gsharma / traffic-shaper

Traffic shaping

Traffic Shaper

Overview

The Traffic Shaper allows for customizable time-windowed (both sliding and tumbling windows) traffic shaping (eg. rate throttling of any invocations in a selectable time-unit). An example use would be say we want to generate an event if our subscription service receives 20000 new user subscription messages in 3 seconds.

Since throttling is in-memory but at the same time, we care for data reliability, there's full state-snapshotting available on-demand or pre-shutdown; similarly state-reconstruction happens at boot-time but is also available on-demand.

Two modes of traffic shaping are supported via Leaky and Token buckets.

Quick Start - Rate Throttler

Assuming you dropped the ratethrottler jar in your classpath:

1. Create an instance ServiceRateThrottler throttler = new ServiceRateThrottler();
2. Create an invocation Invocation invocation = new Invocation("dispatchPayment", 50000L, 5L, WindowType.SECONDS);
3. Register invocation's interest with the throttler throttler.setupInvocationThrottler(invocation);
4. Tick the event at every invocation and watch outcome boolean limitReached = throttler.throttle(invocation);

API

1. Setup invocation throttler

void setupInvocationThrottler(final Invocation invocation)

2. Tick invocation and signal throttling outcome

boolean throttle(final Invocation invocation)

3. Purge previous recordings for invocation

void purgeInvocationThrottler(final Invocation invocation)

4. Drop throttler

void dropInvocationThrottler(final Invocation invocation)

5. Count active throttlers

int reportActiveThrottlerCount()

6. Check existence of throttler for invocation

boolean existsInvocationThrottler(final Invocation invocation)

7. Purge all runtime throttling state

void purgeAllState()

8. Snaphsot all runtime throttling state to bson

String takeSnapshot()

9. Reconstruct throttling state from a previous snapshot

void reconstructFromSnapshot(String bsonSnapshot)

License

MIT License - Copyright (c) 2012 Gaurav Sharma