Merge pull request #735 from dhermes/default-project-lazy-loaded

Adding lazy loading behavior for default project (storage).

Author: dhermes

gcloud/_localstack.py renamed to gcloud/_helpers.py

@@ -59,3 +59,46 @@ def top(self):
  """
  if len(self._stack) > 0:
  return self._stack[-1]
+
+
+class _LazyProperty(object):
+ """Descriptor for lazy loaded property.
+
+ This follows the reify pattern: lazy evaluation and then replacement
+ after evaluation.
+
+ :type name: string
+ :param name: The name of the attribute / property being evaluated.
+
+ :type deferred_callable: callable that takes no arguments
+ :param deferred_callable: The function / method used to evaluate the
+ property.
+ """
+
+ def __init__(self, name, deferred_callable):
+ self._name = name
+ self._deferred_callable = deferred_callable
+
+ def __get__(self, obj, objtype):
+ if obj is None:
+ return self
+
+ setattr(obj, self._name, self._deferred_callable())
+ return getattr(obj, self._name)
+
+
+def _lazy_property_deco(deferred_callable):
+ """Decorator a method to create a :class:`_LazyProperty`.
+
+ :type deferred_callable: callable that takes no arguments
+ :param deferred_callable: The function / method used to evaluate the
+ property.
+
+ :rtype: :class:`_LazyProperty`.
+ :returns: A lazy property which defers the deferred_callable.
+ """
+ if isinstance(deferred_callable, staticmethod):
+ # H/T: http://stackoverflow.com/a/9527450/1068170
+ # For Python2.7+ deferred_callable.__func__ would suffice.
+ deferred_callable = deferred_callable.__get__(True)
+ return _LazyProperty(deferred_callable.__name__, deferred_callable)

gcloud/datastore/_implicit_environ.py

@@ -28,6 +28,7 @@
 except ImportError:
  app_identity = None
 
+from gcloud._helpers import _lazy_property_deco
 from gcloud import credentials
 from gcloud.datastore.connection import Connection
 
@@ -201,49 +202,6 @@ def get_default_connection():
  return _DEFAULTS.connection
 
 
-class _LazyProperty(object):
- """Descriptor for lazy loaded property.
-
- This follows the reify pattern: lazy evaluation and then replacement
- after evaluation.
-
- :type name: string
- :param name: The name of the attribute / property being evaluated.
-
- :type deferred_callable: callable that takes no arguments
- :param deferred_callable: The function / method used to evaluate the
- property.
- """
-
- def __init__(self, name, deferred_callable):
- self._name = name
- self._deferred_callable = deferred_callable
-
- def __get__(self, obj, objtype):
- if obj is None or objtype is not _DefaultsContainer:
- return self
-
- setattr(obj, self._name, self._deferred_callable())
- return getattr(obj, self._name)
-
-
-def _lazy_property_deco(deferred_callable):
- """Decorator a method to create a :class:`_LazyProperty`.
-
- :type deferred_callable: callable that takes no arguments
- :param deferred_callable: The function / method used to evaluate the
- property.
-
- :rtype: :class:`_LazyProperty`.
- :returns: A lazy property which defers the deferred_callable.
- """
- if isinstance(deferred_callable, staticmethod):
- # H/T: http://stackoverflow.com/a/9527450/1068170
- # For Python2.7+ deferred_callable.__func__ would suffice.
- deferred_callable = deferred_callable.__get__(True)
- return _LazyProperty(deferred_callable.__name__, deferred_callable)
-
-
 class _DefaultsContainer(object):
  """Container for defaults.
 

gcloud/datastore/batch.py

@@ -14,7 +14,7 @@
 
 """Create / interact with a batch of updates / deletes."""
 
-from gcloud._localstack import _LocalStack
+from gcloud._helpers import _LocalStack
 from gcloud.datastore import _implicit_environ
 from gcloud.datastore import helpers
 from gcloud.datastore.key import _dataset_ids_equal

gcloud/datastore/test__implicit_environ.py

@@ -315,29 +315,6 @@ def mock_determine(dataset_id):
  self.assertEqual(_called_dataset_id, [None])
 
 
-class Test__lazy_property_deco(unittest2.TestCase):
-
- def _callFUT(self, deferred_callable):
- from gcloud.datastore._implicit_environ import _lazy_property_deco
- return _lazy_property_deco(deferred_callable)
-
- def test_on_function(self):
- def test_func():
- pass # pragma: NO COVER never gets called
-
- lazy_prop = self._callFUT(test_func)
- self.assertTrue(lazy_prop._deferred_callable is test_func)
- self.assertEqual(lazy_prop._name, 'test_func')
-
- def test_on_staticmethod(self):
- def test_func():
- pass # pragma: NO COVER never gets called
-
- lazy_prop = self._callFUT(staticmethod(test_func))
- self.assertTrue(lazy_prop._deferred_callable is test_func)
- self.assertEqual(lazy_prop._name, 'test_func')
-
-
 class Test_lazy_loading(unittest2.TestCase):
 
  def setUp(self):
@@ -348,19 +325,6 @@ def tearDown(self):
  from gcloud.datastore._testing import _tear_down_defaults
  _tear_down_defaults(self)
 
- def test_prop_on_wrong_class(self):
- from gcloud.datastore._implicit_environ import _LazyProperty
-
- # Don't actually need a callable for ``method`` since
- # __get__ will just return ``self`` in this test.
- data_prop = _LazyProperty('dataset_id', None)
-
- class FakeEnv(object):
- dataset_id = data_prop
-
- self.assertTrue(FakeEnv.dataset_id is data_prop)
- self.assertTrue(FakeEnv().dataset_id is data_prop)
-
  def test_descriptor_for_dataset_id(self):
  from gcloud._testing import _Monkey
  from gcloud.datastore import _implicit_environ

gcloud/storage/__init__.py

@@ -45,6 +45,7 @@
 from gcloud.storage._implicit_environ import get_default_bucket
 from gcloud.storage._implicit_environ import get_default_connection
 from gcloud.storage._implicit_environ import get_default_project
+from gcloud.storage._implicit_environ import set_default_project
 from gcloud.storage.api import create_bucket
 from gcloud.storage.api import get_all_buckets
 from gcloud.storage.api import get_bucket
@@ -59,7 +60,6 @@
  'https://www.googleapis.com/auth/devstorage.read_write')
 
 _BUCKET_ENV_VAR_NAME = 'GCLOUD_BUCKET_NAME'
-_PROJECT_ENV_VAR_NAME = 'GCLOUD_PROJECT'
 
 
 def set_default_bucket(bucket=None):
@@ -88,25 +88,6 @@ def set_default_bucket(bucket=None):
  _implicit_environ._DEFAULTS.bucket = bucket
 
 
-def set_default_project(project=None):
- """Set default bucket name either explicitly or implicitly as fall-back.
-
- In implicit case, currently only supports enviroment variable but will
- support App Engine, Compute Engine and other environments in the future.
-
- Local environment variable used is:
- - GCLOUD_PROJECT
-
- :type project: string
- :param project: Optional. The project name to use as default.
- """
- if project is None:
- project = os.getenv(_PROJECT_ENV_VAR_NAME)
-
- if project is not None:
- _implicit_environ._DEFAULTS.project = project
-
-
 def set_default_connection(connection=None):
  """Set default connection either explicitly or implicitly as fall-back.
 

gcloud/storage/_implicit_environ.py

@@ -19,6 +19,55 @@
 """
 
 
+import os
+
+from gcloud._helpers import _lazy_property_deco
+
+
+_PROJECT_ENV_VAR_NAME = 'GCLOUD_PROJECT'
+
+
+def _get_production_project():
+ """Gets the production project if it can be inferred."""
+ return os.getenv(_PROJECT_ENV_VAR_NAME)
+
+
+def _determine_default_project(project=None):
+ """Determine default project ID explicitly or implicitly as fall-back.
+
+ In implicit case, currently only supports enviroment variable but will
+ support App Engine, Compute Engine and other environments in the future.
+
+ Local environment variable used is:
+ - GCLOUD_PROJECT
+
+ :type project: string
+ :param project: Optional. The project name to use as default.
+
+ :rtype: string or ``NoneType``
+ :returns: Default project if it can be determined.
+ """
+ if project is None:
+ project = _get_production_project()
+
+ return project
+
+
+def set_default_project(project=None):
+ """Set default project either explicitly or implicitly as fall-back.
+
+ :type project: string
+ :param project: Optional. The project name to use as default.
+
+ :raises: :class:`EnvironmentError` if no project was found.
+ """
+ project = _determine_default_project(project=project)
+ if project is not None:
+ _DEFAULTS.project = project
+ else:
+ raise EnvironmentError('No project could be inferred.')
+
+
 class _DefaultsContainer(object):
  """Container for defaults.
 
@@ -32,8 +81,16 @@ class _DefaultsContainer(object):
  :param connection: Persistent implied connection from environment.
  """
 
- def __init__(self, project=None, bucket=None, connection=None):
- self.project = project
+ @_lazy_property_deco
+ @staticmethod
+ def project():
+ """Return the implicit default project."""
+ return _determine_default_project()
+
+ def __init__(self, project=None, bucket=None, connection=None,
+ implicit=False):
+ if project is not None or not implicit:
+ self.project = project
  self.bucket = bucket
  self.connection = connection
 
@@ -65,4 +122,4 @@ def get_default_connection():
  return _DEFAULTS.connection
 
 
-_DEFAULTS = _DefaultsContainer()
+_DEFAULTS = _DefaultsContainer(implicit=True)

gcloud/storage/batch.py

@@ -25,7 +25,7 @@
 
 import six
 
-from gcloud._localstack import _LocalStack
+from gcloud._helpers import _LocalStack
 from gcloud.storage import _implicit_environ
 from gcloud.storage.connection import Connection
 

gcloud/storage/test___init__.py

@@ -135,73 +135,6 @@ def test_set_explicit_None_w_env_var_set(self):
  self.assertEqual(default_bucket.connection, CONNECTION)
 
 
-class Test_set_default_project(unittest2.TestCase):
-
- def setUp(self):
- from gcloud.storage._testing import _setup_defaults
- _setup_defaults(self)
-
- def tearDown(self):
- from gcloud.storage._testing import _tear_down_defaults
- _tear_down_defaults(self)
-
- def _callFUT(self, project=None):
- from gcloud.storage import set_default_project
- return set_default_project(project=project)
-
- def _monkey(self, implicit_project):
- import os
- from gcloud.storage import _PROJECT_ENV_VAR_NAME
- from gcloud._testing import _Monkey
- environ = {_PROJECT_ENV_VAR_NAME: implicit_project}
- return _Monkey(os, getenv=environ.get)
-
- def test_no_env_var_set(self):
- from gcloud.storage import _implicit_environ
- with self._monkey(None):
- self._callFUT()
- self.assertEqual(_implicit_environ.get_default_project(), None)
-
- def test_set_from_env_var(self):
- from gcloud.storage import _implicit_environ
- IMPLICIT_PROJECT = 'IMPLICIT'
- with self._monkey(IMPLICIT_PROJECT):
- self._callFUT()
- self.assertEqual(_implicit_environ.get_default_project(),
- IMPLICIT_PROJECT)
-
- def test_set_explicit_w_env_var_set(self):
- from gcloud.storage import _implicit_environ
- EXPLICIT_PROJECT = 'EXPLICIT'
- with self._monkey(None):
- self._callFUT(EXPLICIT_PROJECT)
- self.assertEqual(_implicit_environ.get_default_project(),
- EXPLICIT_PROJECT)
-
- def test_set_explicit_no_env_var_set(self):
- from gcloud.storage import _implicit_environ
- IMPLICIT_PROJECT = 'IMPLICIT'
- EXPLICIT_PROJECT = 'EXPLICIT'
- with self._monkey(IMPLICIT_PROJECT):
- self._callFUT(EXPLICIT_PROJECT)
- self.assertEqual(_implicit_environ.get_default_project(),
- EXPLICIT_PROJECT)
-
- def test_set_explicit_None_wo_env_var_set(self):
- from gcloud.storage import _implicit_environ
- with self._monkey(None):
- self._callFUT(None)
- self.assertEqual(_implicit_environ.get_default_project(), None)
-
- def test_set_explicit_None_w_env_var_set(self):
- from gcloud.storage import _implicit_environ
- IMPLICIT_PROJECT = 'IMPLICIT'
- with self._monkey(IMPLICIT_PROJECT):
- self._callFUT(None)
- self.assertEqual(_implicit_environ.get_default_project(),
- IMPLICIT_PROJECT)
-
-
 class Test_set_default_connection(unittest2.TestCase):
 
  def setUp(self):