Add env variable support pointing to feature_store.yaml #5416

Is your feature request related to a problem? Please describe.

I'm building a solution that uses Feast under the hood, and I want to abstract away infrastructure details from end users — specifically, the location of the feature_store.yaml file. Currently, Feast requires the path to be passed via -f for every CLI command, or the file must exist in the current working directory.

This tightly couples user workflows to the project structure and forces them to think about internal config paths. I’d prefer to centralize this configuration and avoid exposing it to end users.

Describe the solution you'd like

I would like Feast to support a new environment variable, e.g., FEAST_FEATURE_STORE_YAML_PATH, that allows specifying the path to the feature_store.yaml file. If this env var is set, Feast should use it as the default location for the config file — so users don’t have to pass -f every time or change directories.

This would allow me to provide a smoother, zero-config CLI experience to users, while still maintaining flexibility and modularity internally.

Describe alternatives you've considered

• Using the -f flag repeatedly — functional, but leaks internal file structure to the user and adds CLI overhead.
• Changing the working directory to match the config location — fragile in some execution environments.

Additional context

Here’s an example of what this could look like in practice:

export FEAST_FEATURE_STORE_YAML_PATH=/my/app/internal/feature_store.yaml
feast apply    # No -f needed
feast ui       # Still picks up the right config