Continue FeatureService and FeatureViewProjection cleanup

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

sdk/python/feast/feature_service.py

@@ -11,8 +11,10 @@
     FeatureService as FeatureServiceProto,
 )
 from feast.protos.feast.core.FeatureService_pb2 import (
-    FeatureServiceMeta,
-    FeatureServiceSpec,
+    FeatureServiceMeta as FeatureServiceMetaProto,
+)
+from feast.protos.feast.core.FeatureService_pb2 import (
+    FeatureServiceSpec as FeatureServiceSpecProto,
 )
 from feast.usage import log_exceptions
 
@@ -28,7 +30,8 @@ class FeatureService:
             projections, representing the features in the feature service.
         description: A human-readable description.
         tags: A dictionary of key-value pairs to store arbitrary metadata.
-        owner: The owner of the feature service.
+        owner: The owner of the feature service, typically the email of the primary
+            maintainer.
         created_timestamp: The time when the feature service was created.
         last_updated_timestamp: The time when the feature service was last updated.
     """
@@ -163,15 +166,15 @@ def last_updated_timestamp(self) -> Optional[datetime]:
     def last_updated_timestamp(self, last_updated_timestamp: datetime):
         self._last_updated_timestamp = last_updated_timestamp
 
-    @staticmethod
-    def from_proto(feature_service_proto: FeatureServiceProto):
+    @classmethod
+    def from_proto(cls, feature_service_proto: FeatureServiceProto):
         """
         Converts a FeatureServiceProto to a FeatureService object.
 
         Args:
             feature_service_proto: A protobuf representation of a FeatureService.
         """
-        fs = FeatureService(
+        fs = cls(
             name=feature_service_proto.spec.name,
             features=[],
             tags=dict(feature_service_proto.spec.tags),
@@ -203,13 +206,13 @@ def to_proto(self) -> FeatureServiceProto:
         Returns:
             A FeatureServiceProto protobuf.
         """
-        meta = FeatureServiceMeta()
+        meta = FeatureServiceMetaProto()
         if self.created_timestamp:
             meta.created_timestamp.FromDatetime(self.created_timestamp)
         if self.last_updated_timestamp:
             meta.last_updated_timestamp.FromDatetime(self.last_updated_timestamp)
 
-        spec = FeatureServiceSpec(
+        spec = FeatureServiceSpecProto(
             name=self.name,
             features=[
                 projection.to_proto() for projection in self.feature_view_projections

sdk/python/feast/feature_view_projection.py

@@ -1,4 +1,4 @@
-from typing import Dict, List
+from typing import Dict, List, Optional
 
 from attr import dataclass
 
@@ -11,19 +11,20 @@
 @dataclass
 class FeatureViewProjection:
     """
-    A feature view projection represents a set of features from a single feature view.
+    A feature view projection represents a selection of one or more features from a
+    single feature view.
 
     Attributes:
-        name: The unique name of the feature view projection.
+        name: The unique name of the feature view from which this projection is created.
         name_alias: An optional alias for the name.
         features: The list of features represented by the feature view projection.
         join_key_map: A map to modify join key columns during retrieval of this feature
             view projection.
     """
 
     name: str
-    name_alias: str = ""
-    features: List[Feature] = []
+    name_alias: Optional[str]
+    features: List[Feature]
     join_key_map: Dict[str, str] = {}
 
     def name_to_use(self):
@@ -32,7 +33,7 @@ def name_to_use(self):
     def to_proto(self) -> FeatureViewProjectionProto:
         feature_reference_proto = FeatureViewProjectionProto(
             feature_view_name=self.name,
-            feature_view_name_alias=self.name_alias,
+            feature_view_name_alias=self.name_alias or "",
             join_key_map=self.join_key_map,
         )
         for feature in self.features:
@@ -56,5 +57,7 @@ def from_proto(proto: FeatureViewProjectionProto):
     @staticmethod
     def from_definition(feature_grouping):
         return FeatureViewProjection(
-            name=feature_grouping.name, features=feature_grouping.features,
+            name=feature_grouping.name,
+            name_alias=None,
+            features=feature_grouping.features,
         )