text: # Copyright 2020 The Feast Authors
  #
  # 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
  #
  #     https://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 typing import Dict, Optional
  
  from feast.protos.feast.core.Feature_pb2 import FeatureSpecV2 as FeatureSpecProto
  from feast.protos.feast.types.Value_pb2 import ValueType as ValueTypeProto
  from feast.value_type import ValueType
  
  
  class Feature:
      """
      A Feature represents a class of serveable feature.
  
      Args:
          name: Name of the feature.
          dtype: The type of the feature, such as string or float.
          labels (optional): User-defined metadata in dictionary form.
      """
  
      def __init__(
          self, name: str, dtype: ValueType, labels: Optional[Dict[str, str]] = None,
      ):
          """Creates a Feature object."""
          self._name = name
          if not isinstance(dtype, ValueType):
              raise ValueError("dtype is not a valid ValueType")
          if dtype is ValueType.UNKNOWN:
              raise ValueError(f"dtype cannot be {dtype}")
          self._dtype = dtype
          if labels is None:
              self._labels = dict()
          else:
              self._labels = labels
  
      def __eq__(self, other):
          if self.name != other.name or self.dtype != other.dtype:
              return False
          return True
  
      def __lt__(self, other):
          return self.name < other.name
  
      def __repr__(self):
          # return string representation of the reference
          return f"{self.name}-{self.dtype}"
  
      def __str__(self):
          # readable string of the reference
          return f"Feature<{self.__repr__()}>"
  
      @property
      def name(self):
          """
          Gets the name of this feature.
          """
          return self._name
  
      @property
      def dtype(self) -> ValueType:
          """
          Gets the data type of this feature.
          """
          return self._dtype
  
      @property
      def labels(self) -> Dict[str, str]:
          """
          Gets the labels of this feature.
          """
          return self._labels
  
      def to_proto(self) -> FeatureSpecProto:
          """
          Converts Feature object to its Protocol Buffer representation.
  
          Returns:
              A FeatureSpecProto protobuf.
          """
          value_type = ValueTypeProto.Enum.Value(self.dtype.name)
  
          return FeatureSpecProto(
              name=self.name, value_type=value_type, labels=self.labels,
          )
  
      @classmethod
      def from_proto(cls, feature_proto: FeatureSpecProto):
          """
          Args:
              feature_proto: FeatureSpecV2 protobuf object
  
          Returns:
              Feature object
          """
          feature = cls(
              name=feature_proto.name,
              dtype=ValueType(feature_proto.value_type),
              labels=dict(feature_proto.labels),
          )
  
          return feature
  