HSL iRule to log http status error output to syslog server

All,

I am new to irule. Looking for experts suggestion one of the iRule while will log an output to a syslog server directly. The iRule should check the http status code of the connection and send the logs with some details.

The irule looks below.
when CLIENT_ACCEPTED {set hsl [HSL::open -proto UDP -pool syslog_server_pool] }

when HTTP_RESPONSE {if {HTTP::has_responded]} {return}  ###Some part excluded###

set status_code [HTTP::STATUS]

set log_msg""

append log_msg "$Client_ip" 

append log_msg "$status_code"

HSL::send $hsl"<190> $log_msg"

}

The issue here is the syslog received the logs with status code 200, 302 but not getting 500. We can see LB ltm local logs found Internal server 500 status code error (Logged through another irule) but its not there in syslog server. Can somebody help if any changes required in the irule.

Thanks!