feat: Add column reordering to write_to_offline_store (feast-dev#2876)

* Add feature extraction logic to batch writer

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Enable StreamProcessor to write to both online and offline stores

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Fix incorrect columns error message

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Reorder columns in _write_to_offline_store

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Make _write_to_offline_store a public method

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Import FeatureStore correctly

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Remove defaults for `processing_time` and `query_timeout`

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Clean up `test_offline_write.py`

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Do not do any custom logic for double underscore columns

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Lint

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

* Switch entity values for all tests using push sources to not affect other tests

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

sdk/python/feast/feature_store.py

@@ -1383,7 +1383,7 @@ def push(
                     fv.name, df, allow_registry_cache=allow_registry_cache
                 )
             if to == PushMode.OFFLINE or to == PushMode.ONLINE_AND_OFFLINE:
-                self._write_to_offline_store(
+                self.write_to_offline_store(
                     fv.name, df, allow_registry_cache=allow_registry_cache
                 )
 
@@ -1415,14 +1415,18 @@ def write_to_online_store(
         provider.ingest_df(feature_view, entities, df)
 
     @log_exceptions_and_usage
-    def _write_to_offline_store(
+    def write_to_offline_store(
         self,
         feature_view_name: str,
         df: pd.DataFrame,
         allow_registry_cache: bool = True,
+        reorder_columns: bool = True,
     ):
         """
-        ingests data directly into the Online store
+        Persists the dataframe directly into the batch data source for the given feature view.
+
+        Fails if the dataframe columns do not match the columns of the batch data source. Optionally
+        reorders the columns of the dataframe to match.
         """
         # TODO: restrict this to work with online StreamFeatureViews and validate the FeatureView type
         try:
@@ -1433,7 +1437,21 @@ def _write_to_offline_store(
             feature_view = self.get_feature_view(
                 feature_view_name, allow_registry_cache=allow_registry_cache
             )
-        df.reset_index(drop=True)
+
+        # Get columns of the batch source and the input dataframe.
+        column_names_and_types = feature_view.batch_source.get_table_column_names_and_types(
+            self.config
+        )
+        source_columns = [column for column, _ in column_names_and_types]
+        input_columns = df.columns.values.tolist()
+
+        if set(input_columns) != set(source_columns):
+            raise ValueError(
+                f"The input dataframe has columns {set(input_columns)} but the batch source has columns {set(source_columns)}."
+            )
+
+        if reorder_columns:
+            df = df.reindex(columns=source_columns)
 
         table = pa.Table.from_pandas(df)
         provider = self._get_provider()

sdk/python/feast/infra/contrib/spark_kafka_processor.py

@@ -1,12 +1,14 @@
 from types import MethodType
-from typing import List
+from typing import List, Optional
 
+import pandas as pd
 from pyspark.sql import DataFrame, SparkSession
 from pyspark.sql.avro.functions import from_avro
 from pyspark.sql.functions import col, from_json
 
 from feast.data_format import AvroFormat, JsonFormat
-from feast.data_source import KafkaSource
+from feast.data_source import KafkaSource, PushMode
+from feast.feature_store import FeatureStore
 from feast.infra.contrib.stream_processor import (
     ProcessorConfig,
     StreamProcessor,
@@ -24,16 +26,16 @@ class SparkProcessorConfig(ProcessorConfig):
 class SparkKafkaProcessor(StreamProcessor):
     spark: SparkSession
     format: str
-    write_function: MethodType
+    preprocess_fn: Optional[MethodType]
     join_keys: List[str]
 
     def __init__(
         self,
+        *,
+        fs: FeatureStore,
         sfv: StreamFeatureView,
         config: ProcessorConfig,
-        write_function: MethodType,
-        processing_time: str = "30 seconds",
-        query_timeout: int = 15,
+        preprocess_fn: Optional[MethodType] = None,
     ):
         if not isinstance(sfv.stream_source, KafkaSource):
             raise ValueError("data source is not kafka source")
@@ -55,15 +57,16 @@ def __init__(
         if not isinstance(config, SparkProcessorConfig):
             raise ValueError("config is not spark processor config")
         self.spark = config.spark_session
-        self.write_function = write_function
-        self.processing_time = processing_time
-        self.query_timeout = query_timeout
-        super().__init__(sfv=sfv, data_source=sfv.stream_source)
+        self.preprocess_fn = preprocess_fn
+        self.processing_time = config.processing_time
+        self.query_timeout = config.query_timeout
+        self.join_keys = [fs.get_entity(entity).join_key for entity in sfv.entities]
+        super().__init__(fs=fs, sfv=sfv, data_source=sfv.stream_source)
 
-    def ingest_stream_feature_view(self) -> None:
+    def ingest_stream_feature_view(self, to: PushMode = PushMode.ONLINE) -> None:
         ingested_stream_df = self._ingest_stream_data()
         transformed_df = self._construct_transformation_plan(ingested_stream_df)
-        online_store_query = self._write_to_online_store(transformed_df)
+        online_store_query = self._write_stream_data(transformed_df, to)
         return online_store_query
 
     def _ingest_stream_data(self) -> StreamTable:
@@ -119,13 +122,35 @@ def _ingest_stream_data(self) -> StreamTable:
     def _construct_transformation_plan(self, df: StreamTable) -> StreamTable:
         return self.sfv.udf.__call__(df) if self.sfv.udf else df
 
-    def _write_to_online_store(self, df: StreamTable):
+    def _write_stream_data(self, df: StreamTable, to: PushMode):
         # Validation occurs at the fs.write_to_online_store() phase against the stream feature view schema.
         def batch_write(row: DataFrame, batch_id: int):
-            pd_row = row.toPandas()
-            self.write_function(
-                pd_row, input_timestamp="event_timestamp", output_timestamp=""
+            rows: pd.DataFrame = row.toPandas()
+
+            # Extract the latest feature values for each unique entity row (i.e. the join keys).
+            # Also add a 'created' column.
+            rows = (
+                rows.sort_values(
+                    by=self.join_keys + [self.sfv.timestamp_field], ascending=True
+                )
+                .groupby(self.join_keys)
+                .nth(0)
             )
+            rows["created"] = pd.to_datetime("now", utc=True)
+
+            # Reset indices to ensure the dataframe has all the required columns.
+            rows = rows.reset_index()
+
+            # Optionally execute preprocessor before writing to the online store.
+            if self.preprocess_fn:
+                rows = self.preprocess_fn(rows)
+
+            # Finally persist the data to the online store and/or offline store.
+            if rows.size > 0:
+                if to == PushMode.ONLINE or to == PushMode.ONLINE_AND_OFFLINE:
+                    self.fs.write_to_online_store(self.sfv.name, rows)
+                if to == PushMode.OFFLINE or to == PushMode.ONLINE_AND_OFFLINE:
+                    self.fs.write_to_offline_store(self.sfv.name, rows)
 
         query = (
             df.writeStream.outputMode("update")

sdk/python/feast/infra/contrib/stream_processor.py

@@ -1,14 +1,17 @@
 from abc import ABC
-from typing import Callable
+from types import MethodType
+from typing import TYPE_CHECKING, Optional
 
-import pandas as pd
 from pyspark.sql import DataFrame
 
-from feast.data_source import DataSource
+from feast.data_source import DataSource, PushMode
 from feast.importer import import_class
 from feast.repo_config import FeastConfigBaseModel
 from feast.stream_feature_view import StreamFeatureView
 
+if TYPE_CHECKING:
+    from feast.feature_store import FeatureStore
+
 STREAM_PROCESSOR_CLASS_FOR_TYPE = {
     ("spark", "kafka"): "feast.infra.contrib.spark_kafka_processor.SparkKafkaProcessor",
 }
@@ -30,21 +33,26 @@ class StreamProcessor(ABC):
     and persist that data to the online store.
 
     Attributes:
+        fs: The feature store where data should be persisted.
         sfv: The stream feature view on which the stream processor operates.
         data_source: The stream data source from which data will be ingested.
     """
 
+    fs: "FeatureStore"
     sfv: StreamFeatureView
     data_source: DataSource
 
-    def __init__(self, sfv: StreamFeatureView, data_source: DataSource):
+    def __init__(
+        self, fs: "FeatureStore", sfv: StreamFeatureView, data_source: DataSource
+    ):
+        self.fs = fs
         self.sfv = sfv
         self.data_source = data_source
 
-    def ingest_stream_feature_view(self) -> None:
+    def ingest_stream_feature_view(self, to: PushMode = PushMode.ONLINE) -> None:
         """
         Ingests data from the stream source attached to the stream feature view; transforms the data
-        and then persists it to the online store.
+        and then persists it to the online store and/or offline store, depending on the 'to' parameter.
         """
         pass
 
@@ -62,26 +70,32 @@ def _construct_transformation_plan(self, table: StreamTable) -> StreamTable:
         """
         pass
 
-    def _write_to_online_store(self, table: StreamTable) -> None:
+    def _write_stream_data(self, table: StreamTable, to: PushMode) -> None:
         """
-        Returns query for persisting data to the online store.
+        Launches a job to persist stream data to the online store and/or offline store, depending
+        on the 'to' parameter, and returns a handle for the job.
         """
         pass
 
 
 def get_stream_processor_object(
     config: ProcessorConfig,
+    fs: "FeatureStore",
     sfv: StreamFeatureView,
-    write_function: Callable[[pd.DataFrame, str, str], None],
+    preprocess_fn: Optional[MethodType] = None,
 ):
     """
-    Returns a stream processor object based on the config mode and stream source type. The write function is a
-    function that wraps the feature store "write_to_online_store" capability.
+    Returns a stream processor object based on the config.
+
+    The returned object will be capable of launching an ingestion job that reads data from the
+    given stream feature view's stream source, transforms it if the stream feature view has a
+    transformation, and then writes it to the online store. It will also preprocess the data
+    if a preprocessor method is defined.
     """
     if config.mode == "spark" and config.source == "kafka":
         stream_processor = STREAM_PROCESSOR_CLASS_FOR_TYPE[("spark", "kafka")]
         module_name, class_name = stream_processor.rsplit(".", 1)
         cls = import_class(module_name, class_name, "StreamProcessor")
-        return cls(sfv=sfv, config=config, write_function=write_function,)
+        return cls(fs=fs, sfv=sfv, config=config, preprocess_fn=preprocess_fn)
     else:
         raise ValueError("other processors besides spark-kafka not supported")

sdk/python/feast/infra/offline_stores/bigquery.py

@@ -329,8 +329,8 @@ def offline_write_batch(
         )
         if column_names != table.column_names:
             raise ValueError(
-                f"The input pyarrow table has schema {pa_schema} with the incorrect columns {column_names}. "
-                f"The columns are expected to be (in this order): {column_names}."
+                f"The input pyarrow table has schema {table.schema} with the incorrect columns {table.column_names}. "
+                f"The schema is expected to be {pa_schema} with the columns (in this exact order) to be {column_names}."
             )
 
         if table.schema != pa_schema:

sdk/python/feast/infra/offline_stores/file.py

@@ -430,8 +430,8 @@ def offline_write_batch(
         )
         if column_names != table.column_names:
             raise ValueError(
-                f"The input pyarrow table has schema {pa_schema} with the incorrect columns {column_names}. "
-                f"The columns are expected to be (in this order): {column_names}."
+                f"The input pyarrow table has schema {table.schema} with the incorrect columns {table.column_names}. "
+                f"The schema is expected to be {pa_schema} with the columns (in this exact order) to be {column_names}."
             )
 
         file_options = feature_view.batch_source.file_options

sdk/python/feast/infra/offline_stores/redshift.py

@@ -323,8 +323,8 @@ def offline_write_batch(
         )
         if column_names != table.column_names:
             raise ValueError(
-                f"The input pyarrow table has schema {pa_schema} with the incorrect columns {column_names}. "
-                f"The columns are expected to be (in this order): {column_names}."
+                f"The input pyarrow table has schema {table.schema} with the incorrect columns {table.column_names}. "
+                f"The schema is expected to be {pa_schema} with the columns (in this exact order) to be {column_names}."
             )
 
         if table.schema != pa_schema:

sdk/python/feast/infra/offline_stores/snowflake.py

@@ -332,8 +332,8 @@ def offline_write_batch(
         )
         if column_names != table.column_names:
             raise ValueError(
-                f"The input pyarrow table has schema {pa_schema} with the incorrect columns {column_names}. "
-                f"The columns are expected to be (in this order): {column_names}."
+                f"The input pyarrow table has schema {table.schema} with the incorrect columns {table.column_names}. "
+                f"The schema is expected to be {pa_schema} with the columns (in this exact order) to be {column_names}."
             )
 
         if table.schema != pa_schema:

sdk/python/tests/integration/e2e/test_python_feature_server.py

@@ -63,13 +63,16 @@ def test_get_online_features(python_fs_client):
 @pytest.mark.integration
 @pytest.mark.universal_online_stores
 def test_push(python_fs_client):
-    initial_temp = get_temperatures(python_fs_client, location_ids=[1])[0]
+    # TODO(felixwang9817): Note that we choose an entity value of 102 here since it is not included
+    # in the existing range of entity values (1-49). This allows us to push data for this test
+    # without affecting other tests. This decision is tech debt, and should be resolved by finding a
+    # better way to isolate data sources across tests.
     json_data = json.dumps(
         {
             "push_source_name": "location_stats_push_source",
             "df": {
-                "location_id": [1],
-                "temperature": [initial_temp * 100],
+                "location_id": [102],
+                "temperature": [4],
                 "event_timestamp": [str(datetime.utcnow())],
                 "created": [str(datetime.utcnow())],
             },
@@ -79,7 +82,7 @@ def test_push(python_fs_client):
 
     # Check new pushed temperature is fetched
     assert response.status_code == 200
-    assert get_temperatures(python_fs_client, location_ids=[1]) == [initial_temp * 100]
+    assert get_temperatures(python_fs_client, location_ids=[102]) == [4]
 
 
 def get_temperatures(client, location_ids: List[int]):