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Feature repository

Feast users use Feast to manage two important sets of configuration:
  • Configuration about how to run Feast on your infrastructure
  • Feature definitions
With Feast, the above configuration can be written declaratively and stored as code in a central location. This central location is called a feature repository. The feature repository is the declarative source of truth for what the desired state of a feature store should be.
The Feast CLI uses the feature repository to configure, deploy, and manage your feature store.

What is a feature repository?

A feature repository consists of:
  • A collection of Python files containing feature declarations.
  • A feature_store.yaml file containing infrastructural configuration.
  • A .feastignore file containing paths in the feature repository to ignore.
Typically, users store their feature repositories in a Git repository, especially when working in teams. However, using Git is not a requirement.

Structure of a feature repository

The structure of a feature repository is as follows:
  • The root of the repository should contain a feature_store.yaml file and may contain a .feastignore file.
  • The repository should contain Python files that contain feature definitions.
  • The repository can contain other files as well, including documentation and potentially data files.
An example structure of a feature repository is shown below:
$ tree -a
.
├── data
│ └── driver_stats.parquet
├── driver_features.py
├── feature_store.yaml
└── .feastignore
1 directory, 4 files
A couple of things to note about the feature repository:
  • Feast reads all Python files recursively when feast apply is ran, including subdirectories, even if they don't contain feature definitions.
  • It's recommended to add .feastignore and add paths to all imperative scripts if you need to store them inside the feature registry.

The feature_store.yaml configuration file

The configuration for a feature store is stored in a file named feature_store.yaml , which must be located at the root of a feature repository. An example feature_store.yaml file is shown below:
feature_store.yaml
project: my_feature_repo_1
registry: data/metadata.db
provider: local
online_store:
path: data/online_store.db
The feature_store.yaml file configures how the feature store should run. See feature_store.yaml for more details.

The .feastignore file

This file contains paths that should be ignored when running feast apply. An example .feastignore is shown below:
.feastignore
# Ignore virtual environment
venv
# Ignore a specific Python file
scripts/foo.py
# Ignore all Python files directly under scripts directory
scripts/*.py
# Ignore all "foo.py" anywhere under scripts directory
scripts/**/foo.py
See .feastignore for more details.

Feature definitions

A feature repository can also contain one or more Python files that contain feature definitions. An example feature definition file is shown below:
driver_features.py
from datetime import timedelta
from feast import BigQuerySource, Entity, Feature, FeatureView, Field
from feast.types import Float32, Int64, String
driver_locations_source = BigQuerySource(
table_ref="rh_prod.ride_hailing_co.drivers",
timestamp_field="event_timestamp",
created_timestamp_column="created_timestamp",
)
driver = Entity(
name="driver",
description="driver id",
)
driver_locations = FeatureView(
name="driver_locations",
entities=[driver],
ttl=timedelta(days=1),
schema=[
Field(name="lat", dtype=Float32),
Field(name="lon", dtype=String),
Field(name="driver", dtype=Int64),
],
source=driver_locations_source,
)
To declare new feature definitions, just add code to the feature repository, either in existing files or in a new file. For more information on how to define features, see Feature Views.

Next steps