third_party/google_appengine_cloudstorage/cloudstorage/errors.py

   1 # Copyright 2012 Google Inc. All Rights Reserved.
   2 #
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #    http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing,
  10 # software distributed under the License is distributed on an
  11 # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
  12 # either express or implied. See the License for the specific
  13 # language governing permissions and limitations under the License.
  14
  15 """Google Cloud Storage specific Files API calls."""
  16
  17
  18
  19
  20
  21 __all__ = ['AuthorizationError',
  22            'check_status',
  23            'Error',
  24            'FatalError',
  25            'FileClosedError',
  26            'ForbiddenError',
  27            'NotFoundError',
  28            'ServerError',
  29            'TimeoutError',
  30            'TransientError',
  31           ]
  32
  33 import httplib
  34
  35
  36 class Error(Exception):
  37   """Base error for all gcs operations.
  38
  39   Error can happen on GAE side or GCS server side.
  40   For details on a particular GCS HTTP response code, see
  41   https://developers.google.com/storage/docs/reference-status#standardcodes
  42   """
  43
  44
  45 class TransientError(Error):
  46   """TransientError could be retried."""
  47
  48
  49 class TimeoutError(TransientError):
  50   """HTTP 408 timeout."""
  51
  52
  53 class FatalError(Error):
  54   """FatalError shouldn't be retried."""
  55
  56
  57 class FileClosedError(FatalError):
  58   """File is already closed.
  59
  60   This can happen when the upload has finished but 'write' is called on
  61   a stale upload handle.
  62   """
  63
  64
  65 class NotFoundError(FatalError):
  66   """HTTP 404 resource not found."""
  67
  68
  69 class ForbiddenError(FatalError):
  70   """HTTP 403 Forbidden.
  71
  72   While GCS replies with a 403 error for many reasons, the most common one
  73   is due to bucket permission not correctly setup for your app to access.
  74   """
  75
  76
  77 class AuthorizationError(FatalError):
  78   """HTTP 401 authentication required.
  79
  80   Unauthorized request has been received by GCS.
  81
  82   This error is mostly handled by GCS client. GCS client will request
  83   a new access token and retry the request.
  84   """
  85
  86
  87 class InvalidRange(FatalError):
  88   """HTTP 416 RequestRangeNotSatifiable."""
  89
  90
  91 class ServerError(TransientError):
  92   """HTTP >= 500 server side error."""
  93
  94
  95 def check_status(status, expected, path, headers=None,
  96                  resp_headers=None, extras=None):
  97   """Check HTTP response status is expected.
  98
  99   Args:
 100     status: HTTP response status. int.
 101     expected: a list of expected statuses. A list of ints.
 102     path: filename or a path prefix.
 103     headers: HTTP request headers.
 104     resp_headers: HTTP response headers.
 105     extras: extra info to be logged verbatim if error occurs.
 106
 107   Raises:
 108     AuthorizationError: if authorization failed.
 109     NotFoundError: if an object that's expected to exist doesn't.
 110     TimeoutError: if HTTP request timed out.
 111     ServerError: if server experienced some errors.
 112     FatalError: if any other unexpected errors occurred.
 113   """
 114   if status in expected:
 115     return
 116
 117   msg = ('Expect status %r from Google Storage. But got status %d.\n'
 118          'Path: %r.\n'
 119          'Request headers: %r.\n'
 120          'Response headers: %r.\n'
 121          'Extra info: %r.\n' %
 122          (expected, status, path, headers, resp_headers, extras))
 123
 124   if status == httplib.UNAUTHORIZED:
 125     raise AuthorizationError(msg)
 126   elif status == httplib.FORBIDDEN:
 127     raise ForbiddenError(msg)
 128   elif status == httplib.NOT_FOUND:
 129     raise NotFoundError(msg)
 130   elif status == httplib.REQUEST_TIMEOUT:
 131     raise TimeoutError(msg)
 132   elif status == httplib.REQUESTED_RANGE_NOT_SATISFIABLE:
 133     raise InvalidRange(msg)
 134   elif (status == httplib.OK and 308 in expected and
 135         httplib.OK not in expected):
 136     raise FileClosedError(msg)
 137   elif status >= 500:
 138     raise ServerError(msg)
 139   else:
 140     raise FatalError(msg)