import struct
from typing import List, Tuple
from feast.types.EntityKey_pb2 import EntityKey as EntityKeyProto
from feast.types.Value_pb2 import Value as ValueProto
from feast.types.Value_pb2 import ValueType
def _serialize_val(value_type, v: ValueProto) -> Tuple[bytes, int]:
if value_type == "string_val":
return v.string_val.encode("utf8"), ValueType.STRING
elif value_type == "bytes_val":
return v.bytes_val, ValueType.BYTES
elif value_type == "int32_val":
return struct.pack("<i", v.int32_val), ValueType.INT32
elif value_type == "int64_val":
return struct.pack("<l", v.int64_val), ValueType.INT64
else:
raise ValueError(f"Value type not supported for Firestore: {v}")
[docs]def serialize_entity_key(entity_key: EntityKeyProto) -> bytes:
"""
Serialize entity key to a bytestring so it can be used as a lookup key in a hash table.
We need this encoding to be stable; therefore we cannot just use protobuf serialization
here since it does not guarantee that two proto messages containing the same data will
serialize to the same byte string[1].
[1] https://developers.google.com/protocol-buffers/docs/encoding
"""
sorted_keys, sorted_values = zip(
*sorted(zip(entity_key.entity_names, entity_key.entity_values))
)
output: List[bytes] = []
for k in sorted_keys:
output.append(struct.pack("<I", ValueType.STRING))
output.append(k.encode("utf8"))
for v in sorted_values:
val_bytes, value_type = _serialize_val(v.WhichOneof("val"), v)
output.append(struct.pack("<I", value_type))
output.append(struct.pack("<I", len(val_bytes)))
output.append(val_bytes)
return b"".join(output)