1# Copyright (c) 2013 NEC Corporation
2# All Rights Reserved.
3#
4#    Licensed under the Apache License, Version 2.0 (the "License"); you may
5#    not use this file except in compliance with the License. You may obtain
6#    a copy of the License at
7#
8#         http://www.apache.org/licenses/LICENSE-2.0
9#
10#    Unless required by applicable law or agreed to in writing, software
11#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13#    License for the specific language governing permissions and limitations
14#    under the License.
15
16import logging
17import re
18
19import webob.dec
20import webob.exc
21
22from oslo_middleware import base
23
24
25LOG = logging.getLogger(__name__)
26
27_TOKEN_RE = re.compile(r'^(X-\w+-Token):.*$', flags=re.MULTILINE)
28
29
30class CatchErrors(base.ConfigurableMiddleware):
31    """Middleware that provides high-level error handling.
32
33    It catches all exceptions from subsequent applications in WSGI pipeline
34    to hide internal errors from API response.
35    """
36
37    @webob.dec.wsgify
38    def __call__(self, req):
39        try:
40            response = req.get_response(self.application)
41        except Exception:
42            req_str = _TOKEN_RE.sub(r'\1: *****', req.as_text())
43            LOG.exception('An error occurred during '
44                          'processing the request: %s', req_str)
45            response = webob.exc.HTTPInternalServerError()
46        return response
47