Using ancestor queries for strong consistency.

Integrates changes from googleapis/google-cloud-node#267

regression/data/index.yaml

@@ -1,11 +1,23 @@
 indexes:
 
 - kind: Character
+  ancestor: yes
+  properties:
+  - name: appearances
+
+- kind: Character
+  ancestor: yes
+  properties:
+  - name: alive
+
+- kind: Character
+  ancestor: yes
   properties:
   - name: family
   - name: appearances
 
 - kind: Character
+  ancestor: yes
   properties:
   - name: name
   - name: family

regression/datastore.py

@@ -5,7 +5,7 @@
 from gcloud import datastore
 # This assumes the command is being run via tox hence the
 # repository root is the current directory.
-from regression.populate_datastore import CHARACTERS
+from regression import populate_datastore
 from regression import regression_utils
 
 
@@ -115,11 +115,16 @@ class TestDatastoreQuery(TestDatastore):
     @classmethod
     def setUpClass(cls):
         super(TestDatastoreQuery, cls).setUpClass()
-        cls.CHARACTERS = CHARACTERS
+        cls.CHARACTERS = populate_datastore.CHARACTERS
+        cls.ANCESTOR_KEY = datastore.key.Key(
+            path=[populate_datastore.ANCESTOR])
+
+    def _base_query(self):
+        return self.dataset.query('Character').ancestor(self.ANCESTOR_KEY)
 
     def test_limit_queries(self):
         limit = 5
-        query = self.dataset.query('Character').limit(limit)
+        query = self._base_query().limit(limit)
         # Verify there is not cursor before fetch().
         self.assertRaises(RuntimeError, query.cursor)
 
@@ -132,49 +137,46 @@ def test_limit_queries(self):
         self.assertTrue(cursor is not None)
 
         # Fetch next batch of characters.
-        new_query = self.dataset.query('Character').with_cursor(cursor)
+        new_query = self._base_query().with_cursor(cursor)
         new_character_entities = new_query.fetch()
         characters_remaining = len(self.CHARACTERS) - limit
         self.assertEqual(len(new_character_entities), characters_remaining)
 
     def test_query_simple_filter(self):
-        query = self.dataset.query('Character')
-        query = query.filter('appearances >=', 20)
+        query = self._base_query().filter('appearances >=', 20)
         expected_matches = 6
         # We expect 6, but allow the query to get 1 extra.
         entities = query.fetch(limit=expected_matches + 1)
         self.assertEqual(len(entities), expected_matches)
 
     def test_query_multiple_filters(self):
-        query = self.dataset.query('Character')
-        query = query.filter('appearances >=', 26).filter('family =', 'Stark')
+        query = self._base_query().filter(
+            'appearances >=', 26).filter('family =', 'Stark')
         expected_matches = 4
         # We expect 4, but allow the query to get 1 extra.
         entities = query.fetch(limit=expected_matches + 1)
         self.assertEqual(len(entities), expected_matches)
 
     def test_ancestor_query(self):
-        query = self.dataset.query('Character')
-        filtered_query = query.ancestor(['Character', 'Eddard'])
+        filtered_query = self._base_query()
 
-        expected_matches = 5
-        # We expect 5, but allow the query to get 1 extra.
+        expected_matches = 8
+        # We expect 8, but allow the query to get 1 extra.
         entities = filtered_query.fetch(limit=expected_matches + 1)
         self.assertEqual(len(entities), expected_matches)
 
     def test_query___key___filter(self):
         rickard_key = datastore.key.Key(
-            path=[{'kind': 'Character', 'name': 'Rickard'}])
+            path=[populate_datastore.ANCESTOR, populate_datastore.RICKARD])
 
-        query = self.dataset.query('Character').filter(
-            '__key__ =', rickard_key)
+        query = self._base_query().filter('__key__ =', rickard_key)
         expected_matches = 1
         # We expect 1, but allow the query to get 1 extra.
         entities = query.fetch(limit=expected_matches + 1)
         self.assertEqual(len(entities), expected_matches)
 
     def test_ordered_query(self):
-        query = self.dataset.query('Character').order('appearances')
+        query = self._base_query().order('appearances')
         expected_matches = 8
         # We expect 8, but allow the query to get 1 extra.
         entities = query.fetch(limit=expected_matches + 1)
@@ -185,8 +187,7 @@ def test_ordered_query(self):
         self.assertEqual(entities[7]['name'], self.CHARACTERS[3]['name'])
 
     def test_projection_query(self):
-        query = self.dataset.query('Character')
-        filtered_query = query.projection(['name', 'family'])
+        filtered_query = self._base_query().projection(['name', 'family'])
 
         # NOTE: There are 9 responses because of Catelyn. She has both
         #       Stark and Tully as her families, hence occurs twice in
@@ -220,7 +221,7 @@ def test_projection_query(self):
         self.assertEqual(sansa_dict, {'name': 'Sansa', 'family': 'Stark'})
 
     def test_query_paginate_with_offset(self):
-        query = self.dataset.query('Character')
+        query = self._base_query()
         offset = 2
         limit = 3
         page_query = query.offset(offset).limit(limit).order('appearances')
@@ -246,7 +247,7 @@ def test_query_paginate_with_offset(self):
         self.assertEqual(entities[2]['name'], 'Arya')
 
     def test_query_paginate_with_start_cursor(self):
-        query = self.dataset.query('Character')
+        query = self._base_query()
         offset = 2
         limit = 2
         page_query = query.offset(offset).limit(limit).order('appearances')
@@ -259,7 +260,7 @@ def test_query_paginate_with_start_cursor(self):
 
         # Use cursor to create a fresh query.
         cursor = page_query.cursor()
-        fresh_query = self.dataset.query('Character')
+        fresh_query = self._base_query()
         fresh_query = fresh_query.order('appearances').with_cursor(cursor)
 
         new_entities = fresh_query.fetch()
@@ -269,7 +270,7 @@ def test_query_paginate_with_start_cursor(self):
         self.assertEqual(new_entities[3]['name'], 'Arya')
 
     def test_query_group_by(self):
-        query = self.dataset.query('Character').group_by(['alive'])
+        query = self._base_query().group_by(['alive'])
 
         expected_matches = 2
         # We expect 2, but allow the query to get 1 extra.

regression/populate_datastore.py

@@ -7,20 +7,23 @@
 from regression import regression_utils
 
 
+ANCESTOR = {'kind': 'Book', 'name': 'GoT'}
+RICKARD = {'kind': 'Character', 'name': 'Rickard'}
+EDDARD = {'kind': 'Character', 'name': 'Eddard'}
 KEY_PATHS = [
-    [{'kind': 'Character', 'name': 'Rickard'}],
-    [{'kind': 'Character', 'name': 'Rickard'},
-     {'kind': 'Character', 'name': 'Eddard'}],
-    [{'kind': 'Character', 'name': 'Catelyn'}],
-    [{'kind': 'Character', 'name': 'Eddard'},
+    [ANCESTOR, RICKARD],
+    [ANCESTOR, RICKARD, EDDARD],
+    [ANCESTOR,
+     {'kind': 'Character', 'name': 'Catelyn'}],
+    [ANCESTOR, RICKARD, EDDARD,
      {'kind': 'Character', 'name': 'Arya'}],
-    [{'kind': 'Character', 'name': 'Eddard'},
+    [ANCESTOR, RICKARD, EDDARD,
      {'kind': 'Character', 'name': 'Sansa'}],
-    [{'kind': 'Character', 'name': 'Eddard'},
+    [ANCESTOR, RICKARD, EDDARD,
      {'kind': 'Character', 'name': 'Robb'}],
-    [{'kind': 'Character', 'name': 'Eddard'},
+    [ANCESTOR, RICKARD, EDDARD,
      {'kind': 'Character', 'name': 'Bran'}],
-    [{'kind': 'Character', 'name': 'Eddard'},
+    [ANCESTOR, RICKARD, EDDARD,
      {'kind': 'Character', 'name': 'Jon Snow'}],
 ]
 CHARACTERS = [