support API access to offline/online stores without Feast abstractions

[jeremyary]

Is your feature request related to a problem? Please describe.
Feast should allow for use of just the APIs that talk to online/offline stores without having to use all the Feast constructs like data sources and feature views in order to support use cases that utilize other non-Feast tooling for data frame population.

e.g. User has pipelines that handle getting the data into data frames already and just wants an optimized way to write and read from storage without writing the connections from scratch.

Describe the solution you'd like
API access to offline/online without Feast abstractions

[sudohainguyen]

🤔 sorry I can not capture the idea, but every storage backends have their own native client, don't they?
For example BigQuery, BigTable, Redis. HBase,...

[shuchu]

I guess they want to use Feast as a feature management tool only.

[jeremyary]

I should have done a better job here indicating this issue came up in Slack based on feedback solicited from social media (Reddit, specifically)