Feathr领英开源的企业级特征存储-轻识

Feathr 是领英（LinkedIn）开源的企业级高性能特征存储。

特性：

定义特征：使用简单的 API，基于原始数据源
按名称获取这些特征：在模型训练和模型推理期间
共享特征：在你的团队和公司中

Feathr 会自动计算特征值并将它们加入你的训练数据，使用正确的时间点语义来避免数据泄漏，并支持实现和部署你的特征以在生产中使用。

在本地安装 Feathr 客户端

如果没有使用 Jupyter Notebook 并且想在本地安装 Feathr 客户端，使用这个：

pip install -U feathr

或者使用来自 GitHub 的最新代码：

pip install git+https://github.com/linkedin/feathr.git#subdirectory=feathr_project

亮点

使用转换定义特征

features = [
    Feature(name="f_trip_distance",                         # Ingest feature data as-is
            feature_type=FLOAT),
    Feature(name="f_is_long_trip_distance",
            feature_type=BOOLEAN,
            transform="cast_float(trip_distance)>30"),      # SQL-like syntax to transform raw data into feature
    Feature(name="f_day_of_week",
            feature_type=INT32,
            transform="dayofweek(lpep_dropoff_datetime)")   # Provides built-in transformation
]

anchor = FeatureAnchor(name="request_features",             # Features anchored on same source
                       source=batch_source,
                       features=features)

丰富的 UDF 支持

Feathr 具有高度可定制的 UDF，具有原生 PySpark 和 Spark SQL 集成，可降低数据科学家的学习曲线：

def add_new_dropoff_and_fare_amount_column(df: DataFrame):
    df = df.withColumn("f_day_of_week", dayofweek("lpep_dropoff_datetime"))
    df = df.withColumn("fare_amount_cents", df.fare_amount.cast('double') * 100)
    return df

batch_source = HdfsSource(name="nycTaxiBatchSource",
                        path="abfss://feathrazuretest3fs@feathrazuretest3storage.dfs.core.windows.net/demo_data/green_tripdata_2020-04.csv",
                        preprocessing=add_new_dropoff_and_fare_amount_column,
                        event_timestamp_column="new_lpep_dropoff_datetime",
                        timestamp_format="yyyy-MM-dd HH🇲🇲ss")

访问特征

# Requested features to be joined
# Define the key for your feature
location_id = TypedKey(key_column="DOLocationID",
                       key_column_type=ValueType.INT32,
                       description="location id in NYC",
                       full_name="nyc_taxi.location_id")
feature_query = FeatureQuery(feature_list=["f_location_avg_fare"], key=[location_id])

# Observation dataset settings
settings = ObservationSettings(
  observation_path="abfss://green_tripdata_2020-04.csv",    # Path to your observation data
  event_timestamp_column="lpep_dropoff_datetime",           # Event timepstamp field for your data, optional
  timestamp_format="yyyy-MM-dd HH🇲🇲ss")                   # Event timestamp format， optional

# Prepare training data by joining features to the input (observation) data.
# feature-join.conf and features.conf are detected and used automatically.
feathr_client.get_offline_features(observation_settings=settings,
                                   output_path="abfss://output.avro",
                                   feature_query=feature_query)

部署

client = FeathrClient()
redisSink = RedisSink(table_name="nycTaxiDemoFeature")
# Materialize two features into a redis table.
settings = MaterializationSettings("nycTaxiMaterializationJob",
sinks=[redisSink],
feature_names=["f_location_avg_fare", "f_location_max_fare"])
client.materialize_features(settings)

并从在线存储获取特征：

# Get features for a locationId (key)
client.get_online_features(feature_table = "agg_features",
                           key = "265",
                           feature_names = ['f_location_avg_fare', 'f_location_max_fare'])
# Batch get for multiple locationIds (keys)
client.multi_get_online_features(feature_table = "agg_features",
                                 key = ["239", "265"],
                                 feature_names = ['f_location_avg_fare', 'f_location_max_fare'])