Making cached dataset ID require explicit interaction.

Incorporates feedback from @tseaver. Also
- Fixing bad tests that accidentally leave side-effects.
- Making the method to set the default dataset public.

gcloud/datastore/__init__.py

@@ -58,19 +58,26 @@
 _DATASET_ENV_VAR_NAME = 'GCLOUD_DATASET_ID'
 
 
-def _set_dataset_from_environ():
+def set_default_dataset(dataset_id=None):
     """Determines auth settings from local enviroment.
 
-    Currently only supports enviroment variable but will implicitly
-    support App Engine, Compute Engine and other environments in
-    the future.
+    Sets a default dataset either explicitly or via the local
+    enviroment. Currently only supports enviroment variable but will
+    implicitly support App Engine, Compute Engine and other environments
+    in the future.
 
     Local environment variable used is:
     - GCLOUD_DATASET_ID
+
+    :type dataset_id: :class:`str`.
+    :param dataset_id: Optional. The dataset ID to use for the default
+                       dataset.
     """
-    local_dataset_id = os.getenv(_DATASET_ENV_VAR_NAME)
-    if local_dataset_id is not None:
-        _implicit_environ.DATASET = get_dataset(local_dataset_id)
+    if dataset_id is None:
+        dataset_id = os.getenv(_DATASET_ENV_VAR_NAME)
+
+    if dataset_id is not None:
+        _implicit_environ.DATASET = get_dataset(dataset_id)
 
 
 def get_connection():
@@ -127,7 +134,7 @@ def _require_dataset():
     :raises: :class:`EnvironmentError` if DATASET is not set.
     """
     if _implicit_environ.DATASET is None:
-        raise EnvironmentError('Dataset could not be implied.')
+        raise EnvironmentError('Dataset could not be inferred.')
     return _implicit_environ.DATASET
 
 
@@ -168,7 +175,3 @@ def allocate_ids(incomplete_key, num_ids):
     :return: The (complete) keys allocated with `incomplete_key` as root.
     """
     return _require_dataset().allocate_ids(incomplete_key, num_ids)
-
-
-# Set DATASET if it can be implied from the environment.
-_set_dataset_from_environ()

gcloud/datastore/entity.py

@@ -96,7 +96,7 @@ class Entity(dict):
 
     def __init__(self, dataset=None, kind=None, exclude_from_indexes=()):
         super(Entity, self).__init__()
-        # Does not inherit from object, so we don't use
+        # Does not inherit directly from object, so we don't use
         # _implicit_environ._DatastoreBase to avoid split MRO.
         self._dataset = dataset or _implicit_environ.DATASET
         if kind:

gcloud/datastore/test___init__.py

@@ -35,13 +35,22 @@ def test_it(self):
         self.assertTrue(client._get_app_default_called)
 
 
-class Test__set_dataset_from_environ(unittest2.TestCase):
+class Test_set_default_dataset(unittest2.TestCase):
 
-    def _callFUT(self):
-        from gcloud.datastore import _set_dataset_from_environ
-        return _set_dataset_from_environ()
+    def setUp(self):
+        from gcloud.datastore import _implicit_environ
+        self._replaced_dataset = _implicit_environ.DATASET
+        _implicit_environ.DATASET = None
+
+    def tearDown(self):
+        from gcloud.datastore import _implicit_environ
+        _implicit_environ.DATASET = self._replaced_dataset
 
-    def _test_with_environ(self, environ, expected_result):
+    def _callFUT(self, dataset_id=None):
+        from gcloud.datastore import set_default_dataset
+        return set_default_dataset(dataset_id=dataset_id)
+
+    def _test_with_environ(self, environ, expected_result, dataset_id=None):
         import os
         from gcloud._testing import _Monkey
         from gcloud import datastore
@@ -53,12 +62,12 @@ def _test_with_environ(self, environ, expected_result):
         def custom_getenv(key):
             return environ.get(key)
 
-        def custom_get_dataset(dataset_id):
-            return dataset_id
+        def custom_get_dataset(local_dataset_id):
+            return local_dataset_id
 
         with _Monkey(os, getenv=custom_getenv):
             with _Monkey(datastore, get_dataset=custom_get_dataset):
-                self._callFUT()
+                self._callFUT(dataset_id=dataset_id)
 
         self.assertEqual(_implicit_environ.DATASET, expected_result)
 
@@ -75,6 +84,10 @@ def test_set_from_env_var(self):
     def test_no_env_var_set(self):
         self._test_with_environ({}, None)
 
+    def test_set_explicit(self):
+        DATASET_ID = 'DATASET'
+        self._test_with_environ({}, DATASET_ID, dataset_id=DATASET_ID)
+
 
 class Test_get_dataset(unittest2.TestCase):
 
@@ -161,40 +174,3 @@ def test_allocate_ids(self):
 
         # Check the IDs returned.
         self.assertEqual([key.id() for key in result], range(1, NUM_IDS + 1))
-
-    def test_set_DATASET(self):
-        import os
-        from gcloud._testing import _Monkey
-        from gcloud.test_credentials import _Client
-        from gcloud import credentials
-        from gcloud.datastore import _implicit_environ
-
-        # Make custom client for doing auth. Have to fake auth since we
-        # can't monkey patch `datastore.get_dataset` while reloading the
-        # `datastore.__init__` module.
-        client = _Client()
-
-        # Fake auth variables.
-        DATASET = 'dataset'
-
-        # Make a custom getenv function to Monkey.
-        VALUES = {
-            'GCLOUD_DATASET_ID': DATASET,
-        }
-
-        def custom_getenv(key):
-            return VALUES.get(key)
-
-        # Perform the import again with our test patches.
-        with _Monkey(credentials, client=client):
-            with _Monkey(os, getenv=custom_getenv):
-                import gcloud.datastore
-                reload(gcloud.datastore)
-
-        # Check that the DATASET was correctly implied from the environ.
-        implicit_dataset = _implicit_environ.DATASET
-        self.assertEqual(implicit_dataset.id(), DATASET)
-        # Check that the credentials on the implicit DATASET was set on the
-        # fake client.
-        cnxn_credentials = implicit_dataset.connection().credentials
-        self.assertTrue(cnxn_credentials is client._signed)

gcloud/datastore/test_helpers.py

@@ -19,12 +19,18 @@ class Test_entity_from_protobuf(unittest2.TestCase):
 
     _MARKER = object()
 
-    def _callFUT(self, val, dataset=_MARKER):
+    def setUp(self):
         from gcloud.datastore import _implicit_environ
-        from gcloud.datastore.helpers import entity_from_protobuf
-
+        self._replaced_dataset = _implicit_environ.DATASET
         _implicit_environ.DATASET = None
 
+    def tearDown(self):
+        from gcloud.datastore import _implicit_environ
+        _implicit_environ.DATASET = self._replaced_dataset
+
+    def _callFUT(self, val, dataset=_MARKER):
+        from gcloud.datastore.helpers import entity_from_protobuf
+
         if dataset is self._MARKER:
             return entity_from_protobuf(val)
 

gcloud/datastore/test_query.py

@@ -17,11 +17,17 @@
 
 class TestQuery(unittest2.TestCase):
 
-    def _getTargetClass(self):
+    def setUp(self):
         from gcloud.datastore import _implicit_environ
-        from gcloud.datastore.query import Query
-
+        self._replaced_dataset = _implicit_environ.DATASET
         _implicit_environ.DATASET = None
+
+    def tearDown(self):
+        from gcloud.datastore import _implicit_environ
+        _implicit_environ.DATASET = self._replaced_dataset
+
+    def _getTargetClass(self):
+        from gcloud.datastore.query import Query
         return Query
 
     def _makeOne(self, kind=None, dataset=None, namespace=None):

regression/datastore.py

@@ -13,17 +13,20 @@
 # limitations under the License.
 
 import datetime
+import os
 import pytz
 import unittest2
 
 from gcloud import datastore
-datastore._DATASET_ENV_VAR_NAME = 'GCLOUD_TESTS_DATASET_ID'
-datastore._set_dataset_from_environ()
 # This assumes the command is being run via tox hence the
 # repository root is the current directory.
 from regression import populate_datastore
 
 
+DATASET_ID = os.getenv('GCLOUD_TESTS_DATASET_ID')
+datastore.set_default_dataset(dataset_id=DATASET_ID)
+
+
 class TestDatastore(unittest2.TestCase):
 
     def setUp(self):