Re: Shared var between processes

On 20 Oct 2017 11:17, André Warnier (tomcat) wrote:

> On 20.10.2017 10:50, Ben RUBSON wrote:
>> On 20 Oct 2017 10:38, André Warnier (tomcat) wrote:
>>
>>> On 19.10.2017 22:02, John Dunlap wrote:
>>>> To piggy back onto this question, what is the best way to do this such  
>>>> that the values of
>>>> the variables are different for every virtual host? In our model, all  
>>>> virtual hosts shared
>>>> the same interpreter pool but we need to have different configuration  
>>>> variables on a per
>>>> virtualhost basis. Currently, we are using PerlSetVar for this purpose.
>>>
>>> And that seems the right way to me.
>>
>> What about a startup file, as proposed by Adam, which would return  
>> John's configuration
>> variables according to $ENV{'SERVER_NAME'} ? (using a switch/case for  
>> example)
>> Each virtualhost would then have its own configuration variables, having  
>> a uniq startup
>> file for the whole server.
>>
>> Would it be more performant than the PerlSetVar solution ? (doc  
>> sometimes warns about
>> PerlSet* performance)
> I believe that there is much more of a performance hit, when asking the  
> server to set up an environment ($ENV) for sub-processes, than via the  
> PerlSetVar mechanism.
>
> (...)
>
> In comparison, the mechanism involving the environment has to set up this  
> environment repeatedly (at least each time a new Apache sub-process is  
> started).

Thank you for your deeply detailed answer André !

I think mod_perl already sets $ENV by default, at least $ENV{'SERVER_NAME'}  
is set.
Is there an additional cost to simply read $ENV{'SERVER-NAME'} ?
Goal would then be to set another variable according to it.

(that said, there is also $s->server_hostname() to retrieve server name)

> It seems much more maintainable (and documentable) to have everything in  
> one place.

I agree :)

Thank you !

Ben