Sources

Overview

Sources are descriptions of external feature data and are registered to Feast as part of feature tables. Once registered, Feast can ingest feature data from these sources into stores.

Currently, Feast supports the following source types:

Batch Source

• File (as in Spark): Parquet (only).

• BigQuery

Stream Source

• Kafka

• Kinesis

The following encodings are supported on streams

• Avro

• Protobuf

Structure of a Source

For both batch and stream sources, the following configurations are necessary:

• Event timestamp column: Name of column containing timestamp when event data occurred. Used during point-in-time join of feature values to entity timestamps.
• Created timestamp column: Name of column containing timestamp when data is created. Used to deduplicate data when multiple copies of the same entity key is ingested.

Example data source specifications:

batch_sources.py

from feast import FileSource
from feast.data_format import ParquetFormat

batch_file_source = FileSource(
    file_format=ParquetFormat(),
    file_url="file:///feast/customer.parquet",
    event_timestamp_column="event_timestamp",
    created_timestamp_column="created_timestamp",
)

stream_sources.py

from feast import KafkaSource
from feast.data_format import ProtoFormat

stream_kafka_source = KafkaSource(
    bootstrap_servers="localhost:9094",
    message_format=ProtoFormat(class_path="class.path"),
    topic="driver_trips",
    event_timestamp_column="event_timestamp",
    created_timestamp_column="created_timestamp",
)

The Feast Python API documentation provides more information about options to specify for the above sources.

Working with a Source

Creating a Source

Sources are defined as part of feature tables:

batch_bigquery_source = BigQuerySource(
    table_ref="gcp_project:bq_dataset.bq_table",
    event_timestamp_column="event_timestamp",
    created_timestamp_column="created_timestamp",
)

stream_kinesis_source = KinesisSource(
    bootstrap_servers="localhost:9094",
    record_format=ProtoFormat(class_path="class.path"),
    region="us-east-1",
    stream_name="driver_trips",
    event_timestamp_column="event_timestamp",
    created_timestamp_column="created_timestamp",
)

Feast ensures that the source complies with the schema of the feature table. These specified data sources can then be included inside a feature table specification and registered to Feast Core.