iRules: Dynamic load balancing via URI

The purpose of this iRule is to create a method of load balancing via the URI that is fully dynamic and never requires updating. Example: The URL https://briandeitch.com/gateway/ should be load balanced to the pool pool_gateway The URL https://briandeitch.com/pictures/ should be load balanced to the pool pool_pictures Here is the old iRule:

when HTTP_REQUEST {
      switch -glob [string tolower [HTTP::path]]
          */gateway/ { pool pool_gateway }
          */pictures/ { pool pool_gateway }
     }
}

In the past, every time I had a new URL, I would have to modify the iRule and create the new pool. If I need to add https://briandeitch.com/family/, I would have to modify the iRule:

when HTTP_REQUEST {
      switch -glob [string tolower [HTTP::path]]
          */gateway/* { pool pool_gateway }
          */pictures/* { pool pool_gateway }
          */family/* { pool pool_family }
     }
}

By using the iRule below, pool selection will happen automatically based on the URI.

when HTTP_REQUEST {
     # Grab the 1st folder after the hostname
     set lbfolder [string tolower [URI::path [HTTP::uri] 1 1]]
     # Strip out the "/"
     set lbfolder pool_[string trim $lbfolder "/"]
     # log local0. "testing01 $lbfolder"
if { [catch {pool $lbfolder} exc] } {
     # If a client sends a uri that does not match a pool, send to default pool or throw message
     #pool default
HTTP::respond 200 content "No matching pool for that URI"
persist cookie insert pr_cookie_insert
}
}

By using this iRule, I will never have to update the iRule again. Once I add the new pool, I’m done.

You may also download a txt version of the iRule here.

Regards,

BD