Re: Keeping per-virtual host data?

[Harrie Hazewinkel <ha...@lisanza.net>]

Hi Steve,

--On Monday, September 30, 2002 10:50 PM +0100 Steve Kemp 
<sk...@tardis.ed.ac.uk> wrote:

> Hi All,
>
>   I've written a module for Apache which will limit the
>  amount of data the server may transfer in a given time
>  period.  (OK that's a simplistic overview anyway ;)
>
>   To do this I make use of the information gathered by
>  mod_status, and when the data transferred goes over a
>  given threshhold I cause the server to simply respond
>  to all requests with a redirect.
>
>   This works fine on a per-server basis.
>
>   I'd like to re-code my module to work with virtual
>  hosts; so I believe I need some way of keeping track of
>  the size of data which has been transferred on a
>  per-vhost basis.
>
>   (Or failing that find another module, like mod_status,
>  which contains the necessary magic which I can piggy back
>  upon).
>
>   Is this possible, and if so does anybody have a pointer
>  to a method I could use?

www.mod-snmp.com This is an SNMP module that does per v-host
statistics. With some modifications one could use this for the
purpose you want.

>
>   All of the modules I've studied seem to manage to operate
>  without having per vhost static data which makes me think
>  either I'm missing something obvious, or it's not possible.
>  Either way I'd love to be enlightened.

The only problem you encounter is that the statistics exist in a
side process and you have to make some connection from each
Apache child to the side process.

>
>   It does cross my mind that the forking may rule out persistant
>  static data of the kind I want; but temporary files could be used
>  I guess..

If you are willing to put all the data into temp files that could
be OK. However, in order to avoid dead-locks and many locks for access
to this you better fork of a process that only writes into it where
all children just can read it.

>
>   For those who might be interested my code is online at:
>    http://www.steve.org.uk/Software/mod_curb/
>
>   (Just be gentle; it's my first module ;)
>
> Steve
> ---
> www.steve.org.uk
>



Harrie

Internet Management Consulting
mailto: harrie@lisanza.net                   http://www.lisanza.net/
--------------------------------------------------------------------
Author of MOD-SNMP, enabling SNMP management the Apache HTTP server

Re: Keeping per-virtual host data?

[Steve Kemp <sk...@tardis.ed.ac.uk>]

Hi Harrie,

On Tue, Oct 01, 2002 at 10:42:57AM +0200, Harrie Hazewinkel wrote:

> www.mod-snmp.com This is an SNMP module that does per v-host
> statistics. With some modifications one could use this for the
> purpose you want.

  Thanks for the pointer.  I've had a quick look at this just now
 and it's quite nice.

  (Maybe it'd be a good idea to have the source unpack into it's
 own directory ;)

> The only problem you encounter is that the statistics exist in a
> side process and you have to make some connection from each
> Apache child to the side process.

  Sure.

> If you are willing to put all the data into temp files that could
> be OK. However, in order to avoid dead-locks and many locks for access
> to this you better fork of a process that only writes into it where
> all children just can read it.

  After a bit of trial and error I've managed to get the effect I 
 want.  My big mistake was using 'per_dir_config' rather than the
 per server config.  Once I'd corrected that the rest flowed fairly
 easily.

  (Reading the virtual host from the mod_status is trivial, and that
 allows me to do everything I need to do).

Steve
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