Logging the request coming to a Virtual Server

Since you went there... I wasnt going to as the built-in capability is easier to use and manage.

However if you are going to log from an iRule then you need a way to correlate the log information as their is multiple connections and many http requests. The prefix specified below allows you to correlate each tcp session and the http requests that belong to that session in the logs.

when CLIENT_ACCEPTED {
  set hsl [HSL::open -proto UDP -pool syslog_server_pool]
  set prefix "\[[IP::client_addr]:[TCP::remote_port]\]:" 
  HSL::send $hsl "<190> $prefix New Connection to [virtual]\n"
}

when HTTP_REQUEST {
  set prefix "\[[IP::client_addr]:[TCP::remote_port]:[expr { rand() * 1000000 }]\]:" 
  HSL::send $hsl "<190> $prefix URL http(s)://[HTTP::host][HTTP::uri]"
}