Adding implicit connection fallback in Bucket.

Author: dhermes

gcloud/storage/__init__.py

@@ -51,6 +51,7 @@
 from gcloud.storage.api import get_all_buckets
 from gcloud.storage.api import get_bucket
 from gcloud.storage.api import lookup_bucket
+from gcloud.storage.batch import Batch
 from gcloud.storage.blob import Blob
 from gcloud.storage.bucket import Bucket
 from gcloud.storage.connection import Connection

gcloud/storage/batch.py

@@ -155,6 +155,11 @@ def finish(self):
         self._responses = list(_unpack_batch_response(response, content))
         return self._responses
 
+    @staticmethod
+    def current():
+        """Return the topmost batch, or None."""
+        return _BATCHES.top
+
     def __enter__(self):
         _BATCHES.push(self)
         return self

gcloud/storage/bucket.py

@@ -39,9 +39,11 @@
 from gcloud.exceptions import NotFound
 from gcloud.storage._helpers import _PropertyMixin
 from gcloud.storage._helpers import _scalar_property
+from gcloud.storage import _implicit_environ
 from gcloud.storage.acl import BucketACL
 from gcloud.storage.acl import DefaultObjectACL
 from gcloud.storage.iterator import Iterator
+from gcloud.storage.batch import Batch
 from gcloud.storage.blob import Blob
 
 
@@ -146,7 +148,7 @@ def connection(self):
         :rtype: :class:`gcloud.storage.connection.Connection`
         :returns: The connection to use.
         """
-        return self._connection
+        return _require_connection(self._connection)
 
     @staticmethod
     def path_helper(bucket_name):
@@ -746,3 +748,27 @@ def make_public(self, recursive=False, future=False):
             for blob in self:
                 blob.acl.all().grant_read()
                 blob.save_acl()
+
+
+def _require_connection(connection=None):
+    """Infer a connection from the environment, if not passed explicitly.
+
+    :type connection: :class:`gcloud.storage.connection.Connection`
+    :param connection: Optional.
+
+    :rtype: :class:`gcloud.storage.connection.Connection`
+    :returns: A connection based on the current environment.
+    :raises: :class:`EnvironmentError` if ``connection`` is ``None``, and
+             cannot be inferred from the environment.
+    """
+    # NOTE: We use current Batch directly since it inherits from Connection.
+    if connection is None:
+        connection = Batch.current()
+
+    if connection is None:
+        connection = _implicit_environ.get_default_connection()
+
+    if connection is None:
+        raise EnvironmentError('Connection could not be inferred.')
+
+    return connection

gcloud/storage/test_bucket.py

@@ -71,7 +71,7 @@ def _makeOne(self, *args, **kw):
 
     def test_ctor_defaults(self):
         bucket = self._makeOne()
-        self.assertEqual(bucket.connection, None)
+        self.assertEqual(bucket._connection, None)
         self.assertEqual(bucket.name, None)
         self.assertEqual(bucket._properties, {})
         self.assertTrue(bucket._acl is None)
@@ -1068,6 +1068,44 @@ def get_items_from_response(self, response):
         self.assertEqual(kw[1]['query_params'], {})
 
 
+class Test__require_connection(unittest2.TestCase):
+
+    def _callFUT(self, connection=None):
+        from gcloud.storage.bucket import _require_connection
+        return _require_connection(connection=connection)
+
+    def _monkey(self, connection):
+        from gcloud.storage._testing import _monkey_defaults
+        return _monkey_defaults(connection=connection)
+
+    def test_implicit_unset(self):
+        with self._monkey(None):
+            with self.assertRaises(EnvironmentError):
+                self._callFUT()
+
+    def test_implicit_unset_w_existing_batch(self):
+        CONNECTION = object()
+        with self._monkey(None):
+            with _NoCommitBatch(connection=CONNECTION):
+                self.assertEqual(self._callFUT(), CONNECTION)
+
+    def test_implicit_unset_passed_explicitly(self):
+        CONNECTION = object()
+        with self._monkey(None):
+            self.assertTrue(self._callFUT(CONNECTION) is CONNECTION)
+
+    def test_implicit_set(self):
+        IMPLICIT_CONNECTION = object()
+        with self._monkey(IMPLICIT_CONNECTION):
+            self.assertTrue(self._callFUT() is IMPLICIT_CONNECTION)
+
+    def test_implicit_set_passed_explicitly(self):
+        IMPLICIT_CONNECTION = object()
+        CONNECTION = object()
+        with self._monkey(IMPLICIT_CONNECTION):
+            self.assertTrue(self._callFUT(CONNECTION) is CONNECTION)
+
+
 class _Connection(object):
     _delete_bucket = False
 
@@ -1118,3 +1156,18 @@ class MockFile(io.StringIO):
     def __init__(self, name, buffer_=None):
         super(MockFile, self).__init__(buffer_)
         self.name = name
+
+
+class _NoCommitBatch(object):
+
+    def __init__(self, connection):
+        self._connection = connection
+
+    def __enter__(self):
+        from gcloud.storage.batch import _BATCHES
+        _BATCHES.push(self._connection)
+        return self._connection
+
+    def __exit__(self, *args):
+        from gcloud.storage.batch import _BATCHES
+        _BATCHES.pop()

regression/storage.py

@@ -22,7 +22,6 @@
 from gcloud import storage
 from gcloud import _helpers
 from gcloud.storage._helpers import _base64_md5hash
-from gcloud.storage.batch import Batch
 
 
 HTTP = httplib2.Http()
@@ -52,7 +51,7 @@ def setUp(self):
         self.case_buckets_to_delete = []
 
     def tearDown(self):
-        with Batch() as batch:
+        with storage.Batch() as batch:
             for bucket_name in self.case_buckets_to_delete:
                 storage.Bucket(bucket_name, connection=batch).delete()