Log halt_reason in service log and output error page

def write_error(self, status_code, **kwargs):
        """Log halt_reason in service log and output error page"""
        message = default_message = httplib.responses.get(status_code, '')
        # HTTPError exceptions may have a log_message attribute
        if 'exc_info' in kwargs:
            (_, exc, _) = kwargs['exc_info']
            if hasattr(exc, 'log_message'):
                message = str(exc.log_message) or default_message
        self.logvalue('halt_reason', message)
        title = "{}: {}".format(status_code, default_message)
        body = "{}: {}".format(status_code, message)
        self.finish("<html><title>" + title + "</title>"
                    "<body>" + body + "</body></html>")