On Jul 18, 2006, at 6:24 AM, Matt Mower wrote:
> Hi Ezra,
>
> I''m converting some code I have which basically ran Enumerable#map
> asynchronously using a thread-per-value to use backgroundrb
> (recommended by zedas). That code works but I have a scaling problem
> and needed to introduce throttling.
>
> However now that I''ve looked at it I don''t see any sign
of throttling
> in backgroundrb. It looks like there is a 1:1 relationship between
> workers and threads. Perhaps zed misunderstood what I was looking
> for...
>
> Also I don''t see how:
>
> MiddleMan.get_worker(session[:job_key]).progress
>
> or
>
> MiddleMan.get_worker(session[:job_key]).results
>
> described in the documentation work. Where in the worker are you
> controlling the value of progress or results? Nothing in the
> definition of Backgroundrb::Rails seems to support this. Am I missing
> some magic?
>
> The only docs I seem to be able to find are:
>
> http://backgroundrb.rubyforge.org/
>
> Sorry if I''m being dense and/or inobservant.
>
> Cheers,
>
> Matt
Hey Matt-
Yeah you are right, there is a one worker per thread mapping in
backgroundrb. So I am not clear exactly what you need to achieve with
it. Can you give me a code sample or an outline of what you need to
accomplish?
As far as progress or results goes, you are left to take care of
that yourself if you want to use progress bars. Here is an example
worker that uses progress and result:
class Worker < BackgrounDRb::Rails
attr_reader :result
attr_reader :progress
def do_work(args)
@progress = 0
@result = args[:text]
while @progress < 100
sleep rand / 2
# do some work here and store it in @result
@progress += 1
end
end
def progress
@progress
end
end
The do_work() method is called within the thread for that worker so
it can do its processing loop without blocking the call within rails.
I''m not sure if it is the best match for trying to spawn hundreds of
threads. But if you need to do something like that then it is
possible. Maybe if you can explain what you want to accomplish I can
help you find the right course of action. It could be that
backgroundrb is not the solution you need and maybe you need to make
a custom drb server that is lightweight and just handles your passed
blocks.
Cheers-
-Ezra
