From: Ken Bloom <kbloom@...>
Date: 2009-10-01T23:08:48+09:00
Subject: Re: Monitors on data structures

On Thu, 01 Oct 2009 08:22:26 +0900, Russell Fulton wrote:

> Hi
> 
> I am trying to use monitors for the first time in ruby.  I am familiar
> with the concept but am having some problems making things work.
> 
> Background:  I have a program that uses nmap-parser to parse large nmap
> scans and uses the call back to deliver results for each host.  The call
> back is threaded.
> 
> I want to build lists of IP addresses for further investigation from the
> callback routine.  I have made a class AddressList:
> 
> class AddressList < Array
>   include MonitorMixin
> 
>   def initialise  # redundant ?
>   super
>   end
> 
> 
>   def <<(addr)
>     synchronise do  # make sure we don't clobber another thread
>       super( addr )
>     end
>   end
> 
> end
> 
> we need to protect the push code so that to threads don't collide so I
> put a synchronise block around it.
> 
> What appears to happen is that the code never exits the synchronise
> block.
> 
> puts before the block get executed but ones after do not and nothing is
> ever added to the list.
> 
> Clearly I'm missing something.
> 
> The callback routine:
> 
>     callback = proc do |host|
> 
>       return unless host.status == 'up'
>       host.scripts do |script|
>         s = script.output.gsub(/\n/, ':')
>         next if s =~ / 2008 R2|ERROR/;
>         next unless s =~ /Vista|2008/
>         $addresses << host.addr
>       end # scripts
>       schedule if $addresses.size > BATCH_SIZE
>     end
> 
> yes, I'm looking for machines running smb2 to get them before the worm
> does :)
> 
> BTW I do have this program working without treads but I want to know why
> this does not work !
> 
> 
> Russell

synchronize is spelled with a z. You misspelled it in the example you 
posted here. Is it possible that you misspelled it in your actual code, 
and the NoMethodError is being raised in a place where it doesn't 
generate output to alert you to the problem?

-- 
Chanoch (Ken) Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/