DECKHAND-80: Validations API Implementation

The Validations API has been introduced to Deckhand, allowing users
to register new validation results in Deckhand, as well as query
the API for validation results for a revision. The validation results
include a list of errors that occurred during document validation.

All functional tests related to the API are now passing.

The following endpoints have been implemented:

   * /api/v1.0/revisions/{revision_id}/validations
   * /api/v1.0/revisions/{revision_id}/validations/{validation_name}
   * /api/v1.0/revisions/{revision_id}/validations/{validation_name}/entries
   * /api/v1.0/revisions/{revision_id}/validations/{validation_name}/entries/{entry_id}

Some back-end refactoring was needed to implement this API. In
particular:

  - Added a new Validation sqlalchemy DB model
  - Introduced DataSchema handling to the engine.document_validation
    module so that registered schema validations can be used
  - Changed the way the result of the 'deckhand-schema-validation' internal
    validation is generated: it is now the amalgamation of all the
    internal and registered schema validations executed
  - Introduced rawquery generation so that raw SQL queries can be used to
    get results from DB

Fixed following bug:

  - UniqueConstraint is now used to correctly generate unique constraints
    for sqlalchemy models that are supposed to be combinations of columns

Change-Id: I53c79a6544f44ef8beab2600ddc8a3ea91ada903

deckhand/policies/validation.py

@@ -0,0 +1,63 @@
+# Copyright 2017 AT&T Intellectual Property.  All other rights reserved.
+#
+# 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.
+
+from oslo_policy import policy
+
+from deckhand.policies import base
+
+
+validation_policies = [
+    policy.DocumentedRuleDefault(
+        base.POLICY_ROOT % 'create_validation',
+        base.RULE_ADMIN_API,
+        "Add the results of a validation for a particular revision.",
+        [
+            {
+                'method': 'POST',
+                'path': '/api/v1.0/revisions/{revision_id}/validations'
+            }
+        ]),
+    policy.DocumentedRuleDefault(
+        base.POLICY_ROOT % 'list_validations',
+        base.RULE_ADMIN_API,
+        """"List all validations that have been reported for a revision. Also
+lists the validation entries for a particular validation.""",
+        [
+            {
+                'method': 'GET',
+                'path': '/api/v1.0/revisions/{revision_id}/validations'
+            },
+            {
+                'method': 'GET',
+                'path': '/api/v1.0/revisions/{revision_id}/validations/'
+                        '{validation_name}'
+            }
+        ]),
+    policy.DocumentedRuleDefault(
+        base.POLICY_ROOT % 'show_validation',
+        base.RULE_ADMIN_API,
+        """Gets the full details of a particular validation entry, including
+all posted error details.""",
+        [
+            {
+                'method': 'GET',
+                'path': '/api/v1.0/revisions/{revision_id}/validations/'
+                        '{validation_name}/entries/{entry_id}'
+            }
+        ]),
+]
+
+
+def list_rules():
+    return validation_policies