share variables in perl script (rlm_perl)

[John Dennis]

On 11/29/2012 05:14 PM, laurent.feron at free.fr wrote:
> Hello,
>
> In a perl script (where authorize() and authenticate() are defined),
> i was able to set a global variable. when a radius request comes, the
> script may modify the variable, and the next request has the new
> value. I test with radiusd -X, and everything is fine.
>
> when radiusd is started as a daemon, 5 threads (default value) are
> started. And now, i understood i have 5 different perl
> "environments". Meaning, when i start the first radtest that modifies
> the global variable, only the sixth request can view the global
> variable modified by the first request( i guess the sixth one turns
> into the first thread).
>
> I hope my explanation is clear. I would like to know if it possible
> to have a unique sharing enviroment (the basic solution is maybe to
> have only one thread, but it should be good for performance)
>
> Just for your information, i would like to "cache" some
> information... the script has to find which OTP server the user is
> defined on. The second time the search is not necessary... i use
> Tie::Hash::Expire module for caching information.

Is there a problem with having each thread perform it's own caching? It 
will take slightly longer to populate the cache than if it was shared 
but is that an issue in practice?

You could borrow a technique from web servers where requests are 
typically processed in independent processes but shared caching between 
the processes is desired by utilizing memcache. memcached is a stand 
alone process (daemon) that holds a hash table in memory and processes 
connect to it via sockets (either inet or unix). There are several 
memcache client language bindings, pretty sure there is one for Perl. 
Google memcache, you'll find a ton of information about it.


-- 
John Dennis <jdennis at redhat.com>

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