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OpenStack Study: catch_errors.py**** CubicPower OpenStack Study ****
# Copyright (c) 2010-2012 OpenStack Foundation # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or # implied. # See the License for the specific language governing permissions and # limitations under the License. from swift import gettext_ as _ from swift.common.swob import Request, HTTPServerError from swift.common.utils import get_logger, generate_trans_id from swift.common.wsgi import WSGIContext
**** CubicPower OpenStack Study **** class CatchErrorsContext(WSGIContext):
**** CubicPower OpenStack Study **** def __init__(self, app, logger, trans_id_suffix=''): super(CatchErrorsContext, self).__init__(app) self.logger = logger self.trans_id_suffix = trans_id_suffix
**** CubicPower OpenStack Study **** def handle_request(self, env, start_response): trans_id = generate_trans_id(self.trans_id_suffix) env['swift.trans_id'] = trans_id self.logger.txn_id = trans_id try: # catch any errors in the pipeline resp = self._app_call(env) except: # noqa self.logger.exception(_('Error: An error occurred')) resp = HTTPServerError(request=Request(env), body='An error occurred', content_type='text/plain') resp.headers['X-Trans-Id'] = trans_id return resp(env, start_response) # make sure the response has the trans_id if self._response_headers is None: self._response_headers = [] self._response_headers.append(('X-Trans-Id', trans_id)) start_response(self._response_status, self._response_headers, self._response_exc_info) return resp
**** CubicPower OpenStack Study **** class CatchErrorMiddleware(object): """ Middleware that provides high-level error handling and ensures that a transaction id will be set for every request. """
**** CubicPower OpenStack Study **** def __init__(self, app, conf): self.app = app self.logger = get_logger(conf, log_route='catch-errors') self.trans_id_suffix = conf.get('trans_id_suffix', '')
**** CubicPower OpenStack Study **** def __call__(self, env, start_response): """ If used, this should be the first middleware in pipeline. """ context = CatchErrorsContext(self.app, self.logger, self.trans_id_suffix) return context.handle_request(env, start_response) def filter_factory(global_conf, **local_conf): conf = global_conf.copy() conf.update(local_conf)
**** CubicPower OpenStack Study **** def filter_factory(global_conf, **local_conf): conf = global_conf.copy() conf.update(local_conf)
**** CubicPower OpenStack Study **** def except_filter(app): return CatchErrorMiddleware(app, conf) return except_filter
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