atom feed9 messages in ru.sysoev.nginxRe: Using memcache to set variables
FromSent OnAttachments
Avleen VigAug 7, 2009 8:13 pm 
miradevAug 12, 2009 5:49 am 
Johan BergströmAug 12, 2009 6:08 am 
Valery KholodkovAug 12, 2009 7:01 am 
Avleen VigAug 14, 2009 2:33 am 
Marcus ClyneAug 14, 2009 5:42 am 
Johan BergströmAug 14, 2009 6:19 am 
Valery KholodkovAug 14, 2009 8:22 am 
Valery KholodkovAug 14, 2009 8:27 am 
Subject:Re: Using memcache to set variables
From:Valery Kholodkov (vale@grid.net.ru)
Date:Aug 12, 2009 7:01:28 am
List:ru.sysoev.nginx

----- "Avleen Vig" <avl@gmail.com> wrote:

I started using the geo module to direct users by IP address, this week, and really like it!

It got me thinking about another thing I've been wanting to do: Direct users to different machines based on some arbitrary data. I don't want to rely just on cookies, because those can be manipulated. Here's what I was thinking, and I'm wondering if it can be done some how in nginx?

You might take a look at the eval module I've recently written:

http://www.grid.net.ru/nginx/eval.en.html

The configuration in your case might look like:

location /a { eval_escalate on;

eval $backend { set $memcached_key $cookie_sessionid; memcached_pass http://memcached_host:port; }

proxy_pass http://$backend; }

This makes sense only if the service which you use to locate machine for a
cookie cannot generate X-Accel-Redirect header. If it can, it's faster and more
transparent to use X-Accel-Redirect.

The sessionid is stored in a cookie. This can't be manipulated or the users ends up not being logged in. Store the sessionid in memcache, and have the value set to the name of a location. Have nginx fetch the value for 'sessionid' from memcache, and then redirect the user internally to that location.

Is this even remotely possible? I think some hardware load balancers can do it, but I'm too poor to buy one of those :-)

-- Regards, Valery Kholodkov