Insert text to HTTP header via iRule event during APM execution

when ACCESS_POLICY_AGENT_EVENT {
    if { [ACCESS::policy agent_id] eq "event_1" } {
        ACCESS::session data set session.custom.header "1"
    } else {
        ACCESS::session data set session.custom.header "0"
 }
 
 when HTTP_REQUEST_SEND  {    
    clientside {
    set header [ACCESS::session data get "session.custom.header"]
    if { $header }{ 
	HTTP::header insert "headername" $header
    } else {
	 return
	}
   }	
 }

Hi Sanjay,

This worked for my case with a little tweak, had to set the $header again in HTTP_REQUEST_SEND to proceed with the HTTP header insertion. Also the log local0. helped a lot. Thank you for your inputs in here. Cheers.

I traced the HTTP headers by printing then in ltm logs referring to https://support.f5.com/csp/article/K42210592

when HTTP_REQUEST {
   foreach aHeader [HTTP::header names] {
   log local0. "HTTP Request Headers: $aHeader: [HTTP::header value $aHeader]"
   }
}

Hi Nikoolayy1,

Thank you for your suggestion.

Our expectation is to insert the header when the flow goes through just a certain APM check (branch path) and a certain condition is met, that is because we tried to use ACCESS_POLICY_AGENT_EVENT. Header should not be added by any other APM branch.

If we use "ACCESS_POLICY_COMPLETED" or "HTTP_REQUEST" or "ACCESS_ACL_ALLOWED" or even "HTTP_REQUEST", header will be added for all the checks, not just by a specific APM.