Waiting Room

Good Idea,

 

 

The only problem on that is, the timeliness. The first User who was sent to the sorry page should get the next available session.

 

 

I wrote an iRule which should achive a simular thing, Users who have sessions in the shop get a Cookie called(Client_ID). As soon as the connection limit is reached the next user gets a cookie called ticket with value 1. Next available session is then given to the User with the lower ticket number than the value of the next_please value, and gets the second ticket.

 

 

Somehow the rule dosn´t work (Syntax is ok, but have problems with variables..) Any Ideas on that ?

 

 

when RULE_INIT {

 

set ::total_active_clients 0

 

set ::max_active_clients 100

 

set ticket_number 0

 

set ::next_please 1

 

set client_id 1

 

log local0. "rule session_limit initialized: total/max: $::total_active_clients/$::max_active_clients/$ticket_number"

 

}

 

when HTTP_REQUEST {

 

test client-ID Cookie availability

 

if {[HTTP::cookie exists "ClientID"]} {

 

Client-ID Cookie exists (don't need one )

 

set need_cookie 0

 

set client_id [HTTP::cookie "ClientID"]

 

log local0. "Cookie ClientID Exists = $::total_active_clients/$::max_active_clients/$ticket_number"

 

}

 

elseif {[HTTP::cookie exists "ticket"]} {

 

ticket Cookie exists --don't need one-- log local0. "this is the $ticket_number"

 

set need_cookie 2

 

log local0. "Cookie ticket Exists = $ticket_number" }

 

if {$ticket_number <= $::next_please} {

 

If ticket_number is lower than next_please

 

if {$::total_active_clients < $::max_active_clients} {

 

set need_cookie 1

 

set client_id [format "%08d" [expr { int(100000000 * rand()) }]]

 

incr ::total_active_clients 1

 

log local0. "Ask for new ClientID Cookie $::total_active_clients/$::max_active_clients"

 

}}

 

else {

 

set need_cookie 2

 

set ticket_number [HTTP::cookie "ticket"]

 

log local0. "Cookie ticket Needed = $ticket_number"}

 

}

 

 

when HTTP_RESPONSE {

 

if {$need_cookie == 1} {

 

HTTP::cookie insert name "ClientID" value $client_id

 

log local0. "need cookie is.. $need_cookie"

 

}

 

elseif {$need_cookie ==2} {

 

log local0. "need cookie is2.. $need_cookie"

 

HTTP::cookie insert name "ticket" value $ticket_number

 

}

 

}

 

 

 

when CLIENT_CLOSED {

 

; decrement current connection counter for this client_id

 

if {$::total_active_clients > 0} {

 

incr ::total_active_clients -1

 

}

 

else {

 

set ticket_number 0

 

set ::next_please 1

 

log local0. "ticketReset= $ticket_number/$::next_please" }}

I updated my Waiting iRule. The only Problem still exists is that the client close appears also when browser was not closed.

Any help appreciated.

Jürg

when RULE_INIT {  
 set ::total_active_clients 0  
 set static::max_active_clients 3  
 set ::ticket_number 0  
 set ::next_please 3  
 set ::howlong 3     
 log local0. "rule session_limit initialized: total/max: $::total_active_clients/$static::max_active_clients/$::ticket_number"  
 }  
 when HTTP_REQUEST {  
  test client-ID Cookie availability  
 if {[HTTP::cookie exists "ClientID"]} {  
  Client-ID Cookie exists (don't need one )  
  if ClientID cookie is in the request the client is directly sent to the TicketServer  
 set need_cookie 0  
 set client_id [HTTP::cookie "ClientID"]  
 log local0. "ClientID Exists = $::total_active_clients/$static::max_active_clients/$::ticket_number"  
 log local0. "We have a ClientID and the need cookie value is....$need_cookie and we will return now"  
 return  
 }  
 if {[HTTP::cookie exists "ticket"]} {  
 HTTP::cookie decrypt ticket DEQREddarehf "256"  
  ticket Cookie exists --don't need one--  
  log local0. "We have a Cookie named ticket and the ticket number is: $::ticket_number"  
 log local0. "Cookie ticket Exists = $::ticket_number / $::next_please"   
 if {$::ticket_number <= $::next_please} {  
  If ticket_number is lower than next_please  
 if  {$::total_active_clients < $static::max_active_clients} {  
 set need_cookie 1  
 set client_id [string range [AES::key 128] 8 end]   
 incr ::total_active_clients 1  
 log local0. "Ask for new ClientID Cookie $::total_active_clients/$static::max_active_clients/$::ticket_number"   
 }}  
 else {  
 HTTP::respond 200 content {  
   
   
 Sorry  
   
   
 The System was closed due to high demand. Please wait a few seconds we will try to connect you shortly 
   
  }  
 }}  
 if {not [HTTP::cookie exists "ticket"]} {  
 incr ::ticket_number 1       
 set ticket_number [HTTP::cookie "ticket"]  
 log local0. "Cookie ticket Needed = $::ticket_number"  
 HTTP::respond 302 Location "http://[HTTP::host][HTTP::uri]" "Set-Cookie" ticket=$::ticket_number  
 }}  
 when HTTP_RESPONSE {  
 if {$need_cookie == 1} {  
 HTTP::cookie insert name "ClientID" value $client_id  
 log local0. "We insert the ClientID Cookie"  
 }  
  else {  
  log local0. "need cookie is.. $need_cookie"  
  HTTP::cookie insert name "ticket" value $::ticket_number  
  HTTP::cookie encrypt ticket DEQREddarehf "256"  
     }  
 }   
 when CLIENT_CLOSED {  
 decrement current connection counter for this client_id  
 if {$::total_active_clients > 0} {  
 incr ::total_active_clients -1  
 log local0. "ClientClosed $::total_active_clients"  
 }  
 else {  
 set ::ticket_number 0  
 set ::next_please 3  
 log local0. "ticketReset= $::ticket_number/$::next_please" }}

The CLIENT_CLOSED event is triggered when the client to VIP TCP connection is closed--not only when the client closes their browser.

 

 

Aaron

Hi Aaron,

 

Yes I agree, have you got an idea how we can maintain the connection so it dosn't close.

 

We use HTTP 1.1 and Keepalive should keep connection open.

 

 

Since HTTP is a stateless Protocol. Do you see any chance maintaining the session ?

 

Many thanks

 

 

Jürg

Hi Jürg,

 

 

By default LTM doesn't restrict the number of HTTP requests that a client can make over a TCP connection. The default TCP idle timeout is 300 seconds. It's probably down to the client for how long they use the same TCP connection. I wouldn't expect/depend on a client using a single TCP connection for an HTTP "session". Maintaining state across multiple TCP connections and HTTP requests is the primary function of HTTP cookies though. So use the cookie to track the client.

 

 

Aaron