiveRecord::base

   include DRbUndumped

#the rewst of your code

end

	If you add that to the models you need to send to the drb server it  
will work.

Cheers-
-Ezra

Hi Ezra,

thank a lot for the fast answer!
I think this plugin is one of the most useful around.
>     If you need to pass an active record object to one of your workers
> as an argument then you need to add one line of code to each model
> that you intend on using this way. So if the model you want to send
> from rails to the drb server is Post then you need to add this line:
>
> class Post < ActiveRecord::base
>
>   include DRbUndumped
If my understanding of DRb is correct, this will stop me from storing
these objects in a session...
As a workaround, I will try to store them with BackgroundDRb instead of
the session.

Thanks again,

Max

On Jul 7, 2006, at 11:34 AM, Maximilian Sch?fmann wrote:
> Hi Ezra,
>
> thank a lot for the fast answer!
> I think this plugin is one of the most useful around.
>>     If you need to pass an active record object to one of your  
>> workers
>> as an argument then you need to add one line of code to each model
>> that you intend on using this way. So if the model you want to send
>> from rails to the drb server is Post then you need to add this line:
>>
>> class Post < ActiveRecord::base
>>
>>   include DRbUndumped
>
> If my understanding of DRb is correct, this will stop me from storing
> these objects in a session...
> As a workaround, I will try to store them with BackgroundDRb  
> instead of
> the session.
>
> Thanks again,
>
> Max

Max-

	I''m not so sure it would keep you from storing models in the  
session. You should experiment before you give up on that. BUt I  
don''t like storing whole models in the session. I avoid it by just  
storing the id of a model in the session and using a before fiulter  
to repopulate the model from its id on each requests. Believe it or  
not this is usually faster then unmarshaling an object out of the  
session.

	Also what are you doing that requires you to send full AR objects to  
the drb server as args? Couldn''t you just as easily send the id of  
the record or a name and then do a find in the drb server instead of  
sending a full AR object as an arg?

	Thanks for the kind words. I''m glad you find the plugin useful. I  
use it all the time now ;)

Cheers-
-Ezra

Hi Ezra,

storing them in the session indeed doesn''t work (I tried just PStore,  
but I think others will use Marshall, too). Marshalling them using  
YAML would maybe work.
> Believe it or not this is usually faster then unmarshaling an  
> object out of the session.
>
I didn''t consider that until now, because i thought fetching them  
from the db would be slower than unmarshalling. This would of course  
be an option for me. I will give it a try.

Thanks for your suggestions

Cheers,
Max