Chris Dent
5f881ff030
Prior to this patch placement was using the nova FaultWrapper middleware as a final guard against unexpected exceptions. That middleware does more than required and also imports stuff that placement does not otherwise require. The new middleware is only for exceptions that have fallen through previous handling and need to be turned into 500 responses, formatted to JSON, and logged. While doing this it became clear that the limited Exception catching in handler.py was redundant if FaultWrapper and the Microversion middlewares (both required for the operation of the system) are involved, so that has been removed, with a comment. This should not require a microversion as the structure of successful responses and expected error responses does not change. What does change is that a 500 response will be formatted more as the api-wg errors guideline[1] desires. [1] http://specs.openstack.org/openstack/api-wg/guidelines/errors.html Change-Id: Ib2c3250b964a30239f298cdf13ea2020f205f67d Partial-Bug: #1743120
49 lines
1.7 KiB
Python
49 lines
1.7 KiB
Python
# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""Simple middleware for safely catching unexpected exceptions."""
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# NOTE(cdent): This is a super simplified replacement for the nova
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# FaultWrapper, which does more than placement needs.
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from oslo_log import log as logging
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import six
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from webob import exc
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from nova.api.openstack.placement import util
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LOG = logging.getLogger(__name__)
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class FaultWrapper(object):
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"""Turn an uncaught exception into a status 500.
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Uncaught exceptions usually shouldn't happen, if it does it
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means there is a bug in the placement service, which should be
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fixed.
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"""
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def __init__(self, application):
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self.application = application
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def __call__(self, environ, start_response):
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try:
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return self.application(environ, start_response)
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except Exception as unexpected_exception:
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LOG.exception('Placement API unexpected error: %s',
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unexpected_exception)
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formatted_exception = exc.HTTPInternalServerError(
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six.text_type(unexpected_exception))
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formatted_exception.json_formatter = util.json_error_formatter
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return formatted_exception.generate_response(
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environ, start_response)
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