Storey

Storey is an asynchronous streaming library, for real time event processing and feature extraction.

In This Document

• API Walkthrough
• Usage Examples

API Walkthrough

A Storey flow consist of steps linked together by the build_flow function, each doing it's designated work.

Supported Steps

Input Steps

• Source -
• AsyncSource -
• ReadCSV -

Processing Steps

• Filter -
• Map -
• FlatMap -
• MapWithState -
• Batch(max_events, timeout) - Batches events. This step emits a batch every max_events events, or when timeout seconds have passed since the first event in the batch was received.
• Choice -
• JoinWithV3IOTable -
• SendToHttp -
• AggregateByKey(aggregations,cache, key=None, emit_policy=EmitEveryEvent(), augmentation_fn=None) - This step aggregates the data into the cache object provided for later persistence, and outputs an event enriched with the requested aggregation features.
• QueryByKey(features, cache, key=None, augmentation_fn=None, aliases=None) - Similar to to AggregateByKey, but this step is for serving only and does not aggregate the event.
• WriteToTable(table) - Persists the data in table to its associated storage by key.

Output Steps

• Complete -
• Reduce -
• WriteToV3IOStream -

Usage Examples

Using Aggregates

The following example reads user data, creates features using Storey's aggregates, persists the data to V3IO and emits events containing the features to a V3IO Stream for further processing.

from storey import build_flow, Source, Table, V3ioDriver, AggregateByKey, FieldAggregator, WriteToTable
from storey.dtypes import SlidingWindows

v3io_web_api = 'https://webapi.change-me.com'
v3io_acceess_key = '1284ne83-i262-46m6-9a23-810n41f169ea'
table_object = Table('/bigdata/my_features', V3ioDriver(v3io_web_api, v3io_acceess_key))

def enrich(event, state):
    if 'first_activity' not in state:
        state['first_activity'] = event.time
    event.body['time_since_activity'] = (event.time - state['first_activity']).seconds
    state['last_event'] = event.time
    event.body['total_activities'] = state['total_activities'] = state.get('total_activities', 0) + 1
    return event, state

controller = build_flow([
    Source(),
    MapWithState(table_object, enrich, group_by_key=True, full_event=True),
    AggregateByKey([FieldAggregator("number_of_clicks", "click", ["count"],
                                    SlidingWindows(['1h','2h', '24h'], '10m')),
                    FieldAggregator("purchases", "purchase_amount", ["avg", "min", "max"],
                                    SlidingWindows(['1h','2h', '24h'], '10m')),
                    FieldAggregator("failed_activities", "activity", ["count"],
                                    SlidingWindows(['1h'], '10m'),
                                    aggr_filter=lambda element: element['activity_status'] == 'fail'))],
                   table_object),
    WriteToTable(table_object),
    WriteToV3IOStream(V3ioDriver(v3io_web_api, v3io_acceess_key), 'features_stream')
]).run()

We can also create a serving function, which sole purpose is to read data from the feature store and emit it further

controller = build_flow([
    Source(),
    QueryAggregationByKey([FieldAggregator("number_of_clicks", "click", ["count"],
                                           SlidingWindows(['1h','2h', '24h'], '10m')),
                           FieldAggregator("purchases", "purchase_amount", ["avg", "min", "max"],
                                           SlidingWindows(['1h','2h', '24h'], '10m')),
                           FieldAggregator("failed_activities", "activity", ["count"],
                                           SlidingWindows(['1h'], '10m'),
                                           aggr_filter=lambda element: element['activity_status'] == 'fail'))],
                           table_object)
]).run()