chrome/common/extensions/docs/server2/gcs_file_system_provider.py

   1 # Copyright 2014 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import os
   6 import environment
   7
   8 from caching_file_system import CachingFileSystem
   9 from empty_dir_file_system import EmptyDirFileSystem
  10 from extensions_paths import LOCAL_GCS_DIR, LOCAL_GCS_DEBUG_CONF
  11 from local_file_system import LocalFileSystem
  12 from path_util import IsDirectory, ToDirectory
  13
  14 class CloudStorageFileSystemProvider(object):
  15   '''Provides CloudStorageFileSystem bound to a GCS bucket.
  16   '''
  17   def __init__(self, object_store_creator):
  18     self._object_store_creator = object_store_creator
  19
  20   def Create(self, bucket):
  21     '''Creates a CloudStorageFileSystemProvider.
  22
  23     |bucket| is the name of GCS bucket, eg devtools-docs. It is expected
  24              that this bucket has Read permission for this app in its ACLs.
  25
  26     Optional configuration can be set in a local_debug/gcs_debug.conf file:
  27       use_local_fs=True|False
  28       access_token=<token>
  29       remote_bucket_prefix=<prefix>
  30
  31     If running in Preview mode or in Development mode with use_local_fs set to
  32     True, buckets and files are looked inside the local_debug folder instead
  33     of in the real GCS server. Preview server does not support direct GCS
  34     access, so it is always forced to use a LocalFileSystem.
  35
  36     For real GCS access in the Development mode (dev_appserver.py),
  37     access_token and remote_bucket_prefix options can be
  38     used to change the way GCS files are accessed. Both are ignored in a real
  39     appengine instance.
  40
  41     "access_token" is always REQUIRED on dev_appengine, otherwise you will
  42     get 404 (auth) errors. You can get one access_token valid for a few minutes
  43     by typing:
  44       gsutil -d ls 2>&1 | grep "Bearer" |
  45          sed "s/.*Bearer \(.*\).r.nUser-Agent.*/access_token=\1/" )"
  46
  47     A sample output would be:
  48       access_token=ya29.1.AADtN_VW5ibbfLHV5cMIK5ss4bHtVzBXpa4byjd
  49
  50     Now add this line to the local_debug/gcs_debug.conf file and restart the
  51     appengine development server.
  52
  53     Remember that you will need a new access_token every ten minutes or
  54     so. If you get 404 errors on log, update it. Access token is not
  55     used for a deployed appengine app, only if you use dev_appengine.py.
  56
  57     remote_bucket_prefix is useful if you want to test on your own GCS buckets
  58     before using the real GCS buckets.
  59
  60     '''
  61     if not environment.IsReleaseServer() and not environment.IsDevServer():
  62       bucket_local_path = os.path.join(LOCAL_GCS_DIR, bucket)
  63       if IsDirectory(bucket_local_path):
  64         return LocalFileSystem(bucket_local_path)
  65       else:
  66         return EmptyDirFileSystem()
  67
  68     debug_access_token = None
  69     debug_bucket_prefix = None
  70     use_local_fs = False
  71
  72     if environment.IsDevServer() and os.path.exists(LOCAL_GCS_DEBUG_CONF):
  73       with open(LOCAL_GCS_DEBUG_CONF, "r") as token_file:
  74         properties = dict(line.strip().split('=', 1) for line in token_file)
  75       use_local_fs = properties.get('use_local_fs', 'False')=='True'
  76       debug_access_token = properties.get('access_token', None)
  77       debug_bucket_prefix = properties.get('remote_bucket_prefix', None)
  78
  79     if environment.IsDevServer() and use_local_fs:
  80       return LocalFileSystem(ToDirectory(os.path.join(LOCAL_GCS_DIR, bucket)))
  81
  82     # gcs_file_system has strong dependencies on runtime appengine APIs,
  83     # so we only import it when we are sure we are not on preview.py or tests.
  84     from gcs_file_system import CloudStorageFileSystem
  85     return CachingFileSystem(CloudStorageFileSystem(bucket,
  86         debug_access_token, debug_bucket_prefix),
  87         self._object_store_creator)
  88
  89   @staticmethod
  90   def ForEmpty():
  91     class EmptyImpl(object):
  92       def Create(self, bucket):
  93         return EmptyDirFileSystem()
  94     return EmptyImpl()