feat: Add Feast types in preparation for changing type system

sdk/python/feast/feature.py

@@ -15,7 +15,7 @@
 from typing import Dict, Optional
 
 from feast.protos.feast.core.Feature_pb2 import FeatureSpecV2 as FeatureSpecProto
-from feast.protos.feast.types import Value_pb2 as ValueTypeProto
+from feast.protos.feast.types.Value_pb2 import ValueType as ValueTypeProto
 from feast.value_type import ValueType
 
 
@@ -88,7 +88,7 @@ def to_proto(self) -> FeatureSpecProto:
         Returns:
             A FeatureSpecProto protobuf.
         """
-        value_type = ValueTypeProto.ValueType.Enum.Value(self.dtype.name)
+        value_type = ValueTypeProto.Enum.Value(self.dtype.name)
 
         return FeatureSpecProto(
             name=self.name, value_type=value_type, labels=self.labels,

sdk/python/feast/types.py

@@ -0,0 +1,117 @@
+# Copyright 2022 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 abc import ABC, abstractmethod
+from enum import Enum
+from typing import Union
+
+from feast.protos.feast.types.Value_pb2 import ValueType as ValueTypeProto
+
+PRIMITIVE_FEAST_TYPES_TO_VALUE_TYPES = {
+    "INVALID": "INVALID",
+    "STRING": "STRING",
+    "BYTES": "BYTES",
+    "BOOL": "BOOL",
+    "INT32": "INT32",
+    "INT64": "INT64",
+    "FLOAT32": "FLOAT",
+    "FLOAT64": "DOUBLE",
+    "UNIX_TIMESTAMP": "UNIX_TIMESTAMP",
+}
+
+
+class ComplexFeastType(ABC):
+    """
+    A ComplexFeastType represents a structured type that is recognized by Feast.
+    """
+
+    def __init__(self):
+        """Creates a ComplexFeastType object."""
+        pass
+
+    @abstractmethod
+    def to_int(self) -> int:
+        """
+        Converts a ComplexFeastType object to the appropriate int value corresponding to
+        the correct ValueTypeProto.Enum value.
+        """
+        raise NotImplementedError
+
+
+class PrimitiveFeastType(Enum):
+    """
+    A PrimitiveFeastType represents a primitive type in Feast.
+    """
+
+    INVALID = 0
+    BYTES = 1
+    STRING = 2
+    INT32 = 3
+    INT64 = 4
+    FLOAT32 = 5
+    FLOAT64 = 6
+    BOOL = 7
+    UNIX_TIMESTAMP = 8
+
+    def to_int(self) -> int:
+        value_type_name = PRIMITIVE_FEAST_TYPES_TO_VALUE_TYPES[self.name]
+        return ValueTypeProto.Enum.Value(value_type_name)
+
+
+Invalid = PrimitiveFeastType.INVALID
+Bytes = PrimitiveFeastType.BYTES
+String = PrimitiveFeastType.STRING
+Bool = PrimitiveFeastType.BOOL
+Int32 = PrimitiveFeastType.INT32
+Int64 = PrimitiveFeastType.INT64
+Float32 = PrimitiveFeastType.FLOAT32
+Float64 = PrimitiveFeastType.FLOAT64
+UnixTimestamp = PrimitiveFeastType.UNIX_TIMESTAMP
+
+
+SUPPORTED_BASE_TYPES = [
+    Invalid,
+    String,
+    Bytes,
+    Bool,
+    Int32,
+    Int64,
+    Float32,
+    Float64,
+    UnixTimestamp,
+]
+
+
+class Array(ComplexFeastType):
+    """
+    An Array represents a list of types.
+
+    Attributes:
+        base_type: The base type of the array.
+    """
+
+    base_type: Union[PrimitiveFeastType, ComplexFeastType]
+
+    def __init__(self, base_type: Union[PrimitiveFeastType, ComplexFeastType]):
+        if base_type not in SUPPORTED_BASE_TYPES:
+            raise ValueError(
+                f"Type {type(base_type)} is currently not supported as a base type for Array."
+            )
+
+        self.base_type = base_type
+
+    def to_int(self) -> int:
+        assert isinstance(self.base_type, PrimitiveFeastType)
+        value_type_name = PRIMITIVE_FEAST_TYPES_TO_VALUE_TYPES[self.base_type.name]
+        value_type_list_name = value_type_name + "_LIST"
+        return ValueTypeProto.Enum.Value(value_type_list_name)

sdk/python/tests/unit/test_types.py

@@ -0,0 +1,23 @@
+import pytest
+
+from feast.protos.feast.types.Value_pb2 import ValueType as ValueTypeProto
+from feast.types import Array, Float32, String
+
+
+def test_primitive_feast_type():
+    assert String.to_int() == ValueTypeProto.Enum.Value("STRING")
+    assert Float32.to_int() == ValueTypeProto.Enum.Value("FLOAT")
+
+
+def test_array_feast_type():
+    array_float_32 = Array(Float32)
+    assert array_float_32.to_int() == ValueTypeProto.Enum.Value("FLOAT_LIST")
+
+    array_string = Array(String)
+    assert array_string.to_int() == ValueTypeProto.Enum.Value("STRING_LIST")
+
+    with pytest.raises(ValueError):
+        _ = Array(Array)
+
+    with pytest.raises(ValueError):
+        _ = Array(Array(String))