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ahmetnuman's avatar
ahmetnuman
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Nov 14, 2020

Limit HTTP Request on LTM

Hello ,

 

I want to limit total number of HTTP request on our web application uri (like /test/test1). Is there any irule to accomplish this ?

 

Thank you very much

  • Hello.

     

    You can use this approach replacing those global variables by table variables (for being CMP compatible).

    https://devcentral.f5.com/s/articles/http-session-limit-1

    https://clouddocs.f5.com/api/irules/table.html

     

    The basic idea is to increase the counter value when HTTP_REQUEST is executed and decrease the same variable when HTTP_RESPONSE_RELEASE is executed.

     

    Regards,

    Dario.

  • Hello Dario thank you very much for reply,

     

    I solved my problem via using following irule, it works very well, this i rule briefly count the coming http request on the vip ip if the uri's are /bla/blaservice or /bla/blaservices, then if maximum rate is reached within 2 sec, then bigip response http 2oo status code with blank pages.

     

    when RULE_INIT {
        set static::maxRate 4000
        set static::windowSecs 2
    }
    when HTTP_REQUEST {
            
        if { [HTTP::uri] == "/blablaservice" or [HTTP::uri] == "/blablaservices/"} {
            # set variables
            set limiter [string tolower [HTTP::uri]]
            set vip_limitervar [IP::local_addr]:$limiter
            set get_count [table key -count -subtable $vip_limitervar]
            # main condition
            if { $get_count < $static::maxRate } {
                incr get_count 1
                 table set -subtable $vip_limitervar $get_count $vip_limitervar indefinite $static::windowSecs
            } else {
                #log local0. "$vip_limitervar has exceeded the number of requests allowed."
                HTTP::respond 200 content ""
                return
            }
        }
    }