Anyone using HSL with Graylog

I managed to get this working but forgot to share the result.

The iRule below works and sends access log type of information to Graylog using HSL. Information is send in the GELF format (JSON string). The result is that one can create nice dashboards based on HTTP status codes, response times etc.

when RULE_INIT {
  set static::graylog_pool udp_graylog]
}

when CLIENT_ACCEPTED {
  set hsl [HSL::open -proto UDP -pool $static::graylog_pool]
}

when HTTP_REQUEST {
  set startTime [clock clicks -milliseconds]
  set virtualHost [HTTP::host]
  set protocol [HTTP::header "X-Forwarded-Proto"]
  set xForwardedFor [HTTP::header "X-Forwarded-For"]
  set path [HTTP::path]
  set query [HTTP::query]
  set method [HTTP::method]
  set httpVersion [HTTP::version]
  set correlationId [HTTP::cookie "correlation_id"]
  set userAgent [regsub -all "\"" [HTTP::header "User-Agent"] "\\\""]
  if { [HTTP::header Content-Length] ne "" } then {
    set reqBytes [HTTP::header Content-Length]
  } else {
    set reqBytes 0
  }
  if { [HTTP::header "Referer"] ne "" } then {
    set referer [regsub -all "\"" [HTTP::header "Referer"] "\\\""]
  } else {
    set referer -
  }
}

when HTTP_RESPONSE {
  set endTime [clock clicks -milliseconds]
  set elapsed [expr {$endTime - $startTime}]
  set backend [IP::server_addr]:[TCP::server_port]
  set status [HTTP::status]
   if { [HTTP::header Content-Length] ne "" } then {
    set respBytes [HTTP::header Content-Length]
  } else {
    set respBytes 0
  }
  HSL::send $hsl "{\"version\": \"1.1\",\"host\":\"$virtualHost\",\"short_message\":\"$method $path $status\",\"level\":6,\"_facility\":\"F5_access_log\",\"_query\":\"$query\",\"_url\":\"$path\",\"_httpVersion\":\"$httpVersion\",\"_httpStatus\":$status,\"_method\":\"$method\",\"_protocol\":\"$protocol\",\"_referer\":\"$referer\",\"_userAgent\":\"$userAgent\",\"_x-forwarded-for\":\"$xForwardedFor\",\"_reqBytes\":$reqBytes,\"_respBytes\":$respBytes,\"_elapsed\":$elapsed,\"_correlationId\":\"$correlationId\"}"
}