fix: Convert uuid.UUID to string for Arrow and JSON serialization

Signed-off-by: soojin <soojin@dable.io>

Author: soooojinlee

sdk/python/feast/infra/online_stores/remote.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 import json
 import logging
+import uuid as uuid_module
 from collections import defaultdict
 from datetime import datetime
 from typing import Any, Callable, Dict, List, Literal, Optional, Sequence, Tuple
@@ -38,6 +39,15 @@
 logger = logging.getLogger(__name__)
 
 
+def _json_safe(val: Any) -> Any:
+    """Convert uuid.UUID objects to strings for JSON serialization."""
+    if isinstance(val, uuid_module.UUID):
+        return str(val)
+    if isinstance(val, list):
+        return [str(v) if isinstance(v, uuid_module.UUID) else v for v in val]
+    return val
+
+
 class RemoteOnlineStoreConfig(FeastConfigBaseModel):
     """Remote Online store config for remote online store"""
 
@@ -93,15 +103,13 @@ def online_write_batch(
             for join_key, entity_value_proto in zip(
                 entity_key_proto.join_keys, entity_key_proto.entity_values
             ):
-                columnar_data[join_key].append(
-                    feast_value_type_to_python_type(entity_value_proto)
-                )
+                val = feast_value_type_to_python_type(entity_value_proto)
+                columnar_data[join_key].append(_json_safe(val))
 
             # Populate feature values
             for feature_name, feature_value_proto in feature_values_proto.items():
-                columnar_data[feature_name].append(
-                    feast_value_type_to_python_type(feature_value_proto)
-                )
+                val = feast_value_type_to_python_type(feature_value_proto)
+                columnar_data[feature_name].append(_json_safe(val))
 
             # Populate timestamps
             columnar_data["event_timestamp"].append(_to_naive_utc(event_ts).isoformat())

sdk/python/feast/online_response.py

@@ -103,8 +103,26 @@ def to_arrow(self, include_event_timestamps: bool = False) -> pa.Table:
         Args:
         include_event_timestamps: bool Optionally include feature timestamps in the table
         """
+        import uuid as uuid_module
 
-        return pa.Table.from_pydict(self.to_dict(include_event_timestamps))
+        result = self.to_dict(include_event_timestamps)
+        # Convert uuid.UUID objects to strings for PyArrow compatibility
+        for key, values in result.items():
+            first_valid = next((v for v in values if v is not None), None)
+            if isinstance(first_valid, uuid_module.UUID):
+                result[key] = [
+                    str(v) if isinstance(v, uuid_module.UUID) else v for v in values
+                ]
+            elif isinstance(first_valid, list):
+                inner = next((e for e in first_valid if e is not None), None)
+                if isinstance(inner, uuid_module.UUID):
+                    result[key] = [
+                        [str(e) if isinstance(e, uuid_module.UUID) else e for e in v]
+                        if isinstance(v, list)
+                        else v
+                        for v in values
+                    ]
+        return pa.Table.from_pydict(result)
 
     def to_tensor(
         self,