Deckhand initial ORM implementation

This commit adds the initial implementation for the Deckhand ORM.
It is fashioned after Drydock's ORM, which in turn follows
OpenStack conventions.

This commit specifically:
  - creates the deckhand.objects package
  - includes base ORM classes
  - includes document ORM class which consists of the following
    fields:
      - blob: the document payload itself stored as an object
              that adheres to the bare minimum schema of
              schemaVersion, kind, metadata and data.
      - name: the name of the document, nullable
      - revision_index: the revision number for the document
      - status: the status of the document
  - includes basic fields for documents, i.e. what status
    the document is in

deckhand/objects/base.py

@@ -0,0 +1,85 @@
+# 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.
+
+import datetime
+
+from oslo_versionedobjects import base
+from oslo_versionedobjects import fields as obj_fields
+
+import Deckhand_provisioner.objects as objects
+
+
+class DeckhandObjectRegistry(base.VersionedObjectRegistry):
+
+    # Steal this from Cinder to bring all registered objects
+    # into the Deckhand_provisioner.objects namespace.
+    def registration_hook(self, cls, index):
+        setattr(objects, cls.obj_name(), cls)
+
+
+class DeckhandObject(base.VersionedObject):
+
+    # Version 1.0: Initial version
+    VERSION = '1.0'
+
+    OBJ_PROJECT_NAMESPACE = 'deckhand.objects'
+
+    def obj_load_attr(self, attrname):
+        if attrname in self.fields.keys():
+            setattr(self, attrname, None)
+        else:
+            raise ValueError("Unknown field %s." % (attrname))
+
+    def obj_to_simple(self):
+        """
+        Create a simple primitive representation of this object excluding
+        all the versioning stuff. Used to serialize an object for public
+        consumption, not intended to be deserialized by OVO.
+        """
+
+        primitive = dict()
+
+        primitive['model_type'] = self.__class__.__name__
+        primitive['model_version'] = self.VERSION
+
+        for name, field in self.fields.items():
+            if self.obj_attr_is_set(name):
+                value = getattr(self, name)
+                if (hasattr(value, 'obj_to_simple') and
+                    callable(value.obj_to_simple)):
+                    primitive[name] = value.obj_to_simple()
+                else:
+                    value = field.to_primitive(self, name, value)
+                    if value is not None:
+                        primitive[name] = value
+
+        return primitive
+
+
+class DeckhandPersistentObject(base.VersionedObject):
+
+    fields = {
+        'created_at': obj_fields.DateTimeField(nullable=False),
+        'created_by': obj_fields.StringField(nullable=False),
+        'updated_at': obj_fields.DateTimeField(nullable=True),
+        'updated_by': obj_fields.StringField(nullable=True),
+    }
+
+    def set_create_fields(self, context):
+        self.created_at = datetime.datetime.now()
+        self.created_by = context.user
+
+    def set_update_fields(self, context):
+        self.updated_at = datetime.datetime.now()
+        self.updated_by = context.user

deckhand/objects/document.py

@@ -0,0 +1,74 @@
+# 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.
+#
+# Models for drydock_provisioner
+#
+
+import oslo_versionedobjects.fields as ovo_fields
+
+import deckhand.objects as objects
+import deckhand.objects.base as base
+import deckhand.objects.fields as fields
+
+
+class DocumentPayload(base.NotificationPayloadBase):
+    SCHEMA = {
+        'schema_version': ('document', 'schema_version'),
+        'kind': ('document', 'uuid'),
+        'metadata': ('document', 'name'),
+        'data': ('document', 'hosts')
+    }
+
+    # Version 1.0: Initial version
+    VERSION = '1.0'
+
+    fields = {
+        'schema_version': fields.StringField(nullable=False),
+        'kind': fields.StringField(nullable=False),
+        'metadata': fields.DictOfStringsField(nullable=False),
+        'data': fields.DictOfStringsField(nullable=False)
+    }
+
+    def __init__(self, document):
+        super(DocumentPayload, self).__init__()
+        self.populate_schema(document=document)
+
+
+@base.DeckhandObjectRegistry.register
+class Document(base.DeckhandPersistentObject, base.DeckhandObject):
+
+    # Version 1.0: Initial version
+    VERSION = '1.0'
+
+    fields = {
+        'blob': ovo_fields.ObjectField('DocumentPayload', nullable=False),
+        'name': ovo_fields.StringField(nullable=True),
+        'revision_index': ovo_fields.NonNegativeIntegerField(nullable=False),
+        'status': fields.DocumentField(nullable=False)
+    }
+
+    def __init__(self, **kwargs):
+        super(Document, self).__init__(**kwargs)
+
+    @property
+    def name(self):
+        return self.name
+
+    @property
+    def revision(self):
+        return self.revision_index
+
+    @property
+    def status(self):
+        return self.status

deckhand/objects/fields.py

@@ -0,0 +1,33 @@
+# 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_versionedobjects import fields
+
+
+class BaseDeckhandEnum(fields.Enum):
+    def __init__(self):
+        super(BaseDeckhandEnum, self).__init__(valid_values=self.__class__.ALL)
+
+
+class DocumentField(BaseDeckhandEnum):
+
+    # A list of potentially valid statuses for a Document to have. This list 
+    # will evolve over time.
+    active = 'ACTIVE'
+    conflict_error = 'CONFLICT_ERROR'
+    merge_error = 'MERGE_ERROR'
+    substitute_error = 'SUBSTITUTE_ERROR'
+    warning = 'WARNING'
+
+    ALL = (active, conflict_error, merge_error, substitute_error, warning)