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From André Warnier ...@ice-sa.com>
Subject Re: Reloading Apache::Registry modules without restarting Apache
Date Fri, 20 Jan 2012 19:32:37 GMT
Desilets, Alain wrote:
> I'm using mod_perl on Windows 7, and am trying to set things up so that I can reload
my script and all the modules it uses, without having to restart Apache.
> 
> The problem is that my script (called webitext.cgi) updates the @INC variable using statements
like these:
> 
> ---
> use lib "$ENV{WEBITEXT_HOME}";
> use lib "$ENV{WEBITEXT_HOME}/bin";
> etc...
> ---
> 
> where the value of $ENV{WEBITEXT_HOME} is set differently depending on the virtual host
it's running on. I use this so I can have two versions of my app on the server, a production
and a test version, each running under a different vhost which defines the env variable differently
(using Apache SetEnv).
> 
> The problem is that when Apache::Reload tries to reload the modules, it does not find
them, because it seems to use the value of @INC as it was BEFORE the script was run (i.e.
not including the ones added with the 'use lib' statements).
> 
> This problem occurs whether I use the 'PerlSetVar ReloadTouchFile' approach or the Apache::StatINC
approach. It seems to be a well documented limitation of Apache::Reload.
> 
> So... I thought about setting the @INC path outside of the script. But I need to do this
on a per-vhost basis. According to this page:
> 
> http://perl.apache.org/docs/2.0/user/config/config.html#Modifying_C__INC__on_a_Per_VirtualHost
> 
> I should be able to do this with something like this:
> 
> ---
> <VirtualHost ...>
>       ServerName webitextprod
>       PerlOptions +Parent
>       PerlSwitches -Idir1 -Idir2 etc...
>   </VirtualHost>
> ---
> 
> But when I tried this and ran httpd.exe -t -c httpd.conf, it crashed with the dreaded
"free to wrong pool" error:
> 
> ---
> Free to wrong pool 2b60100 not 3d4f10.
> ---
> 
> This error seems to be caused by the PerlOptions +Parent line.
> 
> Any suggestion for how to fix or get around this problem would be greatly appreciated.
> 
Hi.
I do not know much about the "reload" side of things, but something in the general logic 
of what you explain above is going against what I know of the Apache logic.

Contrarily to what you seem to expect above, an Apache "virtual host" is not a separate 
process.
Apache starts as a single process, and then it forks "children". Each of these children is

a separate process.  But the "virtual host identity" is something dynamic.  Each Apache 
child can "become" one of the virtual hosts, at each request.  It just "switches 
personality" depending on which Host: header is contained in the current request that it 
processes.
In other words, it does not really make sense to expect a different lib path per virtual 
host, since the perl modules and scripts exist on a "one per process" base, not a "one per

virtual host" base.
Or, you have to really set the lib path dynamically, on a per-request base, not just when

your script is first compiled.




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