[FSTORE-1640] Delta delta streamer repeatable reads (#432)

Author: bubriks

utils/python/hsfs_utils.py

@@ -269,15 +269,13 @@ def offline_fg_materialization(
 
     read_options = engine.get_instance()._get_kafka_config(entity.feature_store_id, {})
 
-    # get offsets
+    # get starting offsets
     offset_location = entity.prepare_spark_location() + "/kafka_offsets"
     try:
         if initial_check_point_string:
-            offset_string = json.dumps(
-                _build_starting_offsets(initial_check_point_string)
-            )
+            starting_offset_string = json.dumps(_build_offsets(initial_check_point_string))
         else:
-            offset_string = spark.read.json(offset_location).toJSON().first()
+            starting_offset_string = spark.read.json(offset_location).toJSON().first()
     except Exception as e:
         print(f"An unexpected error occurred: {e}")
         # if all else fails read from the beggining
@@ -286,15 +284,26 @@ def offline_fg_materialization(
             offline_write_options={},
             high=False,
         )
-        offset_string = json.dumps(_build_starting_offsets(initial_check_point_string))
-    print(f"startingOffsets: {offset_string}")
+        starting_offset_string = json.dumps(_build_offsets(initial_check_point_string))
+    print(f"startingOffsets: {starting_offset_string}")
+
+    # get ending offsets
+    ending_offset_string = kafka_engine.kafka_get_offsets(
+        topic_name=entity._online_topic_name,
+        feature_store_id=entity.feature_store_id,
+        offline_write_options={},
+        high=True,
+    )
+    ending_offset_string = json.dumps(_build_offsets(ending_offset_string))
+    print(f"endingOffsets: {ending_offset_string}")
 
     # read kafka topic
     df = (
         spark.read.format("kafka")
         .options(**read_options)
         .option("subscribe", entity._online_topic_name)
-        .option("startingOffsets", offset_string)
+        .option("startingOffsets", starting_offset_string)
+        .option("endingOffsets", ending_offset_string)
         .option("includeHeaders", "true")
         .option("failOnDataLoss", "false")
         .load()
@@ -326,8 +335,8 @@ def offline_fg_materialization(
     entity.insert(deserialized_df, storage="offline")
 
     # update offsets
-    df_offsets = (df if limit > filtered_df.count() else filtered_df).groupBy("partition").agg(max("offset").alias("offset")).collect()
-    offset_dict = json.loads(offset_string)
+    df_offsets = (df if limit > filtered_df.count() else filtered_df).groupBy('partition').agg(max('offset').alias('offset')).collect()
+    offset_dict = json.loads(starting_offset_string)
     for offset_row in df_offsets:
         offset_dict[entity._online_topic_name][f"{offset_row.partition}"] = (
             offset_row.offset + 1
@@ -350,8 +359,7 @@ def update_table_schema_fg(spark: SparkSession, job_conf: Dict[Any, Any]) -> Non
     entity.stream = False
     engine.get_instance().update_table_schema(entity)
 
-
-def _build_starting_offsets(initial_check_point_string: str):
+def _build_offsets(initial_check_point_string: str):
     if not initial_check_point_string:
         return ""