hamilton_feast_definitions.py

import feast
import datetime


# an entity has no upstream dependencies; it is our join index
def driver_entity() -> feast.Entity:
    """Feast definition: driver entity"""
    return feast.Entity(name="driver", join_keys=["driver_id"], value_type=feast.ValueType.INT64)
  

# the filesource only needs a file path
# it could have been hardcoded, but here we pass it as argument because we want to ensure
# that is it the same value passed as the storage for our feature_transformations.py code
def driver_hourly_stats_source(driver_source_path: str) -> feast.FileSource:
  """Feast definition: source with hourly stats of driver"""
  return feast.FileSource(
      name="driver_hourly_stats",
      path=driver_source_path,
      timestamp_field="event_timestamp",
      created_timestamp_column="created",
  )


# the FeatureView is a 1-to-1 with the DataSource, but adds metadata and time-to-live (TTL)
def driver_hourly_stats_fv(
  driver_entity: feast.Entity,
  driver_hourly_stats_source: feast.FileSource
) -> feast.FeatureView:
  """Feast definition: feature view with hourly stats of driver"""
  return feast.FeatureView(
      name="driver_hourly_stats",
      entities=[driver_entity],
      ttl=timedelta(days=1),
      schema=[
          feast.Field(name="conv_rate", dtype=feast.types.Float32),
          feast.Field(name="acc_rate", dtype=feast.types.Float32),
          feast.Field(
              name="avg_daily_trips", dtype=feast.types.Int64, description="Average daily trips"
          ),
      ],
      online=True,
      source=driver_hourly_stats_source,
      tags={"team": "driver_performance"},
  )


# the FeatureService defines how the data is stored in the online store
# and how it's retrieved
def driver_activity_v1_fs(
   driver_hourly_stats_fv: feast.FeatureView,
) -> feast.FeatureService:
    """Feast definition: grouping of features relative to driver activity"""
    return feast.FeatureService(
        name="driver_activity_v1",
        features=[
            driver_hourly_stats_fv,
        ],
    )