How to configure reverse proxy/loadbalancer for custom routing

Suppose I have 3 webservers behind a reverse proxy/loadbalancer. Currently I use Apache 2 but don't mind switching.

Those webservers are not equal. They have different sets of local data meaning that different kinds of requests will be handled more efficiently on specific webserver.

I want to plug some custom routing logic into my loadbalancer, that would on start of a new session select a webserver for it, then tie that session to that node until it breaks down (sticky session).

For example: a new user comes to the webapp, load balancer runs my custom code somehow, this code finds out information about that user and makes a conclusion that this user should be handled on node1. The balanc开发者_StackOverflower proxies that user to node1 and sticks it to it. When another user comes, custom routing logic suggests node3, to which loadbalancer then proxies this user.

Is it possible to do with Apache 2? If not, what proxy/loadbalancer would give me that ability?

Thank you.

Apache mode_proxy_balancer has stickyness if you want to stay on apache.

Otherwise, have a look at Haproxy. The first line of the abstract states: "route HTTP requests depending on statically assigned cookies ;" You just have to set a cookie to know which backend you want the user to be stuck to.