Kite

Three guards

Say you want to protect a Spring based service with:

• a circuit breaker that trips after three consecutive exceptions, and retries after 30 seconds;
• a concurrency throttle that rejects requests once there are 50 concurrent requests;
• a rate limiter that rejects anything beyond a client's first 5,000 requests in a given hour.

With Kite, that takes two steps.

Step 1. Create your guards

<?xml version="1.0" encoding="UTF-8"?>
<beans ...>
    <kite:annotation-config />
    <kite:circuit-breaker id="circuitBreaker" exceptionThreshold="3" timeout="30000" />
    <kite:concurrency-throttle id="concurrencyThrottle" limit="50" />
    <kite:rate-limiting-throttle id="rateLimiter" limit="5000" />
</beans>

Step 2. Annotate your service

@Service
@Transactional
public class MessageServiceImpl implements MessageService {

    @GuardedBy({ "concurrencyThrottle", "rateLimiter", "circuitBreaker" })
    public List<Message> getMessages() { ... }
}

What the guards do

The circuit breaker stops calls to a failing dependency, then allows a retry after the timeout. The concurrency throttle caps the number of requests in flight. The rate limiter caps the number of requests from a client in a time window.

The guards are declared once and attached to service methods with @GuardedBy. The annotation names map back to the identifiers in the Spring configuration.

Project history

Kite was written for a Spring based service that needed stability controls without a large framework. It moved from Google Code to GitHub in May 2012. The build used Maven, and the continuous integration setup used GitHub, Atlassian Bamboo and a Sonatype Nexus repository.

The project page and the notes are preserved here. Start with Kite documentation for the full setup, or read the build notes:

• Moved Kite from Google Code to GitHub
• Continuous integration with GitHub, Bamboo and Nexus
• All Kite entries

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