Tornado BaseHandler for IOLoop run in executor and error handling

basehandler.py

class BaseHandler(tornado.web.RequestHandler):

    @tornado.gen.coroutine
    def post_async(self, *args):
        resp_dict = yield ioloop.IOLoop.current().run_in_executor(None, self.post_handler, args)
        return resp_dict

    @tornado.web.asynchronous
    @tornado.gen.coroutine
    def post(self, *args):

        response = yield self.post_async(args)
        
        self.set_header("Content-Type", "application/json; charset=UTF-8")

        status_code = response.getField('status_code', 200)
        self.set_status(status_code)
        self.write(json.dumps(response.getData()))
        self.finish()
    
    @tornado.gen.coroutine
    def get_async(self, *args):
        resp_dict = yield ioloop.IOLoop.current().run_in_executor(None, self.get_handler, args)
        return resp_dict
    
    @tornado.web.asynchronous
    @tornado.gen.coroutine
    def get(self, *args):

        response = yield self.get_async(args)
        
        self.set_header("Content-Type", "application/json; charset=UTF-8")

        status_code = response.getField('status_code', 200)
        self.set_status(status_code)
        self.write(json.dumps(response.getData()))
        self.finish()

    def write_error(self, status_code, **kwargs):

        # logger
        logger = MXMLogger.instance().get_logger()

        self.set_header('Content-Type', 'application/json')
        err = {}
        if self.settings.get("serve_traceback") and "exc_info" in kwargs:
            # in debug mode, try to send a traceback
            lines = []
            for line in traceback.format_exception(*kwargs["exc_info"]):
                lines.append(line)
            err = {
                'code': status_code,
                'message': self._reason,
                'traceback': lines
            }
        else:
            err = {
                'code': status_code,
                'message': self._reason
            }
        
        # format error response
        response = ResponseTornado()
        response.addHeader(status_code=err['code'] )
        response.addError(code=err['code'], status=err['code'], hint='', description='', message=err['message'])
        
        logger.error("error %d %s" % (err['code'], err['message']) )

        self.set_status(status_code)
        self.write(json.dumps(response.getData()))
        
class ErrorHandler(tornado.web.ErrorHandler, BaseHandler):
    """Generates an error response with status_code for all requests."""

    def write_error(self, status_code, **kwargs):

        # logger
        logger = MXMLogger.instance().get_logger()

        self.set_header('Content-Type', 'application/json')
        err = {}
        if self.settings.get("serve_traceback") and "exc_info" in kwargs:
            # in debug mode, try to send a traceback
            lines = []
            for line in traceback.format_exception(*kwargs["exc_info"]):
                lines.append(line)
            err = {
                'code': status_code,
                'message': self._reason,
                'traceback': lines
            }
        else:
            err = {
                'code': status_code,
                'message': self._reason
            }
        
        # format error response
        response = ResponseTornado()
        response.addHeader(status_code=err['code'] )
        response.addError(code=err['code'], status=err['code'], hint='', description='', message=err['message'])
        
        logger.error("error %d %s" % (err['code'], err['message']) )

        self.set_status(status_code)
        self.write(json.dumps(response.getData()))