Rails - Jul 2006 - Thread.new with ActiveRecord under Mongrel vs. FastCGI

Hi All,

I''m going to end up hosting a site on a server in a fastcgi
environment,
but I''ve been doing most of my development under mongrel.  I have a bit
of code that spawns a thread, and in the thread it makes some remote 
calls (openuri) and does some database inserts via activerecord.

When I do this under FastCGI, everything appears to work as expected. 
When I do it under Mongrel, things *almost* work but I consistently get 
an error when saving records to the database.

I have a class Bookmark, that has a belongs_to relationship with User, 
and when I assign the user to the bookmark:

azbm.user = auser

I get the error:

User expected, got User 
/usr/lib/ruby/gems/1.8/gems/activerecord-1.14.3/lib/active_record/associations/association_proxy.rb:134

and then more of a stack trace.  Obviously the message is weird (the 
class it reports and the class it got are the same).  I also know the 
code works fine in Mongrel if I''m not using threads, and it works fine 
in FastCGI with or without threads.

Any ideas what''s going on?  As a workaround, is there any way for me to
tell programmatically whether I''m in Mongrel or FastCGI, so that I can 
have the code work during development (albeit slower) and production 
(with the use of threads).

Thanks!
Tom

-- 
Posted via http://www.ruby-forum.com/.

On Mon, 2006-07-24 at 03:12 +0200, Tom Lianza wrote:
> Hi All,
> 
> I have a class Bookmark, that has a belongs_to relationship with User, 
> and when I assign the user to the bookmark:
> 
> azbm.user = auser
> 
> I get the error:
> 
> User expected, got User 
>
/usr/lib/ruby/gems/1.8/gems/activerecord-1.14.3/lib/active_record/associations/association_proxy.rb:134
> 
Typically these errors come from firing off a thread that tries to use
the User model before the dispatcher has actually loaded it.  Dispatcher
does *not* like threads (or used to hate them).

In any case, first thing you have to do when AR complains that a class
don''t exist is:

1) clear all your sessions.
2) at the top of the action explicitly set the model :user.
3) at the top of the action .rb file require the user.rb model file.

Try them in order and see if any work.


-- 
Zed A. Shaw
http://www.zedshaw.com/
http://mongrel.rubyforge.org/
http://www.railsmachine.com/ -- Need Mongrel support?

Zed Shaw wrote:
> On Mon, 2006-07-24 at 03:12 +0200, Tom Lianza wrote:
>>
/usr/lib/ruby/gems/1.8/gems/activerecord-1.14.3/lib/active_record/associations/association_proxy.rb:134
>> 
> 
> Typically these errors come from firing off a thread that tries to use
> the User model before the dispatcher has actually loaded it.  Dispatcher
> does *not* like threads (or used to hate them).
> 
> In any case, first thing you have to do when AR complains that a class
> don''t exist is:
> 
> 1) clear all your sessions.
> 2) at the top of the action explicitly set the model :user.
> 3) at the top of the action .rb file require the user.rb model file.
> 
> Try them in order and see if any work.
None of them worked, unfortunately.

If it''s worth anything, the code I''m executing in a thread, as
well as
the location where the thread itself is spawned, is in a helper, not the 
controller directly.  If it''s useful, here is the full stack trace:

User expected, got User 
/usr/lib/ruby/gems/1.8/gems/activerecord-1.14.3/lib/active_record/associations/association_proxy.rb:134:in
`raise_on_type_mismatch''
/usr/lib/ruby/gems/1.8/gems/activerecord-1.14.3/lib/active_record/associations/belongs_to_association.rb:22:in
`replace''
/usr/lib/ruby/gems/1.8/gems/activerecord-1.14.3/lib/active_record/associations.rb:850:in
`user=''
/home/tlianza/workspace/wishlisting/config/../app/helpers/giftalicious_helper.rb:178:in
`private_get_wishlist_from_amazon''
/home/tlianza/workspace/wishlisting/config/../app/helpers/giftalicious_helper.rb:167:in
`private_get_wishlist_from_amazon''
/home/tlianza/workspace/wishlisting/config/../app/helpers/giftalicious_helper.rb:141:in
`update_amazon_wishlist''
/home/tlianza/workspace/wishlisting/config/../app/helpers/giftalicious_helper.rb:140:in
`update_amazon_wishlist''
/home/tlianza/workspace/wishlisting/config/../app/controllers/giftalicious_controller.rb:299:in
`login''
/usr/lib/ruby/gems/1.8/gems/actionpack-1.12.3/lib/action_controller/base.rb:910:in
`perform_action_without_filters''
/usr/lib/ruby/gems/1.8/gems/actionpack-1.12.3/lib/action_controller/filters.rb:368:in
`perform_action_without_benchmark''
/usr/lib/ruby/gems/1.8/gems/actionpack-1.12.3/lib/action_controller/benchmarking.rb:69:in
`perform_action_without_rescue''
/usr/lib/ruby/1.8/benchmark.rb:300:in `measure''
/usr/lib/ruby/gems/1.8/gems/actionpack-1.12.3/lib/action_controller/benchmarking.rb:69:in
`perform_action_without_rescue''
/usr/lib/ruby/gems/1.8/gems/actionpack-1.12.3/lib/action_controller/rescue.rb:82:in
`perform_action''
/usr/lib/ruby/gems/1.8/gems/actionpack-1.12.3/lib/action_controller/base.rb:381:in
`process_without_filters''
/usr/lib/ruby/gems/1.8/gems/actionpack-1.12.3/lib/action_controller/filters.rb:377:in
`process_without_session_management_support''\n/usr/lib/ruby/gems/1.8/gems/actionpack-1.12.3/lib/action_controller/session_management.rb:117:in
`process''
/usr/lib/ruby/gems/1.8/gems/rails-1.1.4/lib/dispatcher.rb:38:in 
`dispatch''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/lib/mongrel/rails.rb:73:in 
`process''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/lib/mongrel.rb:551:in 
`process_client''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/lib/mongrel.rb:550:in 
`process_client''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/lib/mongrel.rb:636:in
`run''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/lib/mongrel.rb:636:in
`run''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/lib/mongrel.rb:625:in
`run''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/lib/mongrel.rb:956:in
`run''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/lib/mongrel.rb:955:in
`run''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/bin/mongrel_rails:127:in 
`run''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/lib/mongrel/command.rb:199:in 
`run''
/usr/lib/ruby/gems/1.8/gems/mongrel-0.3.13.3/bin/mongrel_rails:235
/usr/bin/mongrel_rails:18

Thanks again,
Tom

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