[GCP-5388] Storage: Blob.exists() does not work within Batch context

storage/google/cloud/storage/blob.py

@@ -56,6 +56,7 @@
 from google.cloud.storage._helpers import _scalar_property
 from google.cloud.storage._signing import generate_signed_url_v2
 from google.cloud.storage._signing import generate_signed_url_v4
+from google.cloud.storage.batch import _FutureDict
 from google.cloud.storage.acl import ACL
 from google.cloud.storage.acl import ObjectACL
 
@@ -466,18 +467,24 @@ def exists(self, client=None):
  query_params["fields"] = "name"
 
  try:
- # We intentionally pass `_target_object=None` since fields=name
- # would limit the local properties.
+ if client.current_batch is not None:
+ target = FutureBoolResult()
+ result = target
+ else:
+ # We intentionally pass `_target_object=None` since fields=name
+ # would limit the local properties.
+ target, result = None, True
+
  client._connection.api_request(
  method="GET",
  path=self.path,
  query_params=query_params,
- _target_object=None,
+ _target_object=target,
  )
  # NOTE: This will not fail immediately in a batch. However, when
  # Batch.finish() is called, the resulting `NotFound` will be
  # raised.
- return True
+ return result
  except NotFound:
  return False
 
@@ -2057,3 +2064,32 @@ def _add_query_parameters(base_url, name_value_pairs):
  query = parse_qsl(query)
  query.extend(name_value_pairs)
  return urlunsplit((scheme, netloc, path, urlencode(query), frag))
+
+
+class FutureBoolResult(object):
+ """Represents the result of future api request.
+
+ This can be used as a target object for the future request
+ (which is part of batch mechanism) to get result of this request.
+ """
+ _properties = {}
+
+ @property
+ def _is_successfull(self):
+ """Checks if binded future request have been completed without any exception."""
+ return not isinstance(self._properties, _FutureDict)
+
+ def __bool__(self):
+ return self._is_successfull
+
+ def __nonzero__(self):
+ return self._is_successfull
+
+ def __repr__(self):
+ return str(self._is_successfull)
+
+ def __eq__(self, other):
+ return self._is_successfull == other
+
+ def __ne__(self, other):
+ return self._is_successfull != other

storage/noxfile.py

@@ -134,7 +134,7 @@ def blacken(session):
  "tests",
  "docs",
  )
-
+
 @nox.session(python="3.7")
 def docs(session):
  """Build the docs for this library."""
@@ -154,4 +154,4 @@ def docs(session):
  os.path.join("docs", "_build", "doctrees", ""),
  os.path.join("docs", ""),
  os.path.join("docs", "_build", "html", ""),
- )
+ )

storage/tests/unit/test_blob.py

@@ -20,13 +20,45 @@
 import os
 import tempfile
 import unittest
+import requests
 
 import google.cloud.storage.blob
 import mock
 import six
 from six.moves import http_client
 
 
+def _make_response(status_code=http_client.OK, content=b"", headers={}):
+ response = requests.Response()
+ response.status_code = status_code
+ response._content = content
+ response.headers = headers
+ response.request = requests.Request()
+ return response
+
+
+def _make_connection():
+ from google.cloud.storage._http import Connection
+
+ mock_conn = mock.create_autospec(Connection)
+ mock_conn.user_agent = "testing 1.2.3"
+ mock_conn._make_request.return_value = _make_response(
+ status_code=200,
+ headers={
+ "content-type": "multipart/mixed; boundary=batch_pK7JBAk73-E=_AA5eFwv4m2Q=",
+ },
+ content=b"""
+--batch_pK7JBAk73-E=_AA5eFwv4m2Q=
+HTTP/1.1 404 NotFound
+
+--batch_pK7JBAk73-E=_AA5eFwv4m2Q=
+HTTP/1.1 200 OK
+
+--batch_pK7JBAk73-E=_AA5eFwv4m2Q=--"""
+ )
+ return mock_conn
+
+
 def _make_credentials():
  import google.auth.credentials
 
@@ -582,6 +614,30 @@ def test_exists_miss(self):
  },
  )
 
+ def test_exists_miss_within_batch(self):
+ from google.cloud.storage.client import Client
+ from google.cloud.exceptions import NotFound
+
+ client = Client(credentials=_make_credentials())
+ client._base_connection = _make_connection()
+
+ bucket = _Bucket(client)
+ blob1 = self._make_one("nonesuch1", bucket=bucket)
+ blob2 = self._make_one("nonesuch2", bucket=bucket)
+
+ try:
+ with client.batch():
+ bool1 = blob1.exists()
+ bool2 = blob2.exists()
+ except NotFound:
+ pass
+
+ self.assertFalse(bool1)
+ self.assertTrue(bool2)
+ self.assertEqual(str(bool1), 'False')
+ self.assertTrue(bool1 != True) # noqa: E712
+ self.assertTrue(bool1 == False) # noqa: E712
+
  def test_exists_hit_w_user_project(self):
  BLOB_NAME = "blob-name"
  USER_PROJECT = "user-project-123"
@@ -3311,6 +3367,7 @@ def delete_blob(self, blob_name, client=None, generation=None):
 class _Client(object):
  def __init__(self, connection):
  self._base_connection = connection
+ self.current_batch = None
 
  @property
  def _connection(self):