def my_log_traceback(severity=logging.CRITICAL):
    """Write the last error's traceback to the cherrypy error log."""
    from cherrypy import _cperror

    h = ["  %s: %s" % (k, v) for k, v in cherrypy.request.header_list]
    cherrypy.log('\nRequest Headers:\n' + '\n'.join(h) + '\n\n' + _cperror.format_exc(), "HTTP", severity=severity)

cherrypy.tools.my_log_tracebacks = cherrypy.Tool('before_error_response', my_log_traceback)