Backgroundrb devel - Oct 2006 - BackgrounDRb newbie stuck at first base. Fresh pair of eyes needed

Can''t believe I can''t see the problem here, but after a few
hours
bashing my head on a brick wall, going to risk looking stupid by seeing 
if anyone can point out my idiocy (that''s the worst thing about coding 
on your own).

Trying to get BackgrounDRb to take over the scraping task which is 
currently being done in a Rails controller. That''s not the problem at 
the moment, as I can''t even get past first base. For some reason, it 
doesn''t seem to be setting up my worker class properly.

Here''s my worker class def:

    |class ScrapeWorker < BackgrounDRb::Rails
      attr_accessor :progress, :message, :ids_retrieved
     
      def do_work(args)
        @progress = 0
        @message = args[:message] || ""
        @job_completed = false
        @hse_notices_retrieved = 0
        puts args[:message]
        get_new_ids(args)
      end

      def get_new_ids(args)
           ....
      end
    end|

However, I get NoMethodError (undefined method `ids_retrieved'' for 
#<ScrapeWorker:0x2a678b8>)

Set up a quick unit test, and not surprisingly fails on first respond_to

    |  def test_should_respond_to_progress_message_and_hse_notices_retrieved
        MiddleMan.new_worker(:class => :scrape_worker, :args  =>
    {:message => "Uh -Oh"}, :job_key => :test_scraper, :ttl
=> 5)
        s = MiddleMan[:test_scraper]
        assert s.respond_to?(:progress)
        assert s.respond_to?(:message)
        assert s.respond_to?(:hse_notices_retrieved)
        assert_equal "Uh -Oh", s.message
      end|

I''m sure it must be something really obviously but can''t for
the life of
me work out what. Any ideas?

Thanks in advance
Chris

p.s. I''m on OS X, though not sure that''s relevant here...

should it be:

s = MiddleMan.get_worker(:test_scraper)

?

On 10/12/06, Chris T <ctmailinglists at googlemail.com>
wrote:
> Can''t believe I can''t see the problem here, but after a
few hours
> bashing my head on a brick wall, going to risk looking stupid by seeing
> if anyone can point out my idiocy (that''s the worst thing about
coding
> on your own).
>
> Trying to get BackgrounDRb to take over the scraping task which is
> currently being done in a Rails controller. That''s not the problem
at
> the moment, as I can''t even get past first base. For some reason,
it
> doesn''t seem to be setting up my worker class properly.
>
> Here''s my worker class def:
>
>     |class ScrapeWorker < BackgrounDRb::Rails
>       attr_accessor :progress, :message, :ids_retrieved
>
>       def do_work(args)
>         @progress = 0
>         @message = args[:message] || ""
>         @job_completed = false
>         @hse_notices_retrieved = 0
>         puts args[:message]
>         get_new_ids(args)
>       end
>
>       def get_new_ids(args)
>            ....
>       end
>     end|
>
> However, I get NoMethodError (undefined method `ids_retrieved'' for
> #<ScrapeWorker:0x2a678b8>)
>
> Set up a quick unit test, and not surprisingly fails on first respond_to
>
>     |  def
test_should_respond_to_progress_message_and_hse_notices_retrieved
>         MiddleMan.new_worker(:class => :scrape_worker, :args  =>
>     {:message => "Uh -Oh"}, :job_key => :test_scraper, :ttl
=> 5)
>         s = MiddleMan[:test_scraper]
>         assert s.respond_to?(:progress)
>         assert s.respond_to?(:message)
>         assert s.respond_to?(:hse_notices_retrieved)
>         assert_equal "Uh -Oh", s.message
>       end|
>
> I''m sure it must be something really obviously but can''t
for the life of
> me work out what. Any ideas?
>
> Thanks in advance
> Chris
>
> p.s. I''m on OS X, though not sure that''s relevant here...
> _______________________________________________
> Backgroundrb-devel mailing list
> Backgroundrb-devel at rubyforge.org
> http://rubyforge.org/mailman/listinfo/backgroundrb-devel
>

-- 
Charles Brian Quinn
self-promotion: www.seebq.com
highgroove studios: www.highgroove.com
slingshot hosting: www.slingshothosting.com

On 12 Oct 2006, at 16:18, Chris T wrote:
> Can''t believe I can''t see the problem here, but after a
few hours
> bashing my head on a brick wall, going to risk looking stupid by  
> seeing
> if anyone can point out my idiocy (that''s the worst thing about
coding
> on your own).
>
Random guess: you haven''t restarted the backgroundrb process since  
you''ve added the progress method ?

Fred

On Oct 12, 2006, at 9:37 AM, Frederick Cheung wrote:
>
> On 12 Oct 2006, at 16:18, Chris T wrote:
>
>> Can''t believe I can''t see the problem here, but after
a few hours
>> bashing my head on a brick wall, going to risk looking stupid by
>> seeing
>> if anyone can point out my idiocy (that''s the worst thing
about
>> coding
>> on your own).
>>
> Random guess: you haven''t restarted the backgroundrb process since
> you''ve added the progress method ?
>
> Fred

	Also I am not entirely sure that you can use respond_to? across a  
drb connection like that. Because drb uses method missing internally  
to dispatch across the wire it won''t be able to respond_to? what you  
are trying to do. Is it just the test case that is failing?

-EZra

On Oct 12, 2006, at 12:28 PM, Chris T wrote:
> Ezra Zygmuntowicz wrote:
>>
>> On Oct 12, 2006, at 9:37 AM, Frederick Cheung wrote:
>>
>>>
>>> On 12 Oct 2006, at 16:18, Chris T wrote:
>>>
>>>> Can''t believe I can''t see the problem here,
but after a few hours
>>>> bashing my head on a brick wall, going to risk looking stupid
by
>>>> seeing
>>>> if anyone can point out my idiocy (that''s the worst
thing about
>>>> coding
>>>> on your own).
>>>>
>>> Random guess: you haven''t restarted the backgroundrb
process since
>>> you''ve added the progress method ?
>>>
>>> Fred
>>
>>
>>     Also I am not entirely sure that you can use respond_to?  
>> across a drb connection like that. Because drb uses method missing  
>> internally to dispatch across the wire it won''t be able to  
>> respond_to? what you are trying to do. Is it just the test case  
>> that is failing?
>>
>> -EZra
>>
> Ezra
> I''ve tried doing this through the console, just to see where the  
> prob is, but keep having difficulties with all the requires. Do I  
> need to do all the requires in the test case, including requiring  
> the worker? Keep getting uninitialized constant... Could that be a  
> clue, or won''t it work via the console.
> Cheers for your help
> Chris
Chris-

	It will work fine from the console as long as the backgroundrb  
server is running before you start script/console then you can just  
access the MidleMan directly. Make sure you have entirely killed the  
drb server and then restart it and drop into script/console and try  
it from there. Does it work if you try to use one of the example  
workers at all? Have you ever had the plugin working yet and just now  
its broken or what? Also I see in your unit test that you are testing  
for hse_notices_retrieved but you didnt make an attr_accessor for it.  
 From what you have showed me I don''t see any reason why it
shouldn''t
be working. Make sure that you have really killed the server and then  
restart it and try again.

-Ezra

Ezra Zygmuntowicz wrote:
>
> On Oct 12, 2006, at 12:28 PM, Chris T wrote:
>
>> Ezra Zygmuntowicz wrote:
>>>
>>> On Oct 12, 2006, at 9:37 AM, Frederick Cheung wrote:
>>>
>>>>
>>>> On 12 Oct 2006, at 16:18, Chris T wrote:
>>>>
>>>>> Can''t believe I can''t see the problem
here, but after a few hours
>>>>> bashing my head on a brick wall, going to risk looking
stupid by
>>>>> seeing
>>>>> if anyone can point out my idiocy (that''s the
worst thing about
>>>>> coding
>>>>> on your own).
>>>>>
>>>> Random guess: you haven''t restarted the backgroundrb
process since
>>>> you''ve added the progress method ?
>>>>
>>>> Fred
>>>
>>>
>>>     Also I am not entirely sure that you can use respond_to? across
>>> a drb connection like that. Because drb uses method missing 
>>> internally to dispatch across the wire it won''t be able to
>>> respond_to? what you are trying to do. Is it just the test case
that
>>> is failing?
>>>
>>> -EZra
>>>
>> Ezra
>> I''ve tried doing this through the console, just to see where
the prob
>> is, but keep having difficulties with all the requires. Do I need to 
>> do all the requires in the test case, including requiring the worker? 
>> Keep getting uninitialized constant... Could that be a clue, or
won''t
>> it work via the console.
>> Cheers for your help
>> Chris
>
> Chris-
>
>     It will work fine from the console as long as the backgroundrb 
> server is running before you start script/console then you can just 
> access the MidleMan directly. Make sure you have entirely killed the 
> drb server and then restart it and drop into script/console and try it 
> from there. Does it work if you try to use one of the example workers 
> at all? Have you ever had the plugin working yet and just now its 
> broken or what? Also I see in your unit test that you are testing for 
> hse_notices_retrieved but you didnt make an attr_accessor for it. From 
> what you have showed me I don''t see any reason why it
shouldn''t be
> working. Make sure that you have really killed the server and then 
> restart it and try again.
>
> -Ezra
>
OK. Sorted this now. It was one those those multiple bugs -- where a 
whole lot of things were not working quite right, and so making it 
difficult to zero in on the problem.

First, the problems were hidden by two things -- I was running autotest 
in the background, which was of course rerunning the test every time I 
changed anything. Second, I had got the sleep set to the default of 60, 
so the worker wasn''t always dead by the time the test was re-run [Note 
to self: not much point in having TTL less than the sleep time]. 
Sometime it was, sometime it wasn''t. Result: inconsistency in error 
messages.

Third, when trying different combinations of things, I tried not 
submitting any args. Result: more apparent (though not actual) 
weirdness: of course the line @message = args[:message] || "" fails 
because args is then nil, not an empty Hash, so the setup fails at that 
point. Hence, why it wasn''t responding to the accessor methods.

Finally, I hadn''t really appreciated (i.e. it hadn''t properly
sunk in)
that you had to restart backgroundrb every time you made a change in the 
worker class. I thought I was doing it, but wit all the inconsistency, 
I''m now not 100% sure.

Anyway, all working now. For future ref the respond_to? works fine as a 
way of testing the accessor methods have been loaded OK, and I''d advise
anyone who is running autotest to turn it off while debugging worker 
classes -- the combination of TTL, sleep, quickly running tests, and the 
need to restart  backgroundrb makes life way to messy.

Thanks for your help, and thanks for the plugin.

Chris
p.s. Is it possible to have different configs for development, test and 
production?

Ezra Zygmuntowicz wrote:
>
> On Oct 12, 2006, at 12:28 PM, Chris T wrote:
>
>> Ezra Zygmuntowicz wrote:
>>>
>>> On Oct 12, 2006, at 9:37 AM, Frederick Cheung wrote:
>>>
>>>>
>>>> On 12 Oct 2006, at 16:18, Chris T wrote:
>>>>
>>>>> Can''t believe I can''t see the problem
here, but after a few hours
>>>>> bashing my head on a brick wall, going to risk looking
stupid by
>>>>> seeing
>>>>> if anyone can point out my idiocy (that''s the
worst thing about
>>>>> coding
>>>>> on your own).
>>>>>
>>>> Random guess: you haven''t restarted the backgroundrb
process since
>>>> you''ve added the progress method ?
>>>>
>>>> Fred
>>>
>>>
>>>     Also I am not entirely sure that you can use respond_to? across
>>> a drb connection like that. Because drb uses method missing 
>>> internally to dispatch across the wire it won''t be able to
>>> respond_to? what you are trying to do. Is it just the test case
that
>>> is failing?
>>>
>>> -EZra
>>>
>> Ezra
>> I''ve tried doing this through the console, just to see where
the prob
>> is, but keep having difficulties with all the requires. Do I need to 
>> do all the requires in the test case, including requiring the worker? 
>> Keep getting uninitialized constant... Could that be a clue, or
won''t
>> it work via the console.
>> Cheers for your help
>> Chris
>
> Chris-
>
>     It will work fine from the console as long as the backgroundrb 
> server is running before you start script/console then you can just 
> access the MidleMan directly. Make sure you have entirely killed the 
> drb server and then restart it and drop into script/console and try it 
> from there. Does it work if you try to use one of the example workers 
> at all? Have you ever had the plugin working yet and just now its 
> broken or what? Also I see in your unit test that you are testing for 
> hse_notices_retrieved but you didnt make an attr_accessor for it. From 
> what you have showed me I don''t see any reason why it
shouldn''t be
> working. Make sure that you have really killed the server and then 
> restart it and try again.
>
> -Ezra
>
One other thing, if backgroundrb crashes or goes off on one (easy to do 
when you''re doing screen scraping, even if you are using mocks), rake 
backgroundrb:stop doesn''t stop the process (although it throws no error
or warning). I had to go into OS X''s activity monitor to kill it. Think
that was possibly causing some of the erratic behaviour. Too new to OS X 
to know whether this is a Mac thing, and haven''t had a chance to look 
into the rake tasks yet, but just thought it was worth reporting.
Cheers
CT