Logs triggering due to irule

You're missing a closing brace "}" I've added it to the last line: I've also moved the 'else' in the first 'if' to be between the close and open braces as TCL sometimes complains about it

when HTTP_REQUEST {
        if {[HTTP::header exists True-Client-IP]}{
                    if {[HTTP::header exists X-Forwarded-For]}{
                                HTTP::header remove X-Forwarded-For
                                HTTP::header insert X-Forwarded-For [HTTP::header True-Client-IP]      
                    } else {  
                    HTTP::header insert X-Forwarded-For [HTTP::header True-Client-IP]      
                    }
        } else {
                    if {[HTTP::header exists X-Forwarded-For]}{
                                HTTP::header remove X-Forwarded-For
                                HTTP::header insert X-Forwarded-For [IP::client_addr]
                    } else {  
                    HTTP::header insert X-Forwarded-For [IP::client_addr]
                    }           
        }
}