Allowing custom directory for well-known file.

Also raising exception if the directory does not exist.

Fixes #151.

oauth2client/client.py

@@ -81,6 +81,8 @@ GOOGLE_APPLICATION_CREDENTIALS = 'GOOGLE_APPLICATION_CREDENTIALS'
 # The ~/.config subdirectory containing gcloud credentials. Intended
 # to be swapped out in tests.
 _CLOUDSDK_CONFIG_DIRECTORY = 'gcloud'
+# The environment variable name which can replace ~/.config if set.
+_CLOUDSDK_CONFIG_ENV_VAR = 'CLOUDSDK_CONFIG'
 
 # The error message we show users when we can't find the Application
 # Default Credentials.
@@ -1268,24 +1270,26 @@ def _get_well_known_file():
 
   WELL_KNOWN_CREDENTIALS_FILE = 'application_default_credentials.json'
 
-  if os.name == 'nt':
+  default_config_dir = os.getenv(_CLOUDSDK_CONFIG_ENV_VAR)
-    try:
+  if default_config_dir is None:
-      default_config_path = os.path.join(os.environ['APPDATA'],
+    if os.name == 'nt':
-                                         _CLOUDSDK_CONFIG_DIRECTORY)
+      try:
-    except KeyError:
+        default_config_dir = os.path.join(os.environ['APPDATA'],
-      # This should never happen unless someone is really messing with things.
+                                          _CLOUDSDK_CONFIG_DIRECTORY)
-      drive = os.environ.get('SystemDrive', 'C:')
+      except KeyError:
-      default_config_path = os.path.join(drive, '\\',
+        # This should never happen unless someone is really messing with things.
-                                         _CLOUDSDK_CONFIG_DIRECTORY)
+        drive = os.environ.get('SystemDrive', 'C:')
-  else:
+        default_config_dir = os.path.join(drive, '\\',
-    default_config_path = os.path.join(os.path.expanduser('~'),
+                                          _CLOUDSDK_CONFIG_DIRECTORY)
-                                       '.config',
+    else:
-                                       _CLOUDSDK_CONFIG_DIRECTORY)
+      default_config_dir = os.path.join(os.path.expanduser('~'),
+                                        '.config',
+                                        _CLOUDSDK_CONFIG_DIRECTORY)
 
-  default_config_path = os.path.join(default_config_path,
+  if not os.path.isdir(default_config_dir):
-                                     WELL_KNOWN_CREDENTIALS_FILE)
+    raise OSError('Config directory does not exist', default_config_dir)
 
-  return default_config_path
+  return os.path.join(default_config_dir, WELL_KNOWN_CREDENTIALS_FILE)
 
 
 def _get_application_default_credential_from_file(filename):

tests/test_devshell.py

@@ -125,6 +125,11 @@ class DevshellCredentialsTests(unittest.TestCase):
       self.assertEqual('sometoken', creds.access_token)
 
   def test_refuses_to_save_to_well_known_file(self):
-    with _AuthReferenceServer():
+    ORIGINAL_ISDIR = os.path.isdir
-      creds = DevshellCredentials()
+    try:
-      self.assertRaises(NotImplementedError, save_to_well_known_file, creds)
+      os.path.isdir = lambda path: True
+      with _AuthReferenceServer():
+        creds = DevshellCredentials()
+        self.assertRaises(NotImplementedError, save_to_well_known_file, creds)
+    finally:
+      os.path.isdir = ORIGINAL_ISDIR

tests/test_gce.py

@@ -97,5 +97,12 @@ class AssertionCredentialsTests(unittest.TestCase):
         'default/acquire?scope=dummy_scope')
 
   def test_save_to_well_known_file(self):
-    credentials = AppAssertionCredentials([])
+    import os
-    self.assertRaises(NotImplementedError, save_to_well_known_file, credentials)
+    ORIGINAL_ISDIR = os.path.isdir
+    try:
+      os.path.isdir = lambda path: True
+      credentials = AppAssertionCredentials([])
+      self.assertRaises(NotImplementedError, save_to_well_known_file,
+                        credentials)
+    finally:
+      os.path.isdir = ORIGINAL_ISDIR

tests/test_oauth2client.py

@@ -247,11 +247,40 @@ class GoogleCredentialsTests(unittest.TestCase):
                        str(error))
 
   def test_get_well_known_file_on_windows(self):
-    well_known_file = datafile(
+    ORIGINAL_ISDIR = os.path.isdir
-        os.path.join('gcloud', 'application_default_credentials.json'))
+    try:
-    os.name = 'nt'
+      os.path.isdir = lambda path: True
-    os.environ['APPDATA'] = DATA_DIR
+      well_known_file = datafile(
-    self.assertEqual(well_known_file, _get_well_known_file())
+          os.path.join(client._CLOUDSDK_CONFIG_DIRECTORY,
+                       'application_default_credentials.json'))
+      os.name = 'nt'
+      os.environ['APPDATA'] = DATA_DIR
+      self.assertEqual(well_known_file, _get_well_known_file())
+    finally:
+      os.path.isdir = ORIGINAL_ISDIR
+
+  def test_get_well_known_file_with_custom_config_dir(self):
+    ORIGINAL_ENVIRON = os.environ
+    ORIGINAL_ISDIR = os.path.isdir
+    CUSTOM_DIR = 'CUSTOM_DIR'
+    EXPECTED_FILE = os.path.join(CUSTOM_DIR,
+                                 'application_default_credentials.json')
+    try:
+      os.environ = {client._CLOUDSDK_CONFIG_ENV_VAR: CUSTOM_DIR}
+      os.path.isdir = lambda path: True
+      well_known_file = _get_well_known_file()
+      self.assertEqual(well_known_file, EXPECTED_FILE)
+    finally:
+      os.environ = ORIGINAL_ENVIRON
+      os.path.isdir = ORIGINAL_ISDIR
+
+  def test_get_well_known_file_with_non_existent_config_dir(self):
+    ORIGINAL_ISDIR = os.path.isdir
+    try:
+      os.path.isdir = lambda path: False
+      self.assertRaises(OSError, _get_well_known_file)
+    finally:
+      os.path.isdir = ORIGINAL_ISDIR
 
   def test_get_application_default_credential_from_file_service_account(self):
     credentials_file = datafile(
@@ -410,13 +439,16 @@ class GoogleCredentialsTests(unittest.TestCase):
     os.environ['APPDATA'] = ''
     # we can't use self.assertRaisesRegexp() because it is only in Python 2.7+
     VALID_CONFIG_DIR = client._CLOUDSDK_CONFIG_DIRECTORY
+    ORIGINAL_ISDIR = os.path.isdir
     try:
+      os.path.isdir = lambda path: True
       client._CLOUDSDK_CONFIG_DIRECTORY = 'BOGUS_CONFIG_DIR'
       GoogleCredentials.get_application_default()
       self.fail('An exception was expected!')
     except ApplicationDefaultCredentialsError as error:
       self.assertEqual(ADC_HELP_MSG, str(error))
     finally:
+      os.path.isdir = ORIGINAL_ISDIR
       client._CLOUDSDK_CONFIG_DIRECTORY = VALID_CONFIG_DIR
 
   def test_from_stream_service_account(self):