Hierarchy removed from level values

We don't need to have duplicate of levels hierarchy in the
level values. Without duplication we can easy change hierarchy
levels in the environment.
Cascade deletion added on level deletion to level values.

Change-Id: I9aded18c93b8c3f0f08e59817d33e7d21ff12d54

tuning_box/db.py

@@ -185,20 +185,15 @@ class EnvironmentHierarchyLevel(ModelMixin, db.Model):
 
 
 class EnvironmentHierarchyLevelValue(ModelMixin, db.Model):
-    level_id = fk(EnvironmentHierarchyLevel)
+    level_id = fk(EnvironmentHierarchyLevel, ondelete='CASCADE')
     level = db.relationship(EnvironmentHierarchyLevel)
     value = db.Column(db.String(128))
 
-    @sa_decl.declared_attr
-    def parent_id(cls):
-        return db.Column(pk_type, db.ForeignKey(cls.id))
+    __table_args__ = (
+        db.UniqueConstraint('level_id', 'value'),
+    )
 
-    @sa_decl.declared_attr
-    def parent(cls):
-        return db.relationship(cls, remote_side=cls.id)
-
-    # TODO(yorik-sar): add UniqueConstraint for all fields
-    __repr_attrs__ = ('id', 'level', 'parent', 'value')
+    __repr_attrs__ = ('id', 'level', 'value')
 
 
 class ResourceValues(ModelMixin, db.Model):

tuning_box/library/levels_hierarchy.py

@@ -18,7 +18,6 @@ from tuning_box import db
 def iter_environment_level_values(environment, levels):
     env_levels = db.EnvironmentHierarchyLevel.get_for_environment(environment)
     level_pairs = zip(env_levels, levels)
-    parent_level_value = None
     for env_level, (level_name, level_value) in level_pairs:
         if env_level.name != level_name:
             raise werkzeug.exceptions.BadRequest(
@@ -27,11 +26,9 @@ def iter_environment_level_values(environment, levels):
         level_value_db = db.get_or_create(
             db.EnvironmentHierarchyLevelValue,
             level=env_level,
-            parent=parent_level_value,
             value=level_value,
         )
         yield level_value_db
-        parent_level_value = level_value_db
 
 
 def get_environment_level_value(environment, levels):

tuning_box/migrations/versions/a86472389a70_remove_hierarchy_for_level_values.py

@@ -0,0 +1,78 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+"""Remove hierarchy for level values
+
+Revision ID: a86472389a70
+Revises: 0c586adad733
+Create Date: 2016-08-18 14:00:03.197693
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'a86472389a70'
+down_revision = '0c586adad733'
+branch_labels = None
+depends_on = None
+
+from alembic import context
+from alembic import op
+import sqlalchemy as sa
+
+
+def upgrade():
+    table_prefix = context.config.get_main_option('table_prefix')
+    table_name = table_prefix + 'environment_hierarchy_level_value'
+    with op.batch_alter_table(table_name) as batch:
+        batch.drop_column('parent_id')
+
+        batch.drop_constraint(
+            table_name + '_level_id_fkey',
+            type_='foreignkey'
+        )
+        batch.create_foreign_key(
+            table_name + '_level_id_fkey',
+            table_prefix + 'environment_hierarchy_level',
+            ['level_id'], ['id'], ondelete='CASCADE'
+        )
+
+        batch.create_unique_constraint(
+            table_name + '_level_id_value_unique',
+            ['level_id', 'value']
+        )
+
+
+def downgrade():
+    table_prefix = context.config.get_main_option('table_prefix')
+    table_name = table_prefix + 'environment_hierarchy_level_value'
+    with op.batch_alter_table(table_name) as batch:
+        batch.drop_constraint(
+            table_name + '_level_id_value_unique',
+            type_='unique'
+        )
+
+        batch.drop_constraint(
+            table_name + '_level_id_fkey',
+            type_='foreignkey'
+        )
+        batch.create_foreign_key(
+            table_name + '_level_id_fkey',
+            table_prefix + 'environment_hierarchy_level',
+            ['level_id'], ['id']
+        )
+
+        batch.add_column(sa.Column('parent_id', sa.Integer(), nullable=True))
+        batch.create_foreign_key(
+            table_name + '_parent_id_fkey',
+            table_name,
+            ['parent_id'], ['id']
+        )

tuning_box/tests/library/test_levels_hierarchy.py

@@ -38,11 +38,10 @@ class TestLevelsHierarchy(BaseTest):
             self.assertIsNotNone(level_value)
             self.assertEqual(level_value.level.name, 'lvl2')
             self.assertEqual(level_value.value, 'val2')
-            level_value = level_value.parent
-            self.assertIsNotNone(level_value)
-            self.assertEqual(level_value.level.name, 'lvl1')
-            self.assertEqual(level_value.value, 'val1')
-            self.assertIsNone(level_value.parent)
+            level = level_value.level.parent
+            self.assertIsNotNone(level)
+            self.assertEqual(level.name, 'lvl1')
+            self.assertIsNone(level.parent)
 
     def test_get_environment_level_value_bad_level(self):
         self._fixture()

tuning_box/tests/library/test_resource_overrides.py

@@ -51,11 +51,10 @@ class TestResourceOverrides(BaseTest):
             self.assertIsNotNone(level_value)
             self.assertEqual(level_value.level.name, 'lvl2')
             self.assertEqual(level_value.value, 'val2')
-            level_value = level_value.parent
-            self.assertIsNotNone(level_value)
-            self.assertEqual(level_value.level.name, 'lvl1')
-            self.assertEqual(level_value.value, 'val1')
-            self.assertIsNone(level_value.parent)
+            level = level_value.level.parent
+            self.assertIsNotNone(level)
+            self.assertEqual(level.name, 'lvl1')
+            self.assertIsNone(level.parent)
 
     def test_get_resource_values_local_override(self):
         self._fixture()

tuning_box/tests/library/test_resource_values.py

@@ -50,10 +50,10 @@ class TestResourceValues(BaseTest):
             level_value = resource_values.level_value
             self.assertEqual(level_value.level.name, 'lvl2')
             self.assertEqual(level_value.value, 'val2')
-            level_value = level_value.parent
-            self.assertEqual(level_value.level.name, 'lvl1')
-            self.assertEqual(level_value.value, 'val1')
-            self.assertIsNone(level_value.parent)
+            level = level_value.level.parent
+            self.assertIsNotNone(level)
+            self.assertEqual(level.name, 'lvl1')
+            self.assertIsNone(level.parent)
 
     def test_put_resource_values_bad_level(self):
         self._fixture()