Decouple On-Demand Features from their Sources #3639

Context: Given a data source that holds the relationships between 2 entities in rows, an on-demand feature that is merely the count of relationships per one of the entities is not neatly possible.

Expected Behavior

A feature-service of only an on-demand feature will infer the required data-sources but not merge the on-demand features with the datasources.

Current Behavior

Requesting features with a feature-service of only an on-demand FeatureView will throw an error:

• eg the entity_df is not transformed to a dask.DataFrame (empty for loop never shadows the variable)

Steps to reproduce

Given a data-source with 2 entities, define an on-demand FeatureView that provides values for the unique-set of one of the entities.
Then define a feature-service that lists only the on-demand FeatureView and not the source FeatureView.

Specifications

• Version: 0.31
• Platform: Linux
• Subsystem: N/A

Possible Solution